Clinical bottom line
The increasing prevalence of cannabis use among surgical patients necessitates a nuanced understanding of its impact on anesthetic management. Current evidence suggests that cannabis use can influence anesthetic requirements, perioperative hemodynamics, and postoperative recovery. Clinicians should be aware of these potential effects and consider them when planning anesthetic care. However, the evidence is still evolving, and further research is needed to establish comprehensive guidelines.
What the evidence shows
Recent studies indicate that regular cannabis users may require higher doses of anesthetic agents. A retrospective study found that cannabis users undergoing surgery required significantly more propofol and sevoflurane compared to non-users (PMID: 30768362, 2019). This finding is supported by another study that reported increased opioid consumption postoperatively in cannabis users (PMID: 31483967, 2019).
Cannabis use has also been associated with altered perioperative hemodynamics. A systematic review highlighted that cannabis can lead to tachycardia and hypertension, which may complicate anesthetic management (PMID: 31512168, 2020). Additionally, cannabis users have been reported to experience increased postoperative nausea and vomiting, potentially due to cannabinoid hyperemesis syndrome (PMID: 32074321, 2020).
Caveats and uncertainty
While these findings provide valuable insights, there are significant limitations and uncertainties. The majority of studies are observational, with inherent biases and confounding factors. The heterogeneity in cannabis products, including varying THC and CBD concentrations, complicates the extrapolation of results. Furthermore, the retrospective nature of many studies limits the ability to establish causality.
The long-term effects of cannabis use on surgical outcomes remain unclear. There is a need for prospective, randomized controlled trials to better understand the implications of cannabis use in the perioperative setting. Additionally, the impact of cannabis on specific patient populations, such as those with chronic pain or psychiatric conditions, requires further investigation.
How this may change practice
Anesthesiologists should consider incorporating questions about cannabis use into preoperative assessments to tailor anesthetic plans accordingly. Awareness of the potential for increased anesthetic and analgesic requirements can guide dosing strategies and improve perioperative care. Monitoring for hemodynamic instability and postoperative complications, such as nausea and vomiting, is crucial in cannabis users.
As evidence continues to evolve, anesthesiologists should remain informed about emerging research and adapt their practice to incorporate new findings. Collaboration with other healthcare providers, including pain specialists and addiction medicine experts, may enhance patient care and outcomes.