Transcript Assessing Driving Risk in Patients with Sleep Apnea

Assessing Driving Risk in
Patients with Sleep Apnea:
Who’s Safe to Drive?
Charles F.P. George MD FRCPC
University Of Western Ontario
London, Canada
Objectives

Discuss the issue of drowsy driving as it
relates to sleep apnea

Review current guidelines on fitness to
drive

Describe the legal implications of
physicians’ decisions about driving
“When I die, I want to go like my
grandmother, who died peacefully
in her sleep. Not screaming like all
the passengers in her car.”
--Author Unknown
Causes of Sleepiness/Drowsy Driving

Sleep loss or sleep restriction
◦ Job-related sleep restriction
◦ Personal demands and lifestyle choices.

Driving patterns (e.g. Night driving)

Use of sedating medications

Alcohol consumption

Untreated/Unrecognized sleep disorders
Risk Factors in Sleep-Related
Crashes
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Holding multiple jobs
Working night shift
Less than 6 hrs sleep/night
Nighttime driving (2400-0600h)
Daytime sleepiness
Driving after awake >15hrs
Long duration driving
Past history of drowsy driving
Stutts JC. Accid Anal Prev. 2003;35:321-331
J Clin Sleep Med 2009; 6:573-581
Crash Risk among Individuals with OSA Compared to Controls
(Random-effects Meta analysis)
Characteristics that may
predict crash:

AHI

BMI

O2 Saturation

Sleepiness
Can you spot the
sleepy, OSA driver?
Which Smoker will get
emphysema, lung cancer?
Operating a Motor Vehicle

A Right or a privilege?

All rights include individual responsibilities.

Every motor vehicle operator is
responsible for operating safely
Liability for Injuries When an
Individual Falls Asleep

A motor vehicle driver has a duty to drive
safely in order to avoid foreseeable harm to
others

When that duty is breached by
unreasonable unsafe, conduct, the driver
may be held liable for the harm proximately
caused.

A driver is not guilty of reckless or careless
driving by reason of what he does when
asleep;

But (s)he can be convicted of careless [or
reckless] driving if he falls asleep at the
wheel

– i.e. (s) he was guilty of the offence not at
the moment when the crash occurred but
at the prior moment when he should have
realized that he was sleepy and should have
stopped driving.
Case of Sleepy Driving

A university student driving home from
studying for year-end exams.

Following an exam, the defendant had
socialized, studied and napped until 6:00 the
next morning, began driving home at about
6:00 a.m.

She failed to notice a highway diversion
barricade and struck and killed a tow truck
operator assisting at the scene of a previous
accident.
R v. Gill 2005 BCPC 0665

“ A reasonable driver, knowing that they had stayed
awake for 24 hours and had already fallen asleep as a
consequence, unexpectedly, during that time period, and
feeling the need to take action while driving to prevent
the onset of sleep, such as turning up a radio (or some
other folk myth like opening windows for a blast of fresh
air), is expected by law to exercise a standard of care by
not driving until the impairment has been corrected.”
Case of OSA

46 y.o. Obese male (BMI=36.3) is
referred for snoring and breath-holding
during sleep. His wife says he gets sleepy
while driving long distances (2 hours).
Both deny any collisions.

Sleep study reveals sleep apnea (AHI=32).
Case of OSA
Is the patient at risk for motor vehicle
collisions?
 How should the physician deal with the
situation?
 When is the physician liable for a patient’s
action?

Should All OSA Patients
Be Allowed To Drive?
YES
NO

Patients with OSA
understand their sleepiness
and respond to it
appropriately. They are
reliable .

Patients with OSA cannot
accurately gauge their
sleepiness and degree of
impairment.

It is inappropriate to punish
all for the rare patient who
has accidents.

The benefit to society
overrules the rights of the
individual patient.
We don’t tolerate drunk
drivers on our roads.
Why should we tolerate
drowsy (OSA) drivers?
Driving Recommendations For
Patients With OSA

Patients with mild OSA without daytime
somnolence who report no difficulty with
driving are at low risk for motor vehicle crashes
and should be safe to drive any type of motor
vehicle.

Patients with OSA, documented by a sleep
study, who are compliant with CPAP or who
have had successful UPPP treatment, should be
safe to drive any type of motor vehicle.

Patients with moderate to severe OSA,
documented by sleep study, who are not
compliant with treatment and are
considered at increased risk for motor
vehicle crashes by the treating physician,
should not drive any type of motor
vehicle.

Patients with OSA who are believed to be
compliant with treatment but who are
subsequently involved in a motor vehicle crash
in which they were at fault should not drive for
at least 1 month.

During this period, their compliance with
therapy must be reassessed. After the 1-month
period, they may or may not drive depending on
the results of the reassessment.
I have sleep apnea but my
Doctor said it was okay to drive!
Ontario Highway Traffic Act
Section 203
203(1): Every legally qualified medical practitioner
shall report to the Registrar (of Motor Vehicles) the
name, address, and clinical condition of every person
16 years of age or over attending upon the medical
practitioner for medical services who, in the opinion
of the medical practitioner, is suffering from a
condition that may make it dangerous for the person
to operate a motor vehicle.
Ignorance of the
law is no defence!
CMPA
Gee, I
didn’t
know that.
CMPA Medico-legal handbook p29.
At Risk Patients

Severe OSA
◦ Defined by what metric?

Excessively sleepy
◦ Objective or subjective measures?

Previous motor vehicle crash
◦ How would you know if the patient doesn’t tell?
Not All OSA Patients Have Accidents
OSA –no Rx
Controls
OSA – on CPAP
for 3 yrs
Controls
3 yrs later
George CF. Thorax 2001;56:508–512
Sleep 2010; 33:745-752
MSLT is predictive of an increased risk of DMV documented
automotive crashes in the general population

A diagnosis of obstructive sleep apnea precludes an
individual from obtaining unconditional certification to
drive a CMV for the purposes of interstate commerce.

An individual with a diagnosis of obstructive sleep
apnea may be certified to drive a CMV if that individual
meets the following criteria:
◦ Has untreated obstructive sleep apnea with an AHI ≤ 20,
AND
◦ Has no daytime sleepiness, OR
◦ Has obstructive sleep apnea that is being effectively
treated.
Treatment with CPAP reduces MVC’s
George C Thorax 2001; 56:508-512
Collisions/driver/year
0.50
OSA
0.40
0.50
Controls
0.40
p = ns
p < 0.001
0.30
0.30
0.20
0.20
0.10
0.10
0.00 3 Years Before 3 Years After
0.00
CPAP
3 Years Before 3 Years After
Same Time Frame
Summary
Some but not all OSA patients are at risk
for motor vehicle accidents.
 MD’s must know their local reporting
requirements and assess each patient.
 Always document in your records.
 Aggressively treat OSA
 Educate all sleepy patients about drowsy
driving.
