practical 1- blood pressure & pulses

how to calculate pulse pressure

systolic BP - diastolic BP

what is palpitation

way to measure arterial pulses (fingers on body & finding the pulse)

3 rules for examining limb pulses

• limb has to be supported & relaxed

• accustom yourself to the rhythm of the pulse before you start counting

• feel & compare pulses bilaterally at the same location

why must the limb be supported & relaxed

when muscle is contracted you will only feel twitching tendons (muscle spindles twitch)

why must you accustom yourself to the pulse rhythm before you start counting

• ensures accurate pulse counts

• allows the heart to settle to a steady rate

3 common pulses

• radial

• brachial

• carotid

how to measure radial pulse

place fingers around or under wrist supporting it on the other side with your thumb

how to measure brachial pulse

place hand under elbow & locate person's bicep tendon, place fingertips medial to tendon (have to use more pressure to feel pulse)

what pulse is used for the measurement of blood pressure

brachial

why shouldn’t you press hard and palpate both sides simultaneously when checking the carotid pulse

• carotid sinuses contain baroreceptors & pressing too hard can cause them to be overstimulated

• can cause reflex bradycardia (slower heart rate), hypotension, reduced blood flow to the brain

what is arterial blood pressure

force blood exerts inside vessels as it presses against vessel walls

how to calculate blood pressure

cardiac output x total peripheral resistance

how to calculate cardiac output

heart rate x stroke volume

how to calculate mean arterial blood pressure

diastolic BP + 1/3 (systolic BP - diastolic BP)

how to indirectly measure blood pressure

sphygymomanometer

6 steps to use a sphygmomanometer

1. person should be sitting with arm resting on table

2. place cuff around the NON-DOMINANT arm, arrow is lined up with brachial artery

3. cuff needs to be positioned so the tubing comes out the bottom & theres enough room above the elbow to place the stethoscope

4. hold the rubber bulb so that you an open & close the screw with your fingers & thumb

5. place stethoscope on the brachial pulse, close screw & pump the cuff pressure to 180mmHg

6. reduce the pressure (2-3mmHg p/s) by opening the screw

7. reduce pressure until you can't hear the sound (or if it gets softer)

why shouldn’t the tubing of the sphygmomanometer touch the stethoscope

if they touch fake sounds could be produced

why should the cuff pressure be 180mmHg for only 1 second

patient discomfort

what does the korotkoff sound represent

systolic BP

how do digital blood pressure monitors work + 2 types

detects oscillations through the skin

• upper arm (measure brachial artery), wrist (measure radial artery)

if blood pressure is lowered what process is occuring

• vasodilation

• reduced total peripheral resistance

• smooth muscles of blood vessels relax

if blood pressure increases what process is occuring

• vasoconstriction

• increased total peripheral resistance

• smooth muscles of blood vessels contract

if pulse pressure & diastolic blood pressure fall at similar rates what can you assume

that systolic blood pressure is staying the same

what is increased heart rate (pulse) caused by

more activation of receptors on the SA node

what statistical test would you carry out to see if a variable had an effect on blood pressure/pulse

• paired t-test

• under the null hypothesis you would assume differences between before & after x variable is 0

why is it important to take 3+ readings of pulse measurements before a variable is added

• to account for normal variations in pulse/blood pressure

• to account for excitedness/nervousness at the start of the experiment

• spacing between measurements is the same after the variable is added so they act as a control