RespiratoryIntermediate

Oxygenation Index (OI)

Assesses the severity of hypoxic respiratory failure.

Clinical Parameters

3 Variables
%
cmH₂O
mmHg

Awaiting Clinical Parameters

Configure the patient variables on the left and select Calculate Result to generate the clinical score and stratification.

Verified 2026 GuidelinesInstant Calculation
Jump to Formula & Clinical Protocol ↓
High Yield Prometric TopicPulmonology & Respiratory

Tested on Gulf Medical Boards (DHA, SMLE, MOH & HAAD)

Clinical calculations and diagnostic scoring systems like Oxygenation Index (OI) frequently appear on Prometric exams. Master high-yield clinical vignettes with instant AI-powered pathophysiology rationales.

Clinical Significance & Diagnostic Standard
2026 Clinical Reference

What is the Oxygenation Index (OI)?

📋Clinical Summary & Definition Capsule

The Oxygenation Index (OI) is an evidence-based clinical decision rule engineered to quantify diagnostic probability, stratify clinical severity, and guide therapeutic decision-making in pulmonology & respiratory practice. The Oxygenation Index (OI) is used in intensive care to assess the severity of hypoxic respiratory failure and ARDS, particularly in neonates and pediatrics. It helps determine the need for advanced therapies like ECMO. Clinical scoring tools like Oxygenation Index (OI) are essential in acute and outpatient management, enabling clinicians to objectively differentiate between low-risk candidates suitable for conservative therapy and high-risk patients requiring urgent interventions. Verified against current 2026 clinical standards, this tool is extensively tested on Gulf health authority licensing exams including DHA (Dubai), SMLE (Saudi Arabia), MOH, HAAD/DOH (Abu Dhabi), OMSB (Oman), and QCHP (Qatar).

💡Clinical Pearls & Diagnostic Utility

OI is the preferred marker of illness severity in pediatric ARDS and persistent pulmonary hypertension of the newborn (PPHN). An OI > 40 is a classic threshold for considering extracorporeal membrane oxygenation (ECMO).

Mathematical Formulation

Formula & Calculation Parameters

The mathematical equation and clinical variables required to calculate Oxygenation Index (OI):

OI = (FiO₂ [%] × Mean Airway Pressure [cmH₂O]) / PaO₂ [mmHg]
Risk Stratification

Score Interpretation & Clinical Stratification

Score RangeClinical InterpretationRisk Tier
≤ 15Mild/Moderategreen
15 – 25Severeyellow
25 – 40Very Severeorange
≥ 40Consider ECMOred
Medical Review & Guidelines Compliance
MD

Clinical Review Board

Dr. Muhammad Nouman, MBBS

Capital Medical University | PMDC Reg No: 117744-P

Clinical Audit Status

✓ Verified for 2026 Guidelines

Last updated: 2026-08-07

Peer-Reviewed Medical Literature

  • Trachsel D, McCrindle BW, Nakagawa S, Bohn D. Oxygenation index predicts outcome in children with acute hypoxemic respiratory failure. Am J Respir Crit Care Med. 2005;172(2):206-211.