Intrathecal diamorphine for perioperative analgesia during colorectal surgery: a cross-sectional survey of current UK practice

OBJECTIVES: To describe current UK clinical practice around the use of intrathecal diamorphine as analgesia for major elective laparoscopic colorectal surgery. DESIGN: Online self-administered survey. SETTING: Acute public hospitals in the UK (National Health Service – NHS). PARTICIPANTS: Consultant anaesthetists involved in colorectal surgery lists. MAIN OUTCOME MEASURES: Rate of intrathecal opioids used by anaesthetists for elective laparoscopic colorectal procedures; minimum, most common and maximum doses of intrathecal diamorphine used, timing of administration of intrathecal injection, and relationship between the number of patients anaesthetised for laparoscopic colorectal resections per month by each anaesthetist, and the doses of intrathecal diamorphine they administer. RESULTS: In total, 479 responses were received. Of these, 399 (83%) use intrathecal opioid routinely: 351/399 (88%) use diamorphine, 35 (8.8%) use morphine, 8 (2%) use fentanyl, and 7 (1.3%) use other drugs. The median intrathecal diamorphine dose most commonly administered by anaesthetists was 500 µg (IQR 400–750 [(range 200–1500])). The median of the maximum dose administered by anaesthetists was 600 µg (IQR 500–1000 [(range 200–2000])). Greater intrathecal diamorphine dosing was positively associated with higher number of cases per month (rho=0.113, pp=0.033). CONCLUSIONS: Intrathecal diamorphine is widely used by UK anaesthetists for patients undergoing major elective laparoscopic colorectal surgery. However, there is little consensus regarding optimal dosing. Therefore, high-quality randomised dose-response trials are needed to investigate the relationship between doses of intrathecal diamorphine and patient outcomes.