Dr Bell was a leader in ME/CFS treatment for many years. He is now retired. There does not appear to be a home test for hypoventilation - another type of OI found in ME/CFS). From his website:
The test is relatively simple. The patient lies comfortably for ten minutes and BP [blood pressure] and pulse are taken several times. Then the patient stands quietly (no moving around) with the blood pressure cuff on, and BP and pulse are taken every few minutes. This is a poor man's tilt test, and I would argue that it is more accurate because it reproduces exactly what happens to a patient waiting in the check out line at the supermarket.
A person with CFS nearly always has orthostatic intolerance. They describe the symptom of fatigue (which is not fatigue at all) which is characterized by being relatively OK while walking down the aisle of the supermarket, but being unable to stand in the checkout line. The orthostatic testing describes physiologically why this occurs.
There are five separate abnormalities than can occur during quiet standing:
Reference [of "Results"]: Streeten DHP. Orthostatic disorders of the circulation. New York: Plenum, 1987:116.
The test is relatively simple. The patient lies comfortably for ten minutes and BP [blood pressure] and pulse are taken several times. Then the patient stands quietly (no moving around) with the blood pressure cuff on, and BP and pulse are taken every few minutes. This is a poor man's tilt test, and I would argue that it is more accurate because it reproduces exactly what happens to a patient waiting in the check out line at the supermarket.
A person with CFS nearly always has orthostatic intolerance. They describe the symptom of fatigue (which is not fatigue at all) which is characterized by being relatively OK while walking down the aisle of the supermarket, but being unable to stand in the checkout line. The orthostatic testing describes physiologically why this occurs.
There are five separate abnormalities than can occur during quiet standing:
- Orthostatic systolic hypotension where the upper number (systolic) blood pressure drops. The normal person will not drop BP more than 20 mmHg on standing up. One patient I follow with CFS had a normal BP lying down (100/60) but it fell to 60/0 on standing. No wonder she was unable to stand up - a blood pressure that low is really unable to circulate blood to the brain. In any ICU [intensive care unit] they would panic seeing a BP like that. And she was turned down for disability because she probably was a hypochondriac.
- POTS stands for postural orthostatic tachycardia syndrome. A healthy person will not change their heart rate standing up for an hour. In a person with POTS, the heart rate increases 28 beats per minute (bpm). Some experts say the heart rate should exceed 120 bpm to have POTS. But either way, this increase occurs frequently in CFS. I think the increase in heart rate is linked to the decrease in blood volume. (Orthostatic intolerance has been called Idiopathic hypovolemia in the past.)
- Orthostatic narrowing of the pulse pressure. The pulse pressure is the difference between the lower number of the BP from the higher number. For example, a normal person with a BP of 100/60 would have a pulse pressure of 40. It is actually the difference between the upper and lower number of the BP that circulates blood. If the pulse pressure drops below 18, it is abnormal and blood would not circulate in the brain well. We routinely see in our patients with CFS blood pressures of 90/80, thus a pulse pressure of 10. The current record holder is a young woman with CFS whose pulse pressure fell to 6 mmHg before she passed out.
- Orthostatic diastolic hypertension. The lower number of the BP often reflects the systemic resistance, and while standing many persons with OI and CFS will raise their lower BP number (diastolic) in an attempt to push blood up to the brain. Sometimes this is dramatic. One patient being followed with CFS had a low blood volume, about 60% of normal. While lying down, his BP was 140/80. After standing, his BP rose to 210/140 before we made him lie down. His pulse went up to 140 bpm. He felt rotten but refused to sit down by himself.
As an aside, everyone thought he was a fruitcake - a healthy looking man who said he felt poorly and couldn't work. He was denied disability as usual. Yet when we did the test, he was so determined to stand up I was afraid he was going to stroke out and croak. But he was standing with a BP of 210/140 and a pulse of 140 bpm. He is definitely not a wimp.
After the test, we gave him a liter of saline in the office because he didn't look too good and his blood pressure fell to 90/60 after an hour or so. It is important to note that we had measured his volume the day before so we knew he was hypovolemic. Normally you would never give saline to someone with high blood pressure, it just makes it go higher. In the future, orthostatic testing will require being done in an intensive care unit because these numbers are so scary. Now it is ignored, and patients with CFS called fruitcakes! - Orthostatic diastolic hypotension. This represents a fall in the lower number of the BP, and seems to be the least frequent abnormality in patients with CFS I have tested.
- Normal sBP: recumbent: 100-142; Standing (4 min) : 94-141; Orthostatic change: -19 to +11
- Normal dBP: recumbent: 55-90; Standing : 61-97; Orthostatic change: -9 to+22
- Normal P: recumbent: 54-96; Standing : 62-108; Orthostatic change: -6 to +27
- Orthostatic systolic hypotension: fall in systolic blood pressure of 20 mmHg or more
- Orthostatic diastolic hypotension: fall in diastolic BP of 10 mm Hg or more.
- Orthostatic diastolic hypertension: rise in diastolic BP to 98 mm Hg or higher
- Orthostatic narrowing of pulse pressure: fall in pulse pressure to 18 mm Hg or lower.
- Orthostatic postural tachycardia: increase in heart rate of 28 bpm or to greater than 110 b/min.
Reference [of "Results"]: Streeten DHP. Orthostatic disorders of the circulation. New York: Plenum, 1987:116.
