RETROBULBAR BLOCK FAILS TO PREVENT AN INCREASE IN SERUM CORTISOL CONCENTRATION ON EMERGENCE FROM ANESTHESIA AFTER CATARACT-SURGERY

We have studied 30 elderly patients undergoing cataract surgery, allocated randomly to receive general anaesthesia, local anaesthesia by retrobulbar block or general anaesthesia combined with retrobulbar block given after induction. Retrobulbar block alone prevented the increases in circulating cortisol and glucose values which occurred in those patients receiving general anaesthesia alone. Retrobulbar block given after induction of general anaesthesia, however, suppressed the cortisol and glucose responses during surgery, but did not prevent a marked increase in cortisol concentrations during the immediate postoperative period. The results suggest a hormonal response to emergence from anaesthesia which has hitherto been masked by the stress response to surgery itself.