Determination of oxygen saturation compared to a prescribed target range using continuous pulse oximetry in acutely unwell medical patients.

Background: Both inadequate and excessive administration of oxygen to acutely unwell patients results in risk of harm. Guidelines recommend titration of oxygen to achieve a target oxygen saturation (SpO) range. Information regarding whether this is being achieved is limited.

Methods: In this two-centre non-interventional study we used continuous pulse oximetry in acutely unwell medical patients over a 24-h period to determine the proportion of time spent with SpO within the prescribed target range and whether this is influenced by the target range, age, care in a high-dependency area and the number of oxygen adjustments.

Results: Eighty participants were included in the analysis. The mean (SD) proportion of time spent in target range was 55.6% (23.6), this was lower in those with a reduced hypercapnic target range (88-92% or below) compared to those with a range of 92-96%; difference - 13.1% (95% CI - 3.0 to - 23.2), P = 0.012. The proportion of time spent above range was 16.2% (22.9); this was higher in those with a reduced hypercapnic range; difference 21.6% (31.4 to 12), P < 0.001. The proportion of time below range was 28.4% (25.2); there was no difference between target ranges. The proportion of time spent in range was higher for those in a high dependency area in the multivariate model; difference 15.5% (95% CI 2.3 to 28.7), P = 0.02.

Conclusions: Medical patients receiving oxygen in a ward setting spend significant periods of time with SpO both above and below the prescribed target range while receiving oxygen therapy.