Relation of colloid osmotic pressure to arterial hypoxemia and cerebral edema during crystalloid volume loading of patients with diabetic ketoacidosis.

The effect of crystalloid volume loading on serum colloid osmotic pressure, arterial oxygen (Po2), alveolar-arterial oxygen gradient (A-aDo2), and cerebral lateral ventricle dimensions was prospectively studied in 18 patients with diabetic ketoacidosis. Serial measurements showed concomitant decreases in colloid osmotic pressure, hematocrit, arterial Po2 (p less than 0.001), and significant increases in A-aDo2 (p less than 0.001) during treatment. Serial echoencephalograms were taken of 11 of the 18 patients; each patient served as his or her own control. Nine of these 11 patients showed significant decreases in lateral ventricle width during treatment; seven patients showed the echoencephalographic "hash" marks characteristic of cerebral edema. Follow up studies showed resolution of these abnormalities. Volume loading with large amounts of crystalloid solution seems to produce an acute hypooncotic state that may cause the development of both subclinical pulmonary and cerebral edema.