Automated oxygen titration kept ward patients in range far more of the time than manual adjustment

Design

Multicentre, unblinded, parallel-group randomised clinical trial

Population

300 acutely ill hospitalised adults receiving supplemental oxygen

Primary outcome

Proportion of time with SpO2 90 to 96% over 72 hours

Effect

85% vs 63%; adjusted difference 21 percentage points (95% CI 18 to 25)

SAVE-O2 AI randomised 300 adults on supplemental oxygen at four US hospitals, admitted with acute respiratory illness, trauma, burns or after acute surgery, to closed-loop automated titration or usual manual titration for 72 hours. The device adjusted flow continuously to keep saturation between 90% and 96%. More than three-quarters of patients had medium or dark skin tone on a standard scale.

Automated titration kept patients in the target range 85% of the time against 63% with usual care, an adjusted difference of 21 percentage points (95% CI 18 to 25). Time with saturation below 88% fell from 3.6% to 2.0%. The biggest change was in over-oxygenation: time above 96% dropped from 29.1% to 9.2%.

The trial measured time in range, not deaths, length of stay or intubation. It was unblinded, and results were consistent across subgroups, including by skin tone.

For most wards the immediate lesson is simpler than the device: patients spend almost a third of their time over-oxygenated with manual titration. Prescribing a target range and turning oxygen down when saturation sits above it is something any team can do now.

• Prescribe an explicit saturation target range for every patient on oxygen
• Turn oxygen down when saturation sits above target; over-oxygenation was the commonest error
• Use a lower target, typically 88 to 92%, for patients at risk of hypercapnic respiratory failure
• Pulse oximetry can overestimate saturation in darker skin; check a blood gas when the reading and the patient do not fit
• Closed-loop titration devices are worth evaluating where nursing time for oxygen checks is limited

Why it matters

It shows manual titration leaves patients over-oxygenated for nearly a third of the time.

Don't overread it

Time in range is a process measure; the trial did not show better clinical outcomes.

The statistics, in plain English

A 21-point gain in time in range is large and precise (18 to 25). The hypoxaemia reduction is small in absolute terms, 1.3 percentage points of time, though it roughly halves exposure. None of this yet shows fewer deaths or complications.

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