Incidence and predictors of moderate to severe acute post caesarean incision pain following intrathecal morphine anaesthesia at Kawempe National Referral Hospital

Abstract

Background The response to morphine varies from person to person owing to genetic variations in mu opioid receptors. As such, findings from studies carried out among other races may not be generalisable to our population. This study determined the incidence and predictors of acute post caesarean incision pain following intrathecal morphine anaesthesia at a Ugandan tertiary hospital. Methods From November, 2020 to February, 2021, we conducted a prospective observational cohort study among 403 consecutively enrolled participants. All got 100μg of intrathecal morphine and 12.5mg of 0.5% hyperbaric bupivacaine. The primary outcome was a cumulative incidence of incision pain intensity score ≥ 4 on the Numeric Pain Rating Scale within the first 24 postincision hours. We used logistic regression analysis to assess the predictors of a pain intensity score ≥ 4. Results The overall cumulative incidence of pain at rest within 24 hours was 31.7% (95% CI; 27.1- 36.2%). Having a first time caesarean delivery (AOR 0.56, 95%CI; 0.34, 0.92, P value 0.023), elective caesarean delivery (AOR 0.32, 95% CI; 0.11, 0.98, P value 0.046) and being a housewife were significantly associated with this pain. Conclusion Without any other additional pain relief medications, 100μg of intrathecal morphine combined with 12.5mg of 0.5% hyperbaric bupivacaine offered optimal post caesarean incision pain relief at rest in more than 65%of the participants within the first 24 hours. The healthcare team should be empowered to use intrathecal morphine for postcesarean pain management.