Metabolic alkalosis in hemodialysis patients.

BACKGROUND: Hemodialysis solutions typically contain a high alkali concentration designed to counter interdialytic acidosis, but this could result in persistent alkalosis in some patients. The prevalence and significance of persistent alkalosis were therefore examined at four outpatient centers over a 10-year period. METHODS: Alkalosis was defined as a pre-dialysis serum [HCO3 ] ≥ 26 meq/L in >6 months of a 12-month period and was persistent if present in a majority of months thereafter. Control patients had a serum [HCO3 ] of 19-23 meq/L > 6 of every 12 months. Standard, citrate-containing dialysate was used in all patients without adjustment of bicarbonate concentration. RESULTS: 444 of 1271 patients had alkalosis that persisted in 73. Compared to control patients, persistently alkalotic patients were older, but gender, race, starting weight, comorbidities, and mortality did not differ. Dialysis dose was 7% greater, protein catabolic rate was 11% lower, and interdialytic weight gain was 29% lower, all p < 0.001. Persistently alkalotic patients had double the incidence of cardiac arrhythmias (p = 0.07) and a 20% greater intradialytic blood pressure decrease (p < 0.001). CONCLUSIONS: Alkalosis is common in hemodialysis patients and can be persistent, likely due to decreased protein catabolic rate and increased dialysis dose, and may have detrimental cardiovascular effects.

Respiratory problems owing to severe metabolic alkalosis in infants presenting with hypertrophic pyloric stenosis.

OBJECTIVE: Uncorrected metabolic alkalosis in infantile hypertrophic pyloric stenosis (IHPS) could lead to perioperative apnea. However, the precise incidence of preoperative respiratory problems and the association with metabolic alkalosis are unknown. Therefore, we aimed to determine the incidence of preoperative respiratory problems in IHPS and to assess the association with metabolic alkalosis. METHODS: We retrospectively reviewed all patients diagnosed with IHPS during 2007-2017. Respiratory problems were classified as present or absent. With multivariate logistic regression we analyzed the association between bicarbonate and respiratory problems, corrected for gestational age and birth weight. RESULTS: We included 459 infants, of whom 23 developed preoperative respiratory problems (5.0%). Infants with preoperative respiratory problems were more often female (43.5% vs. 13.3% p = 0.001) and had significantly higher median serum levels of bicarbonate (32.0 mmol/L vs. 30.0 mmol/L), base excess (6.5 mmol/L vs. 5.3 mmol/L) and pCO2 (6.4 kPa vs. 5.9 kPa), compared to infants without respiratory problems. Multivariate analysis of serum bicarbonate and presence of respiratory problems showed an OR of 2.18 per 10 mmol/L (95% CI 1.21-4.71) (p = 0.009). The optimal bicarbonate cutoff point was 25.7 mmol/L (sensitivity 100%, specificity 13.4%). CONCLUSION: IHPS with metabolic alkalosis potentially results in preoperative respiratory problems. A lower bicarbonate target before surgery might be recommended and respiratory monitoring should be considered. LEVEL OF EVIDENCE: Level IV.

Calcium-Alkali Syndrome Associated with Hypoparathyroidism Following Total Thyroidectomy.

BACKGROUND: Patients with permanent postsurgical hypoparathyroidism, a complication of total thyroidectomy, often require high calcium supplementation with vitamin D to maintain serum calcium levels. The epidemiology of calcium-alkali syndrome (CAS) in patients with hypoparathyroidism after total thyroidectomy remains unclear. This study aimed to investigate the incidence of hypercalcemia, renal impairment, metabolic alkalosis, and CAS in patients treated for presumed hypoparathyroidism after total thyroidectomy. METHODS: Twenty-seven patients with neck cancers who underwent total thyroidectomy without parathyroid autotransplantation between January 2010 and October 2013 at our hospital were consecutively included. All patients received calcium lactate and alfacalcidol for postsurgical hypocalcemia. We defined hypercalcemia as a corrected serum calcium level (cCa) ≥10.5 mg/dL, metabolic alkalosis as a difference in serum sodium and serum chloride ([sNa-sCl]) ≥39 mEq/L, and renal impairment as a ≥50% increase in serum creatine and/or ≥35% decrease in estimated glomerular filtration rate (eGFR) compared to baseline. RESULTS: cCa peaked (11.1 ± 1.5 mg/dL) at a median of 326 days (interquartile range 78-869) after surgery. At peak cCa, [sNa-sCl] was significantly higher (p < 0.01), and eGFR was significantly lower (p < 0.01) than that at baseline. Fifteen patients (55.6%) had hypercalcemia, 19 (70.3%) had alkalosis, 12 (44.4%) had renal impairment, and 9 (33.3%) had CAS. Patients with CAS (mean age 67.1 ± 10.8 years) were older than those without CAS (56.7 ± 13.6 years, p = 0.06). The mean dose of alfacalcidol in the CAS group (3.1 ± 1.2 µg/day) was significantly larger than that in the non-CAS group (2.1 ± 1.0 µg/day, p = 0.03). CONCLUSIONS: This retrospective study reveals the high incidence of CAS in patients with hypoparathyroidism after total thyroidectomy. Furthermore, these findings suggest that the serum calcium level, acid-base balance, and renal function should be closely monitored in patients with postsurgical hypoparathyroidism who receive large doses of active vitamin D.

Effect of Bicarbonate-Buffered Dialysate on Ventricular Arrhythmias in Hemodialysis Patients.

BACKGROUND: The etiology of sudden cardiac death in patients with end-stage renal disease (ESRD) on hemodialysis (HD) is largely unknown, though there is evidence to suggest that metabolic alkalosis induced by HD with a high-bicarbonate dialysate/prescription may play a role. METHODS: We investigated the effects of metabolic alkalosis induced by HD with an acetate-containing bicarbonate-buffered dialysate on frequency of ventricular arrhythmia in 47 patients with ESRD on chronic HD using 48-h Holter monitoring in 3 phases: intra-HD, post-HD day 1, and post-HD day 2. Serum levels of bicarbonate, calcium, and potassium along with hemodynamics were measured pre-HD, post-HD, 20-h post-HD, and 44-h post-HD. Correlations were performed to verify the association between bicarbonate prescription and change in serum bicarbonate levels post-HD and to determine if the HD-induced change in serum bicarbonate level (metabolic alkalosis) had any direct association with ambient ventricular arrhythmia (premature ventricular contractions per hour) or indirect associations with ambient ventricular arrhythmia by affecting electrolytes or hemodynamics that are known to increase the risk of ventricular arrhythmia. RESULTS: Mean pre-HD serum bicarbonate level was 21.3 mEq/L. Dialysate bicarbonate prescription (mean of 36.4 mEq/L) correlated with changes in serum bicarbonate levels immediately post-HD 26.7 mEq/L (r = 0.46, p < 0.01), 20-h post-HD 25.2 mEq/L (r = 0.38), and 44-h post-HD 23.2 mEq/L (r = 0.35, p = 0.01). No statistically significant correlations were found between the post-HD change in serum bicarbonate levels (metabolic alkalosis) with ambient ventricular arrhythmia, changes in serum calcium, potassium, or hemodynamics in any phase. CONCLUSIONS: High-bicarbonate dialysate prescription is associated with metabolic alkalosis following the HD procedure. A mild metabolic alkalosis induced by HD with an acetate-containing bicarbonate-buffered dialysate solution had no direct association with ambient ventricular arrhythmia on Holter monitoring and was not associated with changes in hemodynamics or changes in serum total calcium or potassium levels. This study helps to provide guidance for the safe use of high bicarbonate dialysate/prescription in patients with ESRD on HD.

Study of Acid-Base Disorders and Biochemical Findings of Patients in a Tertiary Care Hospital: A Descriptive Cross-sectional Study.

INTRODUCTION: Acid base disorder is a condition characterized by alteration in blood pH by the imbalance between the components of blood leading to a life threatening situation. The main aim of this study was to find the prevalence of acid-base disorders and biochemical findings of such disorders in patients in a tertairy care hospital. METHODS: This descriptive cross-sectional study was conducted in Nobel Medical College Teaching Hospital from 1st September, 2018 to 31st August, 2019. Ethical apporoval was taken from Institutional Review Committee. All the patients presented to emergency department, intensive care units and wards were included during the study period. Data were entered and calculations were done in Microsoft Excel, point estimate at 95% Confidence Interval was calculated along with frequency and proportion for binary data. RESULTS: Out of arterial blood gas analysis of 1144 patients, the prevalence of acid base disorders was 718 (62.76%) at 95% Confidence Interval (59.96-65.56%). Simple and mixed acid base disorders were observed in 332 (46.24%) and 386 (53.76%) patients respectively. Respiratory alkalosis was most common among 134 (40.36%) cases in simple acid base disorder whereas metabolic acidosis and respiratory alkalosis was most common among 204 (52.85%) in mixed acid base disorder. All types of disorders were observed more in elderly people (41-60 and >60 age group) than other age groups. CONCLUSIONS: Acid base disorder was found to be more common in very ill patients in emergency and intensive care units. Mixed acid base disorder was the most common with male and elderly patients in predominance.

Incidence of hypochloremic metabolic alkalosis in dogs and cats with and without nasogastric tubes over a period of up to 36 hours in the intensive care unit.

OBJECTIVE: To evaluate the incidence of hypochloremic metabolic alkalosis (HCMA) in dogs and cats in the ICU that had intermittent nasogastric tube (NGT) aspiration for up to 36 hours. DESIGN: Prospective cohort study (December 2013 to October 2014). SETTING: Privately owned emergency and referral teaching hospital. ANIMALS: Forty-nine client-owned dogs and 16 client-owned cats. INTERVENTIONS: Patients wherein NGT placement was recommended and client consent was obtained were included in the interventional group. Those with an NGT placed (NGT group) had the NGT aspirated every 4 hours. Patients for whom placement of a NGT was declined by the owner served as a reference group (NoNGT). Venous blood gas and electrolyte values were obtained every 12 hours. MEASUREMENTS AND MAIN RESULTS: Thirty-five dogs and cats had an NGT placed. Thirty dogs and cats did not have an NGT placed. The serum venous blood gas and electrolyte changes were compared over time within the NGT group and between the NGT and NoNGT groups. No cases developed HCMA. In the NGT group, blood pH increased over time. There was no significant difference between the NGT and the NoNGT group in the average value of pH, HCO3- , base excess, chloride, or corrected chloride. Serum venous blood gas, chloride, and corrected chloride changes were not associated with the volumes of gastric fluid aspirated over time. CONCLUSIONS: In this small population of dogs and cats, intermittent NGT aspiration was not associated with the development of HCMA over a period of up to 36 hours after NGT placement.

Pseudo-bartter syndrome, pattern and correlation with other cystic fibrosis features.

Pseudo-Bartter Syndrome (PBS), although quite common in patients with cystic fibrosis (CF), is often missed as simple dehydration or Bartter syndrome. This study was performed in patients with PBS to compare the pattern and course of the disease with those with CF not manifesting with this syndrome. All patients with CF who attended the respiratory clinic at Queen Rania Al-Abdallah Hospital from January 2000 to April 2010 were included in this retrospective case-control study. A specially formulated data sheet was used and those with PBS and those not having the syndrome were identified. A total of 110 patients (51% female) with CF with a median age of seven years were followed-up. Eighteen (16.3%) of them had one or more episodes of PBS. The median follow-up period was 6.2 years. All the episodes occurred during summer and in infancy. Median age of the initial episode of PBS was three months. One-third of them were initially followed at the nephrology clinic. Three patterns of PBS were identified: single episode in three (16.6%) patients, recurrent in 12 (66.6%) patients and chronic in three (16.6%) patients. Early colonization of Pseudomonas spp before 1 st birthday was seen in 44% patients with PBS compared with 12% in other CF patients (P-value = 0.0075). The total number of colonized patients and other CF features at the time of the study did not differ significantly among patients, although the mean Shwachman-Kulczycki score is significantly lower in those with recurrent PBS (69 compared with 85 in other CF patients). Gene mutation was identified in only 30% of the entire cohort. PBS is common in patients with CF, and it should be kept in mind in any patient with hypotonic dehydration and metabolic alkalosis. Recurrent pattern is associated with earlier Pseudomonas colonization.

Metabolic alkalosis from unsuspected ingestion: use of urine pH and anion gap.

Underlying causes of metabolic alkalosis may be evident from history, evaluation of effective circulatory volume, and measurement of urine chloride concentration. However, identification of causes may be difficult for certain conditions associated with clandestine behaviors, such as surreptitious vomiting, use of drugs or herbal supplements with mineralocorticoid activity, abuse of laxatives or diuretics, and long-term use of alkalis. In these circumstances, clinicians often are bewildered by unexplained metabolic alkalosis from an incomplete history or persistent deception by the patient, leading to misdiagnosis and poor outcome. We present a case of severe metabolic alkalosis and hypokalemia with a borderline urine chloride concentration in an alcoholic patient treated with a thiazide. The cause of the patient's metabolic alkalosis eventually was linked to surreptitious ingestion of baking soda. This case highlights the necessity of a high index of suspicion for the diverse clandestine behaviors that can cause metabolic alkalosis and the usefulness of urine pH and anion gap in its differential diagnosis.

Post-hypercapnic alkalosis is associated with ventilator dependence and increased ICU stay.

Posthypercapnic alkalosis (PHA) is frequently overlooked as a complication of mechanical ventilation in patients with exacerbation of chronic obstructive pulmonary disease (COPD). The current study was conducted to determine the incidence, risk factors for development and effect on outcome of PHA. Eighty-four patients (62 +/- 11 years, range 42-78 years, M:F 58: 26) with exacerbation of COPD with underlying chronic hypercapnic respiratory failure requiring mechanical ventilation were included in a retrospective fashion. PHA was defined as static or rising serum bicarbonate levels, 72 hours or more after return of PaCO2 to baseline, with concurrent pH > 7.44. Development of PHA was noted in 17 patients (20.2%). Corticosteroid use >or=10 days during the hospital stay was an independent risk factor for development of PHA (Adjusted OR, 95% CI: 9.4, 1.6-55.3; P = 0.013). Development of PHA was associated with an increased incidence of ventilator dependence (64.7% vs. 37.3%, OR, 95% CI: 3.1, 1.1-9.4, P = 0.04) and duration of ICU stay (14.7 +/- 6.7 vs. 9.5 +/- 5.9, P = 0.01) but no increase in hospital mortality (43.3% vs. 41.2%, P = NS). It is concluded that PHA is a common complication in patients with exacerbation of COPD requiring mechanical ventilation and is associated with increased incidence of ventilator dependence and ICU stay.

Delay in onset of metabolic alkalosis during regional citrate anti-coagulation in continuous renal replacement therapy with calcium-free replacement solution.

Regional citrate anti-coagulation for continuous renal replacement therapy chelates calcium to produce the anti- coagulation effect. We hypothesise that a calcium-free replacement solution will require less citrate and produce fewer metabolic side effects. Fifty patients, in a Medical Intensive Care Unit of a tertiary teaching hospital (25 in each group), received continuous venovenous hemofiltration using either calcium-containing or calcium-free replacement solutions. Both groups had no significant differences in filter life, metabolic alkalosis, hypernatremia, hypocalcemia, and hypercalcemia. However, patients using calcium-containing solution developed metabolic alkalosis earlier, compared to patients using calcium-free solution (mean 24.6 hours,CI 0.8-48.4 vs. 37.2 hours, CI 9.4-65, P = 0.020). When calcium-containing replacement solution was used, more citrate was required (mean 280 ml/h, CI 227.2-332.8 vs. 265 ml/h, CI 203.4-326.6, P = 0.069), but less calcium was infused (mean 21.2 ml/h, CI 1.2-21.2 vs 51.6 ml/h, CI 26.8-76.4, P < or = 0.0001).

Prevalence of sodium bicarbonate-induced alkalemia in cardiopulmonary arrest patients.

BACKGROUND: Intravenous sodium bicarbonate (SB) administration during cardiopulmonary arrest (CPA) is intended to counteract lactic acidosis due to hypoxia, poor perfusion, and anaerobic metabolism. Despite a lack of documented efficacy and a level III recommendation from the American Heart Association, SB is widely used during resuscitation events. SB has both theoretical and measurable adverse effects. Excess or poorly timed administration during a CPA may elevate a patient's pH, inducing alkalemia. Despite decades of controversy surrounding use of this drug, the prevalence of SB-induced alkalemia has not been previously documented. OBJECTIVE: To estimate the prevalence of SB-induced alkalemia in inpatients after CPA and to investigate the pattern of SB administration. METHODS: Medical records were retrospectively reviewed with attention to SB administration and arterial blood gas (ABG) data. After application of inclusion and exclusion criteria to 264 CPA patients, the study group comprised 88 patients. When measured, if PCO(2) and pH were above normal limits after SB administration, we concluded that SB contributed to the alkalemia. RESULTS: Twenty-seven (31%) patients received SB without any ABG data, and 70 (79%) patients received at least one empiric SB dose. Of the 61 patients with ABG data, alkalemia occurred in 10, a prevalence of 16%. Administration of SB increased pH in only 9 (15%) other CPA patients and had no effect in the 42 (69%) remaining patients. CONCLUSIONS: Administration of SB during CPA was causally linked with inducing alkalemia in 16% of patients. Early collection of ABG samples may assist in optimizing pH during CPA and thus reduce unwarranted empiric use of SB.

Metabolic alkalosis in skilled nursing patients.

Renal failure is common among the long-term care (LTC) elderly. Little is known about the acid/base status of these patients. The aim of this study is to evaluate the relationship between the acid base status and renal function in a representative group of skilled nursing patients and relate it to their feeding status. LTC elderly patients, in stable clinical condition, 50 on naso-gastric tube (NGT) feeding, 40 orally fed (OF), were recruited to this study. As controls, we studied a group of 30 elderly independent, ambulatory patients admitted to the acute geriatric departments of the hospital for different causes which were not related to their acid-base status. Venous blood was taken for the routine tests and blood gases. In the LTC study groups a 24-h urine collection was examined for biochemical parameters and calculations of all clearances. Glomerular filtration rate (GFR) was estimated by the Cockroft and Goult and MDRD formulas. Renal function was similar in the two main study groups. Daily secretion of sodium and chloride were 50% lower in the NGT fed patients (p<0.001). The LTC elderly patients had significantly higher venous pH values, with no differences in pCO(2) or HCO(3). An alkalotic state (pH>7.45) was found in 13.6% of them (18% in the NGT and 6.5% in the OF) while none of the independent elderly had such values (p<0.05). Similarly, HCO(3)>34 was found in 12% of the LTC elderly versus none in the independents (p=0.06). Values of pO(2) and O(2) saturation were significantly higher in the nursing elderly and mainly those fed by NGT. Hemoglobin levels had a significantly negative correlation with the pH (r=-0.3, p<0.002). In conclusion, unexpected metabolic alkalosis was found in a group of skilled nursing patients, more prominent in those fed by NGT. This finding warrants the inclusion of routine pH determination in patients whenever pharmacokinetic considerations are essential.

Iraq: the environmental challenge to HM land forces.

In 2003, occasional military patients with hyponatraemia, hypokalaemia and alkalosis were encountered in Iraq. Development of central pontine myelinolysis in one patient indicated treatment should be cautious. Two years later, heat illness continued to occur during the very hot summer months and 23 cases were admitted to a British military field hospital near Basra, Iraq. Incidence was < 0.15% of deployed personnel per summer month. Serum sodium and potassium concentrations were directly (r = 0.66, p = 0.0002) and serum sodium and bicarbonate concentrations inversely (r= -0.64, p = 0.002) correlated. The magnitude of these changes was unrelated to the glomerular filtered load of sodium. While blood pressure was undiminished, estimated glomerular filtration rate was reduced. These electrolyte changes were compatible with secondary hyperaldosteronism but field conditions constrained further investigation. Hyponatraemia was probably due to salt deficiency rather than overhydration. In some military personnel summer salt supplementation could be essential during operations in hot countries.

Serum biochemical abnormalities in goats with uroliths: 107 cases (1992-2003).

OBJECTIVE: To characterize serum biochemical abnormalities in goats with uroliths. DESIGN: Retrospective case-control series. ANIMALS: 107 male goats with uroliths and 94 male goats with various nonrenal diseases (controls). PROCEDURES: For male goats, results of serum biochemical analyses collected from 1992 through 2003 were retrieved from computerized records, as were signalment, clinical diagnoses, and discharge status. Results of analyses for BUN, creatinine, phosphorus, calcium, Na, K, Cl, total CO2, anion gap, and glucose were compared between goats with uroliths and control goats. RESULTS: Goats with uroliths had higher mean BUN, creatinine, total CO2, K, and glucose concentrations and lower mean phosphorus, Na, and Cl concentrations than control goats, with no difference in mean calcium concentration and anion gap. Goats with uroliths had higher frequency of azotemia, hypophosphatemia, hypochloridemia, and increased total CO2 and lower frequency of decreased total CO2 than control goats. Urolithiasis occurred more frequently in castrated males than in sexually intact males and in dwarf African breeds than in other breeds. CONCLUSIONS AND CLINICAL RELEVANCE: Goats with uroliths often had hypophosphatemia at admission. Hypochloridemic metabolic alkalosis was the most common acid-base disorder. Rupture in the urinary tract system was associated with increased prevalence of hyponatremia and hyperkalemia. Clinicians should be aware of these abnormalities when determining fluid therapy.

A male patient with right-sided thoracic kidney, diabetes mellitus, hearing loss and renal dysfunction.

A 48-year-old man with diabetes mellitus and hypertension was found to have a thoracic right-sided ectopic kidney with a sensorineuronal hearing loss and tubular abnormalities such as hyponatremia, hypokalemia, metabolic alkalosis with microalbuminuria. He was treated with ACEI and sodium and potassium supplements. However, this only partially corrected his metabolic abnormalities.

Gitelman's syndrome with mental retardation.

A 56-year-old mentally retarded Japanese woman (intelligence quotient: 49) was admitted to our hospital with the chief complaints of headache, dizziness, vomiting, and lower limb paralysis. Laboratory tests showed severe hypokalemia, metabolic alkalosis, hypomagnesemia, and hypocalciuria. These findings suggested a diagnosis of Gitelman's syndrome (GS). We examined the thiazide-sensitive Na-Cl cotransporter (TSC) gene for the mutations that can be responsible for Gitelman's syndrome, and confirmed the diagnosis. After potassium and magnesium supplementation, her paralysis improved dramatically. The marriage of her parents was consanguineous. She had nine siblings (all with mental retardation), among whom five had died of unknown causes during childhood. Familial mental retardation has never been detected before in Gitelman's syndrome. Here we report a rare case of Gitelman's syndrome with familial mental retardation.

Acetazolamide-mediated decrease in strong ion difference accounts for the correction of metabolic alkalosis in critically ill patients.

INTRODUCTION: Metabolic alkalosis is a commonly encountered acid-base derangement in the intensive care unit. Treatment with the carbonic anhydrase inhibitor acetazolamide is indicated in selected cases. According to the quantitative approach described by Stewart, correction of serum pH due to carbonic anhydrase inhibition in the proximal tubule cannot be explained by excretion of bicarbonate. Using the Stewart approach, we studied the mechanism of action of acetazolamide in critically ill patients with a metabolic alkalosis. METHODS: Fifteen consecutive intensive care unit patients with metabolic alkalosis (pH > or = 7.48 and HCO3- > or = 28 mmol/l) were treated with a single administration of 500 mg acetazolamide intravenously. Serum levels of strong ions, creatinine, lactate, weak acids, pH and partial carbon dioxide tension were measured at 0, 12, 24, 48 and 72 hours. The main strong ions in urine and pH were measured at 0, 3, 6, 12, 24, 48 and 72 hours. Strong ion difference (SID), strong ion gap, sodium-chloride effect, and the urinary SID were calculated. Data (mean +/- standard error were analyzed by comparing baseline variables and time dependent changes by one way analysis of variance for repeated measures. RESULTS: After a single administration of acetazolamide, correction of serum pH (from 7.49 +/- 0.01 to 7.46 +/- 0.01; P = 0.001) was maximal at 24 hours and sustained during the period of observation. The parallel decrease in partial carbon dioxide tension was not significant (from 5.7 +/- 0.2 to 5.3 +/- 0.2 kPa; P = 0.08) and there was no significant change in total concentration of weak acids. Serum SID decreased significantly (from 41.5 +/- 1.3 to 38.0 +/- 1.0 mEq/l; P = 0.03) due to an increase in serum chloride (from 105 +/- 1.2 to 110 +/- 1.2 mmol/l; P < 0.0001). The decrease in serum SID was explained by a significant increase in the urinary excretion of sodium without chloride during the first 24 hours (increase in urinary SID: from 48.4 +/- 15.1 to 85.3 +/- 7.7; P = 0.02). CONCLUSION: A single dose of acetazolamide effectively corrects metabolic alkalosis in critically ill patients by decreasing the serum SID. This effect is completely explained by the increased renal excretion ratio of sodium to chloride, resulting in an increase in serum chloride.

Metabolic alkalosis contributes to acute hypercapnic respiratory failure in adult cystic fibrosis.

BACKGROUND: and study objectives: Patients with end-stage cystic fibrosis (CF) develop respiratory failure and hypercapnia. In contrast to COPD patients, altered electrolyte transport and malnutrition in CF patients may predispose them to metabolic alkalosis and, therefore, may contribute to hypercapnia. The aim of this study was to determine the prevalence of metabolic alkalosis in adults with hypercapnic respiratory failure in the setting of acute exacerbations of CF compared with COPD. DESIGN: Levels of arterial blood gases, plasma electrolytes, and serum albumin from 14 consecutive hypercapnic CF patients who had been admitted to the hospital with a respiratory exacerbation were compared with 49 consecutive hypercapnic patients with exacerbations of COPD. Hypercapnia was defined as a PaCO(2) of > or = 45 mm Hg. RESULTS: Despite similar PaCO(2) values, patients in the CF group were significantly more alkalotic than were those in the COPD group (mean [+/- SD] pH, 7.43 +/- 0.03 vs 7.37 +/- 0.05, respectively; p < 0.01). A mixed respiratory acidosis and metabolic alkalosis was evident in 71% of CF patients and 22% of COPD patients (p < 0.01). The mean concentrations of plasma chloride (95.1 +/- 4.9 vs 99.8 +/- 5.2 mmol/L, respectively; p < 0.01) and sodium (136.5 +/- 2.8 vs 140.4 +/- 4.5 mmol/L, respectively; p < 0.01) were significantly lower in the CF group, and the levels of serum albumin were significantly reduced (27.4 +/- 5.8 vs 33.7 +/- 4.8 mmol/L, respectively; p < 0.01). CONCLUSION: Metabolic alkalosis contributes to hypercapnic respiratory failure in adults with acute exacerbations of CF. This acid-base disturbance occurs in conjunction with reduced total body salt levels and hypoalbuminemia.