Neuroendocrine and haemodynamic responses to abdominal aortic cross clamp and release during high-dose opiate-oxygen-isoflurane anaesthesia

The haemodynamic and neuroendocrine responses and beta adrenoceptor distribution associated with aortic cross clamping and release were quantified in 14 patients undergoing elective abdominal aortic aneurysm surgery using a high-dose opiate-oxygen-isoflurane anaesthetic technique. These changes were correlated with neutrophil beta adrenoceptor distribution. Aortic cross clamp application was associated with increased systemic vascular resistance (SVR), and decreased cardiac index (CI). Left ventricular stroke work index remained constant during the period of cross clamp application and following release. Cross clamp release was associated with increased CI and decreased SVR. Plasma cortisol concentrations did not change during the study period. Plasma catecholamine concentrations, although elevated prior to surgery, remained unchanged during aortic cross clamping and following release. The percentage of internalised beta adrenoceptors was elevated before surgery and was unaffected by surgical intervention. This study suggests that a high-dose fentanyl-oxygen-isoflurane anaesthetic technique in a patient population with high circulating catecholamine levels and downregulation of beta adrenoceptors is associated with cardiovascular stability and attenuated neuroendocrine responses.