This is a young patient with no comorbidities and is therefore a candidate for treatment with curative intent, so option 4 is ruled out. Option 3 is also incorrect since we cannot know the patient's IPSS since we do not know the number of blasts and the number of leukocytes and platelets to calculate the risk. Option 2 is also incorrect since the indication for a bone marrow transplant in MDS is those patients with high or intermediate-2 IPSS, and in this case we do not know the risk, the only thing we know about the risk is the cytogenetics which is of good prognosis that would give us 0 points. Therefore the correct one is 1 since it is true that it has a favorable cytogenetics (5q-) and has a specific treatment lenalidomide, also used in other pathologies such as multiple myeloma.

This is a young patient with no comorbidities and is therefore a candidate for treatment with curative intent, so [HIDDEN]. Option 3 is also [HIDDEN] since we cannot know the patient's IPSS since we do not know the number of blasts and the number of leukocytes and platelets to calculate the risk. Option 2 is also [HIDDEN] since the indication for a bone marrow transplant in MDS is those patients with high or intermediate-2 IPSS, and in this case we do not know the risk, the only thing we know about the risk is the cytogenetics which is of good prognosis that would give us 0 points. Therefore [HIDDEN] since it is true that it has a favorable cytogenetics (5q-) and has a specific treatment lenalidomide, also used in other pathologies such as multiple myeloma.

A 51-year-old man is admitted from the emergency department for macrocytic anemia (Hb 6.3 g/dL, MCV 120 fL). Studies ruled out a deficiency origin. Reticulocytes were 24000/microL. The bone marrow study is compatible with myelodysplastic syndrome (MDS). Cytogenetics shows a 5q deletion. Which is the correct statement regarding this patient?

This deletion (5q-) is an alteration of good prognosis and has a specific treatment (lenalidomide).

It would be advisable in this patient to perform HLA typing in order to organize an allogeneic transplant.

This is a patient with a high International Prognostic Index (IPSS).

Treatment in this case would be transfusion only.

Long-Term Response in a Patient with del(5q) Myelodysplastic Syndrome Who Discontinued Lenalidomide and Obtained a Good Response and Tolerance to Rechallenge.

The introduction of the immunomodulatory drug lenalidomide has revolutionized the treatment of patients with myelodysplastic syndromes (MDS) and deletion of the long arm of chromosome 5. Treatment with lenalidomide results in transfusion independence in the majority of patients, but some questions remain unresolved, among them the duration of treatment. Moreover, a number of unexpected long-term remissions in patients who stopped lenalidomide for various reasons have been observed. We report the case of a 60-year-old Caucasian male with deletion of the long arm of chromosome 5 and International Prognostic Scoring System (IPSS)-defined low-risk MDS who was treated with lenalidomide, achieving complete cytogenetic remission and erythroid response. After tapering off and interrupting the treatment, the patient relapsed and showed a new response by lenalidomide retreatment. Six years after the initial treatment, we registered a durable erythroid long-term response and good tolerance, but there was no evidence of a very profound cytogenetic response compared to using lenalidomide as a first-line treatment. Cytogenetic and fluorescence in situ hybridization together with hemoglobin level, mean corpuscular volume (MCV) and vitamin B12 level helped us to monitor the patient response; during the various phases of lenalidomide treatment, MCV and vitamin B12 normalization correlated with good response. Lenalidomide interruption and rechallenge in some 5q- MDS patients, with low risk according to the IPSS, is safe and feasible but does not result in a profound cytogenetic response.

Myelodysplastic syndrome

5q- syndrome Since at least 1974, the deletion in the long arm of chromosome 5 has been known to be associated with dysplastic abnormalities of hematopoietic stem cells. By 2005, lenalidomide, a chemotherapy drug, was recognized to be effective in MDS patients with the 5q- syndrome, and in December 2005, the US FDA approved the drug for this indication. Patients with isolated 5q-, low IPSS risk, and transfusion dependence respond best to lenalidomide. Typically, prognosis for these patients is favorable, with a 63-month median survival. Lenalidomide has dual action, by lowering the malignant clone number in patients with 5q-, and by inducing better differentiation of healthy erythroid cells, as seen in patients without 5q deletion. Splicing factor mutations Mutations in splicing factors have been found in 40–80% of cases with myelodysplastic syndrome, particularly in those with ringed sideroblasts.

How we manage adults with myelodysplastic syndrome.

The prognosis in Myelodysplastic syndromes (MDS), although recently refined by molecular studies, remains largely based on conventional prognostic scores [International Prognostic Scoring System (IPSS), revised IPSS], classifying patients into "lower risk" MDS (LR-MDS) and "higher risk" MDS (HR-MDS). In LR-MDS, treatment mainly aims at improving cytopenias, principally anaemia, while in HR-MDS it aims at delaying disease progression and prolonging survival. In LR-MDS without deletion 5q, anaemia is generally treated first by erythropoietic stimulating factors, while second line treatments are currently not approved [lenalidomide, hypomethylating agents (HMA), luspatercept] or rarely indicated (antithymocyte globulin). Lenalidomide has major efficacy in LR-MDS with deletion 5q. Allogeneic stem cell transplantation (allo-SCT) is sometimes considered in LR-MDS, and iron chelation can be considered when multiple red blood cell transfusions are required. Allo-SCT is the only potentially curative treatment for HR-MDS; however, it is rarely applicable. It is generally preceded by intensive chemotherapy (IC) or HMA in patients with excess of marrow blasts (especially if >10%). In other patients, HMA can improve survival. The role of new drugs, including venetoclax or, in case of specific mutations, IDH1 or IDH2 inhibitors, is investigated. IC is mainly indicated as a bridge to allo-SCT, in the absence of unfavourable karyotype.

[Myelodysplastic syndromes].

Myelodysplastic syndrome (MDS) encompasses a heterogeneous group of diseases originating in hematopoietic stem cells and is characterized by inefficient hematopoiesis and dysplastic changes in the bone marrow. In peripheral blood patients show anemia (mostly macrocytic), frequently accompanied by neutropenia and thrombocytopenia. Thus, clinically the patients suffer from fatigue (anemia), increased bleeding (thrombocytopenia) and infectious complications (neutropenia). Approximately one quarter of MDS patients develop acute myeloid leukemia (AML) in the course of the disease, which is characterized by a 20 % or more increase of blasts in the bone marrow. The estimated overall survival as well as the risk for AML transformation can be calculated with the international prognostic scoring system (IPSS) as well as the revised IPSS score (IPSS-R). Novel sequencing methods (e.g. next generation sequencing) allow the detection of recurrent gene mutations in MDS patients. Genes of the splicing machinery as well as genes involved in epigenetic regulation (e.g. ASXL1 and TET2) are most frequently mutated in MDS. Therapy is selected based on the patient risk profile (IPSS). Allogeneic stem cell transplantation is a curative approach for high risk patients (i.e. IPSS int-2 and higher) with a good performance status and a biological age below 70 years. Otherwise, high risk patients are treated with demethylating agents (e.g. decitabine and azacitidine). Low risk patients (IPSS low and int-1) mainly receive supportive therapy including iron chelation. An exceptional position is presented by MDS with an isolated 5q deletion as it can be treated with lenalidomide with good success. Enrolling patients in clinical trials is strongly recommended to improve the prospects of this disease.

[Lenalidomide treatment in myelodysplastic syndrome with 5q deletion--Czech MDS group experience].

Myelodysplastic syndrome (MDS) is a common hematological disease in patients over sixty. Despite intensive research, the therapy of this heterogeneous blood disease is complicated. In recent years, two new therapeutic approaches have been proposed: immunomodulation and demethylation therapy. Immunomodulation therapy with lenalidomide represents a meaningful advance in the treatment of anemic patients, specifically those with 5q- aberrations. As much as 60-70% of patients respond and achieve transfusion independence. We present the initial lenalidomide experience of the Czech MDS group. We analyze Czech MDS register data of 34 (31 female; 3 male; median age 69 years) chronically transfused low risk MDS patients with 5q- aberration treated by lenalidomide. Twenty-seven (79.4%) patients were diagnosed with 5q- syndrome, 5 patients with refractory anemia with multilineage dysplasia, 1 patient with refractory anemia with excess of blasts 1, and 1 patient with myelodysplastic/myeloproliferative unclassified. Response, as represented by achieving complete transfusion independence, was achieved in 91% of patients. A true 5q- syndrome diagnosis in most our patients may be responsible for such a high response rate. Complete cytogenetic response was reached in 15% of patients and partial cytogenetic response in 67%, within a median time of 12 months. TP53 mutation was detected in 15% (3 from 18 tested) and 2 of these patients progressed to higher grade MDS. The majority of patients tolerated lenalidomide very well. Based on this albeit small study, we present our findings of high lenalidomide efficacy as well as the basic principles and problems of lenalidomide therapy.

Myelodysplastic syndromes: diagnosis, prognosis, and treatment.

Myelodysplastic syndromes (MDS) are malignant stem-cell diseases that are usually diagnosed in elderly patients who present with anemia or, less commonly, bi- or pancytopenia. Their incidence in persons over age 80 is above 50 new cases per 100,000 persons per year. Their clinical course is highly variable. About one-quarter of all patients with MDS develop acute leukemia. The median survival time from the moment of diagnosis is about 30 months. We selectively searched the PubMed database for pertinent articles and guidelines from the years 2000-2013. We used the search term "myelodysplastic syndromes." MDS are diagnosed by cytology, with consideration of the degree of dysplasia and the percentage of blast cells in the blood and bone marrow, and on a cytogenetic basis, as recommended in the WHO classification. In particular, chromosomal analysis is necessary for prognostication. The Revised International Prognosis Scoring System (IPSS-R) enables more accurate prediction of the course of disease by dividing patients into a number of low- and high-risk groups. The median survival time ranges from a few months to many years. The approved treatments, aside from transfusion therapy, include iron depletion therapy for low-risk patients, lenalidomide for low-risk patients with a deletion on the long arm of chromosome 5, and 5-azacytidine for high-risk patients. High-risk patients up to age 70 who have no major accompanying illnesses should be offered allogenic stem-cell transplantation with curative intent. The cure rates range from 30% to 50%. Mucositis, hemorrhages, infections, and graft-versus-host diseases are the most common complications of this form of treatment. Myelodysplastic syndromes are treated on an individualized, risk-adapted basis after precise diagnostic evaluation and after assessment of the prognosis. More studies are needed so that stage-adapted treatment can be improved still further.

Practical recommendations on the use of lenalidomide in the management of myelodysplastic syndromes.

Lenalidomide, an oral immunomodulatory agent, has received approval in the USA from the Food and Drug Administration (FDA) for the management of myelodysplastic syndromes (MDS) classified by the International Prognostic Scoring System (IPSS) as low risk or intermediate-1 risk and with a deletion 5q (del(5q)) cytogenetic abnormality. Although some patients with del(5q) have a relatively good prognosis, all del(5q) patients will become transfusion-dependent at some point during the course of their disease. The results of two clinical trials in more than 160 patients with MDS have demonstrated clear therapeutic benefits of lenalidomide, with >60% of patients achieving independence from transfusion during therapy, irrespective of age, prior therapy, sex, or disease-risk assessment. The recommendations presented in this review will aid the safe administration of lenalidomide for the treatment of patients with low-risk or intermediate-1-risk MDS and a del(5q) cytogenetic abnormality, and they will help physicians avoid unnecessary dose reduction or interruption, thus assuring the best efficacy for patients.

Polish experience of lenalidomide in the treatment of lower risk myelodysplastic syndrome with isolated del(5q).

Lenalidomide has been approved for the treatment of lower-risk myelodysplastic syndrome (MDS) with 5q deletion (del(5q)). We present for the first time a retrospective analysis of low-risk MDS with isolated del5q treated with lenalidomide, outside the clinical trials. 36 red blood cell (RBC) transfusion-dependent patients have been included in the study. Patients received lenalidomide 10 mg/day on days 1-21 of 28-day cycles. 91.7 % of patients responded to lenalidomide treatment: 72.2 % achieved erythroid response, 19.4 % achieved minor erythroid response and 8.4 % of patients did not respond to treatment. Response depended on number of previous treatment lines (p = 0.0101), International Prognostic System Score (IPSS; p = 0.0067) and RBC transfusion frequency (p = 0.0139). Median duration of response was 16 months (range 6-60 months). Treatment was well tolerated. We observed hematological toxicity (grade 3 and 4): neutropenia in 16 (44.4 %) patients and thrombocytopenia in 9 (25 %) patients. Two patients (5.5 %) progressed to high-risk MDS and two subsequent progressed to acute myeloid leukemia. A Kaplan-Meier estimate for overall survival at 5 years in the study group was 79.0 ± 8.8 %. Lenalidomide in this group of patients was beneficial for the treatment of RBC transfusion-dependency with well-known safety profile.

Clinical management of myelodysplastic syndromes with interstitial deletion of chromosome 5q.

Deletions of the long (q) arm of chromosome 5 [del(5q)]occur in patients with myelodysplastic syndromes (MDS) including, but not limited to, those who meet the WHO definition of the 5q- syndrome. Del(5q) MDS patients frequently have symptomatic anemia, and its treatment has traditionally consisted of RBC transfusions and, for some, iron chelation therapy. Erythropoietin, darbepoetin, hypomethylating agents, and lenalidomide can enhance erythropoiesis in MDS patients with anemia, increasing hemoglobin levels and abrogating RBC transfusion requirements. Lenalidomide is particularly active in treating the anemia of del(5q) MDS, which is especially relevant given the low response rate to erythropoietin in this group of patients. In a recent study of 43 MDS patients, 10 of 12 patients (83%) with del(5q) MDS achieved sustained RBC transfusion independence (or a > 2 g/dL increase in hemoglobin), compared with 57% of those with a normal karyotype and 12% of those with other karyotypic abnormalities. Complete cytogenetic remissions were achieved in 75% (nine of 12) of the del(5q) MDS patients, suggesting that lenalidomide targets a fundamental pathogenetic feature of MDS that is more pronounced in the presence of chromosomal 5q deletions. This review highlights some issues about the classification and treatment of del(5q) MDS.

Lenalidomide for del(5q) and non-del(5q) myelodysplastic syndromes.

Lenalidomide leads to high rates of erythroid transfusion independence in low and intermediate-1 risk International Prognostic Scoring System (IPSS) del(5q) myelodysplastic syndromes (MDS), with a considerable number of patients achieving complete and partial cytogenetic remissions. The median duration of transfusion independence is 2 years, mainly at the expense of neutropenia and thrombocytopenia in the first courses of therapy. At present, the optimal initial treatment dose has been determined to be 10 mg administered orally daily for 21 out of 28 days. In general, the effects in non-del(5q) disease can be divided by 50%: non-del(5q) patients show 50% of erythroid response, 50% of duration of response, and 50% incidence of grade 3 and 4 neutropenia and thrombocytopenia compared to del(5q) patients. Recent data suggest that the risk of acute myeloid leukemia (AML) progression of del(5q) patients is dependent on their individual risk factors before treatment initiation, including World Health Organization (WHO) prognostic scoring system parameters and TP53 mutations. These data also indicate that lenalidomide per se is not leukemogenic. Length of treatment can be tailored according to response, and patients who relapse during treatment might restart after a period of drug holiday. This article will also discuss combination strategies with lenalidomide in higher risk disease.

Chromosome 5q deletion syndrome

Diagnosis Treatment Lenalidomide has activity in 5q- syndrome and is FDA approved for red blood cell (RBC) transfusion-dependent anemia due to low or intermediate-1 (int-1) risk myelodysplastic syndrome (MDS) associated with chromosome 5q deletion with or without additional cytogenetic abnormalities. There are several possible mechanisms that link the haploinsufficiency molecular lesions with lenalidomide sensitivity. Prognosis Most affected people have a stable clinical course but are often transfusion dependent. References External links Myeloid neoplasia Rare syndromes Autosomal monosomies and deletions Syndromes affecting blood

Outcomes in RBC transfusion-dependent patients with Low-/Intermediate-1-risk myelodysplastic syndromes with isolated deletion 5q treated with lenalidomide: a subset analysis from the MDS-004 study.

A subset analysis of the randomised, phase 3, MDS-004 study to evaluate outcomes in patients with International Prognostic Scoring System (IPSS)-defined Low-/Intermediate (Int)-1-risk myelodysplastic syndromes (MDS) with isolated del(5q). Patients received lenalidomide 10 mg/d (days 1-21; n = 47) or 5 mg/d (days 1-28; n = 43) on 28-d cycles or placebo (n = 45). From the placebo and lenalidomide 5 mg groups, 84% and 58% of patients, respectively, crossed over to lenalidomide 5 or 10 mg at 16 wk, respectively. Rates of red blood cell-transfusion independence (RBC-TI) ≥182 d were higher in the lenalidomide 10 mg (57.4%; P < 0.0001) and 5 mg (37.2%; P = 0.0001) groups vs. placebo (2.2%). Cytogenetic response rates (major + minor responses) were 56.8% (P < 0.0001), 23.1% (P = 0.0299) and 0%, respectively. Two-year cumulative risk of acute myeloid leukaemia progression was 12.6%, 17.4% and 16.7% in the lenalidomide 10 mg, 5 mg, and placebo groups, respectively. In a 6-month landmark analysis, overall survival was longer in lenalidomide-treated patients with RBC-TI ≥182 d vs. non-responders (P = 0.0072). The most common grade 3-4 adverse event was myelosuppression. These data support the clinical benefits and acceptable safety profile of lenalidomide in transfusion-dependent patients with IPSS-defined Low-/Int-1-risk MDS with isolated del(5q).

Peripheral blood cytogenetics allows treatment monitoring and early identification of treatment failure to lenalidomide in MDS patients: results of the LE-MON-5 trial.

Transfusion-dependent patients with low- or intermediate-1-risk myelodysplastic syndrome, <5% bone marrow (BM) blasts and isolated 5q-deletion received lenalidomide within the German MDS study group phase-II clinical trial LE-MON-5 (EudraCT:2008-001866-10) of the University of Duesseldorf, Germany. Cytogenetic monitoring was performed by chromosome banding analyses (CBA) of BM cells and fluorescence in situ hybridization (FISH) analyses of peripheral blood (PB) mononuclear CD34+ cells using extended probe panels. Out of 144 patients screened for study enrollment, 24% failed to meet inclusion criteria due to cytogenetic findings. Eighty-seven patients were followed with a median observation time of 30 months. Cytogenetic response detected by FISH and CBA in 74 and 66% of patients, respectively, was predictive for hematologic response as well as of high prognostic relevance. After 2 years, AML rate was 8% for all patients. Karyotype evolution was detected in 21 (FISH)-34% (CBA) of patients associated with significantly shorter AML-free survival. Disease progression was first detectable on the cytogenetic level on average 5-6 months before recurrence of transfusion dependence. Our data show for the first time in a prospective setting that a cytogenetic monitoring from the PB helps to early identify treatment failure and progressive disease in lenalidomide-treated patients to improve clinical management. EudraCT:2008-001866-10.

Myelodysplastic syndromes: 2018 update on diagnosis, risk-stratification and management.

The myelodysplastic syndromes (MDS) are a very heterogeneous group of myeloid disorders characterized by peripheral blood cytopenias and increased risk of transformation to acute myelogenous leukemia (AML). MDS occurs more frequently in older males and in individuals with prior exposure to cytotoxic therapy. Diagnosis of MDS is based on morphological evidence of dysplasia upon visual examination of a bone marrow aspirate and biopsy. Information obtained from additional studies such as karyotype, flow cytometry or molecular genetics is usually complementary and may help refine diagnosis. Prognosis of patients with MDS can be calculated using a number of scoring systems. In general, all these scoring systems include analysis of peripheral cytopenias, percentage of blasts in the bone marrow and cytogenetic characteristics. The most commonly used system is probably the International Prognostic Scoring System (IPSS). IPSS is now replaced by the revised IPSS-R score. Although not systematically incorporated into new validated prognostic systems, somatic mutations can help define prognosis and should be considered as new prognostic factors. Therapy is selected based on risk, transfusion needs, percent of bone marrow blasts and cytogenetic and mutational profiles. Goals of therapy are different in lower risk patients than in higher risk. In lower risk, the goal is to decrease transfusion needs and transformation to higher risk disease or AML, as well as to improve survival. In higher risk, the goal is to prolong survival. Current available therapies include growth factor support, lenalidomide, hypomethylating agents, intensive chemotherapy and allogeneic stem cell transplantation. The use of lenalidomide has significant clinical activity in patients with lower risk disease, anemia and a chromosome 5 alteration. 5-azacitidine and decitabine have activity in both lower and higher-risk MDS. 5-azacitidine has been shown to improve survival in higher risk MDS. A number of new molecular lesions have been described in MDS that may serve as new therapeutic targets or aid in the selection of currently available agents. Additional supportive care measures may include the use of prophylactic antibiotics and iron chelation. At the present time there are no approved interventions for patients with progressive or refractory disease particularly after hypomethylating based therapy. Options include participation in a clinical trial or cytarabine based therapy and stem cell transplantation.

Lenalidomide

Myelodysplastic syndromes Lenalidomide was approved by the FDA on 27 December 2005 for patients with low- or intermediate-1-risk myelodysplastic syndromes who have chromosome 5q deletion syndrome (5q- syndrome) with or without additional cytogenetic abnormalities. It was approved on 17 June 2013 by the European Medicines Agency for use in patients with low- or intermediate-1-risk myelodysplastic syndromes who have 5q- deletion syndrome but no other cytogenetic abnormalities and are dependent on red blood cell transfusions, for whom other treatment options have been found to be insufficient or inadequate. Mantle cell lymphoma Lenalidomide is approved by FDA as a specialty drug requiring a specialty pharmacy distribution for mantle cell lymphoma in patients whose disease has relapsed or progressed after at least two prior therapies, one of which must have included the medicine bortezomib.

Myelodysplastic syndrome

Agents have been approved by the U.S. Food and Drug Administration (FDA) for the treatment of MDS: 5-azacytidine: 21-month median survival Decitabine: Complete response rate reported as high as 43%. A phase I study has shown efficacy in AML when decitabine is combined with valproic acid. Lenalidomide: Effective in reducing red blood cell transfusion requirement in patients with the chromosome 5q deletion subtype of MDS Decitabine/cedazuridine (Inqovi) is a fixed-dosed combination medication for the treatment of adults with myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML).

Short- and long-term benefits of lenalidomide treatment in patients with lower-risk del(5q) myelodysplastic syndromes.

The treatment of patients with myelodysplastic syndromes (MDS) begins with assessment of karyotype and risk. Lenalidomide is approved for the treatment of patients who have transfusion-dependent anemia due to lower-risk MDS with chromosome 5q deletion (del(5q)) with or without additional cytogenetic abnormalities, and isolated del(5q) only in the European Union. Mounting evidence suggests that lenalidomide is effective not only in reducing red blood cell (RBC) transfusion burden, but also in modifying the disease natural history by suppressing the malignant clone. Data discussed here from the pivotal phase 2 (MDS-003) and phase 3 (MDS-004) studies of lenalidomide demonstrate that lenalidomide treatment was associated with both short- and long-term benefits. These clinical benefits included high rates of RBC-transfusion independence (TI) with prolonged durations of response, high rates of cytogenetic response (CyR) associated with achievement of durable RBC-TI, no significant difference in rates of progression to acute myeloid leukemia (AML), and improvements in health-related quality of life (HRQOL). Achievement of RBC-TI and CyR with lenalidomide treatment was associated with extended survival and time to AML progression. Achievement of RBC-TI and hemoglobin response was additionally associated with HRQOL benefits. Recent data describing the impact of TP53 mutations and p53 expression on the prognosis of patients with del(5q) and the impact on response to lenalidomide are also discussed. The authors provide practical recommendations for the use of lenalidomide in patients with lower-risk del(5q) MDS.

Myelodysplastic syndrome

Indicators of a poor prognosis: Advanced age; severe neutropenia or thrombocytopenia; high blast count in the bone marrow (20–29%) or blasts in the blood; Auer rods; absence of ringed sideroblasts; abnormal localization or immature granulocyte precursors in bone marrow section; completely or mostly abnormal karyotypes, or complex marrow chromosome abnormalities and in vitro bone marrow culture with a leukemic growth pattern Karyotype prognostic factors: Good: normal, -Y, del(5q), del(20q) Intermediate or variable: +8, other single or double anomalies Poor: complex (>3 chromosomal aberrations); chromosome 7 anomalies The IPSS is the most commonly used tool in MDS to predict long-term outcome. Cytogenetic abnormalities can be detected by conventional cytogenetics, a FISH panel for MDS, or virtual karyotype.

Virtual karyotype

Correlation of prognosis with bone marrow cytogenetic finding in acute lymphoblastic leukemia Unclassified ALL is considered to have an intermediate prognosis. Myelodysplastic syndrome Myelodysplastic syndrome (MDS) has remarkable clinical, morphological, and genetic heterogeneity. Cytogenetics play a decisive role in the World Health Organization's classification-based International Prognostic Scoring System (IPSS) for MDS. Good Prognosis: normal karyotype, isolated del(5q), isolated del(20q), -Y Poor Prognosis: complex abnormalities (i.e., >=3 abnormalities), −7 or del(7q) Intermediate Prognosis: all other abnormalities, including trisomy 8 and del(11q) In a comparison of metaphase cytogenetics, FISH panel, and SNP array karyotyping for MDS, it was found that each technique provided a similar diagnostic yield. No single method detected all defects, and detection rates improved by ~5% when all three methods were used.

Treatment of the 5q- syndrome.

Defined by isolated del 5q and no excess of marrow blasts, the "5q- syndrome" is a specific type of myelodysplastic syndrome (MDS) with particular characteristics, including severe anemia, frequent thrombocytosis, typical dysmegakaryopoiesis and favorable outcome. Its pathogenesis remains uncertain, in particular the role of inactivation of gene(s) situated in 5q. It should be differentiated from other MDS with del 5q having an excess of marrow blasts and/or additional cytogenetic abnormalities, which carry a poor prognosis. Until the advent of lenalidomide, repeated RBC transfusions were generally the only treatment of the 5q- syndrome, which was resistant to other therapeutic approaches. Lenalidomide can lead to RBC transfusion independence in at least two thirds of cases of the 5q- syndrome, two thirds of those responses persisting after 2 years of treatment. Importantly, not only reversal of anemia but also frequent complete pathological and cytogenetic responses are obtained. Grade 3 or 4 neutropenia and thrombocytopenia, especially during the first 6 to 8 weeks of treatment, are the major side effect of lenalidomide, justifying close monitoring of blood counts and regular patient visits. Preliminary results suggest that lenalidomide is also very active in MDS with del 5q other than the 5q-syndrome. Although its mechanism of action remains uncertain, lenalidomide appears to target specifically the del 5q clone. By doing this, lenalidomide may have an effect on disease course and survival, which is currently being assessed in clinical trials.

Myelodysplastic syndromes associated with interstitial deletion of chromosome 5q: clinicopathologic correlations and new insights from the pre-lenalidomide era.

To better estimate prognosis for patients with myelodysplastic syndromes (MDS) associated with clonal interstitial deletions of the long arm of chromosome 5 (del(5q)), we reviewed the medical records of 130 adults with del(5q) MDS seen at our institution over a 15-year period. Overall median survival of this cohort was 9.5 months, shorter than reported in earlier series. The least favorable outcomes are associated with complex cytogenetics, lack of any normal metaphases, normocytic rather than macrocytic erythrocyte indices, and low baseline lymphocyte counts. Lymphopenia but not neutropenia at the time of diagnosis appears to be a new adverse prognostic indicator. Cytogenetic breakpoints defined by G-banded karyotyping correlate poorly with particular disease features. Surprisingly, survival of patients with treatment-related MDS was equivalent to that of de novo MDS with del(5q) in this series. Morphologic features associated with del(5q) are diverse. Most patients with del(5q) MDS do not meet criteria for WHO-defined 5q-syndrome, and the presence of del(5q) does not appear to modify the clinical phenotype otherwise risk-stratified by the International Prognostic Scoring System (IPSS). Additional important prognostic factors not taken into account by the IPSS include the baseline erythrocyte indices, lymphocyte count, and clonal burden.

[Analysis of Cytogenetic Characteristics and Clinical Prognosis in 236 Patients with Myelodysplastic Syndrome].

To investigate the relationship of cytogenetic features, clinical characteristics and prognosis in patients with myelodysplastic syndrome. The clinical characteristics and prognosis of 236 patients with MDS admitted to the Affiliated Hospital of Xuzhou Medical University from January 2013 to September 2017 were analyzed retrospectively, the follow-up observation and correlation analysis were performed. There were 33 cases of refractory cytopenia with unilateral dysplasia (RCUD), 8 cases of refractory anemia with ring-shaped iron granulocytes (RARS), 70 cases of refractory cytopenia with multiple dysplasia (RCMD), 23 cases of refractory anemia (RA), 46 cases of refractory anemia with excessive blasts (RAEB-1), 48 cases of (RAEB-2), MDS-U 2 cases, simple del(5q) 6 cases. The detection analysis showed that the chromosome abnormality rate and complex chromosome abnormality rate in RAEB group (RAEB-1 + RAEB-2) and in non-RAEB group (RARS+RCMD+RCUD+RA) were 48.94% vs 43.94%, and 18.09% vs 12.69%, respectively, which were no statistically different. The grouping according to IPSS-R and IPSS showed that the chromosome abnormality rate gradually increased along with enhancement of risk stratifi-cation (P<0.05). The cytogenetic characteristics analysis showed that a total of 108 cases had chromosomal abnormalities, the detection rate was 45.76%, Out of 108 cases, 36 cases had complicated karyotypes, accounted for 15.25% of all patients. The types of chromosomal abnormalities mainly include numbers, structural abnormalities and mixed abnormalities. The chromosome abnormality with the highest detection rate was +8, accounted for 30.56% (33/100) of patients with chromosome abnormalities; followed by -7/7q-, del(5q), del(20q), etc. -7/7q-chromosome abnormalities accounted for 29.63% of all karyotypic abnormalities (including -7/7q-chromosome abnormalities alone and other chromosome abnormalities). The median age of the patients with MDS was 61 (13-88) years old, and the male-female ratio was 1.36∶1. Analysis of blood cell characteristics showed that the three lines were reduced or increased to varying degrees. The median WBC count was 2.8 (0.3-267.1)×10<sup9</sup/L, the median Hb level was 69 (20-156) g/L, and the median Plt count was 55 (2-1733)×10<sup9</sup/L. The 1 year OS rate in 32 cases of chromosome 7 abnormality and 128 cases of normal chromosome was 25% and 44.53%, respectively, the difference was statistically significant (χ<sup2</sup=4.05, P<0.05) . Chromosome karyotype is an independent factor affecting the prognosis of patients with MDS. It is important for the diagnosis, treatment and prognosis evalnation of patients with MDS. The overall prognosis of patients with abnormal chromosome 7 is poor. .

Myelodysplastic syndromes current treatment algorithm 2018.

Myelodysplastic syndromes (MDS) include a group of clonal myeloid neoplasms characterized by cytopenias due to ineffective hematopoiesis, abnormal blood and marrow cell morphology, and a risk of clonal evolution and progression to acute myeloid leukemia (AML). Because outcomes for patients with MDS are heterogeneous, individual risk stratification using tools such as the revised International Prognostic Scoring System (IPSS-R) is important in managing patients-including selecting candidates for allogeneic hematopoietic stem cell transplantation (ASCT), the only potentially curative therapy for MDS. The IPSS-R can be supplemented by molecular genetic testing, since certain gene mutations such as TP53 influence risk independent of established clinicopathological variables. For lower risk patients with symptomatic anemia, treatment with erythropoiesis-stimulating agents (ESAs) or lenalidomide (especially for those with deletion of chromosome 5q) can ameliorate symptoms. Some lower risk patients may be candidates for immunosuppressive therapy, thrombopoiesis-stimulating agents, or a DNA hypomethylating agent (HMA; azacitidine or decitabine). Among higher risk patients, transplant candidates should undergo ASCT as soon as possible, with HMAs useful as a bridge to transplant. Non-transplant candidates should initiate HMA therapy and continue if tolerated until disease progression. Supportive care with transfusions and antimicrobial drugs as needed remains important in all groups.

Spectrum of Myelodysplastic Syndrome in Patients Evaluated for Cytopenia(s). A Report from a Reference Centre in Saudi Arabia.

Myelodysplastic syndrome (MDS) is a clonal disorder of hematopoietic stem cells, characterized by ineffective hematopoiesis, peripheral cytopenias along with hypercellularity of the bone marrow, and marked dysplastic features. Establishing MDS diagnosis is difficult due to nonspecific clinical presentation and imprecise morphological criteria. In anticipation to improve the diagnostic approach in this field, we aimed to characterize the clinical and morphological features of patients presented with cytopenias with a special focus on MDS. We comprehensively reviewed all medical record of patients who were referred to the hematology laboratory at KFSH-RC, Riyadh, Saudi Arabia, between January 2009 and March 2016 for evaluation of bone marrow aspirates and trephine biopsies due to severe and persistent cytopenia(s) to rule out MDS. A total of 183 patients, 155 adult and 28 pediatric, were identified. In the adult group, MDS was diagnosed in 82 (52.9%) patients, with a male-to-female (M:F) ratio of 1.6:1 and mean age at diagnosis of 50 years. According to the World Health Organization (WHO) 2017 criteria, MDS subtypes were as follows: MDS with single lineage dysplasia (SLD, 5%), MDS with ring sideroblasts and SLD (MDS-RS-SLD 7%), MDS with multilineage dysplasia (MDS-MLD 21%), MDS with deletion of chromosome 5q (MDS del(5q), 2%), MDS unclassifiable (MDS-U7%), hypoplastic MDS (h-MDS 4%), MDS with excess blasts-1 (MDS-EB1, 20%), MDS with excess blasts-2 (MDS-EB2, 28%), and therapy-related MDS (6%). Laboratory and morphological features were described. In both groups, cytogenetic abnormalities were classified according to the Revised International Prognostic Scoring System cytogenetic risk groups. In adults, the dominating cytogenetic abnormalities were monosomy 5 and monosomy 7 seen in 20.7% and 24.4% of patients, respectively. Peripheral cytopenia not due to MDS was diagnosed in 54 (34.8%) patients, with a mean age of 43 years and M:F ratio of 1:1. The cause of these cytopenias were as follows: bone marrow failure (BMF, 22%), peripheral destruction (20%), drug induced (20%), anemia of chronic disease (16%), B12 deficiency (7%), infection (7%), paroxysmal nocturnal hemoglobinuria (4%), idiopathic cytopenia of undetermined significance (2%), and idiopathic dysplasia of undetermined significance (2%). A definite diagnosis of MDS was not possible in 19 patients due to insufficient clinical data. In the pediatric group, MDS was diagnosed in 14/28 (50%) patients, with M:F ratio of 1.8:1 and mean age at diagnosis of 4 years. MDS subtypes (WHO 2017) in 14 patients were as follows: refractory cytopenia of childhood (RCC, 42.8%), MDS-EB1 (42.8%), and MDS-EB2 (14.2%). Laboratory and morphological features were described. The prevalent cytogenetic abnormality was monosomy 7 in six/14 (42.8%) patients. Cytopenias due to other causes were diagnosed in eight/28 patients (28.5%), with a mean age of 6.5 years and M:F ratio of 1.6:1. The causes of non-MDS related cytopenia were: congenital BMF (4 patients), peripheral destruction (2 patients), immune deficiency (1 patient), and viral infection (1 patient). A definite diagnosis of MDS could not be made in six/28 (21.4%) patients. MDS is the cause of cytopenia in a significant number of patients referred for evaluation of cytopenias, appears at younger age, and tends to be more aggressive than that reported in international studies. Anemia, dysplastic neutrophils in the peripheral blood, and dysplastic megakaryocytes in the bone marrow trephine biopsy are the most reliable features in distinguishing MDS from other alternative diagnoses.

Myelodysplastic Syndrome -- Prognosis

The prognosis of patients with MDS varies widely depending upon several characteristics, including cytogenetics and severity of cytopenias. Patients with 5q- generally have a much better prognosis compared to MDS with monosomy 7, for example. The International Prognostic Scoring System (IPSS) and revised IPSS (R-IPSS) are risk stratification systems clinicians use to guide treatment and the potential clinical course. These systems can be used in addition to a clinical patient assessment, including age and co-morbidities, to determine the best therapeutic options. The IPSS includes the percentage of blasts in the bone marrow, karyotype, and the number of cell lineages with cytopenias. Karyotypes with a good prognosis include normal karyotype -Y, deletion 5q, and deletion 20q. Poor risk karyotypes include complex cytogenetics (greater than 3 abnormalities) or chromosome 7 abnormalities. All other karyotypes are categorized as intermediate risk. Based on these findings, a score is calculated to determine a risk score of either low, intermediate-1, intermediate-2, or high risk. [8]

Lenalidomide treatment of myelodysplastic syndromes with chromosome 5q deletion: Results from the National Registry of the Italian Drug Agency.

The most typical cytogenetic aberration in myelodysplastic syndromes is del(5q), which, when isolated, is associated with refractory anaemia and good prognosis. Based on high rates of erythroid response and transfusion independence, Lenalidomide (LEN) became the standard treatment. This multi-centre study was designed to supplement Italian Registry data on LEN by addressing prescription, administration appropriateness, haematological and cytogenetic responses and disease evolution. MORE study was an observational, non-interventional, multi-centre, retrospective and prospective study. Cases were recruited from 45 Haematological Centres throughout Italy. Data were collected from the Italian National Registry for Lenalidomide administration and supplemented by a MORE data form. Data from 190/213 patients were analysed. In all, 149 had been diagnosed by conventional cytogenetics (GROUP A) and 41 only by FISH (GROUP B). Overall erythroid response was obtained in 92.8% of cases. Overall cytogenetic remission was achieved in 22.6% of cases. Disease progression occurred in 15.6% of cases. Clonal cytogenetic evolution characterised progression to AML but not to higher risk MDS. Erythroid response to Lenalidomide was similar in MDS with isolated del(5q) and with del(5q) plus one anomaly. Progression to AML or higher risk MDS showed different cytogenetic features.

Lenalidomide: a review of its use in patients with transfusion-dependent anaemia due to low- or intermediate-1-risk myelodysplastic syndrome associated with 5q chromosome deletion.

Lenalidomide (Revlimid(®)), a thalidomide analogue, is an orally administered second generation immunomodulator with anti-angiogenic, antineoplastic, anti-inflammatory and pro-erythropoietic properties. It is approved for the treatment of patients with transfusion-dependent anaemia due to International Prognostic Scoring System low- or intermediate-1-risk myelodysplastic syndrome (MDS) associated with either chromosome 5q deletion [del(5q)] with or without additional cytogenetic abnormalities (US, Japan and Switzerland etc.), or with an isolated del(5q) cytogenetic abnormality when other therapeutic options are insufficient or inadequate (EU) [featured indication]. In a randomized, double-blind, multicentre, registrational trial (MDS-004; n = 205) in this patient population, a significantly higher proportion of lenalidomide recipients than placebo recipients achieved red blood cell transfusion independence for ≥26 consecutive weeks (primary endpoint for efficacy) and cytogenetic responses. The erythroid response to lenalidomide was accompanied by an increase in the haemoglobin levels. These efficacy outcomes are generally consistent with those seen in an earlier noncomparative registrational trial (MDS-003; n = 148). In MDS-004, lenalidomide also significantly improved health-related quality of life compared with placebo at 12 weeks. Retrospective analyses that compared outcomes between lenalidomide-treated patients with low- or intermediate-1-risk del(5q) MDS and multicentre registry cohorts showed that lenalidomide treatment did not appear to increase the risk of progression to acute myeloid leukaemia. Lenalidomide had a manageable safety profile in the registrational trials, with ≤20 % of patients discontinuing treatment because of adverse events. The most common adverse events (incidence ≥20 %) occurring in lenalidomide recipients were thrombocytopenia and neutropenia, which were generally managed by dosage reductions and/or interruptions, and/or pharmacotherapy. Thus, lenalidomide is a useful option for the treatment of patients with transfusion-dependent anaemia due to low- or intermediate-1-risk del(5q) MDS, with or without additional cytogenetic abnormalities.

Patients with del(5q) MDS who fail to achieve sustained erythroid or cytogenetic remission after treatment with lenalidomide have an increased risk for clonal evolution and AML progression.

Lenalidomide consistently induces transfusion independence and complete cytogenetic response in patients with myelodysplastic syndromes with 5q deletion. Only limited information on long-term outcome is currently available. We performed a long-term follow-up analysis of 42 patients with low or intermediate risk myelodysplastic syndromes and 5q deletion treated with lenalidomide. At a median follow-up of 40 months, 58% of the patients achieved an erythroid response and 48% a cytogenetic response. Thirty-six percent of patients progressed into acute myeloid leukaemia. Most of them (87%) acquired chromosome aberrations in addition to the 5q deletion, i.e. underwent clonal evolution during leukaemogenesis. There were no clinical, cytological or cytogenetic markers at study entry that allowed prediction of increased risk of leukaemic transformation. However, erythroid and cytogenetic responders had a significantly decreased risk of progression to acute myeloid leukaemia (p = 0.001 and p = 0.009, respectively) compared to non-responders. Three and 5 years after study entry, the cumulative incidence of acute myeloid leukaemia for patients with a cytogenetic response was 10% and 21%, respectively, and for patients without cytogenetic response, it was 46% and 60%. Patients with del(5q) myelodysplastic syndromes without erythroid or cytogenetic remission after treatment with lenalidomide have a high risk for clonal evolution and acute myeloid leukaemia progression. In refractory, or relapsing, patients, genetic instability and clonal evolution seem to be the driving forces of leukaemic transformation. Regular follow-up investigations of del(5q) myelodysplastic syndrome patients treated with lenalidomide may help to identify patients requiring alternative treatment strategies.

Transfusion-dependent anemia

Prognosis Prognosis of MDS patients An International Prognostic Scoring System (IPSS) is specially designed to access the prognosis of myelodysplastic syndrome patients. Scores help to classify patients into low, intermediate-1, intermediate-2 and high risks based on their severity levels. Patients in the lower-risk group generally have a longer survival range of 3-8.8 years, comparing to only 0.8-1.6 years for high-risk patients. In general, the survival rate of transfusion-dependent anemia patients is increasing. This is due to the improvements in transfusion procedures, mature use of iron chelation therapies to reduce iron overloading, and more experiences in dealing with associated morbidities. References Transfusion reactions Anemias

Transfusion dependence development and disease evolution in patients with MDS and del(5q) and without transfusion needs at diagnosis.

Patients with isolated del(5q) and MDS are considered to have good prognosis as compared to other MDS subtypes. Most patients suffered of anemia and 50% of them required transfusions at diagnosis. It is known that for patients with MDS and del(5q) in transfusion dependence(TD), Lenalidomide is the first choice treatment. However, there are no data regarding natural evolution of anemia in patients diagnosed in MDS and del(5q) without TD, factors that may impact on the development of TD or disease outcome. In the present study we have performed a retrospective multicenter analysis on 83 patients with low-int 1 MDS and del(5q) without TD. During the study 61 patients became TD at a median of 1.7 years and only the Hb level 9 g/dL was associated with poorer TFS (p = 0.007) in the multivariate analysis. Among these 61 TD patients, 49 received treatment (19 Lenalidomide). Median follow up was 48 months, estimated OS at 2 and 5 year was 92% and 50% respectively. In the multivariate analysis for OS, platelets <100,000 mm(-3) and Lenalidomide treatment retained the statistical significant impact. LFS at 2 and 5 years was 86% and 73% respectively, and median time to sAML was 8.16 years (CI 95%: 6.05-10.27). In the multivariate analysis only thrombocytopenia retained statistical significance. In summary, this retrospective study show that level of Hb is an important parameter in order to determine the time until TD, it should be also stressed the importance of an early treatment in order to prevent TD development and shorter survival.

[Elderly patients with myelodysplastic syndrome with del 5q receiving lenalidomide: two case reports with poor prognosis].

We report two cases of myelodysplastic syndrome (MDS) with del(5q) isolated cytogenetic abnormality in elderly patients: AREB-1 in Patient 1, "5q syndrome" in Patient 2. A first line of treatment including hematopoietic growth factors (darbepoetin alone or associated with G-CSF) failed after several months and a treatment with lenalidomide was initiated in both cases. The treatment was poorly tolerated (myelosuppression) in Patient 1 without an improvement of the quality of life; a progression of the disease was observed with an increase of the bone marrow blastosis and a new acquired karyotypic abnormality (t13;17), leading to the prescription of 5-azacytidine. Patient 2 had a good response to lenalidomide for several months with an increase in the haemoglobin level and a transfusion independence. The patient's prognosis suddenly worsened with the occurrence of a blood blastosis (10%): 5-azacytidine was thus initiated. These two case reports illustrate the recent advances in the management of patients with MDS with del(5q), including the use of lenalidomide.

Diagnosis and therapy of myelodysplastic syndromes in Germany: a retrospective multicenter analysis.

Myelodysplastic syndromes (MDS) are a heterogenous group of clonal hematopoietic stem cell disorders. In order to assess current diagnosis and treatment patterns in Germany, the data of 269 patients with MDS from 57 representative centers were analyzed. The most common symptom leading to an initial diagnosis of MDS was anemia (79%). WHO classification, cytogenetic analysis, and IPSS scoring were performed in 92, 67, and 61% of patients, respectively. 5q deletions were identified in 34% of patients whose cytogenetic status was analyzed. Symptomatic anemia was the major trigger for initiating therapy. 49% of patients received supportive care only, and 49% received active therapy (i.e., chemo-, immunomodulatory, or epigenetic therapy), including 5% who received allogeneic transplantation. Of those patients treated with active therapy, approximately half of the higher-risk patients received azacitidine, and approximately half of the lower-risk patients received lenalidomide. Overall, 80% of patients received some form of supportive care, mainly red blood cell transfusions. While the WHO classification system is widely used in clinical practice, karyotyping and IPSS risk assessment do not seem to be common standard. Despite encouraging data on the use of effective and novel drugs, such as lenalidomide and azacitidine in MDS therapies, management of the disease could be further improved by more widespread use of risk stratification of patients using cytogenetics and IPSS assessment.


Blood gas analysis shows an acute respiratory acidosis, due to an increase in PCO2 of short evolution time because the kidney has not yet had time to retain bicarbonates (bicarbonate level at the high limit of normality). The patient is not hyperventilating but hypoventilating because PCO2 is elevated. The alveolar arterial oxygen gradient is altered since the patient has a normal PaO2, but because he has a high FiO2. If he were without oxygen, he would be hypoxemic. Respiratory acidosis below 7.20 is a reason to consider noninvasive mechanical ventilation acutely and in principle temporarily in a patient with severe COPD.

A patient with severe COPD comes to the ED with an acute onset and presents an arterial blood gas drawn with Fi02 of 31% at sea level with a Pa02 of 86 mm Hg, PaC02 65 mm Hg, pH 7.13 and Bicarbonate 27 mmol/liter. Which of the following statements is FALSE?

The alveolar arterial oxygen gradient is elevated.

Initiation of mechanical ventilation should be considered.

Respiratory acidosis

Diagnosis Diagnoses can be done by doing an ABG (Arterial Blood Gas) laboratory study, with a pH <7.35 and a PaCO2 >45 mmHg in an acute setting. Patients with COPD and other Chronic respiratory diseases will sometimes display higher numbers of PaCO2 with HCO3- >30 and normal pH. Terminology Acidosis refers to disorders that lower cell/tissue pH to < 7.35. Acidemia refers to an arterial pH < 7.36. See also Acidosis Alkalosis Arterial blood gas Chemical equilibrium pCO2 pH pKa Metabolic acidosis Metabolic alkalosis Respiratory alkalosis References External links Acid–base disturbances

Non-invasive ventilation

COPD The most common indication for acute non-invasive ventilation is for acute exacerbation of chronic obstructive pulmonary disease. The decision to commence NIV, usually in the emergency department, depends on the initial response to medication (bronchodilators given by nebulizer) and the results of arterial blood gas tests. If after medical therapy the lungs remain unable to clear carbon dioxide from the bloodstream (respiratory acidosis), NIV may be indicated. Many people with COPD have chronically elevated CO2 levels with metabolic compensation, but NIV is only indicated if the CO2 is acutely increased to the point that the acidity levels of the blood are increased (pH<7.35). There is no level of acidity above which NIV cannot be started, but more severe acidosis carries a higher risk that NIV alone is not effective and that mechanical ventilation will be required instead.

Acetazolamide Causes Worsening Acidosis in Uncompensated COPD Exacerbations: Increased Awareness Needed for Patient Safety.

Acetazolamide has been studied extensively in post-hypercapnic alkalosis as a tool to facilitate ventilator weaning in chronic obstructive pulmonary disease (COPD). It has also been utilized to facilitate respiratory drive in nonmechanically ventilated patients with COPD. Although this is generally a forgiving intervention, providers must carefully select patients for this medication, as it can cause severe acidosis and deterioration of clinical status in severe COPD cases. The present report describes two cases of patients who developed worsening acidosis and hypercapnia after receiving acetazolamide in acute respiratory failure. Case 1 was a 72-year-old obese male with COPD who was dependent on supplemental oxygen and presented to the emergency department (ED) with acute on chronic hypercapnic respiratory failure. He was given a one-time dose of acetazolamide in the ED for "respiratory failure made worse by severe metabolic alkalosis." His arterial blood gas (ABG) worsened overnight, accompanied by decreased mental status: pH 7.32, paCO<sub2</sub 82 mm Hg, paO<sub2</sub 50 mm Hg, HCO<sub3</sub 41.7 mmol/L, FiO<sub2</sub 32% to pH 7.21, paCO<sub2</sub 91.7 mm Hg, paO<sub2</sub 59 mm Hg, HCO<sub3</sub 36.6 mmol/L, and FiO<sub2</sub 32%. Case 2 was a 62-year-old male with COPD who was dependent on supplemental oxygen and presented to the ED with acute on chronic hypercapnic respiratory failure. He was given acetazolamide in the ED with similar results: ABG on presentation pH 7.37, paCO<sub2</sub 79.3 mm Hg, paO<sub2</sub 77.6 mm Hg, HCO<sub3</sub 45.5 mmol/L, and FiO<sub2</sub 32%. The next morning, ABG was pH 7.29, paCO<sub2</sub 79 mm Hg, paO<sub2</sub 77 mm Hg, HCO<sub3</sub 45.5 mmol/L, and FiO<sub2</sub 32%. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Acetazolamide given early in the uncompensated setting can worsen acidosis and potentiate clinical deterioration.

Respiratory acidosis

Types Respiratory acidosis can be acute or chronic. In acute respiratory acidosis, the PaCO2 is elevated above the upper limit of the reference range (over 6.3 kPa or 45 mm Hg) with an accompanying acidemia (pH <7.36). In chronic respiratory acidosis, the PaCO2 is elevated above the upper limit of the reference range, with a normal blood pH (7.35 to 7.45) or near-normal pH secondary to renal compensation and an elevated serum bicarbonate (HCO3− >30 mEq/L). Causes Acute Acute respiratory acidosis occurs when an abrupt failure of ventilation occurs. This failure in ventilation may be caused by depression of the central respiratory center by cerebral disease or drugs, inability to ventilate adequately due to neuromuscular disease (e.g., myasthenia gravis, amyotrophic lateral sclerosis, Guillain–Barré syndrome, muscular dystrophy), or airway obstruction related to asthma or chronic obstructive pulmonary disease (COPD) exacerbation.

Arterial blood gas test

In general, it is much easier to correct acute pH derangement by adjusting respiration. Metabolic compensations take place at a much later stage. However, in a critical setting, a person with a normal pH, a high CO2, and a high bicarbonate means that, although there is a high carbon dioxide level, there is metabolic compensation. As a result, one must be careful as to not artificially adjust breaths to lower the carbon dioxide. In such case, lowering the carbon dioxide abruptly means that the bicarbonate will be in excess and will cause a metabolic alkalosis. In such a case, carbon dioxide levels should be slowly diminished. See also Anion gap Radial artery puncture Chemical equilibrium Hemoximetry Arteriovenous oxygen difference References External links Online arterial blood gas calculator Diagnostic intensive care medicine Respiratory physiology Blood tests Respiratory therapy

Alveolar–arterial gradient

Because A–a gradient is approximated as: (150 − 5/4(P)) – at sea level and on room air (0.21x(760-47) = 149.7 mmHg for the alveolar oxygen partial pressure, after accounting for the water vapor), the direct mathematical cause of a large value is that the blood has a low , a low Pa, or both. is very easily exchanged in the lungs and low Pa directly correlates with high minute ventilation; therefore a low arterial Pa indicates that extra respiratory effort is being used to oxygenate the blood. A low indicates that the patient's current minute ventilation (whether high or normal) is not enough to allow adequate oxygen diffusion into the blood. Therefore, the A–a gradient essentially demonstrates a high respiratory effort (low arterial Pa) relative to the achieved level of oxygenation (arterial ). A high A–a gradient could indicate a patient breathing hard to achieve normal oxygenation, a patient breathing normally and attaining low oxygenation, or a patient breathing hard and still

Effect of acute bicarbonate administration on exercise responses of COPD patients.

Patients with severe chronic obstructive pulmonary disease (COPD) are limited in their exercise tolerance by the level of ventilation (VE) they can sustain. We determined whether acutely increasing blood bicarbonate levels decreased acid stimulation to the respiratory chemoreceptors during exercise, thereby improving exercise tolerance. Responses were compared with those obtained during 100% O2 breathing (known to reduce VE in these patients) and to the responses of healthy young subjects. Participants were six patients with severe COPD (forced expired volume in 1 s = 31 +/- 11% predicted) but without chronic CO2 retention and 5 healthy young subjects. Each subject performed three incremental cycle ergometer exercise tests: 1) control, 2) after ingestion of 0.3 g.kg-1 of sodium bicarbonate and 3) while breathing 100% O2. During these tests VE was measured continuously and arterialized venous blood (patients) or arterial blood (healthy subjects) was sampled serially to assess acid base variables. Bicarbonate loading increased standard bicarbonate by 4-6 mmol.L-1 and this elevation persisted during exercise. In both groups, bicarbonate loading resulted in a substantially higher arterial pH; arterial PCO2 was either unchanged (healthy subjects) or mildly (averaging 5 torr) higher (COPD patients). However, in neither group did bicarbonate loading result in an altered VE response to exercise or an increase in exercise tolerance. In contrast, superimposing hyperoxia on bicarbonate ingestion yielded, on average, 24% reduction in VE and 50% increase in peak work rate in the patients (but not in the healthy young subjects). We conclude that acute bicarbonate loading is not an ergogenic aid in patients with severe COPD.

Pulmonary gas pressures

The alveolar pO2 is not routinely measured but is calculated from blood gas measurements by the alveolar gas equation. Partial pressure of carbon dioxide Pathology The partial pressure of carbon dioxide, along with the pH, can be used to differentiate between metabolic acidosis, metabolic alkalosis, respiratory acidosis, and respiratory alkalosis. Hypoventilation exists when the ratio of carbon dioxide production to alveolar ventilation increases above normal values – greater than 45mmHg. If pH is also less than 7.35 this is respiratory acidosis. Hyperventilation exists when the same ratio decreases – less than 35mmHg. If the pH is also greater than 7.45 this is respiratory alkalosis. See also Alveolar-arterial gradient Diffusing capacity Pulmonary alveolus References Respiratory physiology

Arterial Blood Gas -- Results, Reporting, and Critical Findings

Example 1 [28] : ABG: pH = 7.39, PaCO 2 = 51 mm Hg, PaO 2 = 59 mm Hg, HCO 3 = 30 mEq/L and SaO 2 = 90%, on room air. pH is in the normal range, so use 7.40 as a cutoff point, in which case it is < 7.40, and acidosis is present. The elevated PaCO 2 indicates respiratory acidosis, and the elevated HCO 3 indicates a metabolic alkalosis. The value consistent with the pH is PaCO 2 . Therefore, this is a primary respiratory acidosis. The acid-base that is inconsistent with the pH is the elevated HCO3, indicating a metabolic alkalosis, so there is compensation signifying a non-acute primary disorder because it takes days for metabolic compensation to be effective. Last, the decreased PaO 2 indicates an abnormality with oxygenation. However, a history and physical will help delineate the severity and urgency of required interventions, if any. Example 2 [28] : ABG: pH = 7.45, PaCO 2 = 32 mm Hg, PaO 2 = 138 mm Hg, HCO 3 = 23 mEq/L, the base deficit = 1 mEq/L, and SaO 2 is 92%, on room air.

Intermittent short-term negative pressure ventilation and increased oxygenation in COPD patients with severe hypercapnic respiratory failure.

With the aim of testing a method that allows increasing concentrations of oxygen to be administered to patients with severe hypoxemia and hypercapnia while avoiding the risk of increasing respiratory acidosis, we studied 17 male patients with advanced chronic obstructive pulmonary disease (COPD) and severe hypercapnic respiratory failure. During 6 h and on one day only, all patients were given intermittent negative pressure ventilation (INPV) together with oxygenation starting at a concentration of 24 percent and increasing to 30 percent. Using this procedure, it was possible to raise arterial PaO2 to safe levels (from 47.2 +/- 3 mm Hg to 61.5 +/- 6 mm Hg, p less than 0.001) without increasing hypercapnia, and a significant drop in PaCO2 levels (from 74.4 +/- 9 mm Hg to 65.6 +/- 12 mm Hg, p less than 0.005) was even observed. One hour after INPV ended, the mean values of PaO2, PaCO2, oxygen saturation, and pH were also significantly better than prestudy values. We conclude that INPV and oxygen therapy with increasing oxygen flow could constitute an alternative option to intubation and mechanical ventilation in cases of severe hypercapnic respiratory failure due to advanced COPD.

Respiratory acidosis

In acute respiratory acidosis, compensation occurs in 2 steps. The initial response is cellular buffering (plasma protein buffers) that occurs over minutes to hours. Cellular buffering elevates plasma bicarbonate (HCO3−) only slightly, approximately 1 mEq/L for each 10-mm Hg increase in PaCO2. The second step is renal compensation that occurs over 3–5 days. With renal compensation, renal excretion of carbonic acid is increased and bicarbonate reabsorption is increased. For instance, PEPCK is upregulated in renal proximal tubule brush border cells, in order to secrete more NH3 and thus to produce more HCO3−. Estimated changes In renal compensation, plasma bicarbonate rises 3.5 mEq/L for each increase of 10 mm Hg in PaCO2. The expected change in serum bicarbonate concentration in respiratory acidosis can be estimated as follows:

Arterial blood gas test

Respiratory alkalosis (Pa CO2 < 35 mmHg) occurs when there is too little carbon dioxide in the blood. This may be due to hyperventilation or else excessive breaths given via a mechanical ventilator in a critical care setting. The action to be taken is to calm the person and try to reduce the number of breaths being taken to normalize the pH. The respiratory pathway tries to compensate for the change in pH in a matter of 2–4 hours. If this is not enough, the metabolic pathway takes place. Under normal conditions, the Henderson–Hasselbalch equation will give the blood pH where: 6.1 is the acid dissociation constant (pKa) of carbonic acid () at normal body temperature [] is the concentration of bicarbonate in the blood in mEq/L PaCO2 is the partial pressure of carbon dioxide in the arterial blood in mmHg

Arterial blood gases and pH during sleep in chronic obstructive pulmonary disease.

Arterial blood gases were measured during 7 hours of sleep in 15 patients with severe stable chronic obstructive pulmonary discrease (COPD); 6 awake patients with COPD studies in recumbency for an average of 5 hours served as controls. Mean maximal decrease in arterial oxygen partial pressure (PaO2) (plus or minus SD) was 13.5 plus or minus 3.9 mm Hg for sleeping patients (p less than 0.005) and 5.5 plus or minus 1.7 mm Hg for controls (p less than 0.1), respectively. Changes in pH during sleep were of the magnitude expected with acute changes in arterial carbon dioxide partial pressure (PaCO2) in patients with chronic hypercapnia. Consistent changes in heart rate, respiratory frequency or cardiac rhythm were not observed during sleep. Nocturnal worsening of hypoxemia could be explained by alveolar hypoventilation in six sleeping patients and in five controls; in nine sleeping patients, further impariment of ventilation-perfusion mismatch also contributed to worsening of hypoxemia. There was no relationship between the decrease in PaO2 during sleep and the degree of airways obstruction or the PaO2 level when awake. Because of low PaO2, when awake, a fall in PaO2 during sleep brings values into the steep part of the oxyhemoglobin dissociation curve where slight changes in PaO2 result in marked changes in oxygen content. All patients with COPD whose waking PaO2 was below 60 mm Hg had PaO2 below 50 mm Hg during sleep; nocturnal oxygen therapy should be considered in such patients, particularly in the presence of polycythemia or troublesome right-sided heart failure.

InternalMed_Harrison

Respiratory symptoms associated with acute hyperventilation can be the initial manifestation of systemic illnesses such as diabetic ketoacidosis. Causes of acute hyperventilation need to be excluded before a diagnosis of chronic hyperventilation is considered. Arterial blood gas sampling that demonstrates a compensated respiratory alkalosis with a near normal pH, low PaCO2, and low calculated bicarbonate is necessary to confirm chronic hyperventilation. Other causes of respiratory alkalosis, such as mild asthma, need to be diagnosed and treated before chronic hyperventilation can be considered. A high index of suspicion is required because increased minute ventilation can be difficult to detect on physical examination. Once chronic hyperventilation is established, a sustained 10% increase in alveolar ventilation is enough to perpetuate hypocapnia. This increase can be accomplished with subtle changes in the respiratory pattern, such as occasional sigh breaths or yawning two to three

Ventilator Management -- Clinical Significance -- Special Circumstances

COPD is a special case, as lungs in pure COPD have high compliance which causes a high tendency for dynamic airflow obstruction due to airway collapse and air trapping, making COPD patients very prone to developing auto-PEEP. Using a preventive ventilation strategy with high flow and low respiratory rate may help prevent auto-PEEP. Another important aspect to consider in chronic hypercapnic respiratory failure (due to COPD or another reason) is that there is no need to correct the CO2 back to normal, as these patients usually have a metabolic compensation for their respiratory problems. If a patient is ventilated to normal CO2 levels, his bicarbonate will decrease, and when a patient is extubated he will quickly go to respiratory acidosis as his kidneys cannot respond as fast as his lungs and his CO2 will go back to his baseline, causing respiratory failure and reintubation. To prevent this, CO2 goals should be determined based on pH and previously known or calculated baseline.

Acidosis

However, in cases where chronic illnesses that compromise pulmonary function persist, such as late-stage emphysema and certain types of muscular dystrophy, compensatory mechanisms will be unable to reverse this acidotic condition. As metabolic bicarbonate production becomes exhausted, and extraneous bicarbonate infusion can no longer reverse the extreme buildup of carbon dioxide associated with uncompensated respiratory acidosis, mechanical ventilation will usually be applied. Fetal respiratory acidemia In the fetus, the normal range differs based on which umbilical vessel is sampled (umbilical vein pH is normally 7.25 to 7.45; umbilical artery pH is normally 7.20 to 7.38). In the fetus, the lungs are not used for ventilation. Instead, the placenta performs ventilatory functions (gas exchange). Fetal respiratory acidemia is defined as an umbilical vessel pH of less than 7.20 and an umbilical artery PCO2 of 66 or higher or umbilical vein PCO2 of 50 or higher. See also

Respiratory alkalosis

Diagnosis The diagnosis of respiratory alkalosis is done via test that measure the oxygen and carbon dioxide levels (in the blood), chest x-ray and a pulmonary function test of the individual. The Davenport diagram allows clinicians or investigators to outline blood bicarbonate concentrations (and blood pH) after a respiratory or metabolic acid-base disturbance Classification There are two types of respiratory alkalosis: chronic and acute as a result of the 3–5 day delay in kidney compensation of the abnormality. Acute respiratory alkalosis occurs rapidly, have a high pH because the response of the kidneys is slow. Chronic respiratory alkalosis is a more long-standing condition, here one finds the kidneys have time to decrease the bicarbonate level. pH Alkalosis refers to the process due to which there is elevation of blood pH. Alkalemia refers to an arterial blood pH of greater than 7.45.

Partial Pressure of Carbon Dioxide -- Clinical Significance

There are differences in the acute and chronic stages of respiratory acidosis or alkalosis. Acute respiratory acidosis from increased PCO2 will result in immediate changes to serum bicarbonate levels due to the bicarbonate buffer system; however, this is limited in its ability to achieve homeostasis. The kidney will gradually increase the serum bicarbonate levels in chronic cases. Chronic respiratory acidosis is when the acidemia exists for 3 to 5 days, which is approximately how long it will take the kidney to buffer the acidemia. In acute respiratory acidosis, normally, the serum bicarbonate will increase by 1 mEq/L for every 10 mmHg increase in PCO2. For chronic respiratory acidosis, the serum bicarbonate will increase by 4 to 5 mEq/L for every 10 mmHg rise in PCO2. [6] [5] The result typically causes a mild chronic acidosis or low-normal pH near 7.35. [6] In regards to respiratory alkalosis, the same timeframe applies to acute versus chronic. In acute respiratory alkalosis, for every decrease in PCO2 by 10 mmHg, the serum bicarbonate will also decrease by 2 mEq/L. In chronic respiratory alkalosis, or alkalosis lasting 3 to 5 days, for every 10mmHg drop in PCO2, it is expected that serum bicarbonate will decrease by 4 to 5 mEq/L. [5] [6]

Respiratory acidosis

Acute respiratory acidosis: HCO3− increases 1 mEq/L for each 10 mm Hg rise in PaCO2. Chronic respiratory acidosis: HCO3− rises 3.5 mEq/L for each 10 mm Hg rise in PaCO2. The expected change in pH with respiratory acidosis can be estimated with the following equations: Acute respiratory acidosis: Change in pH = 0.08 X ((40 − PaCO2)/10) Chronic respiratory acidosis: Change in pH = 0.03 X ((40 − PaCO2)/10) Respiratory acidosis does not have a great effect on electrolyte levels. Some small effects occur on calcium and potassium levels. Acidosis decreases binding of calcium to albumin and tends to increase serum ionized calcium levels. In addition, acidemia causes an extracellular shift of potassium, but respiratory acidosis rarely causes clinically significant hyperkalemia. Diagnosis

Hypercapnia

In many people a high causes a feeling of shortness of breath, but the lack of this symptom is no guarantee that the other effects are not occurring. A significant percentage of rebreather deaths have been associated with CO2 retention. The effects of high can take several minutes to hours to resolve once the cause has been removed. Diagnosis Blood gas tests may be performed, typically by radial artery puncture, in the setting of acute breathing problems or other acute medical illness. Hypercapnia is generally defined as an arterial blood carbon dioxide level over 45 mmHg (6 kPa). Since carbon dioxide is in equilibrium with carbonic acid in the blood, hypercapnia drives serum pH down, resulting in respiratory acidosis. Clinically, the effect of hypercapnia on pH is estimated using the ratio of the arterial pressure of carbon dioxide to the concentration of bicarbonate ion, . Tolerance

Blood gas test

A blood gas test or blood gas analysis tests blood to measure blood gas tension values, it also measures blood pH, and the level and base excess of bicarbonate. The source of the blood is reflected in the name of each test; arterial blood gases come from arteries, venous blood gases come from veins and capillary blood gases come from capillaries. The blood gas tension levels of partial pressures can be used as indicators of ventilation, respiration and oxygenation. Analysis of paired arterial and venous specimens can give insights into the aetiology of acidosis in the newborn. Values measured

Base excess

Interpretation Base excess beyond the reference range indicates metabolic alkalosis if too high (more than +2 mEq/L) metabolic acidosis if too low (less than −2 mEq/L) Blood pH is determined by both a metabolic component, measured by base excess, and a respiratory component, measured by PaCO2 (partial pressure of carbon dioxide). Often a disturbance in one triggers a partial compensation in the other. A secondary (compensatory) process can be readily identified because it opposes the observed deviation in blood pH. For example, inadequate ventilation, a respiratory problem, causes a buildup of CO2, hence respiratory acidosis; the kidneys then attempt to compensate for the low pH by raising blood bicarbonate. The kidneys only partially compensate, so the patient may still have a low blood pH, i.e. acidosis. In summary, the kidneys partially compensate for respiratory acidosis by raising blood bicarbonate.

Respiratory CO2 response depends on plasma bicarbonate concentration in mechanically ventilated patients.

There is controversy about the effects of high plasma bicarbonate concentration ([HCO3(-)]) and the CO2 response test. We analyzed the relationship between [HCO3(-)] and the variation in hydrogen ion concentration (pH) for a given change in PaCO2, and its effects upon CO2 response. A retrospective study was carried out. Two intensive care units. Subjects with and without chronic obstructive pulmonary disease (COPD), at the beginning of weaning from mechanical ventilation. The CO2 response was evaluated by the re-inhalation of expired air method, measuring the hypercapnic ventilatory response (ΔVE/ΔPaCO2) and hypercapnic drive response (ΔP01/ΔPaCO2), where VE is minute volume and P0.1 is airway occlusion pressure 0.1s after the initiation of inspiration. [HCO3(-)] and CO2 response. A total of 120 patients in the non-COPD group and 48 in the COPD group were studied. COPD patients had higher mean [HCO3(-)] than non-COPD patients (33.2 ± 5.4 vs. 25.7 ± 3.7 mmol/l, p<0.001). In both non-COPD and COPD patients we observed a significant inverse linear relationship between [HCO3(-)] and pH change per mmHg of PaCO2 (p<0.001), ΔVE/ΔPaCO2 (p<0.001) and ΔP0.1/ΔPaCO2 (p<0.001). There is an inverse linear relationship between [HCO3(-)] and the variation of pH for a given change in PaCO2 and the CO2 response.

Comparison of arterial and venous blood gases analysis in patients with exacerbation of chronic obstructive pulmonary disease.

To investigate whether venous blood gases (VBG) test can be replace by an arterial blood gases (ABG) in exacerbation of chronic obstructive pulmonary disease (COPD). From October 2005 to March 2006, at the Emergency Room of Kashan Beheshti Hospital, the data of 107 patients with exacerbation of COPD were assessed. Arterial blood gases and VBG samples were obtained simultaneously, and indexes of pH, carbon dioxide partial pressure (PCO2), bicarbonate (HCO3), oxygen partial pressure (PO2) and Oxygen (O2) saturation level were analyzed. The mean +/- SD of indexes in ABG and VBG samples were as follows: pH = 7.37 +/- 0.47 versus 7.34 +/- 0.047; PCO2 = 53.88 +/- 7.63 mm Hg versus 59.55 +/- 8.96 mm Hg, HCO3= 30.66 +/- 4.49 mEq/L versus 31.94 +/- 4.39 mEq/L; PO2 = 55.37 +/- 11.19 mm Hg versus 43.08 +/- 10.54 mm Hg. The average difference between indexes in ABG and VBG samples were as follows: pH = 0.0241 +/- 0.004, p<0.001, r = 0.864; PCO2 = 5.673 +/- 1.126 mm Hg, p<0.001, r = 0.761; HCO3 = 1.279 +/- 0.604 mEq/L, p<0.001, r = 0.749; and PO2 = 12.294 +/- 2.115 mm Hg, p<0.001, r = 0.702. Venous blood gases, especially pH and PCO2 levels have relatively good correlation with ABG values. In view of the fact that, this correlation is not close, VBG cannot be substitute for ABG in exacerbation of COPD.

[Fallacies in arterial blood gas interpretation].

The arterial blood gas analysis (ABGA) is a valuable diagnostic tool in daily clinical practice. It yields information about oxygenation, ventilation and acid-base status. ABGAs should always be interpreted within a clinical context. If a result is absolutely not compatible with a clinical situation, the probe should be repeated or prompt further differential diagnoses. A probe should be free of air bubbles and be rapidly proceeded in the laboratory. Body temperature and fraction of inspired oxygen are mandatory prerequisites for adequate interpretation. With CO-oximetry, not only oxygenated hemoglobin but also carboxihemoglobin and met-hemoglobin content can be measured in the case of a suspected intoxication. For the assessment of ventilation, PaCO2 must be interpreted in the context of PaO2, as already a "normal value" of PaCO2 may indicate severe ventilator failure in a patient with hypoxemia. A normal pH does not exclude acid-base disorders, PaCO2 and bicarbonate must also be taken into account. When FIO2 is changed, steady state conditions must be awaited before a next control especially in the case of ventilation-perfusion mismatch, e. g. in COPD, pneumonia, pulmonary embolism. In a hypoxic state, immediate application of oxygen is warranted, in hypercapnia, ventilation should be increased. In acid-base disorders, treatment of the underlying disease is most often conducive.

Studies on the physiopathology of chronic obstructive pulmonary disease in the horse. IV. Blood gas and acid-base values at rest.

Radiometer Blood Micro-system 2 was used in studies designed to, (a) compare the mean blood gas and acid-base values of 38 normal horses and 20 horses with chronic obstructive pulmonary disease (COPD), (b) determine the means and standard deviations of blood gas and acid-base values of Thoroughbred horses in training, and (c) investigate the relationships between clinical data, blood gas values, intracardiac and pulmonary arterial pressures in subjects with COPD. There were significant differences between the mean values for partial pressure of arterial oxygen (PaO2), arterial carbon dioxide (PaCO2) and mixed venous carbon dioxide (PvCO2) in normal and COPD subjects. The mean values and standard deviations for determinations of blood gases and acid-base status in Thoroughbred horses in training were as follows: PaO2 = 77,4 +/- 4,3 mm Hg; PvO2 (mixed venous oxygen partial pressure) = 36,2 +/- 4,1 mm Hg; PaCO2 = 40,9 +/- 5,8 mm Hg; PvCO2 = 49,4 +/- 5,0 mm Hg; pHa (arterial) = 7,358 +/- 0,051; pHv (venous) = 7,343 +/- 0,027; standard bicarbonate = 22,7 mM/l. The PaO2, the PaCO2 and the arterial pH were significantly correlated to the respiratory frequency in COPD subjects. The correlations of pulmonary diastolic pressure to both PaO2 and pHa were of probable significance (P less than 0,05) in COPD subjects. PaCO2 was highly significantly correlated to PaO2 and pHa in COPD subjects.

Chronic respiratory alkalosis. The effect of sustained hyperventilation on renal regulation of acid-base equilibrium.

In normal subjects, chronic hyperventilation lowers plasma bicarbonate concentration, primarily by inhibiting the urinary excretion of net acid. The quantitative relation between reduced arterial carbon dioxide tension (PaCO2) and the plasma bicarbonate concentration in the chronic steady state has not been studied in humans, however, and the laboratory criteria for the diagnosis of chronic respiratory alkalosis therefore remain undefined. We wished to provide such reference data for clinical use. Moreover, because chronic hyperventilation paradoxically lowers blood pH still further in dogs with metabolic acidosis, we desired to study the effect of chronic hypocapnia on the plasma bicarbonate concentration (and blood pH) in normal human subjects in whom acidosis had been induced with ammonium chloride. Under metabolic-balance conditions, we used altitude-induced hypobaric hypoxia to produce chronic hypocapnia in nine normal young men, five of whom received ammonium chloride daily to cause metabolic acidosis (the mean [+/- SE] steady-state plasma bicarbonate level in these five was 12.0 +/- 0.5 mmol per liter). For each decrease of 1 mm Hg (0.13 kPa) in the PaCO2, the plasma bicarbonate concentration decreased by 0.41 mmol per liter in the subjects who started with a normal plasma bicarbonate concentration and by 0.42 mmol per liter in the subjects with acidosis. In contrast to the findings in previous studies of dogs, hypocapnia increased blood pH similarly in both groups; the blood hydrogen ion concentration decreased by about 0.4 nmol per liter for every decrease of 1 mm Hg (0.13 kPa) in PaCO2. These results provide reference data for the diagnosis of chronic respiratory alkalosis in humans. Although chronic hypocapnia decreased plasma bicarbonate levels similarly in normal subjects with acidosis and without acidosis, the percent reduction in PaCO2 was always greater than the corresponding percent reduction in the plasma bicarbonate concentration. Therefore, as was not true of the response in dogs, the subjects' blood pH always increased with hyperventilation, regardless of the initial plasma bicarbonate concentration.

Towards evidence-based emergency medicine: best BETs from the Manchester Royal Infirmary. BET 2: In patients presenting with an exacerbation of COPD can a normal venous blood gas pCO2 rule out arterial hypercarbia?

A shortcut review was carried out to establish whether a normal partial pressure of carbon dioxide (pCO2) on a venous blood sample could be used to rule out hypercarbia. Eleven studies were directly relevant to the question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these papers are tabulated. The clinical bottom line is that a normal venous pCO2 effectively rules out arterial hypercarbia.

The metabolic and respiratory alterations of heat stroke.

The metabolic and respiratory changes of 21 patients with heat stroke were studied. Admission arterial blood gas levels were measured, and serum bicarbonate, lactate, calcium, phosphorus, and anion gap determinations were performed. Seven patients had a metabolic acidosis (pH 7.20 +/- 0.04, PCO2 32 +/- 2 mm Hg, and bicarbonate 12 +/- 1 mEq/L), seven a combined metabolic acidosis and respiratory alkalosis (pH 7.39 +/- 0.01, PCO2 25 +/- 1 mm Hg, and bicarbonate 15 +/- 1 mEq/L), four a respiratory alkalosis (pH 7.45 +/- 0.01, PCO2 30 +/- 1 mm Hg, and bicarbonate 20 +/- 1 mEq/L), one a metabolic and respiratory acidosis (pH 7.13, PCO2 52 mm Hg, and bicarbonate 17 mEq/L), and one a respiratory acidosis (pH 7.30, PCO2 56 MM Hg, and bicarbonate 27 mEq/L). The 15 patients with a metabolic acidosis had a pH of 7.28 +/- 0.03, PCO2 of 30 +/- 2 mm Hg, bicarbonate level of 14 +/- 1 mEq/L, lactate concentration of 6.5 +/- 1.0 mEq/L, and an anion gap of 26 +/- 4 mEq/L. Nine patients were hypocalcemic (7.8 +/- 0.3 mg/dL), and five patients were hypophosphatemic (2.0 +/- 0.2 mg/dL). The predominant metabolic change in heat stroke is a metabolic acidosis secondary to increased lactate content and/or a respiratory alkalosis. Hypocalcemia is common and hypophosphatemia is not infrequent.

[Correlation between arterial and venous blood gas analysis parameters in patients with acute exacerbation of chronic obstructive pulmonary disease].

Arterial blood gas (ABG) analyses have an important role in the assessment and monitoring of the metabolic and oxygen status of patients with acute exacerbation of chronic obstructive pulmonary disease (COPD). Arterial puncture could have a lot of adverse effects, while sampling of venous blood is simpler and is not so invasive. The aim of this study was to evaluate whether venous blood gas (VBG) values of pH, partial pressure of carbon dioxide (PCO2), partial oxygen pressure (PO2), bicarbonate (HCO3), and venous and arterial blood oxygen saturation (SO2) can reliably predict ABG levels in patients with acute exacerbation of COPD. Forty-seven patients with a prior diagnosis of COPD were included in this prospective study. The patients with acute exacerbation of this disease were examined at the General Hospital EMS Department in Prijepolje. ABG samples were taken immediately after venous sampling, and both were analyzed. The Pearson correlation coefficients between arterial and venous parameters were 0.828, 0.877, 0.599, 0.896 and 0.312 for pH, PCO2, PO2, HCO3 and SO2, respectively. The statistically significant correlation between arterial and venous pH, PCO2 and HCO3, values was found in patients with acute exacerbation of COPD (p<0.001). When we cannot provide arterial blood for analysis, venous values of the pH, Pv,CO2 and HCO3 parameters can be an alternative to their arterial equivalents in the interpretation of the metabolic status in patients with acute exacerbation of COPD, while the values of venous Pv,O, and Sv,O2 cannot be used as predictors in the assessment of oxygen status of such patients.

Tracheal intubation

Intubation may be necessary for a patient with decreased oxygen content and oxygen saturation of the blood caused when their breathing is inadequate (hypoventilation), suspended (apnea), or when the lungs are unable to sufficiently transfer gasses to the blood. Such patients, who may be awake and alert, are typically critically ill with a multisystem disease or multiple severe injuries. Examples of such conditions include cervical spine injury, multiple rib fractures, severe pneumonia, acute respiratory distress syndrome (ARDS), or near-drowning. Specifically, intubation is considered if the arterial partial pressure of oxygen (PaO2) is less than 60 millimeters of mercury (mm Hg) while breathing an inspired O2 concentration (FIO2) of 50% or greater. In patients with elevated arterial carbon dioxide, an arterial partial pressure of CO2 (PaCO2) greater than 45 mm Hg in the setting of acidemia would prompt intubation, especially if a series of measurements demonstrate a worsening

Below what FEV1 should arterial blood be routinely taken to detect chronic respiratory failure in COPD?

To diagnose and assess chronic respiratory failure in stable chronic obstructive pulmonary disease (COPD) the measurement of arterial blood gases (ABG) is required. It has been suggested that ABG be determined for this purpose when FEV1 ranges between 50% and 30% predicted, but these thresholds are not evidence-based. To identify the post-bronchodilator (BD) FEV₁ and arterial oxygen saturation (SaO(2)) values that provide the best sensitivity, specificity, and likelihood ratio (LR) for the diagnosis of hypoxaemic and/or hypercapnic chronic respiratory failure in stable COPD. A total of 150 patients were included (39 with PaO₂ < 60 mmHg [8 kPa], 14 of them with a PaCO₂ ≥ 50 mmHg [6.7 kPa]). The best post-BD FEV(1) and SaO(2) cut-off points to predict chronic respiratory failure were selected using the PC and the Receiver Operating Characteristics (ROC) curves. A post-BD FEV(1) equal to 36% and an SaO(2) of 90% were the best predictive values for hypoxaemic respiratory failure and a post-BD FEV(1) equal to 33% for the hypercapnic variant. An FEV(1) ≥ 45% ruled out hypoxaemic respiratory failure. A post-BD FEV(1) of 36% is the best cut-off point to adequately predict both hypoxaemic and hypercapnic respiratory failure in the patient with stable COPD. For its part, an SaO(2) of 90% is the best value for isolated hypoxaemic failure. These values could be considered for future clinical recommendations/guidelines for COPD.