A patient receiving continuous positive airway pressure of 7.5 cm ...

[tingc95]

A patient receiving continuous positive airway pressure of 7.5 cm H2O via a mask and freestand-ing system appears to be in distress. The patient is using accessory muscles and is diaphoretic.
 
  The manometer is fluctuating between 5 cm H2O on inspiration and 7.5 cm H2O on expiration. The most apparent cause of the patient's distress is which of the following?
  a. Leak in the system c. Inadequate flow rate
  b. Improper mask fit-ting d. Obstruction of the threshold resistor

Question 2

A separation bubble in a fluidic device does which of the following?
 
  a. Causes a flip-flop to occur
  b. Causes a high-pressure vortex
  c. Bends the gas jet stream toward the wall
  d. Pushes the gas jet stream away from the wall

[kmb352]

Answer to Question 1

ANS: C
The patient is pulling in more than the flow of the continuous positive airway pressure system was set to deliver. This is apparent because of the wide fluctuation in the pressures. If there was a leak or improperly fitting mask, the pressure on expiration would not be at the set pressure. If there was an obstruction of the threshold resistor, it would prevent the patient's exhaled gas from exiting and cause the pressure-release valve to pop off.

Answer to Question 2

ANS: C
A separation bubble is a low-pressure vortex that develops between a wall and a jet stream of gas. The bubble attracts or bends the jet stream toward the wall. The pocket of turbulence forms an air foil, similar to that seen with an airplane wing. When the gas entrained into the bubble from the jet stream equals the amount of air moving from the vortex flow of the bubble back to the jet stream, the attachment is stable.