1. Vital Signs Bp and SpO2
Marija Buttery 2010

2. BLOOD PRESSURE

3. BLOOD PRESSURE
Blood pressure is the measurement of force exerted by the blood on the walls of the blood vessels as the heart contracts and relaxes
Systolic – is the pressure of the blood exerted on the walls of the vessels when the heart contracts
Diastolic – is the pressure of the blood exerted on the walls of the vessels when the heart is relaxed.
For example Mr Harris’ Bp is 150/80 – 150(systolic) / 80(diastolic)

4. BLOOD PRESSURE
Blood pressure is measured in mmHg (millimetres of mercury)
A rise or fall in blood pressure can cause significant problems for the entire body
The pressure is what enables to blood to go from the heart around the entire body then back to the heart
Where there is not enough blood pressure, parts of the body will not be supplied with enough blood, oxygen and nutrients.
Where the blood pressure is too high it puts a strain on all the parts of the body.

5. BLOOD PRESSURE Hypertension – elevated blood pressure
Hypotension – low blood pressure
There is also postural hypotension where the blood pressure drops when the patient stands

6. Definitions and classification of BP levels (measured in mm Hg) Heart Foundation 2004
Category
Systolic
Diastolic
Normal
High-normal
120 – 139
Grade 1 (mild)
140 – 159
Grade 2 (moderate)
160 – 179
Grade 3 (severe)
≥ 180
≥ 110
“Hypertension Management Guide for Doctors 2004” p 10 accessed 23/2/06

7. Blood Pressure (BP) Measurement of cardiovascular function
Force resulting from cardiac output and peripheral vascular resistance
Indirectly measured with sphygmomanometer and stethoscope

8. Blood Pressure Systolic pressure/diastolic pressure
BP is an easily measured vital sign that is a screening tool for identifying hypertension
Hypertension is a silent disease, often without symptoms, yet can be fatal and/or cause significant morbidity

9. Blood Pressure Hypertension:
Elevated systolic pressure only
Elevated diastolic pressure only
Elevated systolic and diastolic pressures
Which ever value is most out of range is used to classify the degree of hypertension

10. Hypertension Facts (HT)
High BP is major risk for heart disease and chief risk factor for:
Stroke
Congestive Heart Failure
Myocardial infarction (MI)
Can lead to kidney, liver and retinal changes

11. Hypertension Facts (HT)
Lifestyle measures are a crucial part of treatment
Lose excess weight
Be physically active
Limit alcoholic beverages
Decrease salt intake
Decrease fat intake - cholesterol
Follow a heart-healthy eating plan
Quit smoking

12. Conditions that increase BP
Stress – physical or emotional
Steroid therapy and other medications
Hypercholesterolemia
Diabetes mellitus
Renal disease
Hyperthyroidism

13. Risk Factors for HT Obesity Disease - diabetes Lack of exercise
Age
Obesity
Disease - diabetes
Lack of exercise
Smoking
Alcohol
Stress
Diet

14. Diagnosis of HT
Made after three readings on separate days when all are elevated beyond normal
If you determine a reading that is abnormal:
Report to RN, may need MO review
Recheck after 5 minutes
Assess patient for cause (e.g. stress, just had a cigarette)

15. Hypotension
BP < 90/60 mm Hg
Orthostatic / postural hypotension
Excessive fall in BP (> 20/10 mm Hg) on assuming the upright position
Gravitational stress
Autonomic reflex
Hypovolaemia

16. 5 Factors Determine BP Level
Cardiac output
Peripheral vascular resistance
Total blood volume
Viscosity of the blood
Compliance of the arterial wall

17. Factors Contributing to Inaccurate BP Measurement
Defective equipment
Faulty technique
Clinical error
Failure to consider patient factors

18. Factors Contributing to Inaccurate BP Measurement
Defective equipment
Inflating system, exhaust valve & tubing without leaks
Cuff fabric should be intact so pressure is distributed evenly
Adjust the “0” on Hg manometers

19. Factors Contributing to Inaccurate BP Measurement
Faulty Technique
Incorrect positioning of the patient/artery
Cuff size (too small or too big)
Not Applying cuff evenly, snugly
Placing stethoscope under the cuff

20. Factors Contributing to Inaccurate BP Measurement
Clinician Error
Same as previous
Be sure to estimate systolic blood pressure
Refrain from rechecking repeatedly without allowing for pressure equilibration
Patient Factors
Emotion, anger, anxiety, pain, frustration, sudden noises, sedation, fever

21. Positioning the Bp Cuff
Cuff applied evenly, snugly with bottom edge about 1 inch above the antecubital fossa (elbow)
Valve tubing attached to the cuff should be placed over the brachial arterial. Palpate the artery
It may be difficult to hear the BP sounds in an obese patient, in the case of hypotension or if the artery is very deep in a muscular person

22. Measuring the BP Patient should be at rest
Position the patient so that the arm is at the height of the heart
Remove any clothing that may be restrictive
Estimate the systolic BP

23. Estimating the systolic BP
Palpate the radial artery (with index/middle finger)
Inflate the cuff to a pressure 20 mm Hg above the point at which the radial pulsation disappears, slowly release cuff whilst feeling for return of pulse. Note the number - that is your palpable systolic pressure
Deflate the cuff and wait a short time

24. Measuring the BP
Place the diaphragm of the stethoscope over the brachial artery
Close the valve of the pressure bulb
Inflate the cuff to the estimated point
Slowly release valve
Systolic pressure is when the first sound is heard
Diastolic pressure is when the sound disappears
Deflate the cuff & remove

25. THE BRACHIAL ARTERY PULSE UNTIL THE CUFF IS INFLATED!!
YOU WILL NOT HEAR
THE BRACHIAL ARTERY PULSE UNTIL THE CUFF IS INFLATED!!

26. Systolic and Diastolic Readings
Top number
When the heart is contracting
Diastolic
Bottom number
When the heart is resting (or refilling)
110 75
Marieb, E N., Essentials of Human Anatomy & Physiology 8th Ed (San Francisco: Benjamin Cummings, 2006) Fig 11.4 “Operation of the heart valves . . “ P 333 26

27. S for Systolic
S for Squish!

28. Pulse Oximetry
Oximeter
SpO2
Sats
SaO2

29. Pulse Oximetry
A non invasive measurement of arterial blood oxygen saturation
A Light Emitting Diode (LED) measures the amount of oxygen on the haemoglobin (Hb)
Light waves are absorbed then reflected back by oxygenated and deoxygenated Hb molecules
The light is processed by the oximeter, which calculates the pulse oxygen saturation (Sp02).
It is recorded as a percentage

30. Inaccurate Readings Can be caused by: Movement False nails
Some red/dark nail polish
Direct sunlight
Hypotension
Peripheral vascular disease
Hypothermia
Oedema