A systematic review of morphine equivalent conversions in plastic surgery: Current methods and future directions

Abstract

INTRODUCTIONProtocols surrounding opioid reduction have become commonplace in plastic surgery to improve peri-operative outcomes. Within studies on these protocols, one frequently analyzed outcome is opioid requirement. Though often examined, at present there is no literature standard conversion for morphine milligram equivalents (ME), leading to questionable external validity. We hypothesized significant heterogeneity of ME reporting would exist within plastic surgery literature. METHODSFollowing PRISMA guidelines, the authors conducted a systematic review of sixteen journals. Clinical studies focused on opioid reduction within plastic surgery were identified. Primary outcomes included reporting of morphine equivalents (ME) delivery (IV/oral), operative ME, inpatient ME, outpatient ME, timeline, and method of calculation. RESULTSOf the 101 studies analyzed, 73% reported opioid requirements in the form of morphine equivalents (ME). Of these that utilized ME, 3% reported IV ME, 41% reported oral, 32% reported both, and 25% gave no indication of either. Operative ME were reported in 19% of studies. 54% of studies reported inpatient ME while 32% of studies reported outpatient ME. Only 19% reported the number of days opioids were consumed post-operatively. 27% of studies reported the actual method of ME conversion, with seventeen unique methods described. Only eight studies (8%) reported using the CDC guidelines for ME conversion. CONCLUSIONThere is significant variability among reported ME conversion methodology within plastic surgery literature. Highlighting these discrepancies is an essential step in creating and implementing a single, standard method to mitigate opioid morbidity in plastic surgery and to optimize enhanced recovery protocols.