Abstinent smokers may have reduced preoperative pain tolerance and increased postoperative opioid use compared with nonsmokers, according to a study recently published in Addictive Behaviors.
To evaluate the influence of smoking cessation on preoperative pain tolerance and postoperative pain perception, researchers enrolled men who underwent hepatic resection (68 nonsmokers, 80 abstinent smokers). Participants received patient-controlled intravenous analgesia following surgery.
In all study participants, the pain threshold in response to electrical stimuli was assessed before surgery, and cumulative morphine equivalent doses during the 48 hours following surgery were recorded. Analgesia consumption (determined by button pressing) and pain scores assessed using the Visual Analog Scale were also compared between the 2 groups.
Abstinent smokers had a lower electrical pain threshold compared with nonsmokers prior to surgery (0.9 mA and 1.3 mA, respectively; P <.001). Compared with nonsmokers, abstinent smokers were administered higher quantities of extra morphine equivalent during the first 48 hours postoperatively (11.3 mg vs 6.6 mg, respectively; P =.046). In addition, a greater percentage of abstinent smokers vs nonsmokers requested additional rescue analgesics during the first 48 hours after surgery (68.75% vs 54.41%; P =.049). Pain scores were higher in the abstinent smokers compared with nonsmokers at 6, 24, and 48 hours postsurgery (P <.01).
The study authors concluded that, “abstinent smokers were more sensitive to pain before surgery and had an increased risk of postoperative pain.” They suggested that a potential explanation for these findings, “is that abstaining from smoking can produce profound changes in physiology,” but the authors acknowledged that additional research would be needed to further elucidate the underlying mechanisms.
Shen L, Wei K, Chen Q, et al. Decreased pain tolerance before surgery and increased postoperative narcotic requirements in abstinent tobacco smokers. Addict Behav. 2017;78:9-14.