J Forensic Sci, 2015 doi: 10.1111/1556-4029.12725 Available online at: onlinelibrary.wiley.com
PAPER TOXICOLOGY
Karen L. Woodall,1 Ph.D.; Betty L.C. Chow,1 M.Sc.; Albert Lauwers,2 M.D.; and Dan Cass,3 M.D.
Toxicological Findings in Fatal Motor Vehicle Collisions in Ontario, Canada: A One-Year Study
ABSTRACT: Drug-impaired driving is a complex area of forensic toxicology due in part to limited data concerning the type of drugs
involved and the concentrations detected. This study analyzed toxicological findings in drivers from fatal motor vehicle collisions (FMVCs) in Ontario, Canada, over a one-year period using a standardized protocol. Of the 229 cases included in the study, 56% were positive for alcohol and/or drugs. After alcohol, cannabis was the most frequently encountered substance (27%), followed by benzodiazepines (17%) and antidepressants (17%). There were differences in drugs detected by age but no marked difference in drugs detected between single and multiple FMVC’s. Not all drugs detected were considered impairing either due to drug type, concentration or case history. The findings indicate the importance of comprehensive drug testing in FMVCs and highlight the need to consider a variety of factors, in addition to drug type and concentration, when assessing the role of drugs in driving impairment.
KEYWORDS: forensic science, driving impairment, drugs, alcohol, toxicology, motor vehicle collisions The complexity of driving requires skills that include concentration, perception, motor coordination and judgment. Consequently, any factor that can diminish these skills has a potential causal or contributory role in motor vehicle collisions. Such factors may include age, driving experience, fatigue and the use of alcohol and/or drugs. It has long been recognized that alcohol and certain drugs may impair a person’s driving ability. The impairing effects of alcohol have been extensively studied for many years (1); however, the role of drugs in impaired driving is complicated and, when compared to alcohol, detailed data including specific drug type with concentrations, are limited (2). This is especially true in fatal motor vehicle collisions. In a recent report by Logan et al., (3) the authors discussed the limitations of interpreting data collected from traffic fatalities in that the variability in testing approaches makes it extremely difficult to make conclusions on the impact, if any, of drug involvement in fatal motor vehicle collisions. The authors suggest that a consistent analytical approach from toxicology laboratories will allow collection of more useful data and contribute to public safety. The Canadian Medical Association recommends that patients should be advised not to drive until they are aware of their individual response to medication (e.g., patients on long-term opioid therapy) (4). In addition, patients may not be aware that concomitant use of many drugs and/or alcohol can intensify impairing 1
Toxicology Section, Centre of Forensic Sciences, 25 Morton Shulman Avenue, Toronto, ON M3M 0B1, Canada. 2 Ross Memorial Hospital, 10 Angeline St. N., Lindsay, ON K9V 4M8, Canada. 3 Office of the Chief Coroner, 25 Morton Shulman Avenue, Toronto, ON M3M 0B1, Canada. Received 24 Oct. 2013; and in revised form 7 Mar. 2014; accepted 27 May 2014. © 2015 American Academy of Forensic Sciences
effects of both prescription and over-the-counter (OTC) drugs (e.g., certain antihistamines). Driving following illicit drug use also has important public safety implications. For example, selfreported data from the Canadian Addiction Survey found that 4.8% of drivers in Canada admitted driving within two hours of using cannabis on at least one occasion in the past year (5). This poses serious concerns as a recent study clearly demonstrated a strong correlation between acute cannabis administration and the increased risk of motor vehicle collision resulting in severe injury or death (6). One important area of research which can provide valuable information about the incidence, characteristics, and implications of drug use in relation to driving impairment, is the analysis of drugs in drivers involved in fatal motor vehicle collisions (FMVCs). There are a number of studies describing the presence of drugs in deceased drivers, and this study adds to that growing field of research and further discusses the limitations of interpreting toxicology results (7–10). A study by Beasley et al. (5) established the increased prevalence of drug use in FMVCs in Canada and suggested the use of drugs by drivers may be an important public safety issue; however, this study was limited by the wide variation in the extent of testing performed in different provinces. Ontario, which had the highest number of FMVCs in the study, had one of the lowest percent testing for drugs (36%). All toxicological testing in cases from Ontario are performed at the Centre of Forensic Sciences (CFS), and prior to this study, only analysis for alcohol was routinely performed; testing for drugs was only performed if there was a specific history of drug use. The purpose of this study was to perform comprehensive toxicology testing on all drivers from FMVCs in Ontario for a one-year period and to use the results to establish a standardized testing protocol in the province of Ontario. In addition, the 1
2
JOURNAL OF FORENSIC SCIENCES
results from this study will provide useful information regarding the role of drugs in FMVCs through the assessment of drug concentrations and discusses important factors to consider when interpreting the significance of toxicological findings in FMVCs. Methods Standardized comprehensive testing was performed on samples from FMVCs submitted for toxicological analysis for a oneyear period (Feb. 1, 2011 until Jan. 31, 2012). The toxicology testing procedures including immunoassay, head-space gas chromatography with flame ionization detection (GC-FID) and a screening procedure (capable of detecting over 300 drugs including over-the-counter medications (OTCs), prescription drugs and illicit substances) using GC with nitrogen–phosphorus detectors and GC–mass spectrometry (GC and GC-MS) have been described elsewhere (11). Immunoassay was used to screen for the presence of drug categories including barbiturates, cocaine metabolite, cannabis and opioids. Head-space GC-FID was used in the analysis of alcohols (including ethyl alcohol, methyl alcohol and isopropyl alcohol). A benzodiazepine analysis using liquid chromatography–tandem mass spectrometry (LC-MS/MS) was performed. Confirmation of any positive drug findings was analyzed and quantified using gas chromatography–mass spectrometry (GC-MS) or LC-MS/MS. A positive cannabis result from IA was confirmed using GC/MS which can detect and quantify both tetrahydrocannabinol (THC) and carboxy-tetrahydrocannabinol (COOH-THC). A positive cocaine metabolite result from IA was confirmed using LC-MS/MS which can detect and quantify cocaine and benzoylecgonine (BE). Cases were included in the study when blood samples were available from fatalities involving car, truck, ATV and motorcycle drivers. Postmortem blood samples were analyzed in the majority of the cases unless details from the case history would indicate a long survival period. In these cases, antemortem (admission) samples were obtained and analyzed. Cases were excluded from the study if there was limited volume of sample, unsuitable biological samples for quantitation of drugs (e.g., vitreous fluid), if the blood was not taken from an intact vessel (e.g., chest cavity) or if the cause of death was determined to be due to natural causes. Information regarding the age, sex, circumstances of death and pathology findings were obtained from the coroner’s investigation.
FIG. 1––Percentage (%) of drugs detected in fatal motor vehicle collisions with positive drug findings.
Results Of the 252 cases submitted for testing, 229 cases met the inclusion criteria (see Table 1 for excluded cases). The ages of the drivers ranged from 15 to 92 years with 76% male and 24% female. Of the cases included in this study, 44.1% detected neither alcohol nor drugs, 12.2% detected alcohol only, 28.4% detected drugs only and 15.3% detected both alcohol and drugs. The most common drug finding was cannabis (27% of drug positive cases) which includes THC and/or COOH-THC (Fig. 1). Of the 49 cases where THC and/or COOH-THC were detected, only one case did not detect THC. For the remaining 48 incidences of THC, blood concentrations ranged from
PAPER TOXICOLOGY
Karen L. Woodall,1 Ph.D.; Betty L.C. Chow,1 M.Sc.; Albert Lauwers,2 M.D.; and Dan Cass,3 M.D.
Toxicological Findings in Fatal Motor Vehicle Collisions in Ontario, Canada: A One-Year Study
ABSTRACT: Drug-impaired driving is a complex area of forensic toxicology due in part to limited data concerning the type of drugs
involved and the concentrations detected. This study analyzed toxicological findings in drivers from fatal motor vehicle collisions (FMVCs) in Ontario, Canada, over a one-year period using a standardized protocol. Of the 229 cases included in the study, 56% were positive for alcohol and/or drugs. After alcohol, cannabis was the most frequently encountered substance (27%), followed by benzodiazepines (17%) and antidepressants (17%). There were differences in drugs detected by age but no marked difference in drugs detected between single and multiple FMVC’s. Not all drugs detected were considered impairing either due to drug type, concentration or case history. The findings indicate the importance of comprehensive drug testing in FMVCs and highlight the need to consider a variety of factors, in addition to drug type and concentration, when assessing the role of drugs in driving impairment.
KEYWORDS: forensic science, driving impairment, drugs, alcohol, toxicology, motor vehicle collisions The complexity of driving requires skills that include concentration, perception, motor coordination and judgment. Consequently, any factor that can diminish these skills has a potential causal or contributory role in motor vehicle collisions. Such factors may include age, driving experience, fatigue and the use of alcohol and/or drugs. It has long been recognized that alcohol and certain drugs may impair a person’s driving ability. The impairing effects of alcohol have been extensively studied for many years (1); however, the role of drugs in impaired driving is complicated and, when compared to alcohol, detailed data including specific drug type with concentrations, are limited (2). This is especially true in fatal motor vehicle collisions. In a recent report by Logan et al., (3) the authors discussed the limitations of interpreting data collected from traffic fatalities in that the variability in testing approaches makes it extremely difficult to make conclusions on the impact, if any, of drug involvement in fatal motor vehicle collisions. The authors suggest that a consistent analytical approach from toxicology laboratories will allow collection of more useful data and contribute to public safety. The Canadian Medical Association recommends that patients should be advised not to drive until they are aware of their individual response to medication (e.g., patients on long-term opioid therapy) (4). In addition, patients may not be aware that concomitant use of many drugs and/or alcohol can intensify impairing 1
Toxicology Section, Centre of Forensic Sciences, 25 Morton Shulman Avenue, Toronto, ON M3M 0B1, Canada. 2 Ross Memorial Hospital, 10 Angeline St. N., Lindsay, ON K9V 4M8, Canada. 3 Office of the Chief Coroner, 25 Morton Shulman Avenue, Toronto, ON M3M 0B1, Canada. Received 24 Oct. 2013; and in revised form 7 Mar. 2014; accepted 27 May 2014. © 2015 American Academy of Forensic Sciences
effects of both prescription and over-the-counter (OTC) drugs (e.g., certain antihistamines). Driving following illicit drug use also has important public safety implications. For example, selfreported data from the Canadian Addiction Survey found that 4.8% of drivers in Canada admitted driving within two hours of using cannabis on at least one occasion in the past year (5). This poses serious concerns as a recent study clearly demonstrated a strong correlation between acute cannabis administration and the increased risk of motor vehicle collision resulting in severe injury or death (6). One important area of research which can provide valuable information about the incidence, characteristics, and implications of drug use in relation to driving impairment, is the analysis of drugs in drivers involved in fatal motor vehicle collisions (FMVCs). There are a number of studies describing the presence of drugs in deceased drivers, and this study adds to that growing field of research and further discusses the limitations of interpreting toxicology results (7–10). A study by Beasley et al. (5) established the increased prevalence of drug use in FMVCs in Canada and suggested the use of drugs by drivers may be an important public safety issue; however, this study was limited by the wide variation in the extent of testing performed in different provinces. Ontario, which had the highest number of FMVCs in the study, had one of the lowest percent testing for drugs (36%). All toxicological testing in cases from Ontario are performed at the Centre of Forensic Sciences (CFS), and prior to this study, only analysis for alcohol was routinely performed; testing for drugs was only performed if there was a specific history of drug use. The purpose of this study was to perform comprehensive toxicology testing on all drivers from FMVCs in Ontario for a one-year period and to use the results to establish a standardized testing protocol in the province of Ontario. In addition, the 1
2
JOURNAL OF FORENSIC SCIENCES
results from this study will provide useful information regarding the role of drugs in FMVCs through the assessment of drug concentrations and discusses important factors to consider when interpreting the significance of toxicological findings in FMVCs. Methods Standardized comprehensive testing was performed on samples from FMVCs submitted for toxicological analysis for a oneyear period (Feb. 1, 2011 until Jan. 31, 2012). The toxicology testing procedures including immunoassay, head-space gas chromatography with flame ionization detection (GC-FID) and a screening procedure (capable of detecting over 300 drugs including over-the-counter medications (OTCs), prescription drugs and illicit substances) using GC with nitrogen–phosphorus detectors and GC–mass spectrometry (GC and GC-MS) have been described elsewhere (11). Immunoassay was used to screen for the presence of drug categories including barbiturates, cocaine metabolite, cannabis and opioids. Head-space GC-FID was used in the analysis of alcohols (including ethyl alcohol, methyl alcohol and isopropyl alcohol). A benzodiazepine analysis using liquid chromatography–tandem mass spectrometry (LC-MS/MS) was performed. Confirmation of any positive drug findings was analyzed and quantified using gas chromatography–mass spectrometry (GC-MS) or LC-MS/MS. A positive cannabis result from IA was confirmed using GC/MS which can detect and quantify both tetrahydrocannabinol (THC) and carboxy-tetrahydrocannabinol (COOH-THC). A positive cocaine metabolite result from IA was confirmed using LC-MS/MS which can detect and quantify cocaine and benzoylecgonine (BE). Cases were included in the study when blood samples were available from fatalities involving car, truck, ATV and motorcycle drivers. Postmortem blood samples were analyzed in the majority of the cases unless details from the case history would indicate a long survival period. In these cases, antemortem (admission) samples were obtained and analyzed. Cases were excluded from the study if there was limited volume of sample, unsuitable biological samples for quantitation of drugs (e.g., vitreous fluid), if the blood was not taken from an intact vessel (e.g., chest cavity) or if the cause of death was determined to be due to natural causes. Information regarding the age, sex, circumstances of death and pathology findings were obtained from the coroner’s investigation.
FIG. 1––Percentage (%) of drugs detected in fatal motor vehicle collisions with positive drug findings.
Results Of the 252 cases submitted for testing, 229 cases met the inclusion criteria (see Table 1 for excluded cases). The ages of the drivers ranged from 15 to 92 years with 76% male and 24% female. Of the cases included in this study, 44.1% detected neither alcohol nor drugs, 12.2% detected alcohol only, 28.4% detected drugs only and 15.3% detected both alcohol and drugs. The most common drug finding was cannabis (27% of drug positive cases) which includes THC and/or COOH-THC (Fig. 1). Of the 49 cases where THC and/or COOH-THC were detected, only one case did not detect THC. For the remaining 48 incidences of THC, blood concentrations ranged from
