PHYL 4504 Lecture Notes - Lecture 4: Kyphoscoliosis, Peak Expiratory Flow, Chronic Obstructive Pulmonary Disease

• School: Dalhousie University
• Department: Physiology
• Course: PHYL 4504
• Professor: Elizabeth Cowley

Document Summary

Phyl 4504 lecture 4 september 16, 2020 mechanics of breathing: ventilation (2) Obstructive disease: during a forced expiration manoeuvre, part of the flow-volume curve becomes effort-independent. The end of exhalation: flow-volume curves often have a characteristic scooped out appearance in one type of pulmonary disease. As alveolar ventilation increases, alveolar po2 increases and pco2 decreases. Instead use concentration of co2 in expired gas. This rearranging of the formula is closely related to the bohr"s methods. In other words, you can determine the alveolar ventilation by dividing the co2 output by the alveolar fractional concentration of co2. If alveolar ventilation is halved (and co2 production remains unchanged) the alveolar (and arterial) pco2 will double. Remember the po2 of 100 mmhg and pco2 of 40 mmhg under normal ventilation. If we increase our ventilation rate, we are breathing more frequently so our pco2 will fall and our po2 will be brought in.