Predictive factors of early morphine requirements in the post-anaesthesia care unit (PACU)

Use of morphine by titration in the post-anaesthesia care unit (PACU) is often the first step in postoperative pain management. This approach provides rapid analgesia but shows a wide inter-individual variability in morphine requirements and may prolong patient stay in the PACU. The aim of this study was to identify the patient characteristics, surgical, anaesthetic, and postoperative factors predictive of early morphine requirements. The study included 149 patients undergoing various non-cardiac surgical procedures under general anaesthesia. In the multiple regression analysis of nine variables, only ethnicity (Caucasian), emergency surgery, major surgery, surgery exceeding 100 min, and pain score on arrival in PACU were predictive factors of morphine requirements. This observational study identifies for the first time independent predictive factors of morphine requirements in the early postoperative period. Future studies are warranted to evaluate the impact of intervention on these factors and any resulting improvement in postoperative pain treatment.