Acid-Base Disorders

Abstract

Diagnosis of acid-base disturbances can be challenging and requires careful clinical evaluation. The initial approach to acid-base disorders requires arterial blood gas analysis. Evaluation of pH, partial pressure of carbon dioxide, and bicarbonate level assists the clinician in determining an acidotic versus alkalotic state and whether respiratory or metabolic etiologies are driving this process. Note that respiratory compensation for primary metabolic disorders occurs rapidly. Conversely, metabolic compensation for primary respiratory disturbances may require 3–5 days for renal adjustment. Metabolic acidosis is a commonly encountered acid-base disturbance in the surgical patient, with reduced end-organ perfusion and ischemia serving as a primary cause. Metabolic acidosis requires determination of anion gap and a differential diagnosis to guide treatment. Lactate levels should also be obtained in these patients. Treatment of acid-base disturbances focuses on correcting the underlying pathophysiology. Special consideration should be given to providing adequate fluid resuscitation and oxygen delivery. Appropriate treatment may include vasopressor support, blood transfusion, renal replacement therapy, ventilator adjustment, and antibiotics when necessary.