Beta 2-adrenergic responsiveness in vivo during abdominal surgery

We have studied adrenergic function in vivo during anaesthesia and surgery.Epinephrine 50 ng kg-1 min-1 was given by i.v. infusion over 30 min to 10healthy adult volunteers and to 10 patients undergoing abdominaloperations. The cAMP response to stimulation by epinephrine, which wasobtained as the area under the curve (AUC) for plasma cAMP concentrationdivided by the AUC for plasma concentration of epinephrine, was morepronounced during surgery (mean ratio 3.5) than in the control situation(ratio 1.4; P < 0.02). This resulted in greater hypokalaemic andhyperglycaemic responses (ratios -0.67 and 4.5) than in the control group(ratios -0.33 and 1.6, respectively; P < 0.004). Mean arterial pressuredecreased in the control group while it increased in the study group, andserum cortisol concentration was higher in those who underwent surgery (P< 0.02). These results are consistent with an increased adrenergicresponse during abdominal surgery.