Post-operative fatigue following coronary artery bypass surgery: relationship to emotional state and to the catecholamine response to surgery.

Post-operative fatigue is an important subjective problem for surgical patients, but its basis is unknown, and the possibility of a psychological component has been neglected. To investigate its putative physiological and psychological bases, 74 patients undergoing coronary artery bypass graft surgery were studied. Circulating catecholamine levels were measured at intervals perioperatively and questionnaires were used to measure fatigue, depression and anxiety up to 30 days post-operatively. We tested whether fatigue was related either to the catecholamine or to the emotional responses to surgery. The second element to the design was a controlled randomized study: patients underwent different forms of psychological preparation or a no-treatment control procedure in an attempt to test whether post-operative fatigue was amenable to psychological manipulation. Psychological preparation had no effect. Fatigue at 30 days was greatest in patients whose noradrenaline levels were greatest perioperatively. Independently of this relationship, fatigue at 30 days correlated with concurrent levels of depression and anxiety. Post-operative fatigue has both physiological and psychological correlates.