GP1b - Are BIS Values During IV Sedation Altered in Cannabis Users Compared to Non-Users?

Abstract: A 2023 report from the National Institute on Drug Abuse states that approximately 42% of US adults aged 19 to 30 reported cannabis use in the past year.¹ With rising use, the effects of cannabis use on perioperative anesthesia has become an increasing area of interest. Current evidence suggests cannabis may alter anesthetic requirements and physiologic responses, though prospective data in oral and maxillofacial surgery literature remain limited.² The Bispectral index (BIS) monitor, which processes electroencephalographic signals to generate a value from 0 (no brain activity) to 100 (fully awake), is commonly used to assess anesthetic depth.² This study aimed to evaluate whether cannabis users undergoing deep intravenous (IV) sedation exhibit higher BIS values at predetermined time intervals.

This prospective cohort study was approved by the Institutional Review Board (IRB) of Temple University Kornberg School of Dentistry. The study included 84 patients aged 13 years or older with an American Society of Anesthesiologists (ASA) classification of I or II. All participants underwent surgical extraction of at least 2 mandibular third molars under IV sedation. The primary outcome variable was BIS value. The primary predictor variable was cannabis use status. Co-variates included age, gender, and body mass index (BMI).

The study participants were divided into 2 groups: cases (cannabis users) and controls (non-cannabis users). BIS values were recorded intraoperatively at 5 standardized time points: baseline (TB), 5 minutes (T5), 10 minutes (T10), 20 minutes (T20), and 30 minutes (T30). Data collection began immediately following the administration of anesthesia.

Descriptive statistics were calculated for all variables. An unpaired 2-sample t-test was used to compare mean BIS values at 5 time points, between cannabis users and non-users. Statistical significance was set at P < .05, with a 95% confidence interval. Data analyses were performed using GraphPad Prism 10.

A total of 78 patients were included, with 38 cannabis users and 40 non-users. The mean age of the cases group was 22.80 ± 5.23 years, while the control group had a mean age of 21.81 ± 5.96 years. The mean BMI for cannabis users was 25.9 ± 6.10, compared to 27.70 ± 6.73 in non-users. The mean BIS value of the case group was 68.41 ± 7.14, compared to 72.09 ± 5.65 in non-users. Statistical analysis showed a significant difference in mean BIS values between groups (P < .01). Cannabis users demonstrated lower average BIS values, suggesting a greater depth of sedation under similar ambulatory conditions (Fig 1).

Our findings demonstrated a difference in BIS values between cannabis users and non-users during IV sedation, with cannabis users exhibiting lower values on average. These results suggest cannabis use may influence anesthetic depth and impact a surgeon's intraoperative anesthetic plan.

This study represents a subset of a larger investigation supported by a research grant from the Oral and Maxillofacial Surgery Foundation.


1. National Institute on Drug Abuse. (2024, August 29). Cannabis and hallucinogen use among adults remained at historic highs in 2023. https://nida.nih.gov/news-events/news-releases/2024/08/cannabis-and-hallucinogen-use-among-adults-remained-at-historic-highs-in-2023

2. Gangwani, P., Kolokythas, A., Lillian, D., Dobbins, J., Feng, C., & Vorrasi, J. (2023). Is recreational marijuana use associated with changes in the vital signs or anesthetic requirements during intravenous sedation? Journal of Oral and Maxillofacial Surgery, 81(5), 678-685. https://doi.org/10.1016/j.joms.2023.01.007