What is the maximum tidal volume available for a time-triggered, ...

[shenderson6]

What is the maximum tidal volume available for a time-triggered, pressure-limited, time-cycled infant ventilator with a set inspiratory time of 0.5 second and a set flow rate of 12 L/min?
 
  a. 36 mL c. 240 mL
  b. 100 mL d. 250 mL

Question 2

Circuit positive end-expiratory pressure may be avoided by using:
 
  a. demand flow. c. flow interrupter.
  b. continuous flow. d. overpressure-relief valve.

[Danny Ewald]

Answer to Question 1

ANS: B
Tidal volume = Inspiratory time (seconds)  Flow (L/min)  60 = 0.5  12 L/min  60 = 0.1 L, or 100 mL.

Answer to Question 2

ANS: A
Demand flow is believed by some clinicians to be advantageous to operator-selected, continu-ous-flow systems because continuous-flow systems tend to produce resistance to expiration at the airway, commonly known as circuit positive end-expiratory pressure. For patients whose ven-tilatory needs include high inspiratory flows but low end-expiratory pressure, the demand system eliminates the need to set a high continuous flow.