passing out

Monday, April 3, 2017

Fans watch where the action is but video cameras record all, including what happens well away from the play. Low motion instant replay is usually saved for highlights or controversial plays, but for Philadelphia Flyer Michal Neuvirth, those cameras captured him collapsing in his goal, 100 feet away from the puck Without warning, Neuvirth fell to the ice and remained motionless for a few minutes until he gradually wakened and was rushed to the hospital. He was observed overnight, and with initial testing being normal, he was discharged home, no doubt to be poked and prodded to find out just what happened.

Passing out is never normal. At its very basic, the purpose of the body is to protect the brain at all costs. Brain cells need very little to function, oxygen, sugar and that’s about it, but it takes a complicated factory to deliver those two basic goods. A person needs to be able to breathe to get air into the lungs, where oxygen needs to be extracted and tacked onto red blood cells. The heart pumps those cell through arteries to the brain. Glucose is added to that oxygen supply when digestive system extracts glucose from food and dumps it into the bloodstream.

With those two building blocks, a person will be awake if two structures in the brain are working. The reticular activating system, the on/off switch in the brainstem, needs to be in the on position and at least one hemisphere of the brain needs to work. Blood supply needs to be cut to one or both of these parts of the brain for a person to become unconscious.

It may be a true emergency when a patient has a syncopal event, meaning that they passed out. If the patient remains unconscious, treatment and diagnosis happen together. Blood is tested for low blood sugar (hypoglycemia), a dose of Narcan might be given in case the person overdosed on a narcotic and an EKG with a heart rhythm strip is done, looking for a heart rhythm disturbance. Most often, though, the patient is awake by the time they are seen by the doctor and the detective work begins to look for clues as to the reason why the patient passed out, make certain that no disaster has occurred and hopefully prevent another passing out episode.

Passing out often is a fluid delivery problem. Cardiac output measures how much blood the heart pumps per minute. Enough output and the blood pressure is maintained to push blood uphill to the brain. The cardiac output formula is relatively simple:

      Cardiac output = Stroke volume x Heart Rate

Output equals how much blood is pumped per heartbeat multiplied by how often the heart beats per minute, and is a measure of how effective the heart is in meeting the body’s and the brain’s demands for energy. Problems may exist with the heart rate and rhythm or with the red blood cells and fluid. Anemia (low red blood cell count) or dehydration (decrease fluid in the body) may decrease how much blood is pumped per heartbeat. A heart that beats too slow, too fast or not at all, will also decrease cardiac output.

Some problems are not very serious, like a vasovagal episode, where the heart slows and blood vessels dilate because a noxious stimulus that stimulates the vagus nerve. Imagine a medical student fainting when he sees his first operation or a patient who passes out because of pain. Other causes can be life threatening, like a massive pulmonary embolus or blood clot to their lung (25% of patients with PE present with sudden death), a structural problem with the heart or a major electrolyte crisis in the body.

ESPN reported that Mr. Neuvirth had been recently ill recently with a virus infection and perhaps his syncope was due to dehydration. Standing in full equipment can make a goalie sweat up a storm…but while dehydration is a possibility, the big worry is whether Mr. Neuvirth had a heart rhythm abnormality, an electrical disaster like ventricular fibrillation nor ventricular tachycardia. When the bottom half of the heart does not get an organized electrical signal, it can’t squeeze in a coordinated fashion, it can’t squeeze, blood doesn’t flow through the body, including the brain, and the patient can pass out. V fib and V tach may be the cause of sudden death.

Since the patient is usually not on a monitor when the event happens, and if no other easy diagnosis can be found to explain the syncope, admission to the hospital to watch the heart rate and rhythm is usually the safest plan. Sometimes a clue can be found on the EKG or during observation, but often not. The patient is usully discharged home with no solid answer but with the expectation that further tests might need to be done. Since people live in the real world and not a hospital bed, people can have their hearts monitored in the real world for durations of 1-2 days or even months at a time. Every heartbeat can be recorded and analyzed fro potential problmes.

The treatment of syncope depends on the cause but from a practical standpoint, sometimes the cause is never found. The question then becomes, what advice should be given to the patient regarding activity. There is no right answer when the diagnosis is not known. In the ER, the unknown syncope decision is easy; the patient needs to stay in the hospital to be monitored. But once the dust has settled, it’s a risk-reward discussion between doctor and patient to decide when it’s safe to return to full activity, whether that’s work, driving a car or playing goalie in the NHL.

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