Anesthesia in the News
  • Anesthesia in Patients Using Marijuana

    It is estimated that there are over 36 million cannabis users in the United States, making it the country’s most popular illicit drug. Its medicinal use is now legal in 33 states, even though, on the federal level, it remains illegal and is listed as a Schedule I substance under the Controlled Substances Act.

    Unfortunately, this federal listing also limits research on the anesthetic implications of cannabis use, even as its use becomes more widespread and efforts to legalize its recreational use gain more traction, e.g., New York state’s legalization of it in March.

    Dawn Lewellen, DNP, CRNA, practicing at Parkland Health and Hospital Systems, Dallas, Texas, recently published a brief and incisive review of the special considerations and recommendations in the patient using marijuana about to undergo a GI endoscopy procedure.

    Pot is problematic

    In addition to citing its historical clinical role, today’s surge in availability and use, and its action on the human endocannabinoid system, Ms. Lewellen reviews the amped up potency of cannabis over the past two decades and the myriad means of consumption of it and its derivative substances, from smoked and vaporized to topicals and edibles.

    CNS, cardio, and respiratory concerns

    Ms. Lewellen itemizes the most common central nervous system (CNS) effects commonly reported by marijuana users as well as the most prevalent negative CNS effects and the importance of clinicians’ awareness that these effects may be potentiated by CNS suppressant drugs.

    Cardiovascular effects from marijuana use are another significant concern for anesthesia providers, she notes, with marijuana use associated with tachycardia, bradycardia, postural hypotension, increased cardiac output, and increased myocardial oxygen demand.

    Cannabis use also caused similar pulmonary complications to those of a tobacco smoker, including bronchitis, cough, emphysema, and airway hyper-reactivity. And she has a special caution to her anesthesia provider colleagues regarding patients with a history of vaping THC, recommending that this patient cohort be evaluated for any signs of respiratory distress.

    Procedure anticipation anxiety

    Further, the author points out the potential that many prospective endoscopy patients may seek to alleviate their pre-procedure anxiety through self-medication with cannabis, underscoring the essential exploration of recent use with the patient upon arrival for the procedure.

    She adds that the most concerning procedural implication is acute intoxication and that anesthesia providers clinicians recognize the signs of acute marijuana intoxication and acute marijuana withdrawal.

    In conclusion, while most patients who are using cannabis can be safely sedated, she notes the paucity of research on the effects of marijuana on anesthesia. This limited data makes it imperative for the anesthesia provider to keep in mind that each patient’s response to any cannabis product may vary tremendously due to the various THC concentrations in different strains of marijuana and each patient’s variable response to marijuana. And to recognize when pre-procedure patient queries on recent usage and the clinician’s observations may warrant delay of the procedure.

    Read Ms. Lewellen’s full review as she seeks to answer the question, “Should we proceed?” Lewellen D. SHOULD WE PROCEED? IMPLICATIONS OF MARIJUANA USE FOR GI ENDOSCOPY PROCEDURES. Gastroenterol Nurs. 2020 Nov/Dec;43(6):480-482. at