The Pulse | Friday, June 28, 2019
Nurse-Administered Sedation for the Cannabis Patient for Colonoscopy Procedures
A study was performed to determine whether patients with a history of chronic cannabis use require higher dosages of fentanyl and midazolam to achieve adequate sedation levels during an elective colonoscopy procedure. Fentanyl and midazolam are the primary sedation medications administered by a nurse during an endoscopic procedure. Significantly higher drug dose requirements could indicate that the patient with chronic cannabis use is high-risk for unsatisfactory sedation levels and may require monitored anesthesia care (MAC) sedation, a deeper level of sedation administered by an anesthesia provider.
The ability to identify high-risk patients who would benefit from MAC sedation would enable patients to be properly scheduled to receive the mode of sedation that would provide the optimal level of comfort during a procedure.
A MAC sedation is usually reserved for patients who have complex comorbidities. Patients are also scheduled with MAC sedation when presenting with selected diagnoses, such as alcohol abuse, anxiety disorders and other illicit drug use (including cannabis), because these groups of patients have been historically difficult to sedate with fentanyl and midazolam alone.
A quantitative study using a retrospective design compared the mean drug dosages required for sedation between a control group and a cannabis group. The decision was made to review only the records of patients who underwent colonoscopy. Elective colonoscopies with nurse-administered sedation have a more consistent treatment duration compared to EGD, increasing the chance that the study participants would have similar experiences.
The study inclusion criteria were males, ages 50-75, who underwent an elective colonoscopy at the Richard L. Roudebush VA Medical Center during 2013-2017. All confounding variables identified as increasing sedation requirements, including female gender, low BMI, opioid and benzodiazepine use, an alcohol use disorder and anxiety, were controlled. Patients with a cannabis sse disorder (CUD) were the only patients selected for the cannabis group.
The use of patients with a CUD diagnosis predicted inclusion of patients with regular and ongoing use of cannabis. All patients were male with a BMI over 21. Patients with an alcohol use disorder were excluded. Patients were also excluded when they had an active prescription for opioids or benzodiazepines. Researchers recorded data for the following variables: Age, BMI, cannabis use, anxiety (PTSD), diphenhydramine administration, fentanyl dose and midazolam dose. The number of patients in the control group was 65 and the number of patients in the cannabis group was 61.
Each group underwent statistical analysis for age, BMI, mean fentanyl dose and mean midazolam dose. The mean age of the participants was between 60.49 and 64.79 years. The mean BMI for the groups was between 30.30 and 32.18. The mean fentanyl dose was 121.92 mg for the control group and 130.74 mg for the cannabis group. The mean midazolam dose for the control group was 5.89 and 6.16 mg for the cannabis group.
The results of the one-way ANOVA also determined that there was no significant statistical difference in mean fentanyl and midazolam dose requirements between the groups. This analysis showed that patients with chronic cannabis use did not require higher drug dosages to achieve satisfactory sedation levels when fentanyl and midazolam are administered.
There was a difference between the groups with respect to diphenhydramine use during the procedure. In the control group, 15% of the patients received diphenhydramine, but the cannabis group received diphenhydramine at a higher rate of 33%. In addition, statistical analysis revealed that the mean requirement for fentanyl was significantly higher when diphenhydramine was given.
This finding was independent of group status. The mean dose of fentanyl given to the participants in the control group who received diphenhydramine was 150 mcg compared to 116.8 mcg for those who did not receive diphenhydramine. The results were similar for the patients in the Cannabis group. Although the findings were statistically significant, the mean doses were well within the dose ranges given during nurse-administered sedation.
The patient with cannabis use can be scheduled to receive nurse-administered sedation for elective endoscopic procedures. This conclusion should translate to other types of procedures performed when fentanyl and midazolam are used for sedation, but further studies need to be performed that include a wider range of age groups and women undergoing a variety of procedures to confirm the results.
This material is the result of work supported with resources and the use of facilities at the Richard L. Roudebush Veterans Administration Medical Center in Indianapolis, Indiana.
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