Intravenous morphine for breakthrough (episodic-) pain in an acute palliative care unit: a confirmatory study

Abstract

The aim of this prospective cohort study was to confirm the safety of intravenous morphine (IV-M) used in doses proportional to the basal opioid regimen for the management of breakthrough pain and to record the nurse compliance on regularly recording data regarding breakthrough pain treated by IV-M. Over a one-year period, 99 patients received IV-M for breakthrough pain during 116 admissions. The IV-M dose was 1/5 of the oral daily dose, converted using an equianalgesic ratio of 1/3 (IV/oral). For each episode, nurses were instructed to routinely collect changes in pain intensity and emerging problems when pain became severe (T0), and to reassess the patient 15minutes after IV-M injection (T15). Nurses were unaware of the aim of the study and just followed department policy. In total, 945 breakthrough events treated by IV-M were recorded and the mean number of events per patient per admission was eight (95% confidence interval (CI) 6.9-9.5). The mean dose of IV-M was 12mg (95% CI 9-14mg). In the 469 events (49.6%) with a complete assessment, a decrease in pain of more than 33% and 50% was observed in 287 (61.2%) and 115 (24.5%) breakthrough events, respectively. The mean pain intensity decreased from 7.2 (T0) to 2.7 (T15). In eight episodes, no changes in pain intensity were observed and a further dose of IV-M was given. The remaining patients did not require further interventions. No clinical events requiring medical intervention were recorded. In this confirmatory study, IV-M was administered for the management of breakthrough pain in doses proportional to the basal opioid regimen to all patients, including older patients and those requiring relatively large doses. This did not result in life-threatening adverse effects in a large number of patients and was effective in most cases. The role of nurses is of paramount importance in monitoring and collecting data and gathering information for audit purposes on the unit.