NIBP Flashcards
Perfusion =
Pressure and flow
When you give phenylephrine to treat low BP then what are you effecting?
TPR (total peripheral resistance)
When you give ephedrine to treat low BP then what are you effecting?
TPR , HR, CO
All drugs for induction effect what two parameters?
Coronary blood flow
Cardiac sympathetic discharge
What induction agents effect venous capacity?
Propofol, fent, inhaled gases
What induction agents are vasodilator substances?
Propofol, inhaled gases
What is the normal CO?
5 L / min
What is the normal blood volume ?
5 L / min
When a pt is in sepsis, what physiological status must you account for?
Increased norepi usage
Low BP
CO 2-3x normal
Decreased perfusion to peripheries
What is the mean circulating filling pressure?
Pressure anywhere where flow is stopped
What do baroreceptors do?
Provide the driving pressure that permits local autoregulation of all vascular beds
What are the 2 main baroreceptors used to regulate central blood pressure?
Carotid sinus
Aortic arch baroreceptors
When using auscultation as the means for measuring BP manually, what sounds do you hear?
Korotkoff Sounds
What does NIBP mean?
Non invasive blood pressure
What artery is most used for listening for Korotkoff sounds?
Brachial
What is the most common technique used for measuring NIBP?
Oscillometric
When using oscillometric technique for NIBP, which pressure is most accurate?
Mean
Remember in Biggs class, we measure VARIABLES and not PARAMETERS
DUH
What law do you use when talking about wall pressure and and blood vessels?
Laplace’s law
NIBP overestimates at what state? (HTN, or hypotension?)
Hypotensive
NIBP underestimates at what state?
Hypertensive
Which parameter describes tissue perfusion?
Mean pressure
What is the calculation used to determine perfusion pressure?
PP = arterial P - venous P
Mean pressure is also known as what?
Pressure of perfusion
The majority of blood flow to the LV occurs during what?
Diastole
What is the term that describes the formula we use to calculate Mean Pressure? (formula is M = {(S - D) / 3} + D
Wiggers Estimate
When using wiggers estimate, where must the pressures be derived from?
Cuff must be on Upper arm
What is the k value for the brachial artery?
0.33
When using k values what is the formula you must use to determine mean pressure?
MP = D + k (pulse pressure)
What is the k value for the aorta?
0.41
What is the k value for the femoral artery?
0.30
Define pulse pressure
Difference between systolic and diastolic pressures
What is pulse pressure used for in the clinical setting?
Indicator of stroke volume
When under anesthesia, does your O2 requirement increase or decrease?
Decrease
What is the minimum required blood pressure for a patient?
20% of the systolic pressure
What is the minimum required BP for the brain?
60 mm Hg
CPP stands for what
Cerebral perfusion pressure
What is formula for CPP?
CPP = MAP - ICP
You can assume ICP is close to CVP so can assume 8 - 12 mmHg
Who’s cuff system used an occlusive counter-pressure system to measure BP in 1896?
Scipione Riva-Rocci’s
What size of the limb’s circumference should the cuff width be?
40%
The length is nearly how many times larger than the width of the cuff?
2 times
Which is more critical to the accuracy of the measurement, length or width?
Width
When your cuff size is too small, what will happen to the NIBP reading?
Will be falsely high
What is wrong with the cuff when you are getting falsely low blood pressure readings?
Cuff is too large
What other problem with the cuff can be associated with falsely high BP readings?
Cuff being applied too loosely
When using the return to flow method of determining a BP, what is the only pressure that can be obtained?
Systolic
What is the kind of doppler used when determining pressure by the return to flow method?
Parks doppler
What artery is most used when using the return to flow method for BP?
Radial
What is the return to flow method of determining BP?
Where you apply pressure to a blood vessel above systolic, then decrease the pressure until the first pulse is detected distally from the occluded vessel
(ie pressure applied to upper arm, doppler device placed over radial artery at hand to detect pulse)
What technique is similar to oscillometric but is a continuous recording of the pulse waveform while applying only mean pressure to the vessel?
Vascular unloading
When using the auscultation method, how much pressure do you let off and how often?
3 mmHg for every heart beat
How many phases are there in the ausultatory method of determining BP?
5 phases
What is phase 1 of auscultatory method?
Snapping tones heard
Murmurs are heard during what phase of the auscultatory method?
Phase 2
The auscultatory gap is found in which phase of the auscultatory method?
Phase 2
What is phase 3 of auscultatory method?
Thumping
What is phase 4 of auscultatory method?
Muffling