Tuesday, 14 October 2008

What Is A Tilt Table Test

What is a tilt table test?

Tilt table testing is designed to evaluate how your body regulates blood pressure in response to some very simple stresses.Blood pressure is regulated by a set of nerves which operate continuously and subconsciously and are part of the autonomic nervous system. This set of nerves detects certain bodily needs and they respond by causing the appropriate changes in blood pressure. The purpose of this part of the autonomic nervous system is to insure that there is always enough blood going to the brain, and to distribute blood to other organs according to their needs. For example, during exercise, blood is delivered preferentially to the muscles, whereas during eating blood is delivered preferentially to the intestines. These changes in blood pressure are accomplished by making changes in the way the heart beats and by making changes in the caliber or size of certain blood vessels.At times, the nerves which control blood pressure may not operate properly and may cause a reaction which paradoxically causes the blood pressure to drop suddenly. This reaction may produce a fainting spell or a number of symptoms including severe lightheadedness. Tilt table testing is designed to determine the likelihood that a patient is susceptible to this type of reaction.

Who needs a tilt table test?

Patients that have symptoms suggestive of a sudden drop in blood pressure may benefit from the evaluation of blood pressure regulation with a tilt table test. The tilt table test was originally designed to evaluate patients with fainting spells because many fainting spells are caused by a drop in blood pressure. Tilt table testing may also be useful for patients who have symptoms of severe lightheadedness or dizziness which don't actually cause them to faint, but force them to sit down or lie down. These symptoms, while not progressing on to an actual fainting spell, may still be indicative of a sudden drop in blood pressure. Many patients suffering from the chronic fatigue syndrome have symptoms of lightheadedness and have been referred for tilt table testing.

What does tilt table testing involve?

The first part of a tilt table test evaluates how blood pressure responds to the simple stress of standing up, or in other words, how the blood pressure responds to the stress of gravity. Patients are asked to remove their clothing above the waist, put on a hospital gown, and lie down on a special table. Patients are connected to an electrocardiogram (ECG) type machine, have a small cuff placed around a finger which measures blood pressure, and have a small intravenous line (IV) placed into a vein in the arm. We try to make the setting as relaxing as possible by dimming the lights and by turning on some soft music in the background. After everything is set up we collect baseline blood pressure and ECG data for 10 minutes while you lie quietly on the table.

How long will the tilt table test take?

The duration of the tilt table test depends in part on how you respond. Some patients demonstrate the reaction that causes their blood pressure to fall suddenly in the first 20 minutes of head-up tilt to 60 degrees. Given the time it takes to set up the equipment and collect baseline data, the shortest possible test is 30-40 minutes. Other patients finish the entire protocol without demonstrating any such reaction (a negative test); these patients therefore finish all three stages of the test. If you finish the entire test, it will take approximately 2 hours.

What is a positive test?

A tilt table test is called positive if a patient develops a drop in blood pressure associated with symptoms. The symptoms that patients experience are varied and have included lightheadedness, nausea, a cold and clammy feeling, sweating, a "spacey" feeling, or a feeling like you are about to black out. Rarely, blood pressure falls without the patient developing symptoms.

What does a positive test mean?

A positive tilt table test means that a patient is susceptible to one of the reactions that can cause a drop in blood pressure. Some of the reactions can be dangerous and require treatment, other reactions are benign and may not require treatment. Treatments vary from medication to a change in diet. The interpretation of the tilt table test is up to your physician.

How will I feel after the test?

Many patients who have a positive test feel a little unsettled and sometimes queasy for the first few minutes after the test. The vast majority of patients will return to feeling completely normal within 5 to 10 minutes after the test. Rarely, a patient may continue to experience weakness or fatigue for a longer period of time after the test. Patients that have a negative test often report that the test was tiring but otherwise feel fine. If the patient received isuprel during the test, the effects of isuprel wear off within a few minutes of stopping the infusion.

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