Effect of an acute increase in cerebrospinal fluid pressure on lung compliance in the rabbit.

Cerebrospinal fluid pressure (Pcsf) was increased acutely by the injection of normal saline into the cisterna magna of anaesthetized rabbits to values which interrupted cerebral flow. When increased Pcsf was maintained for a minimum of 3 min, static lung compliance decreased and lung weight (after sacrifice) increased without marked change in arterial blood-gas tensions. The magnitude of the increase in Pcsf did not affect the change in compliance and weight. There was marked unexplained metabolic acidosis. The pulmonary findings may result from a massive shift of blood from the systemic to the pulmonary circulation leading to increased permeability of the interendothelial junctions of the pulmonary capillaries.