Effects of 2-, 4- and 12-hour fasting intervals on preoperative gastric fluid pH and volume, and plasma glucose and lipid homeostasis in children. Gastric pH and volume after oral fluids in the postpartum patient. Preoperative drinking does not affect gastric contents. Paediatric glucose homeostasis during anaesthesia. Gastric residual volume in infants and children following a 3-hour fast. [Possibility of rice porridge for preoperative feeding in children]. Effects of duration of fasting on gastric fluid pH and volume in healthy children. The effect of pre-operative intake of oral water and ranitidine on gastric fluid volume and pH in children undergoing elective surgery. Effect of preoperative oral fluids on gastric volume and pH in postpartum patients. Shortened preanesthetic fasting interval in pediatric cardiac surgical patients. Ingestion of clear fluids is safe for adolescents up to 3 h before anaesthesia.
We evaluated 105 randomly-selected unpremedicated children aged 1-14 years to determine the effects of a 2-, 4- and 12-h preoperative fasting interval on the preoperative gastric fluid pH and volume, and plasma glucose and lipid homeostasis. Each child undergoing elective surgery ingested a large volume (approximately 10 ml/kg b.w.) of apple juice and then fasted for 2, 4 or 12 h before the estimated induction of anaesthesia. After induction of anaesthesia, gastric fluid was aspirated through a large-bore, multiorifice orogastric tube. Plasma concentrations of glucose, total ketone bodies, non-esterified fatty acid (NEFA), triglycerides, and cortisol were measured at the time of induction to evaluate the fasting interval effects on preoperative plasma glucose and lipid homeostasis. There were no significant differences between the three groups in either gastric fluid volume or pH. In addition, there were no significant differences between the groups with respect to the proportion with a pH < 2.5 and volume > 0.4 ml/kg b.w. Neither plasma concentrations of glucose, triglycerides, nor cortisol at the time of anaesthetic induction differed between the three groups. Both 4 and 12 h nil per os (NPO) caused an increase in lipolysis, which was presumably a compensatory mechanism to maintain normoglycaemia. The plasma NEFA and total ketone bodies concentrations were therefore significantly higher in these two fasting intervals than in 2 h NPO. These data suggest that a 2-h NPO, after a large volume of ingested apple juice, may offer additional benefits by preventing an increase in lipolysis during the fasting interval without either increasing the volume of gastric fluid or decreasing the gastric pH.(ABSTRACT TRUNCATED AT 250 WORDS) The aim of this study was to investigate the relationship between preoperative oral fluids and gastric pH and volume in women undergoing sterilization between one and five days postpartum. Fifty postpartum patients received 150 ml water approximately two to three hours before surgery while 50 postpartum and 50 non-pregnant women were fasted from midnight. After induction of anaesthesia, gastric contents were aspirated using a Salem sump tube and the gastric pH and volume were measured. There were no differences in intragastric pH and volume, median (range), among the postpartum fasted group, 1.19 (0.74-4.57), 22 (1-78) ml, postpartum water group 1.18 (0.70-6.4), 25.5 (3-66) ml and the non-pregnant group 1.27 (0.51-6.63), 25 (3-69) ml. There was no correlation between postpartum interval, 60 (12-120) hr, and intragastric pH or volume. It is concluded that oral water may be given safely two to three hours preoperatively to patients more than one day postpartum. Intragastric volume and acidity were not increased and the findings in postpartum patients were similar to those found in non-pregnant patients. We have compared the effect of allowing free clear fluids until the time of oral premedication with conventional preoperative fasting. In a prospective, randomized trial, the residual volume and pH of gastric contents after induction of anaesthesia were measured in 100 elective surgical patients allocated randomly to a group in whom the intake of free clear fluids up to the time of premedication was measured (mean 388 ml in 6 h before surgery) or a control group who were fasted for 6 h. Preoperative drinking did not affect either mean (SD) residual gastric volume (22 (21) ml in the study group vs 19 (16) ml in the control group) or pH (study group 2.64 (1.57) vs control group 2.26 (1.45)). The study group experienced less preoperative thirst. Problems with aspiration or regurgitation were not encountered. We believe that allowing elective surgical patients to drink clear fluids until 2 h before anaesthesia may enhance patient comfort without compromising safety. The perioperative blood glucose regulatory response was compared in 20 healthy children (aged 1-5 yr) presenting for minor surgery and allocated randomly to either a fasted or a glucose group. All children received a milk feed at midnight. The fasted group received no oral intake thereafter, whereas the glucose group received 5% dextrose water 10 ml kg-1 orally about 4 h before operation. The mean plasma glucose concentrations in the two groups were similar before operation and were within normal limits. The pattern of change in the concentrations of plasma glucose, insulin, cortisol, growth hormone and glucagon were also similar between the two groups. Ten percent of patients in the fasted group and 33% in the glucose group had gastric aspirates in excess of 0.4 ml kg-1. The pH of all gastric samples was less than 2.5. The results suggest that healthy preschool children were able to maintain glucose homeostasis after 8 h of fasting. Feeding within 4-6 h before surgery may increase the risk of pulmonary aspiration. The effect of a 3-hour versus a 10-hour preoperative fasting interval on the gastric residual volume and gastric pH of pediatric patients was evaluated. Forty-four healthy infants, 1 month to 5 years of age, were randomly assigned to one of two groups. The 3-hour nil per os (NPO) group consisted of 19 infants kept NPO for 3 hours following ingestion of up to 4 ounces of 5% dextrose in water (D5W). The control group consisted of 25 infants who remained NPO an average of 10 hours prior to surgery. Gastric residual volume was calculated using the dye-dilution technique. After the dye marker was injected into the stomach, complete aspiration of the stomach (including the volume of dye marker plus residual gastric contents) was attempted as another method to measure gastric residual volume. There were no significant differences in gastric residual volume between the 3-hour and the 10-hour NPO groups using either the dye-dilution or aspiration methods. However, there were significant differences between the two measuring techniques. Gastric residual volume was significantly greater in volume when measured by the dye-dilution technique than it was when measured by the aspiration technique in both the 10-hour (p less than 0.009) and the 3-hour (p less than 0.0009) NPO groups. Complete aspiration of a known volume of fluid injected through the orogastric tube was not possible in 23 of the 44 (52.4%) infants. Mean gastric pH was less than 2.0 in both groups.(ABSTRACT TRUNCATED AT 250 WORDS) To determine the effect of rice porridge feeding before elective surgery on preoperative gastric fluid pH, volume and starvation, a prospective study was undertaken in pediatric patients. Twenty healthy children ranged in age from 5 to 12 years were allocated randomly to either a fasted or rice porridge group. The children of fasted group (control group) were allowed to take solid food until midnight before the operation. The rice porridge group (study group) patients received a small amount of rice porridge 5 hours 30 minutes before the induction of anesthesia. The patients of both groups were permitted to take clear fluid until 5 hours before the induction of anesthesia. After the induction of anesthesia, gastric fluid was aspirated through an orogastric tube. The mean gastric fluid volume was 0.43 +/- 0.32 ml.kg-1 in the control group and 0.5 +/- 0.6 ml.kg-1 in the study group. The mean gastric fluid pH was 1.43 +/- 0.27 ml.kg-1 in the control group and 1.89 +/- 0.75 ml.kg-1 in the study group. There were no significant differences between the two groups concerning the gastric fluid volume and pH. The patient of the study group complained of less hunger. Preoperative rice porridge feeding is a possible preoperative feeding for pediatric patients. To determine the effects of duration of fasting before elective surgery on gastric fluid pH and volume in children, a prospective, randomized, blinded study of 100 unpremedicated children, aged 1-14 yr, was undertaken. Each child was given 2 mL/kg of water orally and then fasted 2, 4, or 6 h preoperatively. After induction of anesthesia and tracheal intubation, gastric fluid was aspirated through a large-bore, multiorifice orogastric tube. Gastric fluid pH was measured using a calibrated PHM62 radiometer. Gastric fluid volume was the total volume of fluid aspirated from the stomach. The duration of fasting was between 2.0 and 8.5 h. We found that neither gastric fluid pH nor gastric fluid volume correlated with the duration of fasting. The mean (+/- SD) gastric fluid pH was 1.80 +/- 0.79 and the mean (+/- SD) gastric fluid volume was 0.56 +/- 0.39 mL/kg. Gastric fluid pH was less than 2.5 and volume greater than 0.4 mL/kg in 53% of children. We conclude that healthy children may receive 2 mL/kg of water up to 2 h before elective surgery without decreasing gastric fluid pH or increasing gastric fluid volume beyond values obtained after fasting for 6 h. The effect of pre-operative intake of oral water and ranitidine on gastric fluid volume and pH was studied in 75 children of American Society of Anesthetists (ASA) grade I and grade II undergoing elective surgery. Group I patients fasted from midnight and acted as control. Group II patients received 5 ml/kg plain water orally 3 hours before surgery. Group III children received 5 ml/kg of plain water and 2 mg/kg of ranitidine orally 3 hours before surgery. Mean volume of gastric aspirate was comparable in all 3 groups (p > 0.05). Mean pH was significantly higher in ranitidine treated patients (5.12 +/- 1.73) as compared to non-ranitidine treated patients (2.26 +/- 0.57 and 2.53 +/ 0.79 in group I and group II respectively). Number of patients at risk (pH < or = 2.5 and volume > or = 0.4 ml/kg) was not significantly different in group I and group II. Mean thirst and behaviour scores were significantly higher in fluid treated patients (groups II and III) as compared to control (p < 0.01). To conclude, administration of pre-operative water (5 ml/kg) along with ranitidine (2 mg/kg) favourably modifies gastric fluid volume and pH, improves patient behaviour and minimises the number of patients at risk of aspiration pneumonitis, should the child aspirate. The effect of preoperative oral fluids to postpartum patients on the gastric volume and pH was compared with normally fasting postpartum and non-pregnant patients undergoing sterilisation. Forty consecutive postpartum patients and twenty non-pregnant patients scheduled for sterilisation procedure were selected for the study. All patients were fasted overnight. Twenty postpartum patients were randomly allocated to receive 150 ml of plain water two and half hours before surgery (Group 1), while the remaining postpartum patients (Group 2) and non-pregnant patients (Group 3) continued their overnight fast as usual. After induction of anesthesia, gastric volume and pH was measured in all the patients. The mean gastric volume was found to be 21.9 +/- 8.49 ml in Group 1, 22.55 +/- 8.30 ml in Group 2 and 22.65 +/- 8.17 ml in Group 3. The mean pH was found to be 2.21 +/- 0.98 in Group 1, 2.18 +/- 0.88 in Group 2 and 2.12 +/- 1.02 in Group 3. The difference in the volume and pH in all the three groups was statistically insignificant. The difference in the incidence of patients with combined high risk factors of acid aspiration syndrome (gastric fluid volume > 25 ml and pH < 2.5) among the three groups was also insignificant. The authors conclude that ingestion of 150 ml of plain water approximately two and half hours before scheduled time of surgery in overnight fasted postpartum patients does not increase the risk of aspiration syndrome. The recent liberalization of preoperative feeding orders in healthy pediatric outpatients prompts the question of whether this applies to children about to have cardiac surgery. The authors compared gastric fluid volume and pH in two groups of children undergoing elective cardiac surgery, one of which was not only permitted ad libitum clear liquids but was mandated to drink clear liquids 2-3 h before induction of anesthesia (study group). The other group followed routine inpatient preoperative fasting orders (control group). The study group (n = 44) averaged 3.1 +/- 4.1 yr and weighed 15.3 +/- 16.3 kg; the control group averaged 3.3 +/- 3.9 yr and weighed 14.3 +/- 12.1 kg (P = 0.82, 0.73, respectively). Aspiration of residual gastric fluid volume was attempted in all patients after induction of anesthesia. Gastric fluid volume averaged 0.6 +/- 0.9 mL/kg in the study group and 0.4 +/- 0.6 mL/kg in the control group (P = 0.13). Of the study patients, 41% had a measured gastric volume greater than or equal to 0.4 mL/kg compared with 32% of the control patients (P = 0.50). Of the 42 patients who had residual gastric fluid aspirated, pH determinations were completed on 37 aspirates; of these 19 of 20 (95%) in the study group and 14 of 17 (82%) in the control group had a gastric pH less than or equal to 2.5. Using a linear analogue scale, parents rated children in the study group to be more comfortable, less hungry, and less thirsty compared with the control patients (P = 0.004, 0.002, 0.0001, respectively).(ABSTRACT TRUNCATED AT 250 WORDS) We have studied the effect of ingestion of unlimited clear fluids by adolescents up to 3 h before anaesthesia to determine the effect this fluid ingestion would have on thirst, hunger and gastric contents at induction of anaesthesia. We studied prospectively 152 adolescents (ages 13-19 yr) undergoing elective surgery. Fifty percent of the patients had nothing by mouth after midnight. The other 50% were instructed to ingest unlimited clear fluids up to 3 h before surgery. On arrival in the operating room, subjects were asked to assess thirst and hunger with a linear analogue scale of 0-10 (0 corresponding to no thirst or no hunger). After induction of anaesthesia, gastric contents were aspirated via a 16-French gauge orogastric tube. Gastric fluid volume (GV) was measured with a syringe and gastric pH (GpH) was assessed with Merck pH strips. GV, GpH and subject hunger were unaffected by ingestion of clear fluids. Subject thirst was reduced by clear fluids. It is concluded that unlimited clear fluid ingestion by healthy adolescents up to 3 h before operation decreases thirst and does not affect gastric contents.
There was no evidence to suggest a shortened fluid fast results in an increased risk of aspiration, regurgitation or related morbidity compared with the standard 'nil by mouth from midnight' fasting policy. Permitting patients to drink water preoperatively resulted in significantly lower gastric volumes. Clinicians should be encouraged to appraise this evidence for themselves and when necessary adjust any remaining standard fasting policies (nil-by-mouth from midnight) for patients that are not considered 'at-risk' during anaesthesia.