Clinical Skills: Obtaining blood pressure assessment

Hello. This video covers how to assess BP in a normal assessment.

You do everything on this list, but to keep things concise, this video will focus on the steps in blue and will also cover special populations like infants, Children and the elderly and include a summary to assess BP.

You'll need a BP gauge or a sphygmomanometer and a stethoscope for an accurate measurement, ensure that the individual is calm and comfortable and hasn't recently smoked or consumed caffeine, allow them to sit with their legs uncrossed for five minutes before you begin, support the arm at heart level.

Now, it needs to be at the heart level or the measurement might not come out right. Identify the brachial artery above the antecubital fossa and wrap the deflated cuff around the arm.

The bladder of the cuff should be centered 2.5 centimeters or one inch above the brachial artery. Now palpate the radial or brachial pulse with one hand as you inflate the cuff with the other, once the pulse disappears, read the pressure on the gauge and continue to inflate a further 20 to 30 millimeters of mercury, fully deflate the cuff and wait 15 to 30 seconds, place the diaphragm or the bell of the stethoscope over the artery, ensuring an airtight seal.

If you're new to this, you may find it easier to use the diaphragm of the stethoscope instead. Now quickly reinflate the cuff to the previous level, slowly deflate the cuff about 2 to 3 millimeters of mercury per second.

When you hear two consecutive beats, read the pressure on the gauge. What you're hearing is phase one carot cough sound.

And the reading on the gauge is your systolic BP. As you continue to deflate the cuff, the sound will begin to muffle.

This is the phase four carot cough sound and then it will disappear entirely. And this is the phase five carot cuff sound.

The reading on the gauge when the sound disappears completely is the diastolic BP repeat this process at least once, waiting two minutes or more between each attempt.

Then average the readings. The systolic BP should be no more than 100 and 20 millimeters of mercury.

While the diastolic BP should be no more than 80 millimeters of mercury. If either BP is too high, it's referred to as hypertension or high BP.

Less common is hypotension or low BP, which is when the systolic BP is less than 90 millimeters of mercury or the diastolic BP is less than 60 millimeters of mercury.

If the BP measurement at the arm was abnormally high. You may want to measure the BP at the thigh.

Instead have the individual lie down, preferably in the prone position. Wrap a large cuff around the lower thigh and knee.

The bladder of the cuff should be centered 2.5 centimeters or one inch above the popliteal artery behind the knee repeat the process this time auscultating the popliteal pulse.

The systolic BP at the thigh is usually 10 to 40 millimeters of mercury higher than at the arm. While the diastolic BP is the same.

If BP at the thigh is lower than the BP at the arm, that suggests coarctation of the aorta with younger individuals, you may want to take an additional BP measurement at the ankle or calf.

Both pressures tend to be a little higher than those measured at the arm. Although the ankle is considered a more comfortable site, bear a few things in mind when choosing a site for BP measurement, avoid picking an arm with an IV infusion.

Stay away from sites with an arteriovenous fistula and generally try to avoid anything unusual like a side of the body where our breast or axillary surgery has taken place or a site with trauma or disease.

For an accurate BP measurement. It's essential that you choose a cuff of the right size.

An overly small cuff causes the BP to read too high. While an overly large cuff causes the BP to read too low.

The width of the bladder of the cuff should amount to about 40% of the circumference of the upper arm and the length of the bladder of the cuff should amount to no less than 80% of the circumference of the upper arm.

There are quite a few factors that can prevent accurate measurement of BP. With BP measured at the arm, the arm has to be held at the heart level.

If it's held too low, the BP might read higher than it really is. If the cuff is held too high, the BP might read lower than it really is.

If the cuff is wrapped too loose, it's the same story, the reading might come out as too high. Now, if the cuff is deflated too slowly, then the diastolic BP might read higher than it really is.

And if the cuff is deflated too quickly, the diastolic BP might read too high and the systolic BP might read too low. Finally, if the cuff isn't inflated enough, the systolic BP might again read too low.

So, so far, we've discussed the osculatory approach to measuring BP. It's quick, convenient and not invasive.

If the osculatory approach proves troublesome or frequent BP measurements are needed, you may wish just to use an electronic BP cuff, the procedure is almost the same wrap, the cuff over the same sites as previously ensuring that the bladder of the cuff is centered above the appropriate artery.

However, instead of manually inflating and deflating the device, while you auscultate, just select the appropriate mode and activate the device.

If an abnormal measurement is obtained, consider repeating the procedure with the oscillatory approach. OK.

Now, let's quickly discuss the measurement of BP in special populations with Children. The technique is exactly the same but you might struggle with getting them to cooperate, typical tackle this by introducing the child to the procedure with a quick demonstration before you start the real thing in pregnant women, both systolic and diastolic blood pressures usually fall by about 5 to 10 millimeters of mercury within the first two trimesters.

Then during the third trimester, BP usually climbs back up to normal levels and elevated BP during pregnancy might indicate preeclampsia.

Finally, BP tends to rise with age as such. Elderly populations usually have higher blood pressures and those aged 50 or over elevation and systolic but not diastolic BP is the most prevalent type of hypertension.

It's worth mentioning that you can use a BP gauge and a stethoscope to diagnose for pulsus paradoxus, which often indicates cardiac tamponade constrictive pericarditis or obstructive lung disease.

When measuring BP, normally inflate the cuff fully and begin slowly deflating it at about 2 to 3 millimeters of mercury per second.

Like before when you first hear two consecutive beats, read the pressure on the gauge. This is phase one of carot cough sounds and you shouldn't be able to hear it during inspiration.

As you continue deflating the cuff, there should come a point where you can hear phase one crock cough sound during both inspiration and expiration.

Read the pressure on the gauge. Again, if the difference between the two pressures is greater than 10 millimeters of mercury per second, that's a positive diagnosis for Pulsus paradoxus.