Without evidence of benefit, an intervention should not be presumed to be beneficial or safe.

- Rogue Medic

How Do We Assess Our Equipment – Blood Pressure

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In Ep 44 Abdominal Trauma at Confessions of an EMS Newbie, Ron Davis and Kelly Grayson (of A Day in the Life of an Ambulance Driver) discuss some important points about abdominal trauma, but they also answer questions. One of the questions was about disagreements between the numbers displayed by the random number generators equipment and the numbers we come up with by using our senses.

Kelly makes some great points about the ways that the NIBP (Non-Invasive Blood Pressure or automatic BP taken by a machine), heart rate, and even 12 lead interpretation can be completely wrong.

Just because the machines can be completely wrong, does that mean that they are always completely wrong?

No.

We need to know how to assess our equipment for accuracy.

I do not mean to check to see if the machine is working, but to assess the accuracy of the equipment when there may be no standard to compare with.

I can switch the equipment to myself or to someone else – someone who is not expected to produce an unusual reading. It does help to have an idea of what is normal for this person. That is one way to assess the accuracy of the machine, but it may not tell us what we need to know about accuracy with numbers that are outside of the normal range.

I can take a manual blood pressure to compare with the NIBP. Some people will insist that the NIBP should never be used for the initial BP (Blood Pressure). They state that the NIBP should only be used after a manual BP and then only if it agrees with the manual BP.

That can present a problem. What if the numbers do not agree, but the manual BP does not appear to match the patient presentation, while the NIBP does?

And what about auscultated blood pressure vs. palpated blood pressure?

Do we trust the palpated or the auscultated systolic pressure?

Do we trust the palpated or the auscultated diastolic pressure?

We need to find some other ways of assessing the perfusion of the patient.

BP is really only a surrogate measure of perfusion.

BP is just one part of our assessment of our patient.

What do the radial pulses feel like? Are radial pulses present?

What happens if the patient changes posture? Postural vital signs readings are only relevant if the patient is going from lying down to sitting, lying down to standing, or sitting to standing. Postural vital signs are an assessment of the body’s ability to compensate for increases in demands on the heart, blood vessels, the feedback mechanisms of the body, and may indicate a lack of intravascular volume (a lack of intravascular volume is a fancy way of saying hypovolemia).

Do we have a BP from earlier?

Does the patient/family know what is normal BP for this patient?

Does a reading on the NIBP, other than ?/?, indicate that there is cardiac output and that compressions are not indicated, even though there are no signs of life (e.g. no pulses and no respirations)?

Consider this awake and alert patient we are assessing. We cannot palpate a pulse anywhere. We cannot auscultate a BP? We cannot get any reading we are comfortable with by NIBP.

Do we treat the patient for hypotension?

Will following a protocol protect us?

Which protocol?

Why?

Will following a protocol protect the patient?

Which protocol?

Why?

Go listen to the podcast.

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