Comparison of intrathecal morphine and surgical-site infusion of ropivacaine as adjuncts to intravenous patient-controlled analgesia in living-donor kidney transplant recipients

Abstract

Introduction: This prospective observational study compared the postoperative analgesic effectiveness of intrathecal morphine (ITM) and surgical-site infusion (SSI) of ropivacaine as adjuncts to intravenous (IV) patient-controlled analgesia (PCA) (fentanyl) in living-donor kidney transplant recipients.

Methods: Patients undergoing living-donor kidney transplantation who received ITM or SSI in addition to IV PCA were included. Rescue analgesia was achieved with IV meperidine as required. The primary outcome, measured using the Numeric Pain Rating Scale (NRS), was pain at rest and when coughing. Patients were assessed for 48 hours after surgery.

Results: A total of 53 patients (32 ITM, 21 SSI) were included in the study. The ITM group showed significantly lower NRS scores, at rest and when coughing, for up to 12 and eight hours. NRS scores were comparable between the groups at other times. The ITM group had significantly less postoperative systemic opioid requirement in the first 24 hours, but there was no significant difference between the systemic opioid consumption of the groups on postoperative Day 2. In the ITM group, 3 (9.4%) patients presented with bradypnoea and 1 (3.1%) with excessive sedation in the first 12 postoperative hours. More patients in the ITM group developed pruritus requiring treatment during the first 24 hours. There were no differences between the groups in other outcomes (e.g. nausea/vomiting, change in pulmonary or kidney functions).

Conclusion: Compared with SSI, ITM reduced immediate postoperative pain and IV opioid consumption on postoperative Day 1 after living-donor kidney transplantation, but at the cost of increased pruritus and respiratory depression.

Keywords: analgesia; kidney transplantation; local anaesthetic; morphine; spinal anaesthesia.

Copyright: © Singapore Medical Association

Figures

Fig. 1

CONSORT flowchart shows the enrolment of living-donor kidney transplant recipients in this study. ITM: intrathecal morphine; SSI: surgical-site infusion; IV PCA: intravenous patient-controlled analgesia

Fig. 2

Chart shows Numeric Pain Rating Scale (NRS) scores at rest and when coughing among living-donor kidney transplant recipients at different times after surgery. Bold lines represent medians, bottom of box indicates the first quartile, top of box indicates the third quartile, and whiskers indicate the minimum and maximum non-distant values. Triangles represent distant or extreme values. *p U test. ITM: intrathecal morphine; SSI: surgical-site infusion

Fig. 3

Kaplan-Meier curve shows ratio of living-donor kidney transplant recipients without rescue meperidine at different times after surgery. Significance levels displayed are a comparison of the intrathecal morphine (ITM) and the surgical-site infusion (SSI) groups.

Fig. 4

Chart shows serial changes in perioperative FVC and FEV1 of living-donor kidney transplant recipients after surgery. Connecting lines represent medians and error bars represent interquartile ranges. FEV1: forced expiratory volume in one second; FVC: functional vital capacity; ITM: intrathecal morphine; preop: preoperative period; SSI: surgical-site infusion

Fig. 5

Charts show serial changes in perioperative blood urea nitrogen (BUN), creatinine (Cr) and estimated glomerular filtration rate (GFR) of living-donor kidney transplant recipients after surgery. Bars represent medians and error bars represent interquartile range. Preop: preoperative period; ITM: intrathecal morphine; SSI: surgical-site infusion