How should we record the Blood pressure if the patient has Atrial Fibrillation?

• 3-5 recordings are done. It is the mean of 3-5 recordings.
• Systolic BP is recorded as the maximum audible sound at a particular level.If the difference between the two recording is less than or equal to 5mm, average of the two recordings are taken. 
• Beat to beat variation can lead to underestimation of the blood pressure.
• Blood pressure recorded after a long cycle can be falsely high.

What are the techniques to record Blood pressure?

• Palpatory method
• Auscultatory method
• Flush method
• Ultrasound Doppler method
• Arterial tonometry/ Oscillometric method
• Ambulatory BP monitor(ABPM)

Differential Diagnosis - Upper limb and Lower limb Blood pressure difference

• Coarctation of aorta
• Aortic dissection
• Aortic arch syndrome
• Subclavian steal syndrome
• Severe chronic aortic regurgitation
• Inaapropriate cuff size for thigh

Difference of more than 20 mmHg Blood pressure is considered significant.

 

Differential Diagnosis - Upper limb Blood pressure difference

• Aortic Arch Syndrome/ Coarctation of Aorta
• Supravalvular aortic stenosis
• Subclavian steal syndrome
• Scalenus anticus syndrome/ Cervical rib syndrome
• Aneurysm of subclavian or innominate artery
• Thrombosis of innominate or subclavian artery

A Blood Pressure difference of more than 10 mmHg between the two arms is considered significant. 

What is Mean Blood Pressure?

• It is the average blood pressure during a single cardiac cycle.
• It can be determined from the formula MAP = (CO X SVR) + CVP where CO is cardiac output, SVR is systemic vascular resistance and CVP is central venous pressure.
• At nomal heart rate, it can be estimated as MBP = DBP+ 1/3 PP

(Mean blood pressure = Diastolic blood pressure + 1/3 Pulse pressure,
PP = SBP- DBP)

• At higher heart rate, MAP is the arithmetic mean of systolic and diastolic blood pressure
• The regional blood flow or the organ perfusion depends on MBP
• Normal ranges between 95-100 mmHg.
• MAP greater than 60 mmHg is enough to sustain the perfusion of organs

What are Korotkoff sounds? What are its five phases?

• Korotkoff sound represents arterial oscillation resulting from distension of the arterial wall with each cardiac impulse due to partial occlusion of artery by the cuff. 
•  Low pitch sound
• Five phases are
• PHASE 1 - CLEAR TAPPING SOUND   (SBP)
• PHASE II - ONSET OF SWISHING SOUND OR SOFT MURMUR
• PHASE III- LOUD SLAPPING SOUND
• PHASE IV - SUDDEN MUFFLING OF SOUND
• PHASE V - DISAPPEARANCE OF SOUND / PHASE OF SILENCE (DBP)
• "Tap - Murmur - Slap - Muffle - Silence"
• It was described by Nikolai Korotkoff, a Russian surgeon in 1905

 

What is the average Blood Pressure in children?

• At 1 yr of age , average Systolic Blood Pressure(SBP) is 90mmHg
• Every 3 yr , increases by 5 mmHg
• At 12 yrs , reaches adult level
• Diastolic Blood pressure remains average 60mmHg
• Formula to calculate SBP in children 

SBP = 90+(AGE X 5)/3