RespRespiratory

Alveolar-Arterial Oxygen Gradient

Differentiates causes of hypoxaemia. Elevated gradient suggests V/Q mismatch, shunt or diffusion defect.

PaO₂ from ABG

mmHg

PaCO₂ from ABG

mmHg

FiO₂ (fraction)

Patient age

years

Reference: Normal upper limit ≈ (Age + 10) / 4 mmHg

Medical Disclaimer: This calculator is a clinical decision support tool for qualified healthcare professionals. It does not replace clinical judgement. Always interpret results in the full clinical context. Reference: Normal upper limit ≈ (Age + 10) / 4 mmHg.

More Respiratory Calculators

RespP/F Ratio

Key indicator of oxygenation failure severity. Berlin definition: mild ARDS < 300, moderate < 200, severe < 100.

RespBODE Index

Predicts all-cause and respiratory mortality in COPD. Superior to FEV1 alone as a prognostic marker.

RespSTOP-BANG

Screens for moderate-severe obstructive sleep apnoea using 8 clinical variables. Score ≥3 warrants further evaluation; ≥5 has high sensitivity for severe OSA.

RespPSI/PORT Score

Stratifies CAP severity. Classes I-II: outpatient; Class III: short admission or observation; Classes IV-V: inpatient/ICU.