Comparison of high- and low-dose intrathecal morphine for spinal fusion in children

Abstract

Background. The purpose of this prospective study was to assess the blood-sparing effect, the quality of analgesia, and the incidence of side-effects of a low-dose regime of intrathecal opioids (ITO) when compared with those of a high-dose regime in scoliosis surgery in children. Methods. Forty-six children were randomly included into one of the three groups to receive morphine 5 μg kg-1 plus sufentanil 1 μg kg-1 [low-dose intrathecal opioid (LITO)], morphine 15 μg kg-1 plus sufentanil 1 μg kg-1 [high-dose intrathecal opioid (HITO)] intrathecally, or no intrathecal opioid. Postoperative analgesia was provided by i.v. opioids. Intraoperative blood loss, postoperative quality of analgesia, opioid requirements, and the incidence of side-effects were recorded for 3 days. Results. Intraoperative blood loss was significantly reduced by ITOs [LITO: 41.4 (sd 18.8) ml kg-1; HITO: 37.5 (6.9) ml kg-1; control: 76.9 (15.3) ml kg-1, P<0.001], with no difference between the two intrathecal opioid groups. Mean pain scores on the day of surgery were lower in both intrathecal opioid groups (LITO: 2.2 and HITO: 2.1) when compared with the control group (4.1, P<0.03) and opioid consumption was significantly decreased [LITO: 304.3 (65.0) μg kg-1; HITO: 224.1 (51.8) μg kg-1; control: 667.7 (89.5) μg kg-1, P<0.002]. Side-effects of intrathecally administered opioids were similarly frequent in all groups. Conclusions. Intrathecal administration of opioids significantly reduces blood loss and postoperative opioid demand, thereby showing side-effects comparable with the control group. These effects were already seen with the low-dose regimen and high dose did not further improve efficacy. © The Board of Management and Trustees of the British Journal of Anaesthesia 2008. All rights reserved.