Magnitude and kinetics of alterations in plasma catecholamines and leukocyte beta-adrenergic receptors in response to anaesthesia and surgery

Abstract

We studied the response of the sympatho-adrenal system to varying intensities of different stimuli. Concentrations of norepinephrine and epinephrine in plasma as well as densities of beta 2-adrenergic receptors on mononuclear leukocytes were determined in patients subjected to operations of varying complexity and different types of anaesthesia. In patients undergoing hysterectomy (n = 9), the maximal increases in plasma norepinephrine and epinephrine were 2.7- and 2.8-fold, respectively, corresponding to a post-operative decrease of the mononuclear leukocyte beta 2-adrenergic receptors of 27% after 4 hours. Patients with coronary revascularization (n = 17) were randomly selected to receive either enflurane/N2O or neurolept anaesthesia. During intraoperative periods of stress, such as cardiopulmonary bypass and hypothermia, norepinephrine and epinephrine levels were 2-3 times higher in the neurolept patients, compared with the enflurane patients. In the former group, the respective maximal norepinephrine and epinephrine concentrations were 9.7 and 28 times the vasal values of the non-anaesthetized patients. One day postoperatively, the mononuclear leukocyte beta 2-receptor density decreased maximally by 45 +/- 11% in the enflurane patients, and by 53 +/- 6% in the neurolept patients. As early as two to five days after cardiac surgery, beta 2-receptor densities were no longer distinguishable from the preoperative values. Significant correlations between the increases in catecholamine concentrations and the decreases in beta 2-receptor densities did not exist. It is concluded that enflurane blocks the sympatho-adrenal response to surgical stress more effectively than neurolept anaesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)