How much volume is lost in the ventilator circuit when the volume ...

[geoffrey]

How much volume is lost in the ventilator circuit when the volume is set at 500 mL, the peak in-spiratory pressure is 40 cm H2O, and the tubing compliance is 3 mL/cm H2O?
 
  a. 380 mL c. 150 mL
  b. 280 mL d. 120 mL

Question 2

Plateau pressure may be obtained during volume ventilation by using which of the following?
 
  a. Expiratory pause c. End-expiratory pressure
  b. Inspiratory pause d. Increased inspira-tory time

[mohan]

Answer to Question 1

ANS: D
Volume lost in the ventilator circuit equals tubing compliance multiplied by the measured peak inspiratory pressure. Volume lost = 3 mL/cm H2O  40 cm H2O = 120 mL.

Answer to Question 2

ANS: B
During volume ventilation, plateau pressure is obtained by using the maneuver that extends or delays exhalation by keeping the expiratory valve momentarily closed. This prevents the gas from leaving the circuit. The maneuver is known as an inspiratory pause, inspiratory hold, or inspirato-ry plateau.

[geoffrey]

Excellent

[amcvicar]

Gracias!