Which of the following maneuvers can momentarily raise alveolar pressures, creating zone I conditions?
I.Coughing
II.Blowing a trumpet
III.Positive pressure mechanical ventilation
IV.Exercise

Question

Quizplus · Accepted Answer

Respiratory maneuvers such as exhaling against a closed glottis, blowing a trumpet, or coughing can momentarily raise alveolar pressures above arterial pressures, creating zone I conditions in gravity-independent (uppermost) lung regions. Positive pressure mechanical ventilation may increase alveolar pressure enough to convert some zone II regions to zone I. This is one mechanism whereby positive pressure ventilation increases alveolar dead space. Likewise, a loss of blood volume or massive vasodilation, as in septic shock, may lower PAP enough to create zone I conditions.

Which of the Following Maneuvers Can Momentarily Raise Alveolar Pressures