Patients Should Be Screened For Cannabis Use Before Surgery, Say New Guidelines

All patients undergoing anesthesia should be asked about their cannabis habits, according to new guidelines released this month by the American Society of Regional Anesthesia and Pain Medicine (ASRA Pain Medicine).

These guidelines have been written in light of the growing prevalence of cannabis use, ASRA Pain Medicine says, and were developed by a team of experts based on an extensive literature review.

The guidelines also recommend that healthcare providers inform frequent, heavy users on the potential for cannabis to reduce the effectiveness of post-operative pain control, and that surgical procedures be postponed if a patient shows any kind of intoxication or impaired decision-making at the time of surgery.

Experts produce 21 recommendations for clinical practice

The new guidelines were created by a team of twelve expert panelists, who were anesthesiologists and chronic pain physicians, as well as an additional thirteenth member who was a patient advocate. Using an extensive literature review and a modified Delphi consensus approach, the panel collectively agreed on 21 new recommendations for anesthesiologists and surgeons.

These recommendations form the first US-based guidelines on the perioperative (before, during, and after surgery) management of cannabis, the ASRA says, and are accompanied by a letter grade (A through D, or an I for “insufficient”) to indicate the strength of the evidence and the balance of benefits and harms related to each point.

Four recommendations received an A grade from the panel:

• Universal screening for cannabinoids should be performed before surgery.
• Elective surgeries should be postponed if the patient shows signs of cannabis intoxication.
• Frequent, heavy users of cannabis should be counseled by physicians on the potentially negative effects of cannabis on postoperative pain control.
• Pregnant patients should receive education and counseling on the risks that cannabis use may present to the fetus.

Among the B and C-graded recommendations, the panel also advises that cannabis use during pregnancy and immediately postpartum should be discouraged, that frequent users be monitored for cannabis withdrawal symptoms after the surgery, and that surgery should be delayed by at least two hours after cannabis smoking due to an increased risk of heart attacks.

The only recommendation to receive a D grade – meaning that the panel recommends discouraging this practice – was the idea of requiring patients to undergo universal toxicology screening for cannabinoids prior to surgery.

“Before surgery, anesthesiologists should ask patients if they use cannabis – whether medicinally or recreationally – and be prepared to possibly change the anesthesia plan or delay the procedure in certain situations,” Samer Narouze, a senior author and ASRA Pain Medicine president, said in a statement.

“They also need to counsel patients about the possible risks and effects of cannabis. For example, even though some people use cannabis therapeutically to help relieve pain, studies have shown regular users may have more pain and nausea after surgery, not less, and may need more medications, including opioids, to manage the discomfort,” Narouze continued. “We hope the guidelines will serve as roadmap to help better care for patients who use cannabis and need surgery.”

Evidence in some areas remains inconclusive

Despite the extensive literature review performed here, there were several areas where the panel felt that available evidence was still insufficient (or too inconclusive) to issue more stringent recommendations.

For example, while the panel gave a Grade C to the recommendation advising that elective surgery be delayed by at least two hours after cannabis smoking due to heart attack risk, only a Grade I recommendation could be issued for other consumption methods, as the panel felt that there was not enough published evidence to conclusively endorse if a delay would be warranted.

A Grade I was also given to the idea of using electroencephalogram (EEG) brain activity monitoring during surgery and the adjustment of post-operative opioid prescriptions in cannabis users. The evidence to recommend for or against these actions was deemed insufficient.

In the published guidelines, the ASRA Pain Medicine authors say that they “will continue monitoring newly released relevant publications following the publication of this guideline and may revise the entire document or specific sections if new evidence warrants updated recommendations.”

ASRA Pain Medicine also reports that the American Society of Anesthesiologists has reviewed these new recommendations as they currently stand, and has affirmed its value for practicing anesthesiologists and surgeons.