It’s A Cruel, Cruel Summer: Heat Waves
Well, Summer is here and the West is experiencing record high temperatures in a series of heat waves that may continue until Fall. Even worse, the scorching temperatures are igniting scores of wildfires that are threatening communities throughout the region.
Officials predicted a high-risk situation as the heat surpassed 100 degrees across much of Southern California; desert cities throughout Nevada, Arizona, and New Mexico hit temperatures reaching the 120s. These temperatures place the more than 3,000 firefighters in the area in extreme danger for heat-related complications.
The power grid is being tested by the millions of air conditioning units set on “max cool”, and we can expect to see some major issues if the electricity goes out and people have to fight the heat with hand fans.
You might not consider a heat wave a natural disaster, but it most certainly is. Heat waves can cause mass casualties, as they did in Europe when 70,000 died of exposure (not in the Middle Ages, but in 2003). India, Pakistan, and other underdeveloped tropical countries experience thousands of heat-related deaths yearly. A pre-monsoon heat wave in April killed hundreds in the region. There are already several recorded deaths in the American West.
So how exactly does heat kill a person? Your body core regulates its temperature for optimal organ function. When core body temperature rises excessively (known as “hyperthermia”), damage occurs that leak toxins, cause cell death, and major inflammation. These deaths can occur very quickly without intervention, even in those who are physically fit. Even in modern times, hyperthermia carries a 10% death rate, mostly in the elderly and infirm.
The ill effects due to overheating are called “heat exhaustion” if mild to moderate; if severe, these effects are referred to as “heat stroke”. Heat exhaustion usually does not result in permanent damage, but heat stroke does; indeed, it can permanently disable or even kill its victim. It is a medical emergency that must be diagnosed and treated promptly.
The risk of heat stroke correlates strongly to the “heat index”, a measurement of the effects of air temperature combined with high humidity. Above 60% relative humidity, loss of heat by perspiration is impaired, increasing the chances of heat-related illness. Exposure to full sun increases the reported heat index by as much as 10-15 degrees F.
Simply having muscle cramps or a fainting spell does not necessarily signify a major heat-related medical event. You will see “heat cramps” often in children that have been running around on a hot day. Getting them out of the sun, massaging the affected muscles, and providing hydration will usually resolve the problem.
In addition to muscle cramps and/or fainting, heat exhaustion is characterized by:
- Rapid pulse
- Nausea and Vomiting
- Temperature elevation up to 105 degrees F
If no action is taken to cool the victim, heat stroke may ensue. Heat stroke, in addition to all the possible signs and symptoms of heat exhaustion, will manifest as loss of consciousness, seizures or even bleeding (seen in the urine or vomit). Breathing becomes rapid and shallow.
If not dealt with quickly, shock and organ malfunction may ensue, possibly leading to death. In heat stroke, the skin is likely to be hot to the touch, but dry; sweating might be absent. The body makes efforts to cool itself down until it hits a temperature of 105-6 degrees or so. At that point, thermoregulation breaks down and the body’s ability to use sweating as a natural temperature regulator fails. In heat stroke, the body core can rise to 110 degrees Fahrenheit or more.
You’ll notice that the skin becomes red, not because it is burned, but because the blood vessels are dilating in an effort to dissipate some of the heat.
In some circumstances, the patient’s skin may actually seem cool. It is important to realize that it is the body core temperature that is elevated. A person in shock may feel “cold and clammy” to the touch. You could be misled by this finding, but simply taking a reading with a thermometer will reveal the patient’s true status.
When overheated patients are no longer able to cool themselves, it is up to their rescuers to do the job. If hyperthermia is suspected, the victim should immediately:
- Be removed from the heat source (for example, out of the sun).
- Have their clothing removed.
- Be drenched with cool water (or ice, if available)
- Have their legs elevated above the level of their heart (the shock position)
- Be fanned or otherwise ventilated to help with heat evaporation
- Have moist cold compresses placed in the neck, armpit and groin areas
Why the neck, armpit and groin? Major blood vessels pass close to the skin in these areas, and cold packs will more efficiently cool the body core.
Oral rehydration is useful to replace fluids lost, but only if the patient is awake and alert. If your patient has altered mental status, he or she might “swallow” the fluid into their airways; this causes damage to the lungs and puts you in worse shape than when you started.
Heat stroke is preventable in many cases. The Arizona state department of health recommends the following:
- Drink at least 2 liters (about a half-gallon) of water per day if you are mostly indoors and 1 to 2 additional liters for every hour of outdoor time. Drink before you feel thirsty, and avoid alcohol and caffeine.
- Wear lightweight, light-colored clothing and use a sun hat or an umbrella to deflect the sun’s rays.
- Eat smaller, more frequent meals instead of large ones.
- Avoid strenuous activity.
- Stay indoors as much as possible.
- Take regular breaks if you must exert yourself on warm days.
In a heat wave, it’s important to check on the elderly, the very young, and the infirm regularly and often. These people have more difficulty seeking help, and you might just save a life if you’re vigilant. Know the warning signs and how to help those with hyperthermia.
Joe Alton, MD