Calculate the airway resistance (Raw) using the information from ...

[Capo]

Calculate the airway resistance (Raw) using the information from the scalar below.
 
  a. 0.9 cm H2O/L/sec
  b. 1.1 cm H2O/L/sec
  c. 22.4 cm H2O/L/sec
  d. 60 cm H2O/L/sec

Question 2

The respiratory therapist observes the pressure-time scalar seen below. Wave A was generated at 1300 hour and wave B at 1600 hour. The action that is most appropriate for this situation is which of the following?
 
  a. Add positive end-expiratory pressure (PEEP).
  b. Change the endotracheal tube (ET).
  c. Change to pressure-controlled continuous mandatory ventilation (PC-CMV).
  d. Administer a bronchodilator.

[wshriver]

Answer to Question 1

ANS: C
Airway resistance (Raw) = Peak inspiratory pressure (PIP)  Plateau pressure (Pplateau)/flow (L/sec). PIP = 40 cm H2O; Pplateau = 25 cm H2O; flow = 40 L/min or 0.67 L/sec; Raw = 15/0.67 = 22.4 cm H2O/L/sec.

Answer to Question 2

ANS: D
When comparing the two waveforms it should be noted that the plateau pressures (Pplateau) are the same for both, 15 cm H2O. However, the peak inspiratory pressure (PIP) is higher in waveform B, 35 cm H2O, as opposed to waveform A, 27 mm H2O. This indicates an increase in transairway pressure (PTA) and therefore, airway resistance. The most appropriate answer is to administer a bronchodilator. If the ET tube was too small the PTA would have been consistently high from the start of mechanical ventilation. Adding PEEP or switching to pressure-controlled continuous mandatory ventilation (PC-CMV) would be appropriate if the Pplateau was increasing.

[Capo]

Excellent

[bblaney]

Thanks for the timely response, appreciate it