The Effects of Cannabis: Implications for the Surgical Patient

Background: Cannabis use is increasingly prevalent. Cannabinoid receptors regulate pro-inflammatory cytokines, and compounds in marijuana exert diverse physiologic effects. As more patients use cannabis, clinicians should recognize implications of perioperative cannabis use. Although the role of cannabis use in perioperative pain control has been explored, little is known about its effect on perioperative wound healing or on hematologic, pulmonary, and cardiovascular physiology. Methods: We searched PubMed for English-language articles related to cannabis (ie, marijuana, cannabidiol oil, and tetrahydrocannabinol) and wound healing, cardiovascular, pulmonary, or hematologic outcomes, and surgery. Titles and abstracts were reviewed, and relevant articles were analyzed. Human, animal, and pathology studies were included. Editorials, case reports, and review articles were excluded. Results: In total, 2549 wound healing articles were identified; 5 human studies and 8 animal/pathology studies were included. Results were conflicting. An estimated 2900 articles related to cardiovascular effects were identified, of which 2 human studies were included, which showed tetrahydrocannabinol and marijuana caused tachycardia. A total of 142 studies regarding pulmonary effects were identified. Three human studies were included, which found no difference in respiratory complications. In total, 114 studies regarding hematologic effects were identified. The 3 included human studies found conflicting venous thromboembolism risks. The overall study quality was poor. Information about dose/duration, administration route, and follow-up was reported with variable completeness. Conclusions: Surgeons should consider effects of cannabis in the perioperative setting. Little is known about its perioperative effects on wound healing, or on cardiovascular, pulmonary, and hematologic physiology. Further research should elucidate the effects of administration route, dose, and timing of cannabis use among surgical patients.