Full Text Review
Please note: In 2003, the CTF updated its Grades of
Recommendations to include an "I Recommendation" for situations where
insufficient evidence exists to allow a recommendation to be made.
(Formerly, these situations were captured under a "C
Recommendation".) This change is not retroactive, and all
"C Recommendations" made prior to 2003 have not been
reevaluated in light of the new "I" recommendation grade. For a
discussion of these recommendation grades, please link to the 2003 article in
the Canadian Medical Association Journal here.
Prevention of Motor Vehicle Accident Injuries
Adapted to the Canadian context by R. Wayne Elford, MD, CCFP, FCFP, Professor,
Department of Family Medicine, University of Calgary, from the 1989 report
of the U.S. Preventive Services Task Force
These recommendations were finalized by the Task Force in November
1992
Contents
Overview
In 1979,
the Canadian Task Force on the Periodic Health Examination recommended
that physicians attempt to control underlying medical conditions, counsel
the disabled, and encourage the use of seat belts by all drivers and passengers
(C Recommendation). In 1989,
the U.S. Preventive Services Task Force recommended that all individuals
be urged to use occupant restraints (safety belts and child safety seats)
for themselves and others, to wear safety helmets when riding motorcycles,
and to refrain from driving while under the influence of alcohol or other
drugs.< 1
The Canadian Task Force concurs with these recommendations.
Burden
of Suffering
Of the ten industrialized western countries Canada has
the fourth highest injury mortality rate (37.5/100,000)
and the sixth highest motor vehicle accident (MVA) fatality rate (15.8/100,000).
In 1987,
the crude fatality rate for males was 18.4/100,000
and 9.6/100,000
for females. Figure 1 displays
the fatal injury rate from MVA according to the various age groups. Although
the gender curves are of similar shape, the rate for males is consistently
almost twice that of females. The risk of motor vehicle crashes is also
increased for persons over age 60, but elderly motorists account for only
10%
of fatal crashes, primarily because they drive less distance than younger
persons.<2 Fatalities are but the tip of the iceberg; Figure 2 displays
the nonfatal injury rate for the various age groups. The gender curves
closely approximate each other except for the young adult group (19-34
yr). Motor vehicle injuries occur most commonly in males and in persons
aged 15-24.
This age group has the highest mortality rate and accounts for one-third
of all deaths from motor vehicle crashes. Motor vehicle crashes are the
leading cause of death in persons aged 5-24; in 1986
they accounted for 38% of all deaths in young persons aged 15-24.<3
High Risk Behaviours
The relationship between seatbelt use and the severity
of injury is displayed in Figure 3. The rate of seat belt use among those
persons fatally injured was considerably less than among those with nonfatal
or no injuries from MVAs. The pattern of seatbelt use in Canada closely
parallels the introduction of seatbelt legislation in the various provinces.
For example, the rate in Alberta rose from 28% in 1986
to 83% in 1988
after the introduction of mandatory seatbelt legislation in July 1987
(Figure 4). About 40% of persons killed in motor vehicle crashes are intoxicated
by alcohol.<4 Studies have consistently shown that fatally injured drivers
are more likely to have a blood alcohol level of at least 0.10%
than are drivers who are not killed. In addition to its role as a risk
factor for causing motor vehicle crashes, alcohol intoxication increases
the risk of death or serious injury during and after a crash, and can limit
the ability of the victim to escape from the vehicle. Alcohol-intoxicated
survivors with severe brain injuries appear to have longer hospitalizations
and more persistent neurologic impairment than those who were not intoxicated.
(For more information on problem drinking consult Chapter 42).
Medical Impairment
Impaired vision, impaired hearing, decreased flexibility
and dexterity, and slowing of information processing capability result
in abnormally high accident rates in the elderly when exposure is taken
into account.<5 Less than 0.5% of all deaths of elderly people are the
result of road accidents, but elderly drivers are over represented in low
velocity, property-damage-only collisions. Whether drivers with concomitant
medical conditions have excessive motor vehicle accidents is less clear.
Most studies show that there is an excess of crashes among drivers whose
medical
condition is known to Departments of Motor Vehicles compared to drivers
not reported to have medical problems.<6 An examination of the driving
performance of drivers with selected medical impairments has resulted in
the requirement for medically impaired drivers to obtain medical report
forms from their physicians, and the development of tables of assigned
weights for comorbid conditions. These tables are used by insurance companies
and motor vehicle branches to designate different levels of restriction.
Practitioners must comply with the obligation to report to the regional
Department of Motor Vehicles patients who do not meet the criteria for
maintaining a driver’s license.
Off Road Vehicles
Most injuries associated with all-terrain vehicles (ATVs)
occur when the driver loses control, the vehicle falls over, the driver
is thrown from the vehicle, or the vehicle collides with fixed objects
such as fences or trees. The 1987
data for numbers of vehicles in use and mortality, without reference to
patterns of vehicle use, yielded annual death rates of 1.7/1000
for 3-wheeled and 1.2/1000
for 4-wheeled ATVs.<7 A review of data in 1986
identified 23 deaths and 572 hospitalizations in Quebec. Males accounted
for 85% of hospitalizations. Canadian and U.S. studies have revealed the
following risk factors: excessive speed, improper apparel and nonuse of
helmets, inexperience, and alcohol abuse.<8
Effectiveness
of Prevention Maneuvers
The effectiveness of occupant protection systems has
been demonstrated in a variety of study designs that include laboratory
experiments (using human volunteers, cadavers, and anthropomorphic crash
dummies), postcrash comparisons of injuries sustained by restrained and
unrestrained occupants, and postcrash judgements by crash analysts regarding
the probable effects of restraints had they been used.<9 Based on such
evidence it has been estimated that proper use of lap and shoulder belts
can decrease the risk of moderate to serious injury to front seat occupants
by 45-55% and can reduce crash mortality by 40-50%. When brought to the
hospital, crash victims who were wearing safety belts at the time of the
crash had less severe injuries, were less likely to require admission,
and had lower hospital charges.<10
Airbags are in effect 100%
of the time, whereas it is estimated that currently the 3-point seat belt
is not worn by 25% of Canadians. Seat belts and airbags are not alternatives
– they complement each other. The primary advantage of airbags is that
they require no active participation by the occupants of the vehicle. High
risk groups, in light-trucks and in rural areas are particularly vulnerable
because of their lower rate of seat belt usage. The overall safety benefit
of the combination of lap-shoulder belt and airbag system use has not yet
been determined from field accident data, however, estimates based on the
analysis of fatal crashes involving belted front seated occupants, a potential
additional fatality prevention of 3-5% when a combination lap-shoulder
belt and airbag system is used.<11
Child safety seats also appear to be effective. It has been reported that
unrestrained children are over 10
times as likely to die in a motor vehicle crash than are restrained children,<12
although these data come from studies with important design limitations.
Other studies suggest that child safety seats can reduce serious injury
by 67% and mortality by 71%.
Child restraints may also reduce noncrash injuries to child passengers
by preventing falls both within and out of the vehicle. By wearing safety
helmets, persons who operate or ride on motorcycles or ATVs can reduce
their risk of injury or death from head trauma in the event of a crash.
In regions where their use is required by law, such helmets have been shown
to reduce mortality by about 30%. Head injury rates are reduced by about
75% among motorcyclists who wear safety helmets.<13
Regions that have repealed mandatory motorcycle helmet laws have experienced
significant increases in motorcycle fatalities.
Effectiveness
of Counselling
There is a paucity of information from clinical studies
on the ability of physicians to influence patients to refrain from driving
while intoxicated. Similarly, there have been few studies examining the
effectiveness of physician counselling to use safety belts.<14
The strongest evidence that clinician counselling can be effective comes
from programs that have encouraged parents to use infant safety seats before
the practice became widely mandated by law. Results from such programs
suggest that significant short-term improvements are possible immediately
after newborns are discharged, but the effect is rarely maintained for
more than a few months.<15
A controlled trial without randomization found that the combined intervention
of pediatrician counselling, a prescription for an infant restraint, and
a pamphlet on crash protection was associated with increased correct use
of infant safety seats as assessed at the first two monthly well-baby visits.
A small randomized study demonstrated that a "loaner seat" and instruction
provided by a nurse resulted in increased use after two to four weeks.
The same researchers in a subsequent trial found that a comprehensive hospital
program combined with recent state legislation was effective in improving
correct usage, but intensive counselling from pediatricians and nurses
was of no additional benefit. Another controlled study found that personal
discussion was of limited value; a subgroup receiving free infant restraints
and literature demonstrated slightly higher correct usage at discharge,
but there was no significant difference between the groups in two to four
months. Finally, another study found that pediatrician counselling resulted
in an immediate increase in safety belt use, but there was no difference
in usage rates between the study group and controls at one-year follow-up.<16
Recommendations
of Others
The use of safety belts and child safety seats is widely
recommended by organizations and agencies concerned with injury prevention.
Child safety seats are required by law in all 50 states and all 10
Canadian provinces. Mandatory safety belt laws are in effect in most states
and all the provinces of Canada. Recommendations specifically urging physicians
to counsel patients to use occupant restraints have been issued by a number
of organizations, including the Canadian Medical Association, the College
of Family Physicians, and the National Highway Traffic Safety Administration.
The Canadian Medical Association has made recommendations on a wide range
of vehicle safety standards – restraint systems, running lights, motorcycle
helmets, mopeds, all-terrain vehicles, minivans and light trucks; and supports
legislation aimed at decreasing the incidence of drinking and driving.
General Council resolutions have also been made regarding airbags and elimination
of seat belt use exemptions for police officers and taxi drivers. The American
Academy of Pediatrics also recommends counselling adolescents to abstain
from intoxicants when driving; advising parents and children to discuss
the proper use of alcohol at teen parties; and suggesting alternatives
to driving while intoxicated or riding in a vehicle operated by an intoxicated
driver.<17>
Conclusions
and Recommendations
There is good (grade I) evidence that persons who use
occupant protection<9,10
and avoid driving while intoxicated<4,18
are at significantly decreased risk of injury or death from motor vehicle
accidents. There is fair (grade II-2) evidence that wearing safety helmets
when operating/riding motorcycles or all-terrain vehicles reduces the risk
of accidental injury or death.<7,8 Expert opinion (grade III) suggests
that many patients seen by clinicians could benefit from counselling to
modify their behaviours as drivers and passengers in motorized vehicles.<15
Since motor vehicle crashes represent a leading cause of death and nonfatal
injury, even modest successes through clinical interventions could have
major public health value. In actual practice, however, it is not known
how effectively clinicians can alter these behaviours. Counselling is most
relevant for those at increased risk of motor vehicle injury, such as adolescents
and young adults, persons who use alcohol or other drugs, and patients
with medical conditions that may impair motor vehicle safety.<5 The
optimal frequency for counselling patients about motor vehicle injury has
not been determined and is left to clinical discretion.
Unanswered
Questions (Research Agenda)
Ideally, the effectiveness of physician counselling
concerning a number of efficacious practices related to the prevention
of motor vehicle accident injuries should be evaluated. However, because
many of the preventive maneuvers have become widely mandated by law, the
evidence that clinician counselling can influence patient behaviour concerning
these practices is unlikely to be defined.
Evidence
The Medline search strategy for this review identified
articles for the years 1981-1991
using
the following MESH headings:
-
Motor Vehicle,
-
Accident Prevention,
-
Primary Care Physician,
and produced 151
citations.
The U.S. Preventive Services Task Force 1989
report<1
was used extensively and a number of their references were retained in
the selected bibliography.
This review was initiated in June 1991
and
recommendations were finalized in November
1992.
A technical report with a full reference list dated February, 1993
is available upon request.
Figure
1*
Figure
2*
Figure
3**
Figure
4**
Full Citation
Link to Structured Abstract of
this review
Link to Summary Table of this
review
Link to Selected References list of this review
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