Acid-base disturbance in patients with cirrhosis: relation to hemodynamic dysfunction.

PURPOSE: Acid-base disturbances were investigated in patients with cirrhosis in relation to hemodynamic derangement to analyze the hyperventilatory effects and the metabolic compensation. METHODS: A total of 66 patients with cirrhosis and 44 controls were investigated during a hemodynamic study. RESULTS: Hyperventilatory hypocapnia was present in all patients with cirrhosis and progressed from Child class A to C (P<0.01). Arterial pH increased significantly from class A to C (P<0.001) and was correlated inversely to the mean arterial blood pressure (r=-0.30, P<0.02), systemic vascular resistance (r=-0.25, P<0.05), indocyanine green clearance (r=-0.37, P<0.005), and serum sodium (r=-0.38, P<0.002). Metabolic compensation was shown by a reduced standard base excess in all patients (P<0.001). Standard base excess contained elements related to changes in serum albumin, water dilution, and effects of unidentified ions (all P<0.001). A significant hepatic component in the acid-base disturbances could not be identified. CONCLUSION: Hypocapnic alkalosis is related to disease severity and hyperdynamic systemic circulation in patients with cirrhosis. The metabolic compensation includes alterations in serum albumin and water retention that may result in a delicate acid-base balance in these patients.

Relationship of metabolic alkalosis, azotemia and morbidity in patients with chronic obstructive pulmonary disease and hypercapnia.

BACKGROUND: Exacerbation of chronic obstructive pulmonary disease (COPD) is an important cause of morbidity and mortality, but the effect of metabolic compensation of respiratory acidosis (RA) on mortality is not fully understood. OBJECTIVE: To investigate the relationship between metabolic compensation and mortality in COPD patients with RA. METHODS: We prospectively investigated all COPD patients with RA admitted to the respiratory intensive care unit between February 2001 and March 2007. Two hundred and thirteen patients (159 male, 54 female; mean age 65 +/- 10.8 years) were divided into three groups (71 patients each) according to base excess (BE) levels: (1) low BE, (2) medium BE, and (3) high BE. H(+) concentration was calculated according to their standard formula and BE was calculated according to the Van Slyke equation. RESULTS: The overall mortality rate was 24.9%. The group mortality rates were 32, 17 and 25% in the low, medium and high BE groups, respectively (p = 0.001). When patients were divided into three groups according to the HCO(3)(-) levels, the group mortality rate was 59.1% in the low HCO(3)(-) group and 19.8% in the high HCO(3)(-) group. Based on univariate analysis, six factors affecting mortality were identified. However, multivariate analysis showed that the levels of serum HCO(3)(-) (p = 0.013; OR: 0.552; CI: 0.345-0.882) and creatinine (p = 0.019; OR: 2.114; CI: 1.132-3.949) had an independent effect. CONCLUSION: In patients with COPD exacerbation and hypercapnia, the development of sufficient metabolic compensation and adequate renal function significantly decreases mortality.

Alkalemia-associated morbidity and mortality in medical and surgical patients.

The difference in death rate among medical and surgical inpatients having alkalemia is incompletely defined. This prospective study was done to identify the incidence, mortality, and clinical factors that resulted in a poor outcome in both groups of patients. We screened a total of 10,811 consecutive arterial blood gas values; in 4,427 (40.9%) the pH was greater than 7.44, and in 2,577 (23.8%) the pH was greater than 7.48. The study group consisted of 409 patients (213 medical, 196 surgical) whose pH value was greater than 7.48; 253 of these patients (61.9%) had pure respiratory alkalosis, 120 (29.3%) had mixed respiratory and metabolic alkalosis, 27 (6.6%) had a mixed acid base disorder, and nine (2.2%) had pure metabolic alkalosis. Overall group mortality was 27.9% and increased as pH values rose, reaching 48.5% when the pH was greater than 7.60. The overall mortality among medical patients (36.6%) exceeded that among the surgical patients (12.4%) (P less than .05), an observation that applied over a wide range of pH values. Patients having mixed respiratory and metabolic alkalosis had a significantly poorer outcome (44.2% mortality) than the alkalemic group as a whole (27.9% mortality) (P less than .05). Alkalemia-associated illnesses are common in hospitalized patients and are associated with high mortality in both medical and surgical patients, though the death rate is higher among medical patients. Mixed respiratory and metabolic alkalosis appears to be associated with a particularly poor prognosis.