HYPOXAEMIA AND PAIN RELIEF AFTER UPPER ABDOMINAL SURGERY: COMPARISON OF I.M. AND PATIENT-CONTROLLED ANALGESIA

Forty patients recovering from upper abdominal surgery were allocated randomly to receive i.m. morphine 0.15 mg kg−1 as required or patient-controlled analgesia (PCA), with i.v. morphine 1 mg and a 5-min lock out time. Arterial oxygen saturation (Sp02) was measured continuously the night before and for 24 h immediately after surgery. A significantly greater proportion of patients in the PCA group (nine of 19) rated their analgesia as excellent compared with the i.m. group (two of 20) (P < 0.05). There was no significant difference in the incidence of postoperative hypoxaemia in the two treatment groups. Severe postoperative hypoxaemia (Sp02 <85% for more than 6 min h−1 ) was seen in three patients receiving i.m. analgesia and one patient in the PCA group.