Patients with prior cannabis use may need higher doses of intraoperative inhaled anesthetic and postoperative opioids, according to a study presented at ANESTHESIOLOGY, the annual meeting of the American Society of Anesthesiologists, held virtually from Oct. 2 to 5.
Ian Holmen, M.D., from the University of Colorado in Aurora, and colleagues retrospectively reviewed medical charts for 118 patients who had unilateral tibia fractures and underwent open reduction and internal fixation with an intramedullary nail at a single institution from January 2015 through November 2019.
The researchers found that one-quarter of patients (25.4 percent) reported prior cannabis use. There was no association noted between cannabis use and a higher dose of induction propofol. However, there was a significant association between cannabis use and a higher average volume of intraoperative sevoflurane. There was also an association observed between cannabis use and higher PACU pain scores (6.0 versus 4.8) and initial inpatient pain scores (6.2 versus 5.0). In the cannabis use group, the average total hospitalization morphine milligram equivalents were significantly higher.
“We now understand patients who chronically use opioids prior to surgery often have exaggerated pain responses and need increased pain medication after surgery because they have an increased tolerance,” Holmen in a statement. “We speculate that cannabis use may cause a similar effect, but we need more research to determine if this is the case.”