The degree of volume depletion in severe malaria is currently unknown, although knowledge of fluid compartment volumes can guide therapy. To assist management of severely ill children, and to test the hypothesis that volume changes in fluid compartments reflect disease severity, we measured body compartment volumes in Gabonese children with malaria.Total body water volume (TBW) and extracellular water volume (ECW) were estimated in children with severe or moderate malaria and in convalescence by tracer dilution with heavy water and bromide, respectively. Intracellular water volume (ICW) was derived from these parameters. Bioelectrical impedance analysis estimates of TBW and ECW were calibrated against dilution methods, and bioelectrical impedance analysis measurements were taken daily until discharge. Sixteen children had severe and 19 moderate malaria. Severe childhood malaria was associated with depletion of TBW (mean [SD] of 37  ml/kg, oSignificant hypovolaemia does not exacerbate complications of severe or moderate malaria. As rapid rehydration of children with malaria may have risks, we suggest that fluid replacement regimens should aim to correct fluid losses over 12–24 h. Some investigators have suggested that children with malaria need a lot of fluids. But this paper casts doubt on this assumption, and assesses a novel way to assess fluid balance ICW is calculated by subtraction of the ECW from the TBW.Malaria claims one million lives annually, with more than 90% of these being those of children in sub-Saharan Africa . Most deTracer dilution methods are expensive and invasive and cannot be repeated at short intervals. Therefore, we simultaneously calibrated a noninvasive technique of bioelectrical impedance analysis (BIA)  to estimWe hypothesised that volume changes in fluid compartments would reflect disease severity in malaria and that these changes would be related to established markers of disease severity . We alsoThe study was conducted at the Albert Schweitzer Hospital, Lambaréné, Gabon, and Centre Hospitalier de Libreville, Gabon. It was approved by the ethics committees of the International Foundation of the Albert Schweitzer Hospital, the Gabonese Ministry of Health, and the University of Tübingen.Plasmodium falciparum in thick or thin blood films. Severe malaria was malaria with one or more of the following features: blood lactate ≥ 5 mmol/l, blood glucose ≤ 2.2 mmol/l, Blantyre coma score ≤ 2, or repeated, observed seizures [Children (aged 1 to 10 y, inclusive) admitted with suspected severe or moderate malaria were referred to the study team, who assessed them within 15 min, and the children were admitted to the study once informed consent had been obtained from the parents. Malaria was defined as the presence of asexual forms of On admission children were weighed (undressed) with pediatric scales accurate to within 100 g (Seca, Birmingham, United Kingdom). A history was taken from parents, and the child was examined with particular attention to signs of dehydration, including: capillary refill time, skin turgor, sunken eyes, dry mucous membranes, and absence of tears. Vital signs, blood glucose and lactate concentrations, and hematocrit and parasitaemia were measured every 4 h for the first 24 h and then every 6 h until recovery. If peripheral venous access was impracticable, then a femoral central venous catheter was inserted, and the central venous pressure was measured every 4 h with a manometer zeroed at the midaxillary line.Children were managed in a standard manner as previously described ,11,12. AIn addition to a 5% or 10% dextrose infusion (at least 3 mg/kg/min, i.e., 1.6 or 3.2 ml/kg/h), physicians were free to give any fluid replacement regimen as clinically indicated, including boluses of saline or blood. A strict fluid input/output chart was kept for each child. A blood transfusion of 20 ml/kg of cross-matched whole blood tested for blood-borne pathogens was given over 4 h if the hematocrit fell below 15%.2H2O per litre of 2.315% sodium bromide solution. A baseline sample of blood (3 ml) was drawn, and the plasma frozen at −70 °C for bromide and 2H2O assays. At the start of the study, 2.8 ml/kg of the dosing solution was administered intravenously over 20 min. Four hours after injection a second blood sample was drawn (1.5 ml) for the determination of blood bromide and 2H2O concentrations. Parents were asked to return with their children 28 d after admission; children were examined, and measurement of TBW and ECW repeated.A sterile standard dosing solution was prepared by adding 119 ml of 2H enrichment was measured in duplicate by isotope ratio mass spectrometry, using a Sira 10 instrument (Micromass, Cheshire, United Kingdom) as described [escribed . The preescribed . The intBIA was performed using a SEAC SFB3 multifrequency bioimpedance meter . An alternating electrical current of 200 μAmp was applied between 2 Ag/AgCl electrodes at the right hand and right foot. Whole body and segmental impedance were measured by rotating the sensing Ag/AgCl electrodes between four sites on the ankles or wrists as described . Each sePlasma electrolytes were measured , and osmolality was calculated using freezing point depression on a Micro Osmometer (Vitech Scientific, West Sussex, United Kingdom). Osmol gap was calculated as described :+] is plasma sodium concentration (millimoles/litre), [glucose] is plasma glucose concentration (millimoles/litre), [urea] is plasma urea concentration (millimoles/litre), 1.86 is a correction factor as sodium chloride is only 93% dissociated, and 0.93 is the assumed proportion of water in plasma.where OG is osmol gap, MO is measured osmolality, [NaW test, and transforming data logarithmically if necessary, we analysed normally distributed data by two-tailed Student's t test and nonparametric data with the Wilcoxon sign-rank test. Proportions were compared with Fisher's exact test, and correlations were assessed by linear regression analysis of Pearson or Spearman. Predictive values for TBW and ECW from impedance measurements were obtained by multivariate analysis in a backward elimination process with p < 0.05 for entry and p < 0.10 for exit, confirmed by forward selection. This analysis was based on the first pair of BIA and isotope dilution measurements after admission. In a second step, whole body BIA models were replaced with segmental BIA models as previously described [Statistical analyses were carried out using Stata Statistical Software (Releases 6.0–8.0, College Station, Texas, United States). After checking distributions with the Shapiro-Wilks escribed  and compSample size was calculated from previously published values ,18 assump < 0.001), compared to children with moderate malaria. Capillary refill time and blood lactate concentrations were correlated with each other (adjusted r2 [adj r2] = 0.25, p = 0.031).Between October 1999 and March 2000, 205 children who were judged ill enough to be hospitalised were referred to the study team. One hundred and thirty-two children had malaria, 20 with severe and 35 with moderate disease. Ten children with moderate and two with severe malaria were ineligible for study because of their age, and for seven children  consent could not be obtained. One child died before inclusion into the study, leaving nineteen children with moderate and sixteen with severe malaria admitted to this study. The median (interquartile range [IQR]) time from admission to administration of tracers was 54 (37–84) min, during which complications such as convulsions or hypoglycaemia were treated. The baseline characteristics of children are given in p > 0.5). There was rapid correction of vital signs in all children (2O with no significant rise in the first 24 h.The volume of fluid (including blood) given in the first 4 h of the study was similar in children with severe (median [IQR, range] of 3.7 [2.2–5.8, 2.1–11.4] ml/kg/h) and moderate (median [IQR, range] of 3.3 [2.2–4.2, 1.2–15.1] ml/kg/h) malaria (children , and vitp = 0.028) but not for moderate cases (p = 0.109). The mean (SD) TBW was lower in severe than moderate malaria at admission: 524 (44) ml/kg versus 555 (50) ml/kg (p = 0.052). The mean (SD) change in TBW between admission and follow up was 48 (42) ml/kg and 12 (37) ml/kg for severe and moderate cases, respectively. Individual data from the children with severe malaria are shown in Volume determinations using isotope dilution were available at baseline in all but one of the children with severe malaria. The values for the TBW, ECW, and ICW are given in p = 0.045). Admission ICW measurements were significantly lower in children with severe malaria than in those with moderate malaria (p < 0.001).Bromide space (ECW) measurements were available in all but two children with severe malaria and in all but one of the children with moderate malaria. At baseline, the mean (SD) ECW was significantly lower in children with moderate than in those with severe malaria (2 divided by impedance at 50 kHz (H2/Z50) and measured TBW. The ‘best fit' regression equation to predict TBW from BIA was derived using the variables age, weight, and H2/Z50 (standard error of the estimate [SEE] = 0.435, adj r2 = 0.975):As predicted by theory , there wA is age (months), H is height (centimetres), W is weight (kilograms), and Z50 is impedance at 50 KHz frequency. Disease severity and gender did not contribute significantly to this model, allowing data from admission to be pooled in this prediction equation. Repeating the analysis using impedances measured at other frequencies (4–1012 kHz) did not show a clear advantage, so all data for TBW prediction are given for measurement at 50 kHz.where H2/R0 emerged as the strongest predictive term (SEE = 0.584, adj r2 = 0.753):By contrast, ECW was not significantly associated with age or weight, and in agreement with previous studies in babies  H2/R0 H is height (centimetres), and 0R is resistance at zero frequency. Again, disease severity and gender did not contribute significantly to this model. Prediction equations based on segmental BIA data for ECW and TBW were inferior to whole body BIA models and are therefore not shown here.where Errors in BIA estimates of TBW and ECW compared to values measured by isotope dilution are displayed with 95% limits of agreement in Fluid volume estimates were available from BIA in 14 children with moderate and 11 with severe malaria on admission and 16 with moderate and 12 with severe malaria at discharge. Values for the TBW, ECW, and ICW are shown in p = 0.034). TBW increased from admission to discharge in children with severe malaria by 37 (33) ml/kg or 6.7% (6.0%) (paired t test, p = 0.012), but there were no significant changes in TBW for children with moderate malaria between admission and discharge.BIA-determined TBW was significantly lower in those with severe compared with moderate malaria (mean [SD] of 539  versus 5p = 0.002). ICW remained unchanged between admission and discharge in children with moderate malaria. In the severe malaria group mean (SD) of ICW at admission was 40 (22) ml/kg, or 11.7% (11.0%) lower at admission than at discharge (p = 0.002). There were no differences in the fluid volume measurements of the four children with adverse and those with good outcomes.ECW did not differ between the severe and moderate groups on admission and did not change significantly between admission and discharge. Serial measurements of ECW did not show any rise during the first 4 d after admission, at discharge, or at day 28 in children with severe or moderate malaria (data not shown). ICW at admission was significantly lower in the severe malaria group than in the moderate malaria group, with a mean (SD) of 293 (17) ml/kg versus 325 (28) ml/kg . For those with moderate malaria the deficit was not significant: −0.3% (4.6%) /−0.9% (1.6% to −1.5%, 7.0% to −8.1%) (p = 0.41). As predicted, the deficits in weight and TBW were correlated (adj r2 = 0.67, p < 0.001).Admission weight relative to the weight at discharge showed a mean (SD)/median (IQR, range) percentage deficit of −4.3% (4.4%)/−4.0% (−1.3% to −6.1%, −0.1% to −11.0%) for the children with severe malaria on admission (p = 0.036). Plasma potassium concentration and osmolality were higher in children with severe than in those with moderate malaria (p = 0.039 and p = 0.021, respectively). Plasma urea and creatinine were significantly higher in those with severe malaria. Osmol gap was significantly higher in children with severe than in those with moderate malaria (p < 0.001), with 15/16 children in the severe group having an osmol gap greater than 8.2 mOsm (considered high in United States children [The concentrations of plasma electrolytes are shown in children ).We have shown that severe childhood malaria is associated with mild dehydration in most cases, with a mean (SD) depletion of TBW of 37 (33) ml/kg, or 6.7% (6.0%). Only 3/16 children 19%) in our study had moderate volume depletion (> 60–90 ml/kg), and none were severely dehydrated (> 100 ml/kg) . Moderat% in our Our findings suggest that the degree of dehydration in children with severe malaria is unlikely to be a primary pathological process in the evolution of the disease. These findings are also consistent with our previous suggestion that hyperlactataemia arises from tissue hypoxia resulting from microvascular obstruction by infected erythrocytes ,22 ratheOur estimates of fluid compartment volumes in children after recovery from malaria are entirely consistent with previous work in children  , althougIn sepsis, ECW increases by up to 50% of TBW because capillary permeability increases by up to 300% of normal. There are no significant increases in ECW in children with severe malaria, confirming earlier studies that indicate that sepsis and malaria syndromes result from different pathophysiological processes ,28. StudHyponatraemia  has beenWhat are the implications of our findings for optimal fluid replacement therapy in malaria? We cannot answer precisely on the basis of measuring fluid compartment volumes because regimens are sometimes designed not only to correct existing fluid deficits and to provide maintenance requirements, but also to rehydrate more vigorously to maintain circulating volume. Such approaches are advocated by others for different populations of children with severe malaria, for example, in a series of studies published from Kilifi, Kenya ,5,34. HoThere are risks to over-vigorous fluid administration just as there are with inadequate fluid replacement, particularly in hospitals where measuring plasma electrolyte concentrations and providing assisted ventilation are difficult. These risks include pulmonary  and cereA correlation between capillary refill time and blood lactate concentrations but none with fluid volume status suggests that prolongation of capillary refill time may be due to the common underlying process of microvascular obstruction.Our findings do not support the widespread use of aggressive fluid volume replacement in children with severe malaria. Clearly, volume depletion indicated by hypotension or by CVP measurements requires more aggressive therapy, but wherever possible plasma electrolyte concentrations should be closely monitored. Because of elevated requirements for glucose in childhood severe malaria (3–6 mg/kg/min) , there iThe tracer dilution techniques that we have used are expensive and time-consuming and consequently not amenable to large-scale deployment. We took this opportunity to calibrate a much simpler methodology (BIA) to derive TBW and ECW and validated BIA estimations in this population. We are now using BIA measurements to assess much larger numbers of patients (J. Jarvis and S. K., unpublished data). BIA is an excellent noninvasive screening tool that should detect subgroups of children with severe malaria who may be severely volume depleted.Although we have known for many years what causes malaria, how it is passed from person to person by mosquito, and how to treat the infection, more than a million people still die of malaria every year, mostly children under five years living in Africa. Children are affected most because they have not had the chance to develop the resistance to malaria that normally builds up over a lifetime when living in places with malaria. As well as being given specific drug treatments against the malaria, children are also often given fluids into their veins, as they appear dehydrated.The researchers studied children who were sick with malaria and measured how dehydrated the children were. To do the measurements, they used an accepted technique that required injections into the vein, and also a newer, simpler method that used electrodes. Neither technique suggested that any of the children were severely dehydrated.The study suggests that severe dehydration isn't a big problem in children with severe malaria. So it may not be necessary to give lots of fluids into the vein. The new technique for measuring dehydration will need to be assessed in larger studies: this study is small, so the results may not be entirely accurate.http://www.who.int/topics/malaria/en/).The World Health Organization is coordinating many of the initiatives to combat malaria (http://www.mmv.org/pages/page_main.htm).Medicines for Malaria Venture is trying to develop new affordable antimalarial drugs (


Influenza vaccination has been shown to reduce morbidity and mortality in the older adult population. In Canada, vaccination rates remain suboptimal. We identified factors predictive of influenza vaccination, in order to determine which segments of the older adult population might be targeted to increase coverage in influenza vaccination programs.The Canadian Study of Health and Aging (CSHA) is a population-based national cohort study of 10263 older adults (≥ 65) conducted in 1991. We used data from the 5007 community-dwelling participants in the CSHA without dementia for whom self-reported influenza vaccination status is known.Of 5007 respondents, 2763 (55.2%) reported having received an influenza vaccination within the previous 2 years. The largest predictive factors for flu vaccination included: being married (57.4 vs. 52.6%, p = 0.0007), having attained a higher education (11.0 vs. 10.3 years, p < 0.0001), smoking (57.1% vs. 52.9%, p = 0.0032), more alcohol use (57.9% of those who drank more vs. 53.2% of those who drank less, p = 0.001), poorer self-rated health , regular exercise (56.8% vs. 52.0%, p = 0.001), and urban living (55.8% vs. 51.0%, p = 0.03).While many other differences were statistically significant, most were small , higher comorbidity (2.7 vs. 2.3 comorbidities, p < 0.0001).Residents of Ontario were more likely (64.6%) to report vaccination (p < 0.0001), while those living in Quebec were less likely to do so (48.2%, p < 0.0001). Factors retaining significance in a multivariate analysis included older age, higher education, married status, drinking alcohol, smoking, engaging in regular exercise, and having higher comorbidity.The vaccination rate in this sample, in whom influenza vaccination is indicated, was low (55.2%). Even in a publicly administered health care setting, influenza vaccination did not reach an important proportion of the elderly population. Whether these differences reflect patient preference or access remains to be determined. Influenza has the potential to cause serious complications , especially in the older adult >= 65) population and in those with comorbid illness -3. Influ5 populatDespite current evidence and recommendations, influenza vaccination rates remain suboptimal. Estimates of vaccine coverage in high-risk groups (including older adults) range from 10–40% in the UK , and 45–To our knowledge, no previous studies have examined predictors of vaccination in community-dwelling older Canadians. The objectives of our study were to determine the vaccination rate in this community-dwelling population of older Canadians and to identify factors predictive of influenza vaccination, in order to determine which segments of the older adult population should be targeted to achieve better coverage in influenza vaccination programs.The Canadian Study of Health and Aging (CSHA) is a population-based representative sample drawn from Canadians over the age of 65, designed to study the prevalence, incidence, and risk factors for development of dementia . A technvs. rural residence. As a second step, a multivariate analysis done by stepwise selection of parameters found to be significant in the univariate analysis was then conducted. Analyses comparing responders vs. non-responders to the relevant SARFQ questions as well as comparing respondents who reported first-time vs. regular influenza vaccination were also undertaken. The possibility of interaction between variables was considered. We included in the multivariable model interaction terms of pairs of variables where interaction was plausible .Respondents were designated vaccinated if they reported having had an influenza vaccine within the 2 years preceding completion of the SARFQ. As the data were collected over a two-year period, whereas the question about the last vaccination asked for a date, we designated as unvaccinated those who did not report receiving a vaccination within the previous 2 years. Vaccinated and unvaccinated respondents were compared; as a first step crude analyses were done taking each variable individually (not adjusted for any others). Chi-squared test or Fisher's exact test was used for categorical variables and one-way ANOVA was used for continuous variables. Characteristics analyzed included age, gender, education, region of residence, marital status, smoking status, alcohol intake, self-assessed health status, exercise, diagnosis of dementia, Modified Mini-Mental State Examination (3MS) score, nInfluenza vaccination status could be determined for 5007 (76.8%) of the 6521 non-demented, community-dwelling participants in the CSHA who completed the SARFQ. Of these, 2763 (55.2%) reported having received at least one influenza vaccination within the previous two years.The univariate analysis, in which each variable was examined individually without adjusting for the effects of others, showed several differences between the demographics, region of residence, lifestyle, and health status of the two groups Table . ImmunizOf note, smokers were significantly more likely than non-smokers to have received the influenza vaccination. The same was true of individuals who consumed alcohol regularly when compared with those who drank rarely or not at all. Regular exercise was found to be a predictive factor for vaccination. Those who had received the vaccination had significantly more health problems, as did those who saw themselves as being in poorer health.In the multivariate analysis Table  predictivs. 74.1 years, p < 0.0001), had more comorbid illness (2.7 vs. 2.5, p = 0.0011), and poorer self-rated health . Residents of Atlantic Canada (75.1% vs. 79.3% residing elsewhere, p = 0.0003) and those living in rural areas  were less likely to be regular users.To investigate the impact of response bias, we compared those who had answered the influenza vaccination question and the 23.2% of the original sample who had not Table . Repeat Our data were collected in the early 1990s and may therefore not reflect current practice patterns. Although the Canadian Study of Health and Aging was not designed to study influenza vaccination, it does provide a large and unique data set of primarily community-dwelling older Canadians, and is therefore potentially useful in the examination of health-related risk factors and demographics that may influence decisions to vaccinate. Given the importance of influenza vaccination in the prevention of significant morbidity and mortality in populations at risk, the vaccination rate of 55.2% in our community-dwelling sample of older adults is concerning. People who were not vaccinated tended to be younger, non-smokers and to have fewer co-morbid illnesses. They were also found to have a lower level of education, not to be married and not to engage in regular exercise. These were the factors that retained statistical significance in the multivariable analysis, suggesting that these associations are unlikely to have arisen due to confounding by any of the variables investigated.Vaccination has previously been studied in the CSHA, but only in relation to its status as a potentially protective factor with respect to cognitive impairment . The weiAnother important source of potential error is our reliance on self-reported immunization status. However, self-report of influenza vaccination status in elderly outpatients has been found to be highly sensitive and moderately specific when checked against medical record documentation .Other studies have identified predictive factors for vaccination in other countries ,12. An AOur data suggest that there appears to be an important degree of targeting of vaccination resources within the older adult population to people who are less healthy. Even within these higher risk groups, however, immunization is incomplete. Perhaps such people are perceived by their health care providers as being at higher risk from influenza infection, and are thus more likely to be immunized. Similar explanations may account for the higher vaccination rates among smokers and those who consumed more alcohol. However, according to the current Canadian guidelines , influenRegular exercise was shown to be a factor predictive of influenza vaccination. Interestingly, this association may have been confounded by generally health-protective behaviour (which might be expected to be associated with both regular exercise, the explanatory variable, and vaccination, the outcome), given that individuals exhibiting healthy lifestyle choices (such as exercise) may have been more likely to have sought preventative health care and to have visited their health care providers more regularly, thus providing more opportunity to be vaccinated. Regular exercise did, however, retain significance in our multivariate analysis.vs. urban residence did not retain statistical significance in the multivariable regression model suggests that this crude association may be due to confounding by other factors.The regional differences identified in our study may point to geographic differences in access to influenza vaccination, although the general milieu and level of awareness in both the medical community and society at large may also be significant. These regional differences suggest that certain areas may benefit from targeting of vaccination efforts. However, over and above questions of health policy and public health education, the question of access to vaccination is of vital importance if we are to achieve acceptable rates of coverage in this target population. The finding that rural residence is a negative predictor of vaccination is particularly concerning, and points to the larger equity issue of how uptake of influenza vaccination can be improved outside of major urban centers. However, our finding that rural Our analysis comparing non-responders with those for whom influenza vaccination status was known on the basis of the SARFQ showed that response bias was indeed likely. Non-responders were more likely to drink more alcohol, a factor which was associated with being immunized. However, several factors which were associated with not being immunized, including younger age, good self-rated health, having fewer comorbidities, and residence in a rural area, were more prevalent among non-responders. This over-representation of a number of factors predictive of non-immunization among non-responders suggests that our results may well have been influenced by response bias. For example, we may have over-estimated the prevalence of vaccination in this population.The analysis comparing regular users of the influenza vaccine with those who reported first-time immunization in the SARFQ demonstrated a number of factors that differed between the two groups. The finding that younger age is associated with first time vaccination may be at least partially explained by those at the younger end of the > = 65 age group having spent less time in this "target group" for vaccination. As such, they would be more likely to be receiving the vaccination for the first time. The effect of age may also play a role in the finding that those with better self-assessed health and fewer comorbidities were more likely to be first-time users . However, being in better health was also a predictive factor for non-vaccination within the previous two years, as was rural residence, suggesting that these factors may influence decisions to initiate as well as to sustain influenza vaccination over subsequent years.Despite current recommendations and proven benefit, influenza vaccination rates in our Canadian sample were suboptimal; only 55.2% of older adults in our representative sample reported being vaccinated within the past two years. The predictive factors identified in this analysis may facilitate the study of targeting of older adults in future vaccination programs.SM and HM have been involved in trials of Influenza vaccines funded by ID Biomedical. Neither has received any personal financial compensation for their involvement. MKA and KR have no competing interests.MKA wrote the first draft, and reviewed each of the analyses. SM & KR reviewed the analyses and revised the manuscript. KR is a co-Principal Investigator of the CSHA. HM did the statistical analyses. All authors read and approved the final manuscript.The pre-publication history for this paper can be accessed here:


A readmission is classified as a patient necessitating readmission to hospital due to a post-operative complication following discharge. An overstay however, is classified as a patient having to stay longer than the planned duration in hospital (not having been discharged in the interim) due to a post-operative complication. This study aims to investigate patient-related factors that predispose to readmission or overstay and thus make recommendations to decrease the likelihood of readmission or overstay.In this retrospective study 312 'day-case nasal procedures', were selected from a total cohort of 4274 ENT patients over a 17-month period. This sub-group was investigated for a range of demographic factors including, age, gender and ethnicity with regards to their relationship to readmission rates and overstay frequency and duration.The rates were 2.88% and 9.62% for readmission and overstay respectively. The total number of days spent in hospital as a result of readmission was 27. Epistaxis was the leading cause for readmission/overstay (28.9%) followed by high levels of post-operative pain preventing them from being discharged (23.7%). All procedures in this study had readmission rates that were below those recommended in the guidelines set by the Royal College of Surgeons of England. Women overstayed significantly longer (t = 1.65, p < 0.05) than men.Suitable candidates for day-case ENT surgery highlighted by this study include healthy individuals between the ages of 20 and 60. Operating in the morning would increase the immediate post-operative recovery time, which may reduce the numbers of patients who complain of high levels of pain at the time of discharge. Procedures such as septorhinoplasty being performed routinely in the ambulatory setting require additional research into more effective methods of pain control. Standards need to be improved so that the causes of overstay and readmission are clearly identifiable in patient records. Day-case surgery has rapidly expanded as a cost-effective and resource-conserving surgical intervention to the point that well in excess of two million operations are performed in a day-case/ambulatory setting in the United Kingdom alone each year . Day-casA King's College Hospital Study commissioned by the Department of Health has suggested that day-case surgery may not be saving the NHS money . HoweverStudies have shown that day-case septorhinoplasty is associated with a low complication rate and is a safe and acceptable procedure provided that stringent patient selection criteria are adhered to . A speciThere have been no studies performed, which have directly investigated the 'patient demographic factors' which predict the likelihood readmission or overstaying the electively planned period in hospital following day-case ENT operations. This is of importance as it would be beneficial to know if certain groups of patients require more rigorous screening pre-operatively in an attempt to reduce readmission and 'overstay' rates. By identifying this cohort of patients, the NHS could save substantial amounts of acute and primary care expenditure in the backdrop of ever-rising day-case ENT procedure numbers. Many studies have suggested that ENT procedures currently performed as overnight cases could be performed as day-cases provided strict criteria are applied in the selection of patients ,11. HowePrevious data fails to distinguish between readmissions and overstays following nasal day-case surgery . They alThis study investigates departmental day-case nasal surgery at Guy's hospital and aims to determine:a) If it has readmission rates below that of the accepted standard for day-case surgery stipulated by the Royal College of Surgeons of England.b) If readmission rate and unplanned overnight stay are related to epidemiological characteristics of the sample such as age, gender, and ethnicity.and to report results in the context of clinical management by making recommendations to improve the readmission rates in each category proposed.rd January 2002 and 28th June 2003 were investigated. All ENT patients operated on during this period were selected from the Guy's & St. Thomas' NHS Trust database. The hospital database has a limited range of broad categories and this can limit interpretation of results thus all available patient notes were also reviewed.This is a retrospective study in which the total number of ENT operations performed between the period of 3All planned day-case procedures were selected from the total cohort of elective ENT operative procedures. The day-case procedures were then further narrowed down to 'nasal day-case procedures'.Firstly the total number of readmission episodes, overstay frequency and duration in the 'day-case nasal procedures' were calculated. A readmission is classified as a patient necessitating readmission to hospital due to a post-operative complication following discharge. An overstay however, is classified as a patient having to stay longer than the planned duration in hospital (not having been discharged in the interim) due to a post-operative complication. The groups of nasal operations of interest in this study in the light of previous studies are (septo)rhinoplasty, excision of lesion, polypectomy, sinus operation and other .A range of demographic factors including, age, gender and ethnicity were investigated with regards to their relationship to readmission rates and overstay frequency and duration. Statistical analysis including Chi-square tests, t-tests and ANOVA were performed on the above variables.rd January 2002 and 28th June 2003 were 4274. From this cohort 501 operations (11.72%) were planned as elective ENT day-case procedures. This selected sub-sample of 501 day-cases was further narrowed down to those, which pertained to 'nasal procedures' and this group numbered 312 (62.28%). There were a total of 9 readmission episodes following 'day-case nasal procedures' during the 17-month period, which equates to a readmission rate of 2.88%. The total number of days spent in hospital as a result of readmission was 27. All patients readmitted following day-case nasal procedures were male (Fischer Exact Test = 4.41, p < 0.05). The nasal operations were grouped into (septo)rhinoplasty, excision of lesion, polypectomy, sinus operation and other.The total number of ENT operations performed between the period of 3Those patients that were required to stay longer than electively planned i.e. one day, are termed by the Guy's & St. Thomas' NHS Trust and indeed in this study as 'over-stays'. The minimum duration of overstay in our sample was one day and the maximum was 2 days. The total incidence of patients overstaying was 30 (overstay rate = 9.62%) during the timeframe studied and this equates to a total of 48 overstayed days.n = 11/38 (28.9%) followed by levels of post-operative pain unacceptable to the patient and thus preventing them from being discharged (23.7%).Epistaxis was the leading cause for readmission/overstay The readmission rate for (septo)rhinoplasty is 1.38% and the overstay rate is 9.22%. From the analysis of days overstayed expressed as a fraction of the number of procedures performed, polypectomy and sinus operations have the highest number of days overstayed per procedure. Although the (septo)rhinoplasty overstay rate is 9.22% the number of days overstayed expressed in the context of the number of actual (septo)rhinoplaties performed is equal to the average  than men.The frequency of readmission is highest in those patients aged <20 followed by those in the 60–70 year age category. Although the patients aged above 70 years have the lowest readmission frequency, the sample size is low (n = 5) and thus the 30–40 year age category is more reliable a sample representative of a low readmission frequency. Analysis of the age of patients and frequency of day-case procedures revealed that the group containing those patients aged between 30–40 underwent the greatest number of nasal day-case procedures. However, when considering the number of overstays in terms of the numbers of procedures performed, the 30–40 age category has the lowest overstay duration as opposed to the >70 which has the highest.Analysis of variance (ANOVA) shows that the difference in overstay rates between ethnic groups did not reach statistical significance (F = 1.22, p = 0.40).In July 2000, the Department of Health published that 75% of surgical procedures carried out by the NHS should be performed in a day-case setting by 2010. This initiative was supported by the both The Royal College of Surgeons of England and The Royal College of Physicians of England.Within the period of the current study there were a total of 4274 ENT operations performed at Guy's during the time-frame of investigation. Of this group 501 (11.72%) were planned as elective ambulatory procedures with the intention of same day discharge. Primarily the government target was ambiguous with regard to the types of procedure for which it aimed to conduct on a routine day-case basis. Whilst it is conceivable that some ENT procedures such as myringotomy could be performed safely as a day-case procedure, more complex and involved procedures such as deep exploration of the neck and tumour excision would be unsuitable for such rapid discharge. With no clear guidelines as to which procedures are suitable for the day-case setting, the responsibility of advancing the boundaries of ambulatory surgery rests on the clinicians, with the patients' wellbeing being at the forefront of interest.The readmission in this study is 2.88%. These readmission rates are lower than those reported in the contemporary literature ,8,11. ThEpistaxis was the leading cause for readmission/overstay (28.9%) followed by levels of post-operative pain unacceptable to the patient and thus preventing them from being discharged (23.7%). The cause of epistaxis was not recorded in the notes nor was the reason behind why some patients experience more pain than others. These results are in contrast to previous subjective patient based studies, which show that septorhinoplasty is generally acceptable to the patient in terms of pain and overall satisfaction parameters . Women oAge is not a contraindication for ENT day-case surgery. The low readmission rate of patients over 70 years of age could be attributed to a number of factors including, heightened caution of the clinician in patient discharge, a low sample number and age-related variation of procedure type are dominant.There have been no previous studies, which have investigated the effects of ethnicity on readmission rates or overstay duration. The current study shows that mixed race patients followed by black patients have the highest number of days overstayed per procedure. Analysis of variance (ANOVA) shows that there is no significant difference between ethnic groups and the length of overstay (F = 1.22, p = 0.40).Day-case procedures should be performed on suitable candidates on a sound clinical basis. This includes meticulous patient selection, both on the part of the surgeon and the health care professionals in the preoperative assessment. Suitable candidates for day-case ENT surgery highlighted by this study include healthy individuals between the ages of 20 and 60. A protocol for day-case surgery does exist and this may need revision.In the clinical setting however, epistaxis needs to be made a clinical priority by ensuring that all levels of healthcare professionals are aware of its causes and its effective immediate management. We suggest from experience that operating in the morning would increase the immediate post-operative recovery time, which may reduce the numbers of patients who complain of high levels of pain at the time of discharge. Procedures such as septorhinoplasty being performed routinely in the ambulatory setting require additional research into more effective methods of pain control. Clinical administration standards need to be improved so that the causes of overstay and readmission are clearly identifiable in patient records.The authors declare that they have no competing interests.Mr. Gurminder Singh (first and corresponding author) performed the data collection and wrote the paper with assistance from Mr. David McCormack (second author). Mr. David Roberts supervised the study and reviewed the completed manuscript.The pre-publication history for this paper can be accessed here:


In contrast to gene-mapping studies of simple Mendelian disorders, genetic analyses of complex traits are far more challenging, and high quality data management systems are often critical to the success of these projects. To minimize the difficulties inherent in complex trait studies, we have developed GeneLink, a Web-accessible, password-protected Sybase database.GeneLink is a powerful tool for complex trait mapping, enabling genotypic data to be easily merged with pedigree and extensive phenotypic data. Specifically designed to facilitate large-scale (multi-center) genetic linkage or association studies, GeneLink securely and efficiently handles large amounts of data and provides additional features to facilitate data analysis by existing software packages and quality control. These include the ability to download chromosome-specific data files containing marker data in map order in various formats appropriate for downstream analyses (e.g., GAS and LINKAGE). Furthermore, an unlimited number of phenotypes  can be stored and analyzed. Finally, GeneLink generates several quality assurance reports, including genotyping success rates of specified DNA samples or success and heterozygosity rates for specified markers..GeneLink has already proven an invaluable tool for complex trait mapping studies and is discussed primarily in the context of our large, multi-center study of hereditary prostate cancer (HPC). GeneLink is freely available at  In the past decade, hundreds of genes involved in the etiology of simple Mendelian disorders such as cystic fibrosis and Huntington's disease have been identified -3. The gEfforts to identify susceptibility genes involved in complex traits such as cancer, diabetes, hypertension, or Alzheimer's disease are complicated by genetic heterogeneity, incompplete penetrance, phenocopies, and the later age of onset of disease . Each of these factors results in a significant reduction in power for any given study. Therefore, gene-mapping studies of complex traits require high-throughput genotyping performed on large collections of DNA samples using hundreds to thousands of polymorphic markers. The significant amounts of data generated during these genome surveys pose numerous data management challenges. In order to address these challenges, which are inherent in any large, collaborative genotyping study, we have developed a robust, easy-to-use database system named GeneLink.GeneLink was initially developed to facilitate our studies of genetic susceptibility to prostate cancer, whose aims are to identify novel high- and moderate- penetrance genes involved in hereditary prostate cancer risk. These studies are multi-center collaborative efforts involving researchers from the United States, Finland, and Sweden -7. The padmin (administrator) privilege provides a user the ability to view data as well as manage access to the data. Users without admin privileges can be assigned the following privileges by the administrator: export, import, modify and view, with obvious permissions. Project- or user-specific reports summarizing assigned privileges can be generated. Second, as GeneLink provides the ability to associate a "group" (of users) with a collection site-specific set of families, collaborators can be provided the ability to view and/or manipulate all or only a subset of data.GeneLink is a platform-independent, Web-accessible Sybase database that can manage complete genotypic, phenotypic and pedigree data for genetic linkage or association studies. Figure Currently, GeneLink's database uses Sybase SQL server ASE 12.5.1, which runs on a Sun V880 computer running Unix. GeneLink's Web scripts to access the database require Perl version 5.6.1 or greater. The necessary CPAN Perl modules required by GeneLink are DBI, DBD::Sybase, CGI, and Carp. These modules are usually included in standard Perl 5 releases. A Web server such as Apache 1.3.29 is also required to run the GeneLink Web scripts. GeneLink can operate on a Sun Enterprise 6500 or similar machine configured to operate as a Web server.Families, Pedigrees, Trait Score, Traits Translations, Markers, Primers, Maps, Genotypes, Allele Translations, Liability Classes and DNA. Each table can be populated either by importing multiple records from a delimited text file or by inserting a single record at a time through a Web interface. The Families table stores pertinent clinical information regarding each family as a whole; each record reflects a single family included in the linkage or association study. For example, in our HPC study, we used the Families table to store information regarding evidence of male-to-male transmission of disease as well as the occurrence of other cancer types in the family. The Pedigrees table stores one record per individual within a family and contains the biological relationships (FatherID, MotherID) for each individual. Also included in the Pedigrees table is age, sex, whether the individual has been or will be genotyped (Age, Sex, DNA), two ways to store qualitative phenotype information (StatusBroad, StatusNarrow), and individual liability class information. In our HPC study, we defined prostate cancer affection status in two ways; specifically, we used the StatusBroad field to classify individuals as affected, unaffected or unknown, while the StatusNarrow definition was used for an affecteds-only analysis in which individuals were coded either as affected or unknown. More extensive trait or covariate information can also be stored in the Trait Score table. This table stores an unlimited number of qualitative or quantitative phenotypes as trait 1, trait 2, trait 3, and so forth. Definitions of the traits are stored in the Traits Translation table.Figure Markers table stores information regarding all markers typed in a given project, including the panel in which the marker was run. A panel is defined as a group of microsatellite or SNP markers which can be electrophoresed simultaneously by taking advantage of different fluorescent dye labels and varying amplicon sizes. Also stored in the Markers table is the allele size range (ASR) of the marker, the fluorescent dye used to label the forward primer, and the marker-specific genotype for a CEPH control individual (e.g., CEPH 1347-02 was used in our prostate cancer study). The Primers table provides additional information for each specific marker. This information includes UniSTS ID, GenBank accession number, forward primer sequence, reverse primer sequence, and primer purchasing and inventory information. The Primers table also contains comprehensive genetic map information (deCODE, Généthon, and Marshfield positions) as well as physical location . The Maps table stores the genetic map location of a marker in the genome, as well as the relative order of markers along a chromosome and the distance between adjacent markers. The markers typed thus far in our HPC study are di-, tri-, or tetra- nucleotide repeats; however GeneLink is capable of handling any combination of microsatellite and single nucleotide polymorphisms (SNP) data.The Genotypes table is where final genotype data are stored. Each record represents an individual/marker combination and alleles are stored as size in base pairs. The Genotypes table also holds information regarding the laboratory run (Grid, Lane). When exporting data in LINKAGE or RelCheck format, GeneLink systematically recodes genotype labels (1, 2, 3,...) to provide properly-formatted data for analysis by these programs. The Allele Translations table provides a key or legend linking the newly "translated" genotype to the original size in base-pairs score. Future exports use identical "allele translation codes." New alleles identified after the first export will be added to the end of a marker's allele translation ensuring consistent recoding of alleles across exports . For example, in our HPC study we used five different liability classes  and that the genotype for the control individual (e.g., 1347-02) matches what is expected (Markers table).Each of GeneLink's 11 tables has measures built-in for quality control purposes. First, all changes (import, modification or delete) to GeneLink records are stamped with the date, time, and USER ID of the individual doing the editing. Changes to the families, pedigrees, or genotypes tables can be easily reviewed in a Pedigrees table or the Trait Score table). This facilitates exporting data in formats commonly used in downstream analyses (e.g., GAS or LINKAGE format). There are three ways data can be exported. First, any user with administrator (admin) privileges can export data by Panel in LINKAGE or GAS formats. We use this option when checking our data for Mendelian inconsistencies because most laboratory errors could be detected if multiple markers within a panel showed up as inconsistent. Next, other users with export privileges can export data by chromosome. All data are exported by chromosome in the map order specified in the maps table. Chromosomes are only available for exporting once data for all markers on that chromosome have been imported, though we did design GeneLink to accommodate the possibility that all markers on a chromosome may not have been typed for all sites. The export genotype data screen  to export, how to define liability classes if necessary, what file format is desired and which families to include in the export. Only the family collection sites to which a user's group has access will appear in this screen. The final way data can be exported by users with export privileges is directly from the Families table. Using the Export by chromosome option described above means that all families from the selected site(s) will be exported. Alternatively, exporting directly from the Families table makes it possible to export only a subset of families from a collection site or a subset of families from across sites. Regardless of the exporting mechanism employed, GeneLink generates an Export Report, which summarizes all the pertinent information regarding the export, including families, chromosome (exported markers and distance between them), phenotypes included, liability class definition, and file format  . We are To collect the necessary number of DNA samples needed to provide sufficient power to detect linkage or association, collaborative efforts are almost always required. The Web-based interface of GeneLink facilitates multi-center collaborations, as data can easily be accessed via the Internet. GeneLink's Web-based interface also makes it platform-independent, a feature that was essential given the number of researchers who would be accessing it using various hardware-browser combinations. Other publicly-available databases described in the literature do not have this advantage. In this paper, we have presented GeneLink in the context of a collaborative effort in which multiple sites will need access to data generated in a single laboratory. However, GeneLink would also be valuable in the context of a meta-analysis of data generated in more than one laboratory. Making data access easier for our collaborators translated into the need for a sophisticated security system. Specifically, in our study of hereditary prostate cancer, researchers are permitted access to only their own set of data. This is important because, in some cases, a site's internal review board (IRB) protocol may not allow for raw data to be shared with other analysts.GeneLink provides several other advantages for investigators performing linkage or linkage disequilibrium studies of complex traits. For example, the process by which genotypes can be imported into GeneLink was designed to be flexible enough to handle data from laboratories like our own which employ duplicated samples and double-scoring methods for quality control purposes. Using duplicated samples and double scoring aids us in keeping our genotyping error rate low (< 1%). In our HPC study, we included 92 duplicated samples  in order to evaluate our genotyping error rate. The entire import process is outlined in Figures Allele Translation table allows comparison of alleles across families or across analyses, as each allele for each polymorphic marker will only be recoded once. This is particularly important as linkage disequilibrium or association studies become more common. Fourth, GeneLink's ability to export only a subset of families is critical, as genetic heterogeneity is a significant factor contributing to the difficulty of mapping genes involved in many complex traits. Multiple genes  haveAdditional quality control measures were included in GeneLink's design. First, all changes to the database are recorded. As genetic studies of complex traits can be spread over many years, it is important to keep a detailed log of any changes made to the data. For example, an individual's affection status may change during the course of a study; therefore it is critical to track when this information was updated in the database. Second, in order to monitor data quality, GeneLink was also designed to perform several built-in checks, as described above.Given that genetic studies of complex traits will generate millions (or even billions) of genotypes, it is essential to have appropriate mechanisms in place to ensure data integrity. In our study of hereditary prostate cancer, these checks immediately discovered a typographical error, which, if left undiscovered, would have resulted in data from an affected individual never being exported or analyzed. Finally, GeneLink generates detailed reports storing pertinent information regarding all imports and exports Figures  and 8A, GeneLink was designed primarily in the context of family-based studies of complex traits. It is capable of handling both linkage and association data, and can be used for both whole genome scans and/or candidate-gene studies. Further development of GeneLink will focus on extending its capabilities in regard to the case-based design. We recognize that both the family-based and case-based study designs have unique advantages, so we see it as critical to make GeneLink flexible enough to accommodate a case-based design. Currently, there is no limitation in storing case-based data however changes to GeneLink's exporting mechanisms should be made. Finally, in the same way that GeneLink is capable of storing "exported" data input files, future work will center on the storage of analysis results. Again, this would be helpful for multi-center collaborative studies, which will continue to be critical to successful efforts to identify genes important in complex trait etiology.In summary, GeneLink was designed specifically to ease the data management burden of mapping complex traits. It provides many functions that make it a uniquely powerful tool for use in genetic linkage or association studies. GeneLink simplifies merging genotypic data with pedigree, phenotype, and genetic or physical map information. Specifically, GeneLink's design makes it ideal for large-scale, multi-center studies, which will become more and more common in efforts to dissect the genetic factors contributing to complex trait etiology.Project name: GeneLinkProject home page: Operating system(s): Platform independentProgramming language: PerlOther requirements: Sybase SQL server ASE 12.5.1, Perl version 5.6.1 or greater, CPAN Perl modules DBI, DBD::Sybase, CGI, and Carp, Web server such as Apache 1.3.29License: Sybase SQL server ASE 12.5.1Any restrictions to use by non-academics: noneEG, JT, JEBW and AB participated in database's design. AM, LU, KT and TW did all of the programming. EG, DG, PD, APK, MJ, DFL, and GI performed extensive testing of the database. EG, PD, TW, JEBW and AB drafted the manuscript. All authors read and approved the final manuscript.


The principle of "a calorie is a calorie," that weight change in hypocaloric diets is independent of macronutrient composition, is widely held in the popular and technical literature, and is frequently justified by appeal to the laws of thermodynamics. We review here some aspects of thermodynamics that bear on weight loss and the effect of macronutrient composition. The focus is the so-called metabolic advantage in low-carbohydrate diets – greater weight loss compared to isocaloric diets of different composition. Two laws of thermodynamics are relevant to the systems considered in nutrition and, whereas the first law is a conservation (of energy) law, the second is a dissipation law: something (negative entropy) is lost and therefore balance is not to be expected in diet interventions. Here, we propose that a misunderstanding of the second law accounts for the controversy about the role of macronutrient effect on weight loss and we review some aspects of elementary thermodynamics. We use data in the literature to show that thermogenesis is sufficient to predict metabolic advantage. Whereas homeostasis ensures balance under many conditions, as a general principle, "a calorie is a calorie" violates the second law of thermodynamics. The recent awareness of an epidemic of obesity coincides with, and may have contributed to a dramatic increase in the popularity of a variety of low carbohydrate diets. This rapid switch in dietary habits of a significant part of the population, and the virtual revolution in the food industry, is unusual in that it stands in direct opposition to long-standing recommendations of the majority of the nutritional and medical establishment e.g. ,2). Desp. Desp2])was found. In the absence of an identifiable methodological error, experimental data has to be accepted and numerous investigations, in fact, serve as precedents for Greene et al.'s findings (Reviews: [We recently reviewed the literature on metabolic advantage . We showReviews: ,8).always be independent of macronutrient composition would violate the second law of thermodynamics.In our previous review of metabolic advantage  we showeBecause it is a colloquial phrase, it is important to understand exactly what it is meant by "a calorie is a calorie." The most common meaning is that is it impossible for two isocaloric diets to lead to different weight loss. Frequently, the concept is justified by reference to the "laws of thermodynamics", but an explicit connection has never been spelled out. More recently, Buchholz & Schoeller  appear ts of thermodynamics" it is important to be sure that one is including the second law. The first law is very different in character from the second law [dissipation law: it defines a quantity, the entropy, S, which we traditionally identify with disorder or high probability. The second law says that in any  irreversible process, the entropy must increase (ΔS > 0); balance is not expected. Entropy is, in fact, identifiable with irreversibility.The idea that "a calorie is a calorie" comes from a misunderstanding of the laws of thermodynamics. There are two laws of thermodynamics. (The zeroth law that establishes the concept of temperature and the third law that describes absolute zero are not relevant here). When speaking of "the lawcond law ,11,12. TIt is important to understand that it is the second law that drives chemical reactions. The first law is a bookkeeping law and tells us that the total energy attributed to work, heat and changes in chemical composition will be constant. It does not tell us whether such a reaction will occur, or if it does, what the relative distributions of the forms of energy will be. To predict the tendency of the reaction to occur, we must employ the second law that says the entropy must increase. In a chemical reaction, at constant temperature and pressure, the entropic and energetic effects are combined into the change in the Gibbs free energy, ΔG, whose sign predicts the direction of reaction, and whose magnitude indicates the maximum amount of work realizable from the reaction.in vivo values will differ from standard state values but they are continuous functions of the concentrations and there will be numerous conditions under which ΔG' is not zero. In other words, assuming that protein and carbohydrate are energetically equivalent leads to a contradiction.To understand the implications of "a calorie is a calorie," that energy yield could be path-independent and the same for all diets consider that it implies that carbohydrate and protein are equivalent fuels as shown in Figure is unrecoverable. The efficiency of a machine is dependent on how the machine works and, for a biochemical machine, the nature of the fuel and the processes enlisted by the organism. A simple example is the inefficiency of low-test gasoline in high compression gasoline engines. If a "calorie is a calorie" were true, nobody would pay extra for high test gasoline. . In weight loss diets, of course, inefficiency is desirable and is tied to hormonal levels and enzyme activitiesThe second law was developed in the context of the industrial revolution and the attempt to understand the efficiency of machines. The law describes the theoretical limits on the efficiency of engines and applies as well to living (irreversible) systems. The second law says that no machine is completely efficient. Some of the available energy is lost as heat and in the internal rearrangement of chemical compounds and other changes in entropy. In other words, although the first law holds even in irreversible processes – energy is still conserved – the second law says that something is lost, something possibility of metabolic advantage should not come as a surprise.In nutrition, one component of inefficiency is measured in thermogenesis (thermic effect of feeding), or the heat generated in processing food. There is a large literature on this subject and the general conclusion, as summarized in a recent review by Jéquier , is thatRecommendations for fighting obesity frequently call for small reductions in calories . In facttheoretically required in all cases is mistakenly based on equilibrium, reversible conditions that do not hold for living organisms and an insufficient appreciation of the second law. The second law of thermodynamics says that variation of efficiency for different metabolic pathways is to be expected. Thus, ironically the dictum that a "calorie is a calorie" violates the second law of thermodynamics, as a matter of principle.A review of simple thermodynamic principles shows that weight change on isocaloric diets is not expected to be independent of path (metabolism of macronutrients) and indeed such a general principle would be a violation of the second law. Homeostatic mechanisms are able to insure that, a good deal of the time, weight does not fluctuate much with changes in diet – this might be said to be the true "miraculous metabolic effect" – but it is subject to many exceptions. The idea that this is The analysis above might be said to be over-kill although it is important, intellectually, not to invoke the laws of thermodynamics inappropriately. There are also, however, practical consequences. The seriousness of the obesity epidemic suggests that we attack it with all the means at our disposal. Metabolic advantage with low carbohydrate diets is well established in the literature. It does not always occur but the important point is that it can occur. To ignore its possibilities and to not investigate the precise conditions under which it appears would be cutting ourselves off from potential benefit. The extent to which metabolic advantage will have significant impact in treating obesity is unknown and it is widely said in studies of low carbohydrate diets that "more work needs to be done." However, if the misconception is perpetuated that there is a violation of physical laws, that work will not be done, and if done, will go unpublished due to editorial resistance. Attacking the obesity epidemic will involve giving up many old ideas that have not been productive. "A calorie is a calorie" might be a good place to start.None declared.


Elective endotracheal intubations are still commonly performed without premedication in many institutions. The hypothesis tested in this study was that morphine given prior to elective intubations in neonates would decrease fluctuations in vital signs, shorten the duration of intubation and reduce the number of attempts.2<85%), duration of procedure, duration of hypoxemia (Sp02<85%), number of attempts and change in mean blood pressure were compared between groups.From December 1999 to September 2000, infants of all gestations admitted to a level III neonatal intensive care unit and requiring an elective endotracheal intubation were randomly assigned to receive morphine 0.2 mg/kg IV or placebo 5 minutes before intubation. Duration of severe hypoxemia (HR< 90/min and Sp034 infants (median 989 g and 28 weeks gestation) were included. The duration of severe hypoxemia was similar between groups. Duration of procedure, duration of hypoxemia, number of attempts and increases in mean blood pressure were also similar between groups. 94% of infants experienced bradycardia during the procedure.We failed to demonstrate the effectiveness of morphine in reducing the physiological instability or time needed to perform elective intubations. Alternatives, perhaps with more rapid onset of action, should be considered. Endotracheal intubation is a painful and stressful procedure, which is associated with acute increases in blood pressure and intracranial pressure, bradycardia and hypoxemia . These pMost premature infants and many term infants admitted to neonatal intensive care units (NICU) will require one or more endotracheal intubations during their stay. In 1994, 84% of Canadian NICUs, including ours, rarely or never used premedication for elective intubations . In 2000A literature review revealed six randomized controlled trials -14, compWe reviewed our policy, which did not include premedication for elective endotracheal intubations, in light of the current evidence. As morphine has been used for years in neonates with apparent safety and efficacy for pain and as staff in our unit were comfortable with this medication, we aimed to evaluate the efficacy of morphine, in achieving better intubation conditions and success while maintaining vital signs stability.Infants of all gestations, admitted to McMaster University Medical Center level III NICU and considered likely to need an elective oral or nasotracheal intubation during their hospital stay, were candidates for inclusion in this study. Families were approached for consent as soon as possible after birth when an elective intubation during their hospital stay seemed likely: if their infant(s) was less than 30 weeks gestation, already ventilated , was on NCPAP for respiratory distress or was needing an elective surgery. Others were approached when an elective intubation was needed. At the time of this study, our unit was a 33-bed level 3 NICU, caring for both inborn and outborn patients, and the referral center for 25000 annual deliveries, with 900–1000 admissions per year.Infants were excluded if they met any of the following conditions: 1) absence of an intravenous access, 2) upper airway anomaly potentially leading to a difficult intubation, 3) cyanotic heart disease, 4) upper gastrointestinal obstruction (which would require a rapid sequence intubation) or 5) concurrent opioid administration.Infants requiring an elective intubation were randomly assigned to receive either morphine 0.2 mg/kg IV or placebo (0.9% NaCl), given over 1 minute, followed 5 minutes later by the intubation. This larger dose of morphine was chosen for the perceived acuity of pain produced by an intubation; a larger dose may be more effective to decrease the struggling by infants during the procedure, which is caused by pain. Infants were randomized according to a computer-generated random number table with random block sizes. Morphine and placebo were supplied in identical unidose vials, labeled PIN Rx, which were prepared by one pharmacist according to the randomization sequence and placed in sealed, consecutively numbered envelopes, which were opened just before intubation. Thus, randomization occurred just prior to intubation.2 and hand-ventilated with a self-inflatable bag for 1–2 minutes prior to intubation. Infants having their endotracheal tube replaced were ventilated through their existing tube until it was removed. Vital signs (HR, BP, Sp02) were captured to a laptop computer from the infant's monitor (PC Express, Spacelabs Inc., Redmond WA) every 5 seconds (except blood pressure which was obtained with a self inflating cuff every minute) using Procom Plus Communication Software, from the time the study medication was given (which was considered the baseline) to 5 minutes after the infant's vital signs returned to pre-procedure values. One of three investigators, not involved in the procedure collected the following data manually: duration of the procedure  and the number of intubation attempts (defined as number of times the laryngoscope was inserted in the mouth). If there was more than one attempt, the clock continued between attempts and was stopped only when tube placement was confirmed by auscultation. In our NICU, the preferred method of intubation is via the nasotracheal route if mechanical ventilation is expected for more than a few hours.Three to four minutes after receiving the study medication, infants were preoxygenated with 100% 0a, neonatal fellows b, pediatric residents c, clinical nurse specialists d, clinical nurse specialist students e and transport nurses f. After 2 unsuccessful attempts by a junior team member (c,d,e,f), a more experienced intubator (a,b) was called.All team members performed the intubations: staff neonatologists Institutional ethics committee approval and informed consent from the parents were obtained for this study.2 < 85% with a HR< 90/min. This was felt to be the most undesirable side effect of endotracheal intubation as cerebral blood flow in neonates is highly dependent upon heart rate. Secondary outcomes included: (1) duration of the procedure, (2) duration of hypoxemia (Sp02 < 85%), (3) number of attempts, (4) maximum change in blood pressure from baseline, (5) occurrence of bradycardia (HR<90/min).The study aimed to test the hypothesis that morphine 0.2 mg/kg would decrease fluctuations in vital signs, shorten the duration of the procedure and reduce the number of attempts. The primary outcome was the duration of severe hypoxemia, defined as Sp0The study group's impression was that a majority of infants experience some degree of severe hypoxemia during an elective intubation, which was clinically undesirable. It was estimated to be 30 seconds, based on experience. In order to detect a one standard deviation difference in duration of severe hypoxemia between the 2 groups (α = 0.05, 2-sided, β = 0.2), 17 patients per group were required.Because the distribution of the main outcome was skewed and groups were small, continuous variables were compared using the Mann-Whitney U test. Dichotomous variables were compared using Fisher's exact test or Chi-square test. A p value < 0.05 (2-sided) was considered significant for the primary outcome; p < 0.01 was considered significant for secondary outcomes to account for multiple analyses in a small sample. Level of experience of the intubator, birth weight and gestational age were separately explored as potential confounders of the primary outcome using ANOVA or linear regression.Patients were recruited from December 1999 to September 2000. Patient flow in the study is depicted in figure Baseline characteristics are presented in Table 2 < 85%) during intubation. The median duration of hypoxemia was 235 sec in the treatment group and 90 sec in the control group (p = 0.04). Because of our small sample and the likelihood of finding a significant result by chance alone when assessing multiple outcomes, it was decided a priori that a p value of 0.01 would be considered significant for secondary outcomes. Nevertheless, this represents an interesting but somewhat worrisome trend. No difference was found in the maximal increase in blood pressure. Ninety-four percent of patients experienced bradycardia (HR<90/min) during the procedure with no difference between groups.All patients in the treatment group and 14/17 in the control group experienced hypoxemia , was similar to controls (median 1); total number of attempts was 38 in the premedicated infants versus 31 in the controls. Success rate at first attempt or need to call a more senior intubator after 2 failed attempts did not differ between groups. Because of the higher than usual dose of morphine that was used, we monitored the need to increase ventilator support over the next 24 h, in infants having their tubes changed, but found no difference between groups.Newborn infants, especially premature ones have adverse physiological responses to routine care procedures ,4. EndotOur hypothesis was that a moderate dose of morphine would facilitate intubation and stabilize vital signs better than placebo. Our data does not support this hypothesis. No significant difference was identified between the treatment and the control group in any prespecified outcome. The choice of severe hypoxemia as the primary outcome, although clinically very important, significantly limited the number of observations and increased the possibility of a type 2 error, as few infants met the criteria defining this outcome. The onset of action of morphine is about 5 minutes in infants, but the peak action occurs only at 15 to 30 minutes , perhapsThe only trend we identified was the duration of hypoxemia, which appeared longer in the treatment group. Most desaturations were in the mid 70's to low 80's range, but this is still a worrisome finding. We were unable to identify if birth weight, gestation or experience level of the intubator were significant contributors. Our sample size likely did not permit to identify such a contributor. Although morphine may not be potent enough to significantly relax infants to permit quicker and easier intubations, it may lead to decreased functional residual capacity in partially sedated infants, which could account for prolonged desaturations. The hypoxemia could have been compounded by the use of self-inflating bag and masks, which cannot provide a positive end-expiratory pressure (PEEP). Also, the larger dose of morphine used in this study could have contributed to this potential problem, by further decreasing the FRC in partially sedated infants. This trend is in keeping with the finding that, although not statistically significant, median duration of the procedure was 3 times as long in the treatment group as in the controls.Ninety four percent of infants experienced bradycardia, mostly vagal, during their intubation. As cerebral blood flow in infants is greatly dependent on heart rate, our data adds to the current knowledge that including atropine in the premedication appears warranted. Although there may be concern that atropine could mask hypoxia-induced bradycardia, the now universal use of oxygen saturation monitors should ensure that hypoxemia is identified.Previous trials have used various combinations of drugs for premedication and overall, they suggest that premedication is effective and safe. Kelly  and BarrOur study has several limitations. First, our sample size is relatively small, which precludes us from eliminating a type 2 error. We began this project with the assumption that severe hypoxemia would occur for about 30 seconds, which was not the case. An observational study would have been useful before making this assumption. Although limited in size, results of this trial should be useful for future investigators and clinicians in their choice of premedication. Second, due to limited resources , as this study was planned as a pilot, to assess feasibility and adequacy of equipment to obtain data, we decided not to stratify for gestational age. This could have been very useful in refining the findings, as more immature infants may respond differently to premedication in general and have less strength to struggle during an unpremedicated or not sufficiently premedicated painful procedure. Third, as we wanted to mimic our actual NICU practices, in view of modifying such practices, we did not restrict the study intubations to very experienced operators. As a result, there was substantial variability in the level of experience between individuals. Given our small number of patients, this might have impacted on the outcomes. Fourth, several eligible infants were not enrolled. This was due to unavailability of either trial investigators or parents, as many intubations occurred at night. The infants enrolled and those not enrolled had similar birth weights, gestation and reason for intubation, which is reassuring, but does not eliminate the potential for enrolment bias.Infants are entitled to effective pain management strategies . It seem2 oxygen saturation, ETT endotracheal tube, IVH intraventricular hemorrhage, PVL periventricular leukomalacia, NICU Neonatal Intensive Care Unit, PEEP positive end-expiratory pressureHR heart rate, BP blood pressure, Sp0The authors declare that they have no competing interests.BL led the study design and manuscript preparation and contributed to data collection. MM contributed to the study design and manuscript preparation. JD contributed to the study design, manuscript preparation and data collection. AK contributed to data gathering and manuscript editing. SG prepared the study medication and contributed her pharmaceutical expertise to the choice of medication dose for the study. All authors read and approved the final manuscript.The pre-publication history for this paper can be accessed here:


Cystic fibrosis (CF) lung disease manifest by impaired chloride secretion leads to eventual respiratory failure. Candidate genes that may modify CF lung disease severity include alternative chloride channels. The objectives of this study are to identify single nucleotide polymorphisms (SNPs) in the airway epithelial chloride channel, CLC-2, and correlate these polymorphisms with CF lung disease.The CLC-2 promoter, intron 1 and exon 20 were examined for SNPs in adult CF dF508/dF508 homozygotes with mild and severe lung disease (forced expiratory volume at one second (FEV1) > 70% and < 40%).PCR amplification of genomic CLC-2 and sequence analysis revealed 1 polymorphism in the hClC -2 promoter, 4 in intron 1, and none in exon 20. Fisher's analysis within this data set, did not demonstrate a significant relationship between the severity of lung disease and SNPs in the CLC-2 gene.CLC-2 is not a key modifier gene of CF lung phenotype. Further studies evaluating other phenotypes associated with CF may be useful in the future to assess the ability of CLC-2 to modify CF disease severity. Although greater than 1000 mutations of the CF gene product, CFTR are known, none of these can be used to make predictions about the occurrence of common complications, the severity, or course of pulmonary disease. The identification of a gene, which modifies the phenotypic expression of CF would be very important for understanding this complex disease. Because CF is a disease of chloride transport in respiratory epithelia, alternative chloride channels present in the airway may be able to partially compensate for the CF defect.CLC-2 is one candidate alternative chloride channel in respiratory epithelia. Localization to the luminal surface of the airway and perinatal downregulation of CLC-2 in mammalian lung suggests a role in lung morphogenesis ,2. PersiNasal polyps from CF patients were obtained at the time of elective surgery from 1989 to 1996. Genotypes of CF mutations for each patient was available, but not clinical status, according to approval by the Johns Hopkins Medical Institution Review Board. At harvest, the tissue was washed 3 times in HBSS, and incubated at 4°C overnight in Protease XIV (Sigma). Epithelial cells were isolated by gentle agitation and filtered through a 70-μm nylon cell strainer . Cells were grown on 1% collagen coated 35 mm dishes for 1 week. Cell lysates were prepared using 2% sodium dodecyl sulfate (SDS) at 65°C and a cell scraper. Equivalent amounts of total protein from primary CF nasal polyp cultured cell lysates were loaded onto an SDS-polyacrylamide gel electrophoresis (PAGE) system, electrophoresed and transferred to a nitrocellulose membrane. CLC-2 protein levels were detected using the polyclonal chicken anti-CLC-2 antibody and the enhanced chemiluminescent reaction as previously described [Variable expression of CLC-2 protein in nasal cell lysates (see Results) suggested that CLC-2 is differentially expressed in adults and that examination of human CLC-2 genomic structure would be important to investigate this differential expression. Identification of volunteers for nasal epithelial cell culture was not permitted with the original IRB consent process. Therefore, a cohort of CF patients was recruited for polymorphism analysis. A review of the Johns Hopkins Medical Institution CF center database was conducted in 1998 to identify patients that had reached adulthood (age > 18 years), homozygous for the most common CF genotype delF508, so that the affect of various CFTR genotypes would not affect the investigation of CLC-2 polymorphisms. Status of obstructive lung disease was defined using most recent pulmonary function studies. Those patients with spirometry FEV1 ≤ 40% predicted were classified as severe, those with spirometry FEV1 ≥ 70% predicted as mild in order to classify 2 severity levels of CF lung disease. Of 74 eligible subjects (age > 18 years, del F508 homozygous), 43 had FEV1 ≥ 70%, 9 had FEV1 = 41–69%, and 22 had FEV1 ≤ 40%; 31 were recruited during routine visits to the CF center from June 1998 to January 2000. With informed consent, participants provided blood samples for genomic DNA isolation. This study was approved by the Institutional Review Board at Johns Hopkins Medical Institution. DNA was isolated from lymphocytes using standard procedures.The genomic structure of rat CLC-2 has been previously published ,6and hasE. coli, and DNA isolated using the Mini-prep kit  according to the manufacturer's instructions. The sequence of this ~2000 bp product yielded genomic DNA for design of primer pairs that would yield overlapping PCR-amplified DNA fragments of the promoter.Primer pairs were thus chosen from rat [accession gi|4406230] and human CLC-2 sequence [accession S7770] to amplify the promoter, intron 1 and exon 20 from adult CF subjects homozygous for delF508. Sequencing of the human CLC-2 promoter initially from one human genomic sample was performed by polymerase chain reaction using the 5'-flanking region of rat hpolE1 (dTCC GGG TCA ATA TCC TTC ACA TCG), which is approximately 2000 base pairs upstream from the rat CLC-2 coding sequence [Sequencing and identification of human CLC-2 promoter polymorphisms in 15 CF patients with severe obstructive lung disease (FEV1 ≤ 40% predicted) and 16 CF patients with mild disease (FEV1 ≥ 70% predicted) were performed by polymerase chain reaction using overlapping primers designed from the initial hCLC-2 clone. The only product that yielded a SNP was amplified using primers 15F dGTC CCA GGA GTA GAC TTC C and 16R dCAC TGC CCT CTG GCC TC providing a 760 base pair product, using cycling conditions of 94°C 6 mins, 35 cycles of 94°C 30 s, 59°C 30 s, 72°C 30 s and 72°C 6 min. A nested reaction with 20 uM primers 17F dTCC CCT CCG GCC TAC CCC TTC CGG T and 18R dGGA AGG ATT CGG AGA GGG TTG GGG C amplified both a 150 and 300 bp product using Epicentre MasterAmp™ buffer J (Madison, WI) with cycling conditions 94°C 6 mins, 35 cycles of 94°C 30 s, 64°C 30 s, 74°C 30 s and 74°C 6 min.Because regulation of a gene may occur also through its first intron we amplified this region from all subjects using primers 1F' dCGC TGC AGC ACG AGC AGA C and 1R' dCCC AAG GTC CTG AGT GTA CC, which yielded a product 2273 bp product. Cycling conditions were 95°C 6 mins, 35 cycles of 95°C 30 s, 63°C 30 s, 72°C 3 minutes and 72°C 6 min. Finally, because exon 20 is alternatively spliced in rat lung [With PCR amplification of all 31 genomic CF samples using primers listed in Table CLC-2 protein is nearly undetectable in postnatal rat lung . High leIn order to minimize the confounding of genotype, race and age, all individuals were homozygous for delF508 mutation of CFTR, Caucasian, and over 17 years old. FEV1% determined 2 cohorts, one with mild CF lung disease with average FEV1% of 77.4 ± 3.18 SEM  as expected from the rat genomic structure , which mThere were five subjects with severe CF lung disease (FEV1 < 40%), who had the genotype A/G, whereas eleven had G/G at position -693 (Table The first intron of human CLC-2 was amplified and the 2273 bp product confirmed by gel electrophoresis. This sequence correlates with bp 319453 to 321725 of ref|NT_0292533|Hs_29412. Human CLC-2 intron 1 has regions with as much as 74% sequence identity with rat (gi 2873366) and 85% with mouse (gi28494743) Figure  and 3b. Primers used to examine the potential exon 20 splice variant region in hCLC-2 amplified a 481 bp fragment that correlates with bp 328123 to 328556 of human genomic sequence NT_0292533 and 2446 to 2617 of hCLC-2 cDNA (accession S7770). There were no SNPs identified using all 31 patient samples.With an autosomal recessive pattern of inheritance, CF was long considered a monogenic disease with 1 mutant allele inherited from each parent. While CF neonatal screening is offered in several states of the U.S., counseling of families has been difficult, because CF genotyping does not easily predict onset and severity of pulmonary complications . Strateg++-dependent chloride channel (CaCC) [There are several chloride conductances, which have been characterized in the mammalian lung: the cAMP-dependent cystic fibrosis transmembrane conductance regulator (CFTR) , the Ca+l (CaCC) -18, the l (CaCC) , the purl (CaCC) ,21, and l (CaCC) ,22-24.++-dependent chloride channel [++-dependent chloride conductance is low in the intestine of the CF knock-out mouse. To take advantage of alternative chloride channels in the lung, UTP analogues have been used to stimulate chloride secretion in CF individuals via the purinergic receptor-mediated chloride channels [One or more of the chloride channels present in the respiratory epithelium may be able to partially compensate for defects in another. For example, there was no lung pathology in the first CF knock-out mouse models, where there is enhanced activity of a Ca channel -27, howe channel . The CF channels ,21.One member of the ClC family of chloride channels may also be an alternative chloride conductance in the airway epithelium. We have demonstrated that CLC-2 mRNA and protein are abundantly expressed in the fetal lung ,2 and thIn this study of 31 CF subjects, we identified 5 single nucleotide polymorphisms that have not previously been described for human CLC-2. One of these is -693 relative to the ATG start site of hCLC-2 (Genbank S7770). The -693 G/A polymorphism is a putative AP-2 binding site, predicted by TESS and MATINSPECTOR ,13 and mIn the rat, SP-1 sites are important for gene regulation ,29,30. CWe also identified 4 polymorphisms in hCLC-2 intron1. These did not appear more or less frequently in the mild CF subjects. Two of the polymorphisms were in complete linkage disequilibrium. The polymorphisms were not identified in areas that were highly conserved in rat or mouse. While splice variants of exons may be affected by intron/exon boundaries, we did not find any polymorphisms in the region of the rat exon 20 splice variant .These findings suggest that CLC-2 is not regulated differently at the genomic level in relatively healthy CF adults. Lack of an association in this study does not exclude the possibility that CLC-2 plays a role in modifying the CF phenotype as might be suggested by the variability of CLC-2 protein expression in primary respiratory epithelial cells from CF subjects in this study. Although we were limited by inadequate power with a small sample size and because phenotypic contrast was low, our data suggest that gene regulation of CLC-2 in relation to polymorphisms in regulatory domains does not play a major role in protection against CF lung disease. Studies which rely on recruitment of small numbers of patients have been shown to detect a difference when a strong relationship is present . AnotherThe identification of candidate genes, which may modify CF lung disease is important so that new therapies may be developed. Multi drug resistant genes have recently been identified that provide some "protection" to the CF lung phenotype . Ion traLastly, gene expression and function may be independent of genomic polymorphisms, as suggested by our data demonstrating variable expression of hClC-2 protein in CF nasal polyps and must also be considered as a mechanism whereby, CLC-2 could alter the course of CF disease. Haug et al. recently identified mutations in the CLC-2 coding region that are associated with idiopathic generalized seizures in humans . No lungThis study provides important information about the human CLCN2 genomic organization. Several polymorphisms of key regulatory domains of CLCN2 were identified in a cohort of subjects with cystic fibrosis, who carry the same CF genotype. While we have found no significant association of CLC-2 polymorphisms with FEV1 % predicted in adulthood, further study of potential polymorphisms in CF subjects at an earlier age and investigation of potential mutations in the coding region of CLC-2 that would lead to enhanced transepithelial chloride transport would be necessary to determine if CLC-2 can modify CF.The author(s) declare that they have no competing interests.CB provided overall study design, analysis, and drafted the manuscript. TH designed sequencing methods and analyzed alignment. AS and PB conducted experiments. EB contributed to the design of the study and OS designed sequencing methods and provided analysis including statistics.All authors read and approved the final manuscript.The pre-publication history for this paper can be accessed here: