This study was approved by the Touro University-California Institutional Review Board. Natividad Medical Center (NMC) located in Salinas, CA, has a Level II Trauma Center which was established in January 2015 and serves Monterey County and surrounding areas along California's Central Coast. It is the only trauma center in the county and receives a large variety of trauma pathologies, from high-risk motor vehicle collisions to gunshot wounds. We abstracted data and obtained our endpoints of interest from a de-identified dataset from our trauma registry, which is maintained by dedicated trauma registrars. Our study analyzed demographics and individual trauma criteria collected from all patients admitted to NMC's trauma service from July 1, 2014, to July 1, 2017. The trauma registry includes information pertaining to patient demographics, mechanism of injury, relevant dates of arrival and discharge, International statistical classification of diseases (ICD) codes, blood alcohol content (BAC), urine drug screen findings, LOS in the hospital and intensive care unit (ICU), disposition, initial vital signs, and amount of blood products transfused. Endpoints were followed for the duration that the patient was being evaluated at our facility. Transferred patients were followed for the duration of evaluation at the transfer facility.

There were 3861 cases in the trauma registry queried in total. Patients were included if they were 18 years or older and had toxicology screening results available in the trauma registry. Nearly all of the patients who were excluded from the study did not have toxicology screening results available. Patients testing positive for polysubstance or positive toxicology screen with BAC > 0.08% were excluded from the study as well. Three hundred and eighty-one patients met inclusion criteria and were included in either the study group (marijuana positive) or control group (negative toxicology and BAC < 0.08%). The hospital laboratory uses an immunoassay to screen for marijuana and provides a qualitative result, either “positive” or “negative” – it is a commonly used laboratory test implemented by many hospitals across the country.

The metrics that were compared between the two groups included the following: mortality, rates of major trauma, age, hospital and ICU LOS, systolic blood pressure (SBP) on arrival, heart rate (HR) on arrival, Glasgow Coma Scale (GCS) on arrival, injury severity score (ISS), and units of packed red blood cells (PRBCs) if transfused in initial 24 h. ISS >15 was defined as “major trauma.”[2] An odds ratio (OR) for mortality and rate of suffering major trauma was calculated. Student's t-tests were performed looking at each of the variables mentioned to determine statistical significance. The cohort was stratified by age into one group containing patients <55 years and the other containing patients 55 years and greater for further analysis. The 55-year age cutoff is a commonly used cutoff age in other studies.[3] Student's t-tests were performed within each age stratification to determine if there were significant differences between marijuana positive groups and control groups.

All data were compiled and analyzed using a Microsoft Excel database. All graphs and tables were made using either Microsoft Excel (Microsoft Corp., Redmond, WA, USA) or SPSS (IBM Corp., Armonk, NY, USA). Descriptive statistics were initially calculated for all the primary variables and subsequently in their stratified groups. Means of the primary outcomes were compared between the stratified groups and ORs calculated.