The role of "Integrated Pulmonary Index" monitoring during morphine-based intravenous patient-controlled analgesia administration following supratentorial craniotomies: a prospective, randomized, double-blind controlled study

Objective: Morphine is commonly used in post-operative analgesia, but opioid-related respiratory depression causes a general reluctance for its use. The "Integrated Pulmonary Index" is a tool calculated from non-invasively obtained respiratory and hemodynamic parameters. The aim of this prospective, randomized, double blind, and placebo-controlled study is to determine a more safe and effective dose for morphine in patient-controlled analgesia following supratentorial craniotomy using the "Integrated Pulmonary Index". Methods: This study included 60 patients (ASA I, II, and III). All patients used iv PCA for 24 h following supratentorial craniotomy. The PCA was set to administer a bolus dose of 1 mg morphine in Group 1 and 0.5 mg morphine in Group 2. The PCA contained placebo in Group 3 and patients received dexketoprofen 50 mg iv after awakening, repeated every 8 h. The IPI and NRS scores, total morphine consumption, and morphine related side-effects were recorded at 10 min, 1, 2, 6, 12, and 24 h post-operatively. The lowest IPI score, count of apnea, and desaturation events were recorded during the study period. Results: The IPI scores were similar among the groups. Although a statistically significant difference was not observed among the groups the lowest IPI scores were observed in Group 1; apnea and desaturation counts were also higher in Group 1. Statistically significant differences were not observed among the groups in terms of pain scores, but were lower in Groups 1 and 2 compared to Group 3. Conclusion: Patient controlled analgesia with 0.5 mg morphine may be safe and effective for pain management following supratentorial craniotomies. Integrated pulmonary index can be used for detecting opioid-induced respiratory depression. Clinical Trials registration number: NCT02929147.