and the heat goes on…

Monday, September 1, 2014

She was hunched over, sitting in the courtside chair, an iced towel draped across her neck. The trainer was taking her blood pressure as she sipped a sports drink. While it was her opponent across the net who was ahead on the scoreboard, it was the weather that was the true foe. The combination of heat and humidity had caused Eugenie Bouchard’s body to fail her. While the air temperature was only in the mid-80s, the sun beating down on the Louis Armstrong Court in Flushing Meadows likely drove the temperature higher by 10 degrees or more. However, it was the 70% humidity that was the true villain and that dramatically increased her risk of heat exhaustion.

The body is always producing heat as it goes about its routine daily activities, like breathing and digesting food. Exercise increases that heat production by more than a hundred fold and the body needs to cool itself to be able to function. While we think of exercise as working out or playing a sport, many people exercise on the job. The person doing manual labor is as much an athlete as the person on the field and their body reacts to the environment in just the same way.

The body cools itself by sweating, depositing water on the skin to evaporate and cools. There are certain basic requirements for this to happen. The body needs to have enough water to produce sweat and the air needs to have enough room to accept it. If the air is full, meaning that the relative humidity is very high, the air cannot accept any more water molecules and evaporation from the skin cannot occur. All the sweat in the world will not help cool the body if there is no place for the sweat to go. This is where the heat index comes in to provide a guide to dangerous circumstances.

heatindex-sm12

If sweating and evaporation break down, the body’s temperature begins to rise and all sorts of bad things can happen. The spectrum of heat related illness begins with heat cramps, moves to heat exhaustion and finally to heat stroke, which is a life threatening condition.

But back to the numbers. With exercise, the body can generated up to 10 kilocalories per kilogram per hour of heat. For Ms. Bouchard, who weighs about 60 kilos (130 pounds), that adds up to about 600 kcal per hour. The heat of the sun adds another 150 kcal per hour, so that her body needs to get rid of 750 kcal every hour she is on the court. For a person not used to the heat, the body can produce about 1 liter or a little more than 2 pounds of sweat an hour, just enough to get rid of 580 kcal every hour. Doing the math, if Ms. Bouchard’s body was not acclimated to the heat and humidity, she was falling behind the heat equation every minute she was on the court.

An acclimated athlete can sweat up to 3 liters per hour, more than 6 ½ pounds, and get rid of more than 1700 kcal of heat every hour, but it takes 7-10 days for the body to acclimate to the heat. Even with the awareness that fluid intake is crucial, athletes often fall behind on that equation, and it is not uncommon to see elite athletes requiring IV fluids at halftime and after the game is over.

The loss of water and electrolytes can cause dehydration that also affects the way nerves and muscles interact, leading to muscle cramps. Continued water loss and rising body temperature can cause heat exhaustion with fatigue, lightheadedness, nausea and vomiting. If not removed from the hot environment, the body’s temperature can spiral out of control leading heat stroke with seizures, coma and death.

How to cool the body? The first step is to remove the patient from the hot environment; it may be an air conditioned car that might be the closest best option. Undressing and fanning the patient helps with evaporation, by allowing more air to come into contact with the skin and increasing evaporation. Rehydration is important so that there is enough fluid in the body to continue the sweating process.

The body operates in a narrow range of normal and when it falls outside that range, it works every inefficiently, slowly breaking down. Once Ms. Bouchard started on the downward spiral of getting too hot and too dry, it was inevitable that her performance on the court would deteriorate. Ekatarena Makarova won the match, but aggressive exercise in the heat can cause delayed problems and she may yet develop muscle cramps and fatigue later in the evening or night.

Her responsibility to get hydrated remains, as it does for the construction or foundry worker athlete. Urine production is one signal that the body is finally getting enough fluid. When the body is dry, the kidneys try to hold onto as much water as possible and the amount of urine produced decreases and it becomes very concentrated and yellow. As the fluid status of the body improves, the kidneys begin producing more urine and it becomes clearer.

The ability to compete under any and all conditions perhaps is the mark of a champion, but the conditions at this year’s Open are once again a reminder that Mother Nature a tough opponent and a lady not to be messed with.

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Too many tests

Monday, August 25, 2014

In our mind’s eye, we could all throw it like Peyton, hit like big Papi and be like Mike. But while we aspire to their greatness, we should not ask to have their medical testing inflicted upon us. Today’s elite athletes can no longer be content with medical opinion, rather they or their team management expect that the latest technology be used to help make the diagnosis.

The latest victim of this syndrome is Carolina Panther quarterback, Cam Newton, whose rib injury during a preseason game might have been diagnosed with a brief history and physical examination. Mere mortals might have needed a plain chest x-ray but Mr. Newton also got a CT and MRI of his chest. The verdict? He had a nondisplaced rib fracture. And how did those extra tests affect his care and treatment? They didn’t.

Medicine has gone high tech with imaging tests that can peer inside every nook and cranny of the body to find things that may or may not matter. Chest wall injuries area prime example of what if gone wild. The ribs and muscles that make up the chest wall serve a couple of purposes. Most importantly, they act as a bellows, swinging up and out to suck air into our lungs to help us breathe and then again squeezing back in to make us exhale. It doesn’t matter if a rib is bruised or broken, the pain of either injury makes it difficult to take a deep breath and that interrupts the mechanism of breathing. When the lung does not adequately expand with inspiration, the patient runs the risk of getting pneumonia, an infection of the lung, and that is the great complication of a rib injury. The ribs also protect those organs that are located beneath. The lungs are obvious but the lower ribs also protect the spleen and liver in the abdomen and lower chest trauma can cause damage to the upper abdomen.

This is where the art of medicine comes in. Taking a history allows the doctor or other care provider to understand how much force was inflicted upon the patient and understanding the patient appreciates how much force they can withstand. A frail elderly patient who falls against a countertop and injures ribs is perhaps more likely to have underlying damage than a padded quarterback being hit by a linebacker. The physical examination can help decide whether a small area of the rib cage is damaged or whether numerous ribs are injured. The larger the injured area, the more likely that the breathing mechanism is compromised and the potential for complication increases. For most patients, a plain chest x-ray is adequate to look not for rib fractures but for a pneumothorax (collapsed lung) or pulmonary contusion (a bruised lung). Ordering rib x-rays to look for a fracture is a waste of time, money and radiation. Physical exam will also tell you whether there is enough abdominal tenderness to us CT to look for internal bleeding.

But the art of medicine is not infallible and perhaps that is feeds the fear of missing an injury. Green Bay Packer center TJ Tretter hurt his knee early in the game against Oakland but played on after doctors evaluated him on the sideline and cleared him. Unfortunately, he had a fracture that will sideline him for the next many weeks. The same fear also feeds the use of CT to routinely evaluate concussions when there are clinical guidelines that can help decide who needs a scan and who doesn’t.

One can appreciate the high medical tech approach to those athletes whose salaries run into the tens millions of dollars and those teams who market the player to their maximum advantage, yet the general population takes their cue from what they see on the field, on the sideline and in the training room. Ideally, regular folk should ask the doctor why a test is being ordered and what benefit it will bring. Sometimes, tests are ordered just because with little thought. Other times, the decision as to what test to perform takes great thought. Sometimes, there is risk management involved. The doctor doesn’t want to miss a diagnosis, not only for the patient’s sake but also for fear of being sued. In many situations, if the patient were asked, they might agree the risk of missing the diagnosis was not enough to perform an expensive or painful test.

This shared risk happens routinely when a diagnosis has been made and treatment options are being contemplated. The patient often helps decide if they want aggressive or more conservative treatment options or perhaps an operation now or later. There is no reason that the process of involving the patient cannot happen earlier in the diagnosis phase as well. The key is communication is to allow the patient to become a partner in the all decision making process and not the object of it.

For Mr. Newton, his ribs are going to hurt for the next few weeks, regardless of whether they are broken or bruised. It will hurt to take a deep breath or to twist to throw or hand off the ball. It won’t matter that it took a CT scan or MRI to make the diagnosis of the broken rib. A good physical exam might have been enough, but it wouldn’t have been perfect…but even the best rarely are.

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