What are evidence-based FiO2 and SpO2 targets in critically ill patients?

Current evidence (ICU-ROX, OXYGEN-ICU, HOT-ICU trials) supports a conservative oxygen strategy targeting SpO2 92–96% rather than 97–100% in most critically ill patients. An SpO2 target of 96% with the lowest effective FiO2 balances oxygenation adequacy against hyperoxia-related harm (oxidative stress, absorption atelectasis, coronary vasoconstriction). Lower targets (88–92%) are acceptable in ARDS to minimize ventilator-induced lung injury.

What is oxygen toxicity and when does it occur?

Pulmonary oxygen toxicity occurs when FiO2 exceeds 0.60 for prolonged periods (>24–48 hours), generating reactive oxygen species that damage the alveolar-capillary membrane. Clinical manifestations include tracheobronchitis, absorptive atelectasis, and worsening ARDS-like injury. FiO2 should be reduced to ≤0.60 as soon as oxygenation targets can be maintained — typically by optimizing PEEP, prone positioning, or treating the underlying cause.

FiO2 Titration Calculator

Calculate and titrate the fraction of inspired oxygen (FiO2) to achieve target SpO2 or PaO2 in ICU patients, using ARDSnet tables or oxygen toxicity risk-based guidelines.

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Frequently Asked Questions

What are evidence-based FiO2 and SpO2 targets in critically ill patients?

What is oxygen toxicity and when does it occur?