No abstract

In many countries, liberalisation of the legislation regulating the use of cannabis has outpaced rigorous scientific studies, and a growing number of patients presenting for surgery consume cannabis regularly. Research to date suggests that cannabis can impact perioperative outcomes. We present recommendations obtained using a modified Delphi method for the perioperative care of cannabis-using patients. A steering committee was formed and a review of medical literature with respect to perioperative cannabis use was conducted. This was followed by the recruitment of a panel of 17 experts on the care of cannabis-consuming patients. Panellists were blinded to each other's participation and were provided with rater forms exploring the appropriateness of specific perioperative care elements. The completed rater forms were analysed for consensus. The expert panel was then unblinded and met to discuss the rater form analyses. Draft recommendations were then created and returned to the expert panel for further comment. The draft recommendations were also sent to four independent reviewers (a surgeon, a nurse practitioner, and two patients). The collected feedback was used to finalise the recommendations. The major recommendations obtained included emphasising the importance of eliciting a history of cannabis use, quantifying it, and ensuring contact with a cannabis authoriser (if one exists). Recommendations also included the consideration of perioperative cannabis weaning, additional postoperative nausea and vomiting prophylaxis, and additional attention to monitoring and maintaining anaesthetic depth. Postoperative recommendations included anticipating increased postoperative analgesic requirements and maintaining vigilance for cannabis withdrawal syndrome.

IntroductionAt the conception of this study (January 2019), a literature search by the authors found no evidence-based or consensus perioperative guidelines for patients consuming cannabis products, or for those patients in whom a cannabinoid medication could be considered for perioperative treatment. Currently, there is a large global population that consumes cannabis. The availability of cannabis has also increased this decade with greater legal access to cannabis products in some countries such as USA, Canada, Uruguay, Israel, Australia and Germany. There are recognised possible therapeutic benefits for the use of cannabis in patients with chronic pain, chronic neuropathic pain and chemotherapy-induced nausea and vomiting. There are also potential side effects from cannabis use such as psychosis, cannabis hyperemesis syndrome, misuse disorder and cannabis withdrawal syndrome. There is evidence that cannabis may also affect factors in the perioperative period such as monitoring, quality of analgesia, sleep and opioid consumption. Given the large population of persons using cannabis, the heterogeneity of cannabis products and the paucity (and heterogeneity) of perioperative literature surrounding it, perioperative guidelines for cannabis consuming patients are both lacking and necessary. In this paper, we present the design for a modified Delphi technique that has been started with the intent of deriving cannabis perioperative guidelines from the available medical literature and the consensus of multidisciplinary experts.Materials, methods and analysisThis study will use a scoping narrative literature review and modified Delphi process to generate cannabis perioperative guidelines. A scoping narrative review of cannabis in the perioperative period by the authors of this proposal was completed and provided to a panel of 17 experts. These experts were recruited for their knowledge and expertise regarding cannabis and/or perioperative medicine. They were asked to rate a series of indications and clinical scenarios in two rounds. During the first round, the expert panel was blinded to each other’s participation. During the second round of this process, the expert panel met after being provided with an analysis of the first round’s submissions so they could be discussed further and, if possible, reach a further consensus regarding them. Using the results obtained from the Delphi review process, a draft of proposed cannabis perioperative guidelines will be generated. These proposed guidelines will be returned to the expert panel for critiquing prior to their finalisation.Ethics and disseminationStudy and panellist data will be deidentified and stored as per institutional (Toronto General Hospital) guidelines. Institutional research ethics board provided a waiver for this modified Delphi protocol. Findings will be presented and published in peer-reviewed publications and conferences.