Mod1: Monitoring for Cardiac Surgery - BLOOD PRESSURE MONITORING Flashcards
BLOOD PRESSURE MONITORING
What is the Most frequently monitored hemodynamic variable?
BLOOD PRESSURE
BLOOD PRESSURE MONITORING
Which information is made available to us via the MAP?
Organ perfusion
(Especially Brain, Liver and Kidneys)
BLOOD PRESSURE MONITORING
Which information is made available to us via the diastolic blood pressure?
Coronary perfusion
(Coronaries feel during diastole)
BLOOD PRESSURE MONITORING
Which information is made available to us via the Pulse pressure?
Stroke Volume
(Volume status)
CO
SVR
BLOOD PRESSURE MONITORING
Why is Noninvasive BP not typically used as primary BP monitoring during CPB?
Inadequacy of monitoring hemodynamic parameters
Inaccurate at extreme pressures
Intermittent data, not continuous
Requires pulsatile flow (which is not available during CPB)
Often used merely as adjunct to direct arterial blood pressure monitoring
BLOOD PRESSURE MONITORING
What remains the “Gold Standard” for monitoring BP during cardiac surgery?
Direct arterial blood pressure

BLOOD PRESSURE MONITORING
What are advantages of Direct arterial blood pressure monitoring?
Displays real-time blood pressure monitoring
Allows for pharmacological or mechanical BP manipulation while maintaining awareness of beat to beat BP
Allows for analysis of waveform can give information on SVR, SV, and cardiac output
Allows for close monitoring of ABG’s, coagulation (ACT’s), and electrolytes
Allows for Direct ABP monitoring possible during non-pulsatile CPB

BLOOD PRESSURE MONITORING
Which information can be gathered via analysis of direct arterial BP waveform?
Cardiac Output
SV
SVR

INTERPRETING ARTERIAL WAVEFORM
Which wave on the QRS complex represents the begining of systole?
The R-wave

INTERPRETING ARTERIAL WAVEFORM
When does the arterial pulse wave occur in reference to the ECG tracing?
160-180 milliseconds after the R-wave

INTERPRETING ARTERIAL WAVEFORM
What happens during the Systolic phase or Systolic upstroke?
What is it associated with on the ECG tracing?

Begins with a Rapid increase of pressure to a peak
Opening of the Aortic valve
Blood ejecting into the aorta from LV
Peak systole = Systolic BP
Follows the R-wave on EKG

INTERPRETING ARTERIAL WAVEFORM
What happens during the Systolic runoff?

Represents the time when
the eflux of blood out of the ventricle is lower than
the influx of blood into the aorta

INTERPRETING ARTERIAL WAVEFORM
What does the Dicrotic notch represents?

Closure of the aortic valve

INTERPRETING ARTERIAL WAVEFORM
What happens during the “diastolic runoff”?

Drop in pressure that occurs after the aortic valve closes
Blood is now going into the peripheral circulation

INTERPRETING ARTERIAL WAVEFORM
What does End-Diastolic-Blood-Pressure (EDBP) also referred to as “Aortic Diastolic Pressure” represents?

Pressure exerted by the vasculature back onto the aortic valve

INTERPRETING ARTERIAL WAVEFORM
What reflects DBP on the arterial waveform?

Lowest reading before the next systolic upstroke

INTERPRETING ARTERIAL WAVEFORM
What reflects MAP on the arterial waveform?
Area under the curve

INTERPRETING ARTERIAL WAVEFORM
How is Pulse pressure calculated?
What is its normal value?
PP = SBP - DBP
Normal value: 40 - 60 mmHg

INTERPRETING ARTERIAL WAVEFORM
Which informations could be gathered via Pulse Pressure?
Fluid status and Vascular competence
Via SV, CO, and SVR
INTERPRETING ARTERIAL WAVEFORM
What could a Narrow PP (less than 40mmHg) indicate?
Hypovolemia
Cardiac tamponade
Anything that causes a low CO state

INTERPRETING ARTERIAL WAVEFORM
What could a Widened PP (more than 60mmHg) indicate?
Worsening aortic valve insufficiency
Usually Aortic Regurgitation
During diastole, the arterial BP will drop to backfill the LV through that regurgitant aortic valve that is supposed to be closed
May also get what’s called “Bisferiens pulse” which occurs d/t to run off of blood into the periphery and into the LV

INTERPRETING ARTERIAL WAVEFORM
What’s another name for the biphasic-pulse aortic waveform that shows two peaks per cardiac cycle, a small one followed by a strong and broad one? What does it indicate?
Bisferiens pulse
It is a sign of problems with the aortic valve, including aortic stenosis and aortic regurgitation, as well as hypertrophic cardiomyopathy causing subaortic stenosis
It is associated with a widened Pulse pressure

INTERPRETING ARTERIAL WAVEFORM
Explain the mechanics of Systolic Pressure Variation (SPV), volume status, and how it affects SBP?
PPV causes and increase in intrathoracic pressure which impedes VR, compresses the lungs, and causes blood in the pulmonary vasculature to be pushed to the left side of the heart, and ejected with each beat
This result in increase in BP during inspiration
During expiration, there is no augmentation to the amount of blood pumped out, resulting in a decrease in SBP

INTERPRETING ARTERIAL WAVEFORM
What’s the normal value of Systolic Pressure Variation (SPV)
10 mmHg





































