Mad dogs and Englishmen….

Sunday, July 1, 2007

Just like the robin signaling spring, the first roofer of the year to show up in the ER with heat exhaustion is a certain sign that the dog days of summer are upon us. Muscle cramps, heat exhaustion and heat stroke are all preventable complications of working and playing outside in the summer heat. Roofers tend to be the first signalers of the risk of heat illness because they work in an environment surrounded by dark colors which intensify the ambient heat.

The body works in a very narrow range of normal and when its temperature rises, it cools itself by the process of evaporation; sweat evaporating in the breeze. This works extremely well but it requires enough fluid in the body to make sweat, a breeze and humidity that is low enough to allow evaporation .On those hot, sultry days the last two
Parts of the equation may be lacking and the risk if heat illness increases.

The fluid part should be easy. Drink enough fluid so that the body has enough on board to make clear urine. The kidneys do a great job in regulating the fluid and electrolyte balance in the body, but they need the building blocks to do it. It was recipe for disaster when, a generation ago, coaches withheld water from their athletes to toughen them up.

The spectrum of heat related illness begins with the least serious called heat cramps. Due to muscle dehydration, they often occur a couple hours after the exercise or work and the muscles that were heavily used go into painful spasm. Diagnosis is based on history and treatment is pretty simple: hydration and prevention of future episodes by education.

Heat exhaustion is the next step up in severity. Symptoms include profuse sweating, lightheadedness, nausea, vomiting and weakness. Again the diagnosis should be made by context and treatment in the field or on the roof, includes getting the patient into a cooler environment, loosening clothes to allow air movement to facilitate sweating and drinking fluids. Sometimes people are ill enough or are so nauseated that intravenous or IV fluids are used to rehydrate.

Heat stroke is the most severe type of heat related illness. The body has tried to compensate for the fluid loss and environment but it has reached its limits and it spirals quickly into a life threatening situation. Because of marked dehydration, sweating stops and the body shunts blood and fluid to the core to protect the heart, lungs and brain. That means blood flow to the skin, where heat is dissipated, is stopped and internal temperatures skyrocket to levels above 105F. Blood pressure falls, the pulse becomes very rapid and thready and the patient becomes very confused or even unconscious. This is a true medical crisis and can lead to death. The initial treatment remains the same: Remove the patient to a cool environment, IV fluids and active cooling. Calling 911 and activating EMS is a must.

As is true in post of medicine, prevention is the key to good outcome. People who have to work or exercise in the heat of the day must know their body and must recognize when the environment is winning the battle of fluid and temperature. Given the real world where the show must go on, hydration, cooling fans and a slowing pace of work to decrease the body’s production of internal heat from muscle work are essential when the summer sun and humidity make it tough outside.

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