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Respiratory

PaO₂/FiO₂ Ratio (P/F Ratio)

Oxygenation index for acute respiratory distress, from arterial oxygen and FiO₂.

Inputs

FieldUnitNotes
PaO₂ mmHg 20–700
FiO₂ % 21–100

FAQ

What is the PaO₂/FiO₂ Ratio (P/F Ratio)?

Oxygenation index for acute respiratory distress, from arterial oxygen and FiO₂.

What inputs does the PaO₂/FiO₂ Ratio (P/F Ratio) need?

PaO₂ (mmHg), FiO₂ (%).

Related guides

PaO₂/FiO₂ (P/F) Ratio: Berlin ARDS Grading and Its Limits in Children

The P/F ratio — its formula, the Berlin mild/moderate/severe ARDS bands at PEEP ≥5, a worked example, and why children use OI/OSI instead under PALICC-2.

Related Respiratory calculators

Oxygenation Index

Oxygenation Index for severity stratification of paediatric ARDS (PARDS).

Pediatric Asthma Score (PAS)

Severity assessment of an acute paediatric asthma exacerbation from respiratory rate plus four clinical signs (5–15).

Pediatric Asthma Severity Score (PASS)

Three-item bedside score (0–6) for grading acute asthma severity in children from wheezing, work of breathing, and prolonged expiration.

Westley Croup Score

Grades croup severity from five clinical signs (0–17) to guide treatment and disposition.

Alveolar–Arterial (A–a) Oxygen Gradient

Difference between alveolar and arterial oxygen tension — assesses the cause of hypoxaemia (gas-exchange defect vs hypoventilation).

Oxygen Saturation Index (OSI)

Non-invasive oxygenation severity index (uses SpO₂ instead of PaO₂) for grading pediatric ARDS (PALICC).
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