Sleepiness, Drug Effects, and Driving Impairment Thomas Roth Henry Ford Hospital Sleep Center
OUTLINE Scope of Sleepiness Related Accidents Causes of Sleepiness Other Causes of Accidents How to Measure Driving Ability Relation of Impaired Driving to risk of accidents Other Considerations in Evaluating Risk
The Scope of the Problem Estimates by US National Highway Traffic Safety Administration Principal cause in 100,000 police-reported crashes 71,000 injuries 4% of all fatal accidents caused by sleepiness 1,550/year $12.5 billion in monetary losses A drowsy driver can drift completely off the road in less than 4 seconds at ~4 angle National Highway Traffic Safety Administration 2002. www.nhtsa.dot.gov
4 Accidents Excessive Sleepiness is a direct or contributing factor in 17 to 21% of road accidents (Lyznicki et al., 1998; Garbarino et al., 2001) Road accidents are 2 to 3 times more frequent in drivers with ES (Ohayon et al., 1997; Howard et al., 2004)
100-Car Study Drowsiness also appears to affect crashes and collisions at much higher rates than is reported using existing crash databases. Drowsiness was a contributing factor in 12 percent of all crashes and 10 percent of near-crashes, while most current database estimates place drowsiness-related crashes at approximately 2 to 4 percent of total crashes.
Note: Odds of crash or near-crash with behavior present vs. absent; computed using logistic regression to control for other behaviors; odds ratio > 1 indicates increased risk Results Risk of Crash or Near Crash Behavior Inappropriate Speed (faster than surrounding traffic) Odds Ratio 2.9 (95% CI: 1.7 4.8) Drowsy 2.9 (95% CI: 2.0 4.3) Aggressive Driving 2.1 (95% CI: 1.3 3.4) Eyes Off Road (longer than 2 seconds) 1.9 (95% CI: 1.4 2.5)
How Risky is Driving Post-call? Survey of 697 ER residents at Wayne State Univ: 17% had MVAs 6.7x more likely to fall asleep driving than prior to residency Kowalenko. Acad Emerg Med (2000) 7(5): 451. Survey of Anesthesia residents at U. Penn. 17% had MVAs, all between 8-9 am. 72% had near-miss MVA s, 33%>5! Marcus, CL, Loughlin, GM. Sleep (1996) 19: 763-66.
Risk of Motor Vehicle Crashes Interns Working Extended Shifts Prospective nationwide, Web-based survey of 2737 interns Self-reported work hours and extended work shifts (> 24 hours) were validated 17,003 monthly reports provided detailed information about work hours and health risk data Assessment of driving safety included documented motor vehicle crashes and near-miss incidents Barger LK, et al. N Engl J Med 2005;352:125-134.
Risk of Motor Vehicle Accidents after Extended and Nonextended Shifts Work shift 24 hours Work shift <24 hours Odds Ratio Crashes 58 73 2.3 (1.6-3.3) Near-misses 1,971 1,156 5.9 (5.4-6.3) Commutes 54,121 180,289 Barger. N Eng J Med. 2005;52:125-134.
Drowsy Driving Causes: Sleep Loss/ Sleep Fragmentation Circadian Rhythms CNS Disorders Medications/Drugs
Self-reported sleep duration in the US 11 10 Trend in Sleep Decline in U.S. Sleep (hrs) 9 8 7 6 5 1900 1920 1940 1960 1980 2000 2020 Adults Adolescents
Quantification of Sleep Need 8-hr nights 14-hr nights Epidemiological Samples: Reported sleep = 6.9 hrs/night Days Adapted from: Wehr et al., (1993). Am. J. Physiol., 265, R846-R857.
Multiple Sleep Latency Test Distribution ) MSLT (min)
Daytime Sleepiness in the General Population (N = 618) 7.7 % 29.0 % Excessive Daytime Sleepiness Moderate Sleepiness 8% Anesthesiology Residents Sleep Apnea 0 hr TIB x 1 night 6 hr TIB x 4 nights Narcolepsy Mean = 11.4 10 hours TIB x 14 nights (full alertness) 6% 4% 2% 0% 0 5 10 15 20 MSLT (min) TIB = time in bed Drake CL et al. Sleep Abstract, 2002.
MSLT and Crashes (10-year prevalence) % subjects with crash 60 58 56 54 52 50 48 46 44 42 40 * * N=69 N=204 N=345 < 5 min 5-10 min > 10 min *p <.05; Linear Trend: Cochran-Armitage, p =.048 Odds ratio is 1.26 for low vs. high MSLT groups Multiple Sleep Latency Test Groups Drake et al., 2010
Level of Injury in Types of Crashes Type of Crash No Injury Level C Injury Level B Injury Level A Injury Fatality Fall Asleep 40.6% 21.7% 22.8% 13.5% 1.4% Alcohol 35.2% 20.6% 24.3% 17.8% 2.1% All Others 59.1% 25.4% 9.9% 5.1% 0.5%
Secondary Endpoint: Severe Injury Accidents Only % subjects with crash 5 4.5 4 3.5 3 2.5 2 1.5 1 0.5 0 * * N=69 N=204 N=345 < 5 5-10 >10 Multiple Sleep Latency Test Groups * p <.05; Cochran-Armitage, p =.028 Drake et al., 2010 Severe injury accidents were those which prevent normal activities and require hospitalization
Time of Day of 4,333 Crashes where Driver was Judged: Asleep but Not Intoxicated Number of Crashes 450 400 350 300 250 200 150 100 5 0 Time of peak occurrence 7:00 to 8:00 AM 00 02 04 06 08 10 12 14 16 18 20 22 24 Time of Day Pack AI, Pack AM, Rodgman E et al. Accid Anal Prev. 1995(Dec);27(6):769-775
Vehicle Accident Data 1200 1100 1000 900 800 700 600 500 400 300 200 100 Fatigue-Related Accidents International Data N = 6052 Midnight 6 AM Noon 6 PM Midnight Time of Day Mitler MM, et al. Sleep. 1988.
Temporal Distribution of Fatigue-related Single Vehicle Truck Accidents Number of Accidents 20 18 16 14 12 10 8 6 4 2 0 1:00 AM 3:00 AM 5:00 AM 7:00 AM 9:00 AM 11:00 AM 1:00 PM 3:00 PM 5:00 PM 7:00 PM 9:00 PM 11:00 PM National Transportation Safety Board Safety Study (SS-1995/01)
Numbers of Traffic Accidents on the Mondays before and after the Shifts to and from Daylight Savings Time for the Years 1991 and 1992 Coren S. N Engl J Med 1996;334:924-925
Excessive Sleepiness and Driving Collisions, Costs and Fatalities Consequences of OSAS 810K collisions $15.9 billion in collision costs 1,400 fatalities Estimated cost-savings with CPAP treatment Prevent >500K collisions Reduce collision costs by $11.1 billion Save nearly 1,000 lives Meta-Analysis of 6 studies: Risk of MVC is greater in drivers with OSAS than drivers without OSAS Findley, 1998 Barbe, 1998 Teran-Santos, 1999 Hortsmann, 2000 Lioberes, 2000 George, 2001 Fixed Combined 0.5 1 2 5 10 Odds Ratio CPAP, continuous positive airway pressure; MVC, motor-vehicle collision; OSAS, obstructive sleep apnea syndrome. Sassani A, et al. Sleep. 2004;27(3):453-458.
Sedating Medications Driving Effects Verster and Roth, Psychopharmacology, 2012, 775-781
27 Effects relative to other hypnotics and alcohol
Effects of Sleep Deprivation, Alcohol and OSA on Simulated Steering Performance 30 * Off-Road Events h -1 20 10 * 0 OSA ncpap OSA Untreated Effect of OSA No Alcohol With Alcohol Effect of Alcohol *p<0.005, p<0.01; Hack MA et al. (2001), Respir Med 95:594-601 Normal Sleep Sleep Deprived Effect of Sleep Deprivation
Comparative Impairment of Alcohol vs. Sleep Loss Equivalent Alcohol Dose Sleep Loss (Time-in-Bed) US beers 1 Brace% 2 8 hrs (0 hrs of sleep) 10-11 0.190% 6 hrs (2 hrs of sleep) 7-8 0.102% 4 hrs (4 hrs of sleep) 5-6 0.095% 2 hrs (6 hrs of sleep) 2-3 0.045% 1 Given 14.22 g ethanol in a 12 oz beer 2 Approximate breath ethanol concentration (BrEC) at peak Roehrs et al. SLEEP, 2004
Sleep Loss Ethanol Interaction
Other Causes of Accidents Awareness Risk Taking Sensory Processing
Chronic Sleepiness and Awareness 100 Slepiness Index 80 60 40 20 OSA Patients Normal Controls 0 1 2 3 4 5 Mean SSS Dement and Guillemenault. Sleep Apnea Syndrome. 1978.
Accidents (# Lifetime) * p =.03 vs. Low Motor Vehicle Accidents and Awareness 2.2 2.1 2.0 1.9 1.8 1.7 1.6 1.5 1.4 MSLT= Good (-2.6 min) Moderate (5.4 min) * Poor (21.8 min) 12.6 9.2 9.6 Sleepiness Detection (Accuracy)
AP Photo
Response Requirement and Point Loss Probability in Alert and Sleepy Subjects Probability of Go Choice 1.0 0.8 0.6 0.4 0.2 Alert Sleepy 1.0 0.8 0.6 0.4 0.2 0.0 15 20 25 30 35 40 45 50 Response Requirement (Fixed Ratio) 0.0 12.5 37.5 100 Point Loss Probability Roehrs, et al. Sleep. 2004;27:887.
Driving Ability Endpoints SDLP Stop Driving Episodes Lapses Accidents Out of Lane Events SD speed
Cumulative Sleep Restriction: Dose Dependence PVT Lapses 16 14 12 10 8 6 4 2 16 14 12 10 8 6 4 2 Sleep Latency (Minutes) Dinges DF et al. (1997), Sleep 20(4):267-277 B P1 P2 P3 P4 P5 P6 P7 Day
How do you differentiate between rare events and random events?? Are there any endpoints that have been shown to correlate with driving records??
Other Variables to Consider Subject Population Circadian Time of Testing Duration of Drive Changes Across Time Patient Compliance Pharmacokinetics dose time since drug ingestion individual differences
Sleep Latency as a Function of Time of Day
Alcohol Effects-Time of Drinking 0900 v1700-
PL FL 30 PL FL 30 EARLY p <.01 LATE p >.10
PL PL FL 30 FL 30 EARLY p <.01 LATE p <.01
DOES IMPAIRED DRIVING PREDICT RISK OF SLEEPINESS RLATED ACCIDENTS
Characteristics of Drowsy Driving Crash Younger Drivers (<25 years old) Male Single Vehicle Single Occupant Fatality or Severe Injury Tome of Day Rural Road