Pulmonary Complications and Water Retention in Prolonged Mechanical Ventilation

In a retrospective study of 100 patients treated with prolonged mechanical ventilation, water retention without evidence of cardiac failure developed in 19. This was associated with radiologic evidence of pulmonary edema and with the following significant changes: a mean gain in weight of 2.6 kg; a mean increase in the alveolar-arterial oxygen tension gradient of 127 mm of mercury; a decrease in vital capacity of 29 per cent; a reduction in estimated compliance of 31 per cent; a fall in hematocrit of.13 percent; and a decrease in serum sodium of 5.80 mEq per liter. These changes were reversed after the institution of a negative water balance by restriction of water intake and by diuretic therapy. Radiologic improvement was usually prompt. The appearance of pulmonary edema may be related to a relative water overload, a rise in antidiuretic hormone production or subclinical cardiac failure.