PROMPT RECOVERY OF PLASMA ARGININE VASOPRESSIN IN DIABETIC COMA AFTER INTRAVENOUS-INFUSION OF A SMALL DOSE OF INSULIN AND A LARGE AMOUNT OF FLUID

We studied the changes in plasma arginine vasopressin in 5 patients wiht diabetic ketoacidosis and one patient with non-ketotic hyperosmolar coma who had marked hyperglycemia (36.6 ± 4.6 mmol/l, mean ± SEM) and dehydration. Plasma osmolality (P(osm)) was 342.2 ± 11.4 mOsm/kg H2O, and hematocrit, serum protein, and blood urea nitrogen were also elevated at hospitalization. Circulating blood volume was decreased by approximately 21% as compared with that on day 7. Plasma AVP level was increased to 8.5 ± 1.6 pmol/l at hospitalization. When hyperglycemia was improved by iv infusion of a small dose of insulin plus fluid administration, plasma AVP level promptly decreased to 2.4 ± 0.4 pmol/l within six hours. When plasma AVP level had normalized, P(osm) was still as high as 305 mOsm/kg H2O, but the loss of circulating blood volume was only 4.2% of the control state. Plasma AVP level was positively correlated with change in hematocrit (plasma AVP = 3.58 + 0.45 . hematocrit, r = 0.468, p < 0.01), serum protein (r = 0.487, p < 0.01), P(osm) (r = 0.388, p < 0.01), and blood glucose (r = 0.582, p < 0.01). Plasma AVP level was negatively correlated with the change in circulating blood volume (plasma AVP = 3.6 - 0.14 . change in circulating blood volume, r = -0.469, p < 0.01). These results indicate that both non-osmotic and osmotic stimuli are involved in the mechanism for AVP release in patients with diabetic coma, and that the non-osmotic control of AVP may contribute to circulating homeostasis, protecting against severe blood volume depletion in diabetic patients suffering from hyperglycemia and dehydration.