DUI TMB: Driving Under the Influence of Too Many Birthdays

At his age do you think he should still be driving?

This type of question always gets me into hot water.  My elderly patient is sitting there anxiously awaiting a reply that he will most certainly object to.  He and his daughter have already beaten this issue to death and are now at loggerheads with each other.  Her appeal to me is not really a request for an unbiased opinion as much as a validation of her side of the argument: Dad is now too old to drive a car.

My initial reflex is to dodge the question—after all, his primary doctor is in a better position to address this issue, since for most geriatric patients the heart is not the organ that leads them to drive over the neighbor’s mailbox.  The physical and mental skills required for driving, most of which deteriorate with age, are best assessed by a doctor who has a handle on the cumulative health of the patient.

For any doctor, trying to figure out when to tell a patient to turn their keys in is a challenging thing.  The most reliable assessment would be to climb into the passenger seat and ride shotgun as he takes the Buick down Dodge Street in the middle of rush hour traffic.  If you survive you know your patient is a competent driver (of course you may also find yourself curled into the fetal position begging to be dropped by the side of the road).

While you can take cues from those nearest your patient you can’t base your decision solely on the misgivings of an overly concerned family member.  Many elderly patients are more capable of limited excursions to church and the pharmacy than their children suppose.  Anyway, you can’t yank a license based on one relative’s conviction that your patient is a menace behind the wheel—if that were the case I know of at least one cardiologist who’d be relegated to a bus pass in perpetuity.

Another approach would be to rely on the judgment of the patient himself.  "Do you think you’re a safe driver?" is a fair question, but may not result in the most reliable answer.  It reminds me a little of an experience I had many years ago in the Air Force.

As part of my training I had to spend some time in an altitude chamber, a submarine-looking compartment designed to mimic high altitudes by depressurizing the air.  The purpose of the exercise was to learn how to detect the subtle signs of slow depressurization and low oxygen levels that rarely occur in jet airplanes.  After I donned an oxygen mask the chamber was "taken up" to an altitude of 25,000 feet and I was handed a clipboard with a simple math test attached.  I was told to take off my mask and work through the problems while watching for the subtle symptoms of hypoxia.

I never felt the tingling in the lips that I was taught to watch for and I was able to complete my math test by the end of the exercise.  I put my mask back on, proud that my lungs had been able to suck in enough oxygen to keep me level-headed and functional.  It was only when I took another look at my math test that I realized how wrong I was.  I started off well, but as the questions progressed my ability to correctly compute simple arithmetic went steadily downhill.  At the bottom of the test my penmanship was barely legible and I had given up on the last problem altogether.  I had failed Math 101 and didn’t even know it.

Mental impairment brought on by hypoxia is probably like driving impairment brought on by too many birthdays—it’s hard to judge and by the time you figure out the problem it might be too late.  I found a nice set of recommendations on an AARP website that can serve as clues to help decide if it’s time to retire the driver’s license:

• Almost crashing, with frequent "close calls"
• Finding dents and scrapes on the car, on fences, mailboxes, garage doors, curbs, or the like
• Getting lost, especially in familiar locations
• Having trouble seeing or following traffic signals, road signs, and pavement markings
• Responding more slowly to unexpected situations, or having trouble moving your foot from the gas to the brake pedal; confusing the two pedals
• Misjudging gaps in traffic at intersections and on highway entrance and exit ramps
• Experiencing road rage or having other drivers frequently honk at you
• Easily becoming distracted or having difficulty concentrating while driving
• Having a hard time turning around to check over your shoulder while backing up or changing lanes
• Receiving traffic tickets or "warnings" from traffic or law enforcement officers in the last year or two

Alegent Health also offers a program called "Driver Rehabilitation" that helps people make the decision about their driving abilities and are far more qualified than your local cardiologist at providing an informed opinion.  They can also assist people who have physical impairments in finding ways to make their driving safer and easier.  (Note to my wife: no, they don’t teach men how to "stop driving like a maniac" or to learn the value of asking for directions.)

In the cardiology world the decisions are a little easier.  We’ll temporarily restrict driving for about a month after heart attack or bypass surgery, and for a couple days after an uncomplicated coronary intervention (angioplasty or stent).  The US Department of Transportation recommends no driving for 6 months after an episode of unexplained loss of consciousness.  Interestingly, commercial truck drivers can drive freely with the diagnosis of congestive heart failure and cardiomyopathy, but the moment they receive a defibrillator they lose their license.  This makes no sense to me, since the drivers without the defibrillator—a device which can terminate life-threatening arrhythmias within just a few seconds—are clearly at higher risk of blacking out and barreling into oncoming traffic.

Beyond these straightforward heart-related guidelines there isn’t much to assist doctors trying to help reach this decision.  The whole issue is made worse by the fact that many people don’t really listen to what we say anyway.  In one glaring example of doctor disobedience, the British Medical Journal published a paper in 2003 that surveyed 95 patients who’d experienced fainting and who’d been told to avoid driving.  At the 6-month mark every single person confessed to being back behind the wheel (you have to give them credit for honesty), even the 19 who had experienced yet another episode of loss of consciousness and the handful who had subsequently crashed their cars.

Taking away a person’s driving privilege is a big deal and shouldn’t be recommended lightly.  America—and certainly a city like Omaha—is a car-friendly place that is hard to navigate without a driver’s license.  When an older person loses his ability to drive he is left using a suboptimal public transportation system, relying on helpful family and friends, or contracting the medical transport services.  Most of all, though, he gives up autonomy and personal freedom—losses that can be as much psychological as functional.

As I see it, if the patient is indeed no longer safe at the wheel the best I can do as a doctor is to be firmly persuasive.  If the individual in question (even someone old enough to still consider an Edsel "one of them new-fangled Fords") doesn’t agree with my assessment then no amount of lecturing on my part or arguments with his daughter will get him to turn in his car keys.

I guess at that point it’s time for me to hop into the Buick, buckle up, and take a wild ride down Dodge Street.