RESUMEN
OBJECTIVE: To evaluate the efficacy and safety of inhaled morphine delivered in patients experiencing severe acute pain in an emergency setting. PATIENTS AND METHODS: Patients were eligible for inclusion if they were aged 18 years or older, with a severe acute pain defined by a numerical rating scale (NRS) score of 60/100 or higher. The intervention involved administering a single dose of 0.2 mg/kg morphine nebulized using a Misty-Neb nebulizer system. NRSs were recorded and were repeated at 1, 3, 5, and 10 minute after the end of inhalation (T10). The protocol-defined primary outcome measure was pain relief (defined by an NRS score of 30/100 or lower) at T10. Secondary outcomes included differences between pain scores at baseline and at T10 and incidence of adverse events. RESULTS: A total of 28 patients were included in this study. No patient experienced pain relief 10 minutes after the end of inhalation, and no adverse effects were recorded. Respective initial and final median NRS scores were 80 (70-90) and 70 (60-80), p < 0.0001. Despite achieving statistical significance, the value of this point estimate is less than the 14 NRS difference that was defined a priori as representing a minimum clinically significant difference in pain severity. CONCLUSION: 0.2 mg/kg nebulized morphine is not effective in managing acute pain in an emergency setting. In spite of the potential advantages of the pulmonary route of administration, opioids should be intravenous prescribed at short fixed intervals to control severe acute pain in an emergency setting.