blood pressure monitoring

2. NON-INVASIVE AND INVASIVE BP
MONITORING
By Dr. S.A.Fatima
Dr. Arsalan A. Zaki

3. NON-INVASIVE BP MONITORING

4. WHAT DO WE NEED TO KNOW?
• Techniques
• Principles
• Indications
• Contraindications
• Limitations
• Complications
• cautions.

5. NON INVASIVE BP MONITORING TECHNIQUES
1. Manual intermittent techniques.
• Palpation
• Auscultation
• Doppler probe
2. Automated intermittent techniques.
• Oscillometry
3. Automated continuous techniques.
• Tonometry
• photoplathysmography

6. PRINCIPLES OF DIFFERENT NON-INVASIVE
TECHNIQUES
• Palpation: systolic BP is measured by occluding the artery with
cuff
• Auscultation: turbulent flow of blood with partially occluded
artery produces Korotkoff sounds.
• Doppler: movement of RBCs produces a Doppler frequency
shift.
• Oscillometry: oscillations in the pressure amplitude are
measured in an air filled cuff that slowly deflates from the
pressure well in excess of pressure to occlude the artery.
• Tonometery: sense the pressure required to partially flatten the
superficial artery.
• Phoyoplathysmography: quantification of infrared light

8. INDICATIONS OF NIBP MONITORING
• Any procedure requiring any sort of anesthesia.
• When invasive monitoring is contraindicated.
• Intermittent measurement interval should be 3 to 5 minutes.

9. CONTRAINDICATIONS:
• Cuff based BP monitoring is contraindicated in
Limb with axillary clearance
Limb with AV fistula for dialysis purpose.
Limb with PICC line or peripheral IV line.
Patients with known focal vascular anomalies.
Burnt extremity.

10. LIMITATIONS
• Palpation:
• only detects systolic BP.
• Not useful for continued monitoring.
• Not reliable for conditions of low flow.
• Auscultation:
• MAP cannot be measured directly and has to be calculated by formula
MAP=SBP+ 2(DBP)/3
• Not useful for continued monitoring.
• Interpersonal variability of hearing.
• Not reliable for conditions of low flow.

11. LIMITATIONS
• Ocillometery:
• cuff size is of prime importance in accuracy of the BP.(bladder length 80% of arm ; bladder width 40%
of arm circumference)
• Interpretation varies according to site.
• Underestimate MAP during hypertension and overestimate MAP during hypotension so not reliable
in unstable patients.
• Underestimates SBP and overestimates DBP.
• Dysrhythmias lead to inaccuracy of BP.
Tonomertery
• Need frequent calibration.
• Movement artifacts common.
• Limited applicability in critically ill patients.

12. COMPLICATIONS:
• Pain
• Patechiae and ecchymoses
• Limb edema
• Venous stasis and thrombophlebitis.
• Peripheral neuropathy (radial nerve common).
• Compartment syndrome.
• CAUSIONS:
• Patients with known peripheral neuropathy.
• Arterial or venous insufficiency.
• Severe coagulopathies.
• Recet use of thrombolytic therapy.

13. INVASIVE BP MONITORING

14. WHAT DO WE NEED TO KNOW?
• Basic principle
• Indications
• Percutaneous radial artery cannulation
• Other arteries which can be uses
• Complications
• Components
• Leveling and zeroing
• Normal IBP waveforms
• Abnormal IBP waveforms
• Waveform analysis for prediction of volume responsiveness

15. PRINCIPLE
• Intra-arterial blood pressure monitoring uses fluid filled
tubing to transmit the force of the pressure pulse wave to a pressure
transducer that converts the displacement of a silicon crystal into voltage
changes.
• These electrical signals are amplified, filtered, and displayed as the
arterial pressure trace.

16. INDICATIONS:
• Continuos, real time blood pressure monitoring.
• Anticipated pharmacological and/or mechanical cardiovascular manipulation.
• Repeated blood sampling.
• Anticipated respiratory compromise.
• Faliure of indirect BP measurement.
• Supplementary diagnostic information from the arterial waveform.

17. PERCUTANEOUS RADIAL ARTERY
CANNULATION
Radial artery is the most common artery used for IBP because
• Easy to cannulate due to being superficial
• Technically less incidence of complications.
Modified ALLEN’S Test

19. OTHER SITES

20. COMPLICATIONS
• Distal ischemia
• Pseudoaneurysm
• Arteriovenous fistula
• Hemorrhage
• Arterial embolization
• Infection
• Peripheral neuropathy
• Misinterpretaion of data
• Misuse of equipment

21. COMPONENTS OF IBP MONITORING
EQUIPMENT
• Intra-arterial catheter
• Stopcocks
• In-line blood sampling ports
• Pressure transducer
• Continuoius flush device
• Electronic cable

22. PROPERTIES OF IBP DEVICE
• NATURAL FREQUENCY of a system determines how rapidly the system oscillates after a perturbation.
• DAMPING COEFFICIENT reflects how rapidly it returns to its prior resting state.

23. NATURAL FREQUENCY
• It is imporatant that an IBP system has a very high natural frequency i.e 6 to 10
times the fundamental frequency of the arterial waveform (pulse rate).
• e.G for a system to remaine accurate at a heart rate of 120bpm (2cycles/min or
2Hz) ,it would require a natural frequency 6 to 8 times higher than pulse rate i.e
12 TO 20 Hz.
• If Natural frequency is too low, system will resonate and waveform will be
exaggerated.

24. DAMPING COEFFICIANT
Anything which reduces the energy in an oscillating system will decrease the amplitude of the oscillations. This is
damping.
FACTORES:
Friction
Three way taps
Clots and bubbles
Kinking
Narrow long and compliant tubings
vasospasm

25. LEVELING AND ZEROING
ZEROING
for an IBP system to optimally work, atmospheric pressure should be discounted from the measurement of
arterial pressure.
Done by exposing the transducer to atm pressure and calibrating the pressure reading to zero.
LEVELLING
Transducer should be placed at the level of patient’s heart in midaxillary line at 4thintercostel space
A transducer too low will over-read and a transducer too high will under-read.

26. NORMAL ARTERIAL WAVEFORMS
The systolic waveform immediately follows the EKG and consists of steep pressure upstroke, peak
and ensuing decline.
The downslope of arterial pressure waveform is interrupted by the dicrotic notch, continues its
decline during diastole after the EKG T wave and reaches its nadir at the end diastole.
Dicrotic notch of central aortic pressure is sharply defined and represents the closure of aortic valve.
Dicrotic notch in peripheral arterial pressure waveforms is slightly delayed and mildly blunted
depending upon the arterial wall properties.
Systolic upstroke starts 120 to 180 ms after the R wave.

27. NORMAL IBP WAVEFORM

28. ABNORMAL IBP WAVEFORMS

29. ABNORMAL IBP WAVEFORMS

30. ABNORMAL IBP WAVEFORMS

31. ARTERIAL PRESSURE WAVEFORM ANALYSIS FOR
PREDICTION OF VOLUME RESPONSIVENESS
Pulse pressure variation (PPV) is the difference between maximum pulse
pressure and minimum pulse pressure during a single respiratory cycle
divided by the average of these two values.

32. THANK YOU