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Now we are going to have a look at two different types of blood pressure cuff, the automatic BP cuff, or automatic sphygmomanometer, and the manual sphygmomanometer. These are the more common that you see these days because they're easier and quicker, but in my opinion, these are the more accurate type but take a little bit more time and a little bit more effort to use. So, what do we need to know about them? The preferential arm to always take a blood pressure is the left arm. They are both situated in slightly different places on the arm. Automatic is a wrist-worn BP cuff, whereas the manual sphygmomanometer is always actually on the humerus of the arm, just above the brachial artery. So looking at the automatic cuff first, there is an on/off button, which turns the cuff on, there is a velcro cuff, which goes around the wrist.

So it is placed around the wrist, the velcro is velcroed on tight, it's important that the wrist is level with the heart. We then start the BP cuff, it automatically pumps up a little bladder inside the wrist cuff, which cuts off the blood supply, and then it releases it very gradually, and eventually, it will release totally and give you the reading on the screen. The top reading, the highest number, is always systolic, the bottom reading, the lowest number, is always diastolic. And the gap between the two pressures is your pulse pressure, or in other words, the pressure the heart squeezes every time it beats. Another important thing about blood pressures is, the top line always needs to be above 90.

So, using a manual sphygmomanometer, a little bit more complex, but again in my opinion, far more accurate. Used on the left arm, we always do BPs on the left arm, because of the way the aorta kicks out to the left-hand side of the body, and you always get a more accurate blood pressure reading from the left arm than you will from the right. There won't be much difference, or shouldn't be much difference, but it's always supposed to be the left arm to get the most accurate blood pressure. And always remember also, when we take blood pressure, the patient needs to be calm. If we take blood pressure too early, it won't be accurate. White coat syndrome, fright, shock, nerves, everything else will up the blood pressure and give us a false reading. We need to have an accurate one, so keep the patient calm, reassured, and tell them what you're doing. Looking at the cuff itself, a sizing on it, and this is an adult size, and this is important we understand that cuffs have to be measured properly. You have to use adults on adults and paediatrics on paediatrics for a reason, and the reason is, you won't get an accurate reading if you use an ill-fitting cuff. You'll also see, on the cuff, there is a mark where we go over the artery, the artery in the arm. When we are looking for the brachial artery, just above the brachial artery, over the muscle, is the position the cuff should fit.

The cuff is placed onto the arm, wrapped around the arm, and velcroed against itself. Nice and tight. So it's fixed in place firm and tight and won't slide. We then have a pipe coming out of the cuff that will inflate the bladder inside the cuff. And actually, at the other end of the pipe, we actually have the meter itself. The dial on the front is where we get the reading from. There is a little twist that locks off or opens up the bladder to allow the bladder to inflate or deflate under control, and a little squashy ball which will inflate the cuff as we squeeze. We know a patient's blood pressure should be roughly above 120, so we're gonna blow the cuff up to around the 120 mark and at the same time, we're going to feel for a radial pulse. As soon as the radial pulse disappears, we know we are up high enough to have cut the blood supply off, so we've gone above the maximum pressure that the artery's creating.

So, the next thing we need to do is to use the stethoscope. And the stethoscope working in conjunction with the dial is going to give us the reading. So what the stethoscope does, is it listens for blood pushing its way back through the collar, and the first sounds you get will be a pulse beat as blood forces its way past the collar. That first pulse beat coincides with the first bounce on the needle of the sphygmomanometer, and when you compare the beat and the needle bounce, that is your top line. You carry on lowering the pressure in the cuff until you hear no sounds whatsoever and the beats of the needle stop bouncing. At the time they stop bouncing and the sound goes away, that is your bottom line. So then we have the systolic and diastolic pressures. So, we insert the stethoscope onto the artery, just underneath the cuff itself. We then inflate the cuff by squeezing the bag, until we cut off blood supply and the artery is blocked off completely. Taking care not to bang the pipes, otherwise, so you will get a false reading through the cuff itself. We then release the pressure gradually and allow the needle to fall, and listen for the first bump. Giving us a pressure of 120/80. Perfect blood pressure. But I wouldn't have expected anything other.