BPK 305 Lecture Notes - Lecture 27: Modes Of Mechanical Ventilation, Continuous Positive Airway Pressure, Alveolar Pressure

• School: Simon Fraser University
• Department: Biomedical Physio & Kines
• Course: BPK 305
• Professor: Damon Poburko

Document Summary

Blood flow through the lungs is equal to co, and therefore depends on: Key determinant = distribution of blood throughout the lung tissue. Ex. while hanging from her knees on a trapeze, perfusion zone 4 would occur in the apex of the acrobat"s lungs. Pulmonary vascular resistance decreases by: recruitment, 1) some vessels previously open, but with no flow begin to pass blood, 2) closed vessels begin to open -> occurs with smaller pressure rise, distension. Increases in pressure distends the vessel: occurs with larger pressure rise or lower in lung. Extra-alveolar vessels: at increasing lung volumes, more negative intrapleural pressure pulls extra-alveolar vessels open to larger diameters, high lung volume -> intrapleural pressure is most negative and pulls vessels open. Resistance in alveolar and extra-alveolar vessels depends on lung volume. 6: total pulmonary vascular resistance = lowest around normal resting breath volumes, pulmonary vascular resistance is minimal near frc.