Manual compared to automated closed-loop oxygen control strategies in hospitalised adults: a systematic review and meta-analysis

Abstract

Background Closed-loop oxygen control (CLOC) systems improve accuracy of oxygen delivery compared with standard manual oxygen adjustment. Determination of their efficacy in delivering oxygen noninvasively to adults, using different delivery methods and across different hospital locations, would enhance clinical practice. Methods We conducted a systematic review and meta-analysis, searching Medline, Embase, Scopus Basic and Advanced, and Cochrane databases. Randomised controlled trials comparing time spent within a target peripheral oxygen saturation (SpO2) range between CLOC and manual oxygen control in hospitalised adults (>18 years) were included. Outpatient studies and studies using mechanical ventilation were excluded. The primary outcome was proportion of time spent within a target SpO2 range. Meta-regression was performed for pre-determined study-level covariates, including oxygen delivery mode and locations of care. Results The search identified 3777 papers; of these, seven were included, with 635 participants. The mean proportion of time spent within the target SpO2 range was between 81.2 and 94.9% for CLOC and 51.3–84.0% for manual oxygen control. The mean difference was 21.2% (95% CI 18.5–23.8, p<0.0001), favouring CLOC. Evidence of heterogeneity (I2=87.9) was explained by three studies using low-flow oxygen therapy, mean difference 30.9% (95% CI 27.0–34.8, p<0.0001); compared with four studies using high-flow nasal oxygen therapy, mean difference 12.7% (95% CI 9.1–16.4, p<0.001). Conclusions CLOC improves adherence to a target SpO2 range compared to manual oxygen control and is an effective approach for achieving a target SpO2 range when delivering oxygen noninvasively in hospitalised adults.