Pulm Phys: Defense, Repain, and Changes with Aging, Pregnancy, Obesity, Altitude, and Exercise

Steady-state airway defense mechanisms?

Cough

What triggers innate immunity in the lungs?

PAMPs (pathogen-associated molecular patterns)

Diffuse alveolar damage mechanism?

Cytokine-mediated injury to alveolar epithelium and basement membrane

Role of Type I alveolar cells?

Gas exchange

Role of Type II alveolar cells?

Surfactant production + make type 1 cells

Is the lung sterile?

No — low-biomass microbiome present

Pulmonary aging: what decreases?

Chest wall compliance, repsiratory muscle strength, FEV1, FVC, diffusing capacity

Pulmonary aging: what increases?

Lung compliance, FRC, RV, closing volume, dead space, A-a gradient

Normal FEV1 decline per year after age 30?

~30 mL/year

Pulmonary Physiological changes in pregnancy

Mechanical effects of enlarging uterus, increased ventilatory requirements, increased circulatory requirements, increased metabolism

Pregnancy: what happens to minute ventilation(Ve)? FRC? Spirometry?

Ve Increases 20–50%(increased ventilation»deeper breathes). FRC Decreases 20-30%(due to reduced ERV and RV. Spirometry is normal

Obesity: major mechanical effect?

↓FRC(function of residual capacity), increased work of breathing, decreaed respiratory system compliance

Obesity: effect on ERV?

Significant decrease

Obesity-hypoventilation syndrome

Criteria: Obesity, sleep disordered breathing, hypoventilation (with no other causes).

Sx: sleepiness, morning headache, dyspnea all due to build up of CO2

Tx: Nocturnal positive airway pressure (PAP)

High altitude risk?

HAPE (high-altitude pulmonary edema)