The acidosis of pulmonary edema

The records of 292 patients with acute pulmonary edema were reviewed to determine the frequency, severity and type of acid-base abnormalities. Arterial blood gas analyses were available in 109 patients, including eight patients with submersion complicated by pulmonary edema. Of the 101 cardiac cases, a severe combined metabolic and respiratory acidosis was present in fifty-five, with mean pH 7.11, carbon dioxide pressure (pCO₂) 70 mm Hg and base excess -10 mEq per L. There were fourteen patients with metabolic acidosis, twelve with respiratory acidosis and eight with respiratory alkalosis. Four of the eight patients in the submersion group exhibited a combined acidosis. Treatment included mechanical ventilation, intubation when indicated, and intravenously administered sodium bicarbonate, in addition to conventional therapy for pulmonary edema. Combined respiratory and metabolic acidosis probably occurs in approximately 25 per cent of patients with acute pulmonary edema, and metabolic or respiratory acidosis in another 10 per cent. Serial arterial blood gas analyses are a prerequisite for physiologically appropriate management of these patients.