Really Low Diastolic BP

[Richard B the EMT]

In my over 30 years on ambulances, I have had patients with really low BPs, on both Systolic and Diastolic readings.

On several, I actually caught a Diastolic of ZERO mm.

The first one, on a "Chest Pain" call, after taking the BP twice, as I didn't believe it, I reported my findings to the EMT in charge of the call (Systolic was, if I recall correctly 198 mm), who didn't believe me, until he followed my suggestion to try for himself.

So, a double barrel question:

One) Have any of you had any calls where the reading was "...over zero on the BP"? (Don't include any "...over 'Palp'" for this discussion, please.)

Two) Does anyone have any knowledge of what could cause that condition in a patient who is still with a palpable heart rate?

The floor is open to the discussion.

(FYI, that call I mentioned was back in 1974, the patient was an elderly female, and alert as to who, where, and "when" she was. Other than placing her on Hi-Con Oxygen via Non Re-Breather, I don't really recall any other history or findings from that assignment.)

[EMS49393]

The difference is the pulse pressure. The systolic reading indicates one end of the cardiac cycle, while the diastolic reading is the opposite end of the cycle. The pulse pressure can be measured by subtracting the diastolic from the systolic, i.e. 198/0 = 198 pulse pressure.

Pulse pressure is defined as the amount of force the heart creates during each contraction. High pulse pressures are hard on the heart. It can cause left ventricular hypertrophy and damage to arteries from the force.

I have had patients, usually cardiac patients, with pulse pressures in the 100's myself. The few times I have seen this, my patients were generally in pretty bad condition.

I hope this information was helpful to you.

[mark]

On my first day of medic class, we spent the entire day just going over taking vital signs. It was a very in-depth look at all the things that you can find just from taking vitals, and one of the things covered was a diastolic pressure that never goes away. I can only recall 2 pts that I've heard it on.

There are 5 different sounds you hear while taking a blood pressure.

1) The first Korotkoff sound is the snapping sound first heard at the systolic pressure.

2) The second sounds are the murmurs heard for most of the area between the systolic and diastolic pressures.

3/4) The third and-

the fourth sound, at pressures within 10 mmHg above the diastolic blood pressure were described as "thumping" and "muting"

5) The fifth Korotkoff sound is silence as the cuff pressure drops below the diastolic blood pressure.

Now, I was taught that you will occasionally run across a pt that doesn't have the fifth Korotkoff sound. In these pts, the diastolic pressure is indicated by the change in tone (third and/or fourth Korotkoff sound) even though you continue to hear the pulse.

[AnthonyM83]

Are you talking about when you hear a beat all the way down until deflation? I hear this all the time, sometimes a couple times a day. We verbally report it 120, all the way down, since the diastolic isn't actually zero.

We write it into our chart as 120/0, per company policy, but it's not really accurate.

I was recently told when that happens, you should listen for when the thumps change. A real BP actually has 3 numbers, so an accurate BP would be 120/54/0 but we just leave out the last number.