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, alloc ated randomly to receive general anaesthesia, local anaesthesia by ret robulbar 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 pa tients receiving general anaesthesia alone. Retrobulbar block given af ter induction of general anaesthesia, however, suppressed the cortisol and glucose responses during surgery, but did not prevent a marked in crease in cortisol concentrations during the immediate postoperative p eriod. The results suggest a hormonal response to emergence from anaes thesia which has hitherto been masked by the stress response to surger y itself.