Anesthesia matters: Patients anesthetized with propofol have less postoperative pain than those anesthetized with isoflurane

BACKGROUND: Preclinical studies have suggested that some volatile anesthetics induce a hyperalgesic state that may be secondary to nicotinic inhibition. A previous trial of treatment with nicotine nasal spray demonstrated postoperative analgesia in women anesthetized with isoflurane. To determine whether the effect of nicotine was reversing hyperalgesia induced by isoflurane, or simply acting as an analgesic, we studied the effect of nicotine on postoperative pain in women anesthetized with isoflurane or propofol, with fentanyl. METHODS: In a randomized, prospective, double-blind trial, we assigned 80 women having open uterine surgery to be anesthetized with isoflurane or propofol. Within each anesthetic group, the subjects were further randomly assigned to receive nicotine 3 mg or placebo. Pain reported with a numerical analog scale was the primary outcome variable. RESULTS: The patient demographics were similar. Women who were anesthetized with propofol reported less pain and used less morphine during the first day after surgery than women who were anesthetized with isoflurane (P < 0.01, P < 0.01). Nicotine treatment did not change pain report or morphine use in either anesthetic group (P > 0.05). CONCLUSIONS: General anesthesia with propofol and is associated with less postoperative pain and morphine use than general anesthesia with isoflurane. Nicotine was not analgesic in this trial. If these results are repeated in other populations, reduced postoperative pain can be added to the previously described improvement in nausea and vomiting as a potential benefit of anesthesia with propofol.