Negative-pressure ventilators cause air to enter the lungs by ...

[beccaep]

Negative-pressure ventilators cause air to enter the lungs by increasing ______________ pressure.
 
  a. transairway
  b. transpulmonary
  c. transrespiratory
  d. transthoracic

Question 2

A patient has acute pulmonary edema from left-sided heart failure and acute hypoxemic respira-tory failure that has not responded to conventional pharmacologic and oxygen therapy.
 
  As the next line of therapy, the respiratory therapist should recommend which of the following?
  a. Noninvasive positive-pressure ventilation
  b. Continuous positive airway pressure
  c. Intubation and mechanical ventilation
  d. Bronchial hygiene therapy

[ultraflyy23]

Answer to Question 1

ANS: B
Transpulmonary pressure maintains alveolar inflation due to the decrease in pleural pressure caused by the negative pressure surrounding the chest wall. Positive-pressure ventilators cause air to move into the lungs by increasing the pressure in the upper airways and in the conductive air-ways. Changes in transpulmonary pressure result in corresponding changes in alveolar volume. The transairway pressure is the gradient that produces airway movement in the conductive air-ways and represents the pressure caused by resistance to gas flow in the airways. The transrespir-atory pressure is responsible for gas flow into and out of the alveoli during breathing. The trans-thoracic pressure is the pressure across the chest wall. It represents the pressure necessary to ex-pand or contract the lungs and chest wall together.

Answer to Question 2

ANS: B
The current recommendation for ACPE is for CPAP to be used initially. NIV should be used only in patients who were hypercapnic and continue to be hypercapnic in spite of the CPAP.