Describe the respiratory changes that occur throughout pregnancy.
The question asked for a description of the respiratory changes throughout pregnancy, which includes labour. Simple lists of changes did not score highly. A straightforward structure including; first, second and third trimester delineation would have elevated many answers from below par to a pass. Many good answers gave succinct detail on both mechanical respiratory changes and the hormonal mechanisms behind them. Higher scoring answers also described the overall effect of individual changes to spirometry, geometry or respiratory control.
Pregnancy-related changes | Effect of these changes |
Airway function and structure | |
Mucosal oedema in the upper airway |
|
Structural properties of the chest wall and lung volumes | |
Anatomical changes |
|
Lung volumes |
|
Compliance |
|
Resistance |
|
Gas exchange and gas transport | |
Blood gas tension |
|
Oxygen-carrying capacity |
|
Control of ventilation | |
Central respiratory control |
|
Respiratory workload and demand | |
Demands on the respiratory system |
|
Yeomans, Edward R., and Larry C. Gilstrap III. "Physiologic changes in pregnancy and their impact on critical care." Critical care medicine 33.10 (2005): S256-S258.
Hegewald, Matthew J., and Robert O. Crapo. "Respiratory physiology in pregnancy." Clinics in chest medicine 32.1 (2011): 1-13.
LoMauro, Antonella, and Andrea Aliverti. "Respiratory physiology of pregnancy: physiology masterclass." Breathe 11.4 (2015): 297-301.