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First US guidelines for combination of cannabis and anaesthesia

Surgical patients scheduled for anaesthesia should be screened for cannabis use, and if necessary, the operation delayed or rescheduled, according to new guidelines from the American Society of Regional Anaesthesia and Pain Medicine (ASRA Pain Medicine).

Patients should be quizzed on the type of cannabis product they used, whether it was smoked or ingested, the amount used and how recently, and the frequency of use, reported Dr Shalini Shah of the University of California Irvine and colleagues in Regional Anaesthesia & Pain Medicine.

They also suggest anesthesiologists should be prepared to possibly change the anaesthetic plan or even delay surgery, and let patients know that regular cannabis users may have more pain and nausea after surgery and possibly need more medications to manage post-surgical pain.

The guidance is the first in the US about cannabis and perioperative management, cannabis being the most commonly used recreational drug in the country, and the most commonly used psychoactive substance after alcohol, said guideline co-author and ASRA Pain Medicine president Dr Samer Narouze of Northeast Ohio Medical University in Akron.

About 10% of the population, or some 27.6m people, reported monthly use in 2017, according to data from the Substance Abuse and Mental Health Services Administration (SAMHSA) and that number is growing, Narouze added. Recent Gallup poll numbers place the number of Americans who smoke marijuana at about 16%.

“That’s why we’ve been working on these guidelines for the past two years, because we have millions of people using cannabis recreationally or medicinally,” Narouze told MedPage Today.

“Every day, people who use cannabis present for surgery,” he pointed out. “We’ve seen some observational studies about this in the literature, but there have been no randomised control trials.”

But even in observational studies, patterns were clear, he said. “The main issue we see is more pain in recovery and more nausea and vomiting, also in recovery. We also see associations with increased risk for post-operative cardiovascular morbidity – post-operative myocardial infarction and arrhythmias – and post-operative cerebrovascular morbidity in some patients.”

Cannabis had varying interactions with anaesthetics and sedatives, Narouze added. Some patients also experienced post-operative cannabis withdrawal symptoms.

The guidelines stemmed from a literature review and other work from the ASRA Pain Medicine guideline committee. A consensus recommendation required at least 75% agreement of the committee’s 13 experts.

The committee used the US Preventive Services Task Force (USPSTF) process of assigning an A, B, C, or D letter grade (or I for insufficient) based on evidence strength.

Recommendations receiving an A grade included screening all patients before surgery, postponing elective surgery if patients had altered mental status, counselling heavy users about potentially negative effects of cannabis on post-operative pain control, and counselling pregnant patients on risks associated with cannabis use.

Those receiving a B grade were counselling patients on potential perioperative risks associated with continuing cannabinoids and discouraging cannabis use during pregnancy and immediately after childbirth.

C grade recommendations included delaying elective surgery for at least two hours after patients smoked cannabis, adjusting anaesthesia delivery based on symptoms and timing of last cannabis consumption, increasing vigilance of potential heart and neurological problems after surgery, using multimodal pain control including opioids if needed, and using a cannabinoid agonist like dronabinol to treat severe cannabis withdrawal symptoms post-operatively.

“There’s a large gap in our knowledge about cannabis and surgery,” said Narouze. “That’s why most recommendations did not reach the grade A level.

“However, we do not want to underestimate the information we gather from observational and large data studies, because these are real-world data.”

The ASRA Pain Medicine task force will continue monitoring new research as it becomes available, Shah and colleagues noted. The group may revise the entire document or specific sections if new evidence warrants updated recommendations.

Study details

ASRA Pain Medicine consensus guidelines on the management of the perioperative patient on cannabis and cannabinoids

Shalini Shah, Eric Schwenk, Rakesh Sondekoppam, Hance Clarke, Mark Zakowski,
Rachel Rzasa-Lynn, Brent Yeung, Kate Nicholson, Gary Schwartz, Michael Hooten, Mark Wallace, Eugene Viscusi and Samer Narouze.

Published in Regional Anaesthesia & Pain Medicine on 4 January 2023


The past two decades have seen an increase in cannabis use due to both regulatory changes and an interest in potential therapeutic effects of the substance, yet many aspects of the substance and their health implications remain controversial or unclear.

In November 2020, the American Society of Regional Anesthesia and Pain Medicine charged the Cannabis Working Group to develop guidelines for the perioperative use of cannabis. The Perioperative Use of Cannabis and Cannabinoids Guidelines Committee was charged with drafting responses to the nine key questions using a modified Delphi method with the overall goal of producing a document focused on the safe management of surgical patients using cannabinoids. A consensus recommendation required ≥75% agreement.

Nine questions were selected, with 100% consensus achieved on third-round voting. Topics addressed included perioperative screening, postponement of elective surgery, concomitant use of opioid and cannabis perioperatively, implications for parturients, adjustment in anaesthetic and analgesics intraoperatively, postoperative monitoring, cannabis use disorder, and postoperative concerns. Surgical patients using cannabinoids are at potential increased risk for negative perioperative outcomes.

Specific clinical recommendations for perioperative management of cannabis and cannabinoids were successfully created.

Guidelines rapm-2022-104013.full


MedPage Today article – Screen All Surgery Patients for Cannabis Use, New Guidelines Say (Open access)


See more from MedicalBrief archives:


Cannabis users need more anaesthesia, painkillers for surgery


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