Dilutional acidosis during whole lung lavage under general anesthesia due to excessive absorption of normal saline

Whole lung lavage (WLL) is an effective therapy for pulmonary alveolar proteinosis. We report a rare dilutional acidosis following WLL in a female patient.

Under general anesthesia, a left-sided double-lumen tube was inserted with its bronchial lumen connected to the saline delivery system. Preoperatively, arterial blood gases were within normal limits. During 14 l of fluid was instilled into the lung for 2.5 hours, a decrease in pH, K⁺, and base excess, alongside an increase in Na⁺ and Cl^-, indicated a strong ion difference; the diagnosis was dilutional hyperchloremic metabolic acidosis. Although she remained hemodynamically stable and had no indicators of massive absorption, she stayed in the ICU for mechanical ventilation for one night out of concern of pulmonary edema.

Inappropriate irrigating fluid pressure might lead to absorption of normal saline. Continuous monitoring and careful observation during WLL can help prevent intraoperative dilutional acidosis.