Canadian Journal of Anesthesia, Vol 25, 380-391, Copyright © 1978 by Canadian Anesthesiologists' Society

Effect of Endotoxic Shock On Renal and Hormonal Functions

¹ Department of Anaesthesia, Hirosaki University School of Medicine, Hirosaki, Aomori-ken, Japan

The effect of endotoxic shock on endocrine function and the anti-shock effects of dexamethasone and methylprednisolone were investigated in 44 mongrel dogs. Plasma concentrations of antidiuretic hormone (ADH), adrenocorticotropic hormone (ACTH), epinephrine, norepinephrine, aldosterone, plasma renin activity, cortisol, and insulin were measured simultaneously during and following endotoxic hypotension. Other parameters, such as cardiac output, renal tissue plasma flow, mean arterial blood pressure, urine volume and osmolality, serum and urine electrolytes, blood gas analysis, blood glucose, lactate and pyruvate concentrations were also determined simultaneously during the procedure. Dogs anaesthetized with pentobarbitone were given a fatal intravenous dose of E. coli (Difco) 3 mg per kg body weight. Lactated Ringer's solution 6 ml/kg/hr was given throughout the procedure. Methylprednisolone 30 mg/kg or dexamethasone 5 mg/kg was administered just prior to the administration of the endotoxin.

Plasma ADH concentrations were found to be increased 20 and 25 times at 15 and 30 minutes post-endotoxin, respectively. Plasma levels of epinephrine and norepinephrine, aldosterone, plasma renin activity, cortisol and insulin increased significantly to 21, 4, 4, 2, 3 and 5 times, respectively, 30 minutes post-endotoxin, but thereafter they decreased gradually. Renal cortical tissue blood flow decreased to a low level about 39-42 per cent of control 15 minutes post-endotoxin in all groups. Urine volume, osmolality, as well as sodium and potassium concentrations decreased significantly in the postendotoxin period. Mean arterial blood pressure and cardiac output, blood pH and base excess fell significantly following administration of the endotoxin. Plasma lactic and pyruvic acid, blood glucose and haematocrit increased significantly during the same period.

Methylprednisolone (MP) 30 mg/kg or dexamethasone 5 mg/kg administered intravenously before the endotoxin caused a significant decrease of the plasma levels of ADH, aldosterone and ACTH as compared with the control group which had received no steroids. No significant effect of steroid was observed in renal tissue blood flow or mean arterial blood pressure. Administration of methylprednisolone before the endotoxin improved urine output significantly, but affected elevation in blood pH and cardiac output only to an insignificant degree. Our data suggest that the administration of methylprednisolone or dexamethasone is beneficial in improving endotoxic shock by decreasing the plasma levels of vasoactive hormones such as ADH and the renin-angiotensin-aldosterone system.