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THE IMPACT OF SLEEPINESS AND FATIGUE ON PHYSICIAN PERFORMANCE. Rebecca P. McAlister, MD Washington University School of Medicine. EDUCATIONAL OBJECTIVES.
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THE IMPACT OF SLEEPINESS AND FATIGUE ON PHYSICIAN PERFORMANCE Rebecca P. McAlister, MD Washington University School of Medicine
EDUCATIONAL OBJECTIVES • The basics of sleep physiology and sleep deprivation will be reviewed. The impact of sleepiness & fatigue on physician performance will be examined and suggestions made for alertness management.
July 1, 2003 • ACGME Resident Duty Hour Requirements • No more than 80 hrs/wk averaged over 4 wk • No more than every third night in house call • At least 24 hr away every 7 days • No more than 30 hrs of continuous work • At least 10 hours off between work shifts
Faculty and residents must be educated to recognize the signs of fatigue, and adopt and apply policies to prevent and counteract its potential negative effects. • ACGME Common Requirements 2004 • VI, A3
EDUCATIONAL OBJECTIVES • The basics of sleep physiology and sleep deprivation will be reviewed. The impact of sleepiness & fatigue on physician performance will be examined and suggestions made for alertness management.
INDUSTRY MONTHLY LIMITS • ACGME 320-352 HRS • COMM AVIATION 100 HRS • TRUCKING 260 HRS • SMALL MARITIME 360 HRS • RAIL 432 HRS • UK 224 HRS
SLEEPINESS AND FATIGUE • SLEEPINESS • Acute sleep loss • Chronic sleep restriction • Circadian displaced waking (shift work) • FATIGUE • Physical/cognitive demands without recovery • Psychological exhaustion (“burnout”)
SLEEPINESS • SUBJECTIVE MEASUREMENTS • Epworth Sleepiness Scale • OBJECTIVE MEASUREMENTS • Multiple Sleep Latency Test (MSLT) • EEG Microsleeps
EPWORTH SLEEPINESS SCALE0 - 3 • How likely are you to doze in these places • Sitting and reading • Watching TV • Sitting inactive in public place • Passenger in car >1 hr • Lying down in afternoon • Sitting and talking • Sitting quietly after lunch (w/o ETOH) • In a car, while stopped in traffic
EPWORTH SLEEPINESS SCALE • HIGHEST SCORE POSSIBLE 24 • UPPER NORMAL <11 • MILD SLEEPINESS 11-13 • MODERATE SLEEPINESS 14-17 • SEVERE SLEEPINESS >17
MULTIPLE SLEEP LATENCY TEST • Series of five 20 minute nap opportunities in which the time to onset of EEG documented sleep is measured
MICROSLEEPS Brief intrusions of EEG indications of sleep into the awake state
REGULATION OF SLEEP AND WAKEFULNESS • HOMEOSTATIC SLEEP DRIVE • Sleep dependent process • CIRCADIAN ALERTNESS RHYTHM • Sleep independent process
SLEEP HOMEOSTATIC DRIVE (SLEEP LOAD) • Builds up during wakefulness • Reaches maximum in late evening • Determined by the duration and quality of previous sleep and time awake since last sleep • Significant interaction with the circadian rhythm
SLEEP REQUIREMENTS • Typically 8 hours per day (6-10) • Average American approx 7 hrs per day • Average resident 6 hours per day
INTERACTION OF CIRCADIAN RHYTHM AND HOMEOSTATIC DRIVE • <5 HRS SLEEP CAUSES INCREASED HOMEOSTATIC DRIVE • RESIDENTS ROUGHLY EQUIVALENT TO NARCOLEPSY AND SLEEP APNEA
SLEEP STAGES • NON-REM SLEEP • STAGE 1 (2-5%) • STAGE 2 (45-55%) • STAGES 3 AND 4 (3-23%) SLOW WAVE • REM SLEEP • 20-25% 4-6 EPISODES PER NIGHT • ABSENT MUSCLE TONE • DREAMING / BURST OF EYE MOVEMENTS
SLEEP INERTIA • Cognitive performance impairment, grogginess, amnesia and tendency to return to sleep immediately after awakening • Time course • Experimentally 1-4 hours • Practically 30-60 minutes • Decreased decision making performance • After 3 min, 51% of optimum • After 30 min, 20% below optimum
CONSEQUENCES OF SLEEP DEPRIVATION • Less than 5 hrs, homeostatic drive rises sharply • After 4 hrs, can function reasonably well for 2-3 days • After one night of no sleep, cognitive performance declines 25% • After second missed night, cognitive performance declines to 40%
SLEEPY PEOPLE EXHIBIT Fatigue Lack of initiative Lack of energy Indifference Apathy Irritability Inattention Ptosis/eye irritation Difficulty Slow reaction time concentrating Poor communication Poor decision making
PHYSIOLOGIC EFFECTS OF SLEEP DEPRIVATION • Hypoxemia • Insulin resistance • Elevated sympathetic activity • Blunted arousal response
NEUROBEHAVIORAL EFFECTS OF SLEEP DEPRIVATION • Voluntary / involuntary MSLT shorten • Microsleeps intrude (state instability) • Behavioral lapses (error of omission) • False response (error of commission) • Time on task decrements (fatigue) • Cognitive speed/accuracy trade off • Learning and recall deficits • Working memory etc decline
ADAPTATION TO SLEEP LOSS • EFFECTS OF CIRCADIAN RHYTYM ON SHIFT WORK “LEARNING TO FUNCTION”
MASKING EXCESSIVE SLEEPINESS • Motivation • Emotion • Environment • Posture • Activity • Light • Food intake
CHRONOBIOLOGY • Examines the timing of biologic processes and the effect of time on function • Studies dysharmonies between circadian rhythms and sleep wake cycle • Applies principles to designing work to maximize function over 24 hr day
SLEEPINESS ERODES PERFORMANCE • Pediatric sleepiness scale ratings are inversely related to middle school grades • Performance error peaks reflect circadian troughs • Fatigue related accidents peak at 6AM and 2 PM • Rested night shift workers have lower performance than day shift
Grounding of the Exxon Valdez • Three Mile Island • Erroneous launch of the Challenger • Transportation accidents
IMPACT ON MD/PT SAFETY • BSE • MEDICAL ERRORS • SURGICAL COMPLICATIONS • DROWSY DRIVING
DROWSY DRIVING • 100,000 drowsy driving crashes / yr • 37% driving population have “nodded off” • Population at highest risk • Male 2X • Ages 16 – 29yo • Shift worker, esp rotating shifts and post call • Untreated sleep disorders • NHTSA
Hours slept night before most recent nod off while driving NHTSA survey
EXTENDED SHIFTS & MVAs • Barger et al. NEJM Jan 05 • 2737 interns , 17,003 monthly reports • OR after extended shift • MVA 2.3 • Near miss 5.9 • OR with 5 or more extended shifts in mo • Fall asleep driving 2.39 • Fall asleep at light 3.69
BSE EXPOSURES / TIME OF DAY • Average 40 accidents per hour per 1000 MDs in training 6AM-6PM • Average 60 accidents per hour per 1000 MDs in training 6PM-6AM • RR 1.5 for BSE on nights, esp junior HO • Parks et al, Chronobiol Int 2000
MEDICAL ERRORS • NO study conclusively demonstrates direct causal relationship between fatigue/medical error • 41% residents cited fatigue as cause of most serious medical error • Wu, JAMA 1991 • 10% anesthesia errors found fatigue as factor • Morris, Anaesth Intensive Care, 2000
Harvard ICU/CCU intern study, 2004 • 3 intern traditional vs. 4 intern intervention • 35.9% more serious errors • 20.8% more serious medication errors • 5.6 X more serious diagnostic errors • Landrigan, et al NEJM 2004
SURGICAL COMPLICATIONS • 6371 resident surgical cases 1/85 – 4/88 • Analyzed complications by call status of residents who took q 4th night call • When occurred on a non call day, complication rate was 45% higher post call • Analyzed emergent vs. scheduled cases and no statistically significant difference • Haynes, Southern Medical Journal, 1995
STUDIES ON RESIDENTS Surgical residents Increase in time to complete > accuracy Decreased performance on in training exam Decreased participation in OR Non surgical residents Some studies show higher error in procedures and interpretation of data
STUDIES ON RESIDENTS • Rarely or never controlled for stimulant use, chronic sleep deprivation, circadian rhythm during testing, level of training • Small study size and significant drop out • Self selection of work hours / tolerance • Applicability of test to actual practice • Effect of practice
STUDIES ON RESIDENTS • Perceived vs. objective sleepiness • Diminished mood, increased depression • Increased anger, frustration, dysphoria • Decreased satisfaction with training • Subnormal serum testosterone levels • Singer F, Zumoff B, Steroids 1992
No evidence that 80wk will reduce MD fatigue or its consequences • 24 hr continuous duty limit well beyond the 16-18 hr increased risk rate for wakefulness • Sleep loss / fatigue can be recognized and managed but not eliminated
ALTERTNESS MANAGEMENT • SIGNS AND SYMPTOMS OF SLEEP LOSS AND FATIGUE • INTERVENTION STRATEGIES
SIGNS AND SYMPTOMS Falling asleep while sedentary Irritability Repeatedly checks work Difficulty focusing / concentrating Apathy or indifference
Symptoms of Drowsy Driving • Long blinks • Head nodding • Difficulty focusing on road • Missing exits / forgetting drive • Drifting from lane • Closing eyes at light • Slowed reaction time
NAPPING • PROPHYLACTIC • Brief naps prior to 24 hr loss • THERAPEUTIC • Q 2-3 hrs X 15 min • MAINTENANCE • 2-8 hour nap prior to 24 hr loss