Blood gases
- Normal: pH 7.35–7.45, PaCO2 35–45 mm Hg, HCO3 22–26 mEq/L
- PaO2/FiO2 ratio ≤ 300 suggests ARDS (with other criteria)
- Low pH with high PaCO2 means respiratory acidosis
Ventilation
- Lung-protective tidal volume: about 6 mL/kg of ideal body weight
- Keep plateau pressure ≤ 30 cm H2O
- Driving pressure = plateau pressure − PEEP
Pulmonary function
- FEV1/FVC below 0.70 indicates obstruction
- Reduced TLC confirms restriction
- DLCO falls in emphysema and interstitial disease
Neonatal
- APGAR is scored at 1 and 5 minutes
- Begin PPV for apnea or heart rate below 100/min
- Begin compressions if heart rate stays below 60/min despite effective ventilation
Test yourself on RT
Reading a summary is the easy part. Take the free 10-question diagnostic to see which of these domains you actually have, then drill the rest.