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17 Cards in this Set

  • Front
  • Back
What is NIF?
1)Negative pressure generated by the muscles of inspiration at RV against an occluded airway
When is NIF used?
1)As a weaning parameter in ventilator discontinuance
2)To assess inspiratory muscle strength in neuromuscular disease, paralysis, and disease of the chest wall
What is a normal range for NIF?
Normal range greater than (-) 80 cm H20.
What is the danger zone for NIF?
Around 20 cm H2O
What is MEF?
Positive pressure by the muscles of exhalation at TLC against an occluded airway
What is a normal range for MEF?
80-120 cm H20.
What is MEF used for?
To assess inspiratory muscle strenght in neuromuscular disease, paralysis, disease of the chest wall, and COPD
Pascal's Law
Pressure at one end of the tube will equal pressure at the opposite end of the tube in a closed system.
Testing methods for body box
1)Tight seal with a bite block mouthpiece and noseclips
2)At FRC, gentle pant at 1-2 BPS for two seconds against a closed shutter. The pressure at the airway will equal the pressure at the alveoli.
3)P airway and P box are measured simultenously.
4)Box factor takes into account the weight. When FRC is calculated, the volume will be adjusted according to the box factor.
Body Box advantages
2)Measures TGV or all the gas in the thorax, including areas not in contact with the airways
3)More than one test may be completed to ensure optimal performance and repeatability in a short period of time
4)Patient's performance requirements are minimal.
Acceptability Factors for the body box
1)Closed panting loop with no artifact
2)Panting begins at FRC
3)Pressure and frequency values are within normal limits
Repeatability Factors
1)FRC values are within 10 percent
2)Tangent values are within 10 percent
Body Box errors
1)Leaks around the door
2)Leaks at the mouth
3)calibration errors
4)Patient effort
5)Panting force or rate
6)"unnatural FRC"(FRC shift during seperate manuveur)
Body Box disadvantages
1)Patient fit in box
2)Patient cooperation
If there is a door leak, FRC will be___
1)Lower than normal.
If the patient does not have a good lip seal, FRC will be___
1)Higher than normal
How to calculate the box factor
(volume of air in box)-(weight on individual in liters) all divided by volume of air in box in liters