Exam 2 - Blenders

Question 1

Gas Blender

Answer 1

• Blends room air with 100% O2
• Room air is yellow and O2 is green
• Blender -> flow meter -> gas analyzer -> gas filter -> oxygenator

-Gas filter can be bi or uni directional

Question 2

Blender O2 range

Answer 2

0.21 to 1.0

O2 is 21% of room air) (N2 is 79%

Question 3

FiO2

Answer 3

• Fraction inspired O2 (% O2 in line)

Question 4

Typical dual flow meter set up

Answer 4

• Dual for more precise control
• One meter 0 - 10 L
• Other meter 1 - 1.0 L

Question 5

Steps to calculate gas blend

Answer 5

• Calc total N2 (base off of FiO2….if 75%….then N2 is 25% of total flow)
• Take answer and divide by 0.79
• this is how much from room air….rest comes from pure O2 tank

Question 6

Roller pumps

Answer 6

• Positive displacement
• independent of fluid density as long as set correctly
  - tubing size
  - occlusion settings
• Blood flow = SV * RPM

Question 7

Occlusion settings

Answer 7

• Ideal is just under occluded
• Gold standard method (not really used)
• Pressure drop method (clamp outlet of arterial pump head -> hand rotate pump until 250 - 300 mmHg built up and release -> watch how pressure drops…should be in equilibrium @ 200-250 mmHg)
• Dynamic method (looses occlusion -> clamp outlet -> set RPM to 5 -> occlude until desired pressure reached) (best method due to loosest occlusion)