Norm of Tilt Table Test (Head-Up Tilt Table Test)
Negative or absence of hypotension or bradycardia with position changes.
Usage of Tilt Table Test (Head-Up Tilt Table Test)
Evaluation of recurrent idiopathic syncope once cardiac causes have been ruled out. Vasovagal syncope (also known as vasodepressor, neurodepressor, dysautonomia, or neurogenic syncope) is a sudden, short-term loss of consciousness caused by malfunction in the regulatory mechanisms between the nervous and cardiac systems.
Description of Tilt Table Test (Head-Up Tilt Table Test)
The head-upright table, by sudden assumption of an upright position, can produce passive orthostatic stress, which induces syncope in individuals affected by vasovagal (neurally mediated) syncope. Administration of an intravenous isoproterenol (Isuprel) infusion increases sensitivity of the tilt table test for those susceptible to vasovagal syncope by producing the elevation of circulating catecholamines associated with this type of event.
Professional Considerations of Tilt Table Test (Head-Up Tilt Table Test)
Consent form IS required.
Dizziness, dysrhythmias, hypotension, tachycardia.
Gradual loss of more than 500 mL of blood, hypertension, hypotension.
- See Client and Family Teaching.
- Start an IV at KO (keep-open) rate for administration of isoproterenol or emergency medication.
- The test can be run while the client is medicated or unmedicated.
- Baseline monitoring of heart rate (HR), rhythm (ECG), blood pressure (BP), with the client in a supine resting state every 5 minutes for 15–30 minutes.
- The table is then tilted up to 90 degrees for usually 5–7 minutes (up to 30 minutes). Note: Duration of the tilt has been found to be a more important variable than tilt angle. Duration of the tilt should be determined based on the suspected cause of the orthostatic intolerance: approximately 5 minutes to document orthostatic hypotension, approximately 10 minutes to identify orthostatic tachycardia, or neurally mediated syncope.
- BP and HR are monitored and documented every minute for 25–45 minutes by automatic cuff or arterial line and ECG.
- The test is terminated, and the client is returned to the supine position when presyncopal hypotension and bradycardia or full syncope develop.
- Isoproterenol provocation may be added if no symptoms are produced during the unmedicated test.
- a. Return the client to the supine position for 5 to 10 minutes for the recovery period.
- b. Isoproterenol may then be added as a single-stage protocol (1 μg/minute for 5 minutes) or as a multi-stage protocol (repeated 3 times with progressively increasing doses of 1, 2, and 3 μg/minute).
- c. The table is tilted 60–80 degrees after each stage, and the test proceeds as previously described.
- Monitor vital signs for 15 minutes.
- Full return to consciousness and baseline BP and HR is usually rapid when the client is placed in the supine position.
- Normal intake and activity can be resumed immediately after the test.
- Occasionally temporary residual pallor, weakness, headache, and bradycardia (rarely) last up to 30 minutes.
Client and Family Teaching
- Any medication known to cause orthostatic hypotension or bradycardia should be stopped at least 3 days before the test. Your physician will tell you which drugs to stop.
- Fast from food and fluids for 4–8 hours before the test.
- Describe the procedure and the usual sensations the client can expect related to the tilt table test (see under Procedure). With the medicated test, mild stomach cramping, salty taste in the mouth, and minor vision changes are not unusual. Increased heart rate and light-headedness are common.
- An IV line will be inserted before the test.
- The goal of the test is to reproduce syncope or near-syncope in a carefully controlled environment in which the client will not fall.
- Usual testing time takes 1–2 hours.
- Normal diet and activity may be resumed after the test is complete.
- If you develop chest pain after the procedure, call 911. Do not drive yourself to the hospital.
- Call the doctor if you experience shortness of breath, a fainting spell, a severe headache or dizziness, or pain in your back.
Factors That Affect Results
- The positive effect of the isoproterenol-tilt table declines with age.
- Abrupt infusion of 5 g of isoproterenol may cause intolerable changes in HR and BP.
- This test is up to 75% effective in reproducing vasovagal syncope.