2015.10.13 Measuring Blood Pressure and Pulse

Today we learned how to take blood pressure and pulse and practiced doing so on each other.

Blood pressure is the pressure blood exerts on the walls of arteries when the ventricles of the heart contract and send blood into the body. There are two parts of blood pressure, systolic pressure and diastolic pressure. Systolic pressure is the pressure that the blood exerts on the walls of the arteries when the ventricles contract, so it is higher. Diastolic pressure is the pressure that the blood exerts on the walls of the arteries when the ventricles relax, so it is lower.

Blood pressure can be measured using a digital sphygmomanometer (blood pressure cuff), or using a manual one and a stethoscope. In class we learned how to use a manual sphygmomanometer and a stethoscope to measure blood pressure:

1. Put the patient's arm palm up on a flat surface. Make sure the patient's arm is level with his heart.
2. Wrap the blood pressure cuff around the patient's upper arm, at least 1 inch above his elbow.  The tubes that connect the pressure gauge and the pump to the cuff should be pointing down, in line with the patient's arm. Secure the cuff.
3. Put on the stethoscope. Put the flat part of the stethoscope on top of the brachial artery, on the inside of the patient's arm a little above his elbow. You will not be able to hear anything yet.
4. Make sure the valve on the pump is closed. Start pumping air into the cuff until the pressure gauge reaches about 150 mmHg.
5. Slowly release air from the cuff by opening the valve on the pump slowly. The needle on the gauge should fall about 2 mmHg every time you open the valve.
6. Note the number on the gauge when you hear a very faint tapping sound through the stethoscope. This is the systolic pressure.
7. Keep releasing air from the cuff until you stop hearing anything through the stethoscope. The number on the gauge at which this occurs is the diastolic pressure.
8. Blood pressure is written as a fraction, systolic pressure/diastolic pressure.

We tried taking blood pressure using a sphygmomanometer and a stethoscope on each other:

Blood Pressure Results

	Subject 1	Subject 2
Trial 1	90/50	110/80
Trial 2	100/60	105/70

Pulse is the number of times the heart beats over a certain amount of time. It can be measured by using a stethoscope over the heart, or just with 2 fingers (index and middle) over the radial artery (in the wrist) or over the common carotid artery (in the neck). Count the number of times the heart beats for 15 seconds, then multiply that number by 4. We do not use the thumb to measure pulse because there is also a pulse in thumb, which may throw off how many times we count the heartbeat. We tried taking pulses at different locations on each other:

Pulse Results

	Subject 1	Subject 2	Average for All Subjects
Radial	70	70	70
Carotid	68	70	69
Heart (stethoscope)	72	86	79
Average of Individual Subjects	70	76	73