Author Question: Regarding mechanical loads in the context of mechanical and spontaneous ventilation, how is the load ... (Read 73 times)

appyboo · **on:** Jul 16, 2018

Regarding mechanical loads in the context of mechanical and spontaneous ventilation, how is the load expressed in terms of work?

A. Work expresses load as the integral of volume over pressure.
B. Work expresses load as the integral of flow over volume.
C. Work expresses load as the integral of pressure over volume.
D. Work expresses load as the integral of volume over flow.

Question 2

When airway pressure is integrated over tidal volume during a mechanically controlled breath, work done by which of the following components is provided?

A. work done on the respiratory system by the ventilator
B. work done on the respiratory system by the inspiratory muscles
C. work done on the lungs by the inspiratory muscles
D. work done on the chest wall by the inspiratory muscles

cam1229 · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

ANS: C
A. Incorrect response: See explanation C.
B. Incorrect response: See explanation C.
C. Correct response: Work expresses load as the integral of pressure over volume (W = PdV).
D. Incorrect response: See explanation C.

Answer to Question 2

ANS: A
A. Correct response: During a ventilator controlled breath, integrating airway pressure over tidal volume describes the work done on the respiratory system by the ventilator.
B. Incorrect response: During spontaneous breathing, integrating airway pressure over tidal volume describes the work done on the respiratory system by the inspiratory muscles.
C. Incorrect response: During spontaneous breathing, integrating esophageal pressure over tidal volume describes the work done on the lungs by the inspiratory muscles.
D. Incorrect response: During a ventilator controlled breath, integrating the esophageal pressure over tidal volume describes the work done on the chest wall by the ventilator.