Ethanol Modulation of Plasma Norepinephrine Response to Trauma and Hemorrhage

Abstract

Does ethanol affect the adrenergic response to trauma? In 52 trauma victims, grouped according to blood ethanol concentrations, we found there was a significantly higher mean plasma norepinephrine (NE) concentration in heavy imbibers than in those with no detectable blood ethanol (790 .+-. 84 pg/ml vs. 1,260 .+-. 310; p = 0.02). To control confounding variables such as intensity of pain, injury severity, etc., we selected blood loss (0.9% body weight over 15 min), as an aspect of trauma to study in six normal subjects before and after ingestion of 6 oz and 10 oz of 86-proof liquor on successive days. As expected, the increase in plasma NE upon assumption of an upright position was accentuated by blood loss, (384 .+-. 43 pg/ml prebleed; 694 .+-. 16 post-bleed; p = 0.001). The postural or hypovolemic effect on plasma NE was enhanced by ingestion of ethanol at 6 oz prebleed (529 .+-. 42 pg/ml pre-ethanol vs. 732 .+-. 64 post ethanol; p = 0.02) or at 10 oz post-bleed (694 .+-. 16 pg/ml vs. 1,154 .+-. 166; p = 0.04). There was an approximate dose-response effect of ethanol on plasma NE under all conditions; for example, post-bleeding upright NE: 717 .+-. 57, no ethanol; 1,045 .+-. 221, 6 oz ethanol, and 1,257 .+-. 182, 10 oz ethanol. Plasma epinephrine concentrations were not significantly affected by positional changes, blood loss, or ethanol consumption. Standing systolic blood pressure (BP) fell (139 .+-. 71 mm Hg vs. 113 .+-. 11; p = 0.02) as did diastolic BP (98 .+-. 8 vs. 79 .+-. 11; p = 0.03) after blood loss, but ethanol ingestion did not modify the BP decrease in spite of increased plasma NE. We conclude that ethanol ingestion has a significant enhancing effect on the plasma NE response to hemorrhage. The blunting effect by the ethanol on NE vascular response may moderate the impact of adrenergic stimulation.