Stress responses after major surgery in infant: comparison of two analgesic regimens of morphine

ABSTRACT

Infants under 1 year classified to receive either continuous morphine [CM, 10 microg/kg/h] with three-hourly placebo boluses or intermittent morphine [IM, 30 microg/kg every 3h] with a placebo infusion for postoperative analgesia. Plasma concentration of norepinephrine, insulin, glucose and lactate were measured before and at the end of surgery, 12h and 24h after surgery. Pain was assessed with the comfort scale and visual analogue scale [VAS] with the availability or additional morphine doses. Minor differences occurred between the three groups, IM group in infants aged 6m-1 yr [group 3] having a higher blood glucose concentration [p = 0.003] mean arterial pressure [p = 0.02] and comfort score [p = 0.02] than the CM group. In the neonates, preoperative plasma. Concentration of norepinephrine [p = 0.01] and lactate [p < 0.001] were significantly higher, while the postoperative plasma concentration of insulin significantly higher [p < 0.005] than in the group II and III. Postoperative pain scores [p < 0.003] and morphine consumption [p < 0.001] were significantly lower in the neonates [Group I] than in the group II and III. The study shows that continuous infusion of morphine does not provide any major advantages over intermittent morphine boluses for postoperative analgesia in neonates and infants