Prevalence and management of intrathecal morphine induced pruritus in the New Zealand Māori population

Abstract

Background: The use of intrathecal morphine for patients undergoing total hip and knee joint replacements and for lower segment caesarean sections (LSCS) has gained popularity worldwide since its introduction in 1979 (Gehling & Tryba, 2009). Several studies show that morphine delivered via the intrathecal route is an effective and safe method of pain relief (Dahl, Jeppesen, Jorgensen, Wetterslev, & Moiniche, 1999; Sites et al., 2004). However, while the beneficial effects of intrathecal morphine have been clearly documented in many studies, so also have the adverse effects e.g., nausea and vomiting, pruritus, and respiratory depression (Gehling & Tryba, 2009; Gwirtz et al., 1999). Pruritus is described as one of the most common adverse effects, with a reported incidence of 30% to 100% (Szarvas, Harmon, & Murphy, 2003). Aims: The aims of this research portfolio were to determine if the incidence of intrathecal morphine induced pruritus (ITMI) was influenced by ethnicity, age, or gender, and to explore how this pruritus was managed by health care professionals. Methods: A two-phased approach was undertaken. A retrospective audit was conducted to determine the incidence of intrathecal morphine induced pruritus among certain patient groups and what treatment was received. A health care professional survey was then performed to explore the current awareness, observations, and management of intrathecal morphine induced pruritus. Findings: The findings revealed significant ethnic disparities in patient responses to intrathecal morphine. Results of the health care professional survey show variances in their knowledge base, which has led to development of a framework for improvement in the management of intrathecal morphine induced pruritus. Conclusions: Management of these outcomes can be enhanced by the implementation of the strategies and frameworks outlined. Utilisation of these research portfolio recommendations could enable earlier post-operative recovery and improved patient outcomes. These recommendations could ensure health care professionals maintain competency and awareness in the provision of diligent management of patients receiving intrathecal morphine.