Exam 3 - Faithful Reproduction Flashcards
1
Q
Fluid version of Ohm’s Law
A
Pressure = Flow (Q) x Resistance (R)
R = (8)(n)(L) / (pi)(r^4)
2
Q
What Patient Pressures do we measure
A
- Arterial P
Those measured by SWAN:
- Central Venous P
- Pulmonary Artery P
- Pulmonary capillary wedge pressure
- Reflection of L atrial P (pre-load)
3
Q
System pressures that we measure
A
- Arterial line P
- Cardioplegia line P
- Cardiac chamber pressures
4
Q
Pressure
A
P = Force / Area
N/m^2 = Pascal
5
Q
Hydrostatic Pressure
A
- Force is constant
6
Q
Hydrodynamic Pressure
A
- Force is varying
- Pulsatile nature of arterial blood pressure
7
Q
Closed system
A
- Patient and ECC for our purposes
- Flow is relatively laminar and vessel lumen is small
8
Q
Static fluid pressure key determinant
A
- Height (or difference in)
- Gravity and density will stay the same
9
Q
Artifact
A
- False signals superimposed on true signal
10
Q
Calibration
A
- Making sure system is accurate and can read known values
11
Q
Catheter Whip
A
- Movement of catheter tip in vessel due to pulsatile flow, etc.
12
Q
Damping
A
- Loss of energy and vibrations within monitoring system
- Think of as resistance
13
Q
Dynamic response
A
- System’s ability to measure physiologic pressure changes
14
Q
Fidelity
A
- System’s capability to faithfully reproduce physiologic event
- System accuracy
- can use snap test to check
15
Q
Natural frequency
A
- Frequency at which monitoring system vibrates when stimulated by pulsatile signals
- Resonant frequency
16
Q
Overshoot / Undershoot
A
- When patient’s pressure wave has a component of the system’s natural frequency causing some kind of artifact
