Mechanism of Plasma Catecholamine Increases During Surgical Stress in Man

Abstract

In order to determine whether the sympathetic nervous system participates in the neuroendocrine response to surgical stress in man, plasma levels of norepinephrine (NE) and epinephrine (E) were measured by enzymatic assay in eight patients undergoing elective abdominal operations. Basal NE levels (pre-anesthesia) were comparable to those of 11 normal controls: 180 ± 20 pg/ml, ± sem (patients), vs. 180 ± 20 (controls), but basal E levels were higher: 70 ± 10 (patients) vs. 20 ± 5 (controls), P < .001. Halothane anesthesia caused no changes of plasma NE (Δ NE = +50 ± 40 pg/ml, p = NS), but suppressed plasma E (Δ E = −50 ± 10 pg/ml, P < .01). During the operation plasma catecholamines rose above anesthesia levels in all patients: Δ NE = +380 ± 60, Δ E = +250 ± 100, both P < .01. Plasma catecholamines remained elevated through 2 h after surgery: Δ NE (vs. pre-anesthesia baseline) = +290 ± 60, P < .01, Δ E = +200 ± 60, P < .05. Throughout the procedure Δ NE correlated with Δ E (r = .75, P < .001). These findin...