Page 32 - CASA Bulletin of Anesthesiology 2022; 9(5)

CASA Bulletin of Anesthesiology

others report no difference or even less pain and opioid use in cannabis patients 40-46 . Ladha et al.
states that it is appropriate to consider that postoperative analgesic requirements may be higher
for patient who consume a significant amount of cannabis due to those multiple studies
demonstrating greater levels of postoperative pain in cannabis users [17]. Moreover, it is
important to remain cognizant of other causes of increased postoperative pain as well as the
potential role of cannabis withdrawal, particularly if the cannabis is used for pain or anxiolytic
indications . Thus, a referral to an acute pain service may be beneficial for certain patients.
17
Although cannabis withdrawal syndrome (CWS) is not severe and does not have a high risk
of severe adverse outcomes in most patients, CWS may contribute to morbidity in the
postoperative period 17, 47 . There may be an increased prevalence and severity of withdrawal
symptoms based on certain variables, including cannabis potency, daily cannabis use, female
gender, and comorbid psychiatric disorders or polysubstance use 19, 47 . Notably, CWS is unlikely
to occur in patients consuming 300 mg/day or less of smoked CBD-dominant cannabis and in
patients that are also opioid-dependent 17, 19 . CWS onset generally occurs within 1-2 days, peaks
within 2-6 days, and dissipates within 2-4 weeks . However, the high liposolubility and
47
consequent adipose accumulation may impact this general timeframe and severity of symptoms.

To avoid CWS, providers may instruct patients to continue with cannabis use until surgery,
however this may conflict with the potential for adverse effects of cannabis on anesthesia. If
CWS is suspected, perioperative providers may assess patients with the 19-item Cannabis
Withdrawal Scale, or other withdrawal scales, and should refer to a psychiatry service as
appropriate 17, 48 . Another approach to avoiding CWS is to consider continued administration of
cannabis oil or edible cannabis while hospitalized. The consensus reached by Ladha et al. states
that the continuation of cannabis oils and edibles may be appropriate on a general post-surgical
ward, but no consensus was reached for ICUs, high-dependency units, or step-down units; this
recommendation should be kept in concordance with evidence-based care, institutional
regulations, and current legislation and, moreover, does not apply to inhaled cannabis . Similar
17
to the current regulations regarding tobacco smoking in hospitals, cannabis smoking or vaping is
never appropriate in a hospital setting.

Conclusion

With the continued rise of recreational and medicinal cannabis use, the anesthetic
management for chronic cannabis users requires additional investigation to address the questions
and limitations posed by the current body of literature. Herein, we reviewed the basic
physiologic and pharmacologic principles of the endocannabinoid system and exogenous
cannabinoids that are relevant to perioperative providers, and then discussed considerations and
recommendations for the anesthetic management of chronic cannabis users. Each patient should
be screened for recreational or medicinal cannabis use, with additional information gathering
about cannabis consumption as appropriate. The importance of adequate preoperative
information gathering cannot be overstated because the information regarding frequency,
amount, potency, route of administration, THC/CBD content, adverse effects, and withdrawal
may be valuable during the anesthetic management, particularly with respect to cardiorespiratory
effects, induction and maintenance of anesthesia, and certain postoperative cares. Amongst the
literature, the major research limitations included the variable and unknown composition of the
biologically active compounds of cannabis products, the federal legislation and criminalization

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