Abstract
Investigation of a series of 150 obstetric patients, the majority undergoing caesarean section, showed the expected figure of 2% with factual recall. There was, however, a 17.3% occurrence of unpleasant recall-associated in 10 cases (6.6% of the total) with recall of pain. There was a negative correlation between the giving of a narcotic within six hours of the operation and the occurrence of unpleasant recall. Several other aetiological factors-age, parity, preoperative emotional tension, ventilation, nitrous oxide wash-out with oxygen, and nitrous oxide concentration-were investigated and no relation was found between them and unpleasant recall. It is suggested, therefore, that premedication still has an important function in light anaesthesia, using muscle relaxants, to prevent any form of unpleasant operative awareness.