Purpose: It is a challenge to control oxygen saturation (SpO₂) in patients with exacerbations of COPD during admission. We tested a newly developed closed-loop system, O2matic^®, and its ability to keep SpO₂ within a specified interval compared with manual control by nursing staff.
Patients and methods: We conducted a crossover trial with patients admitted with an exacerbation of COPD and hypoxemia (SpO₂ ≤88% on room air). Patients were monitored with continuous measurement of SpO₂. In random order, they had 4 hours with manually controlled oxygen and 4 hours with oxygen delivery controlled by O2matic. Primary outcome was time within a prespecified SpO₂ target interval. Secondary outcomes were time with SpO₂ <85%, time with SpO₂ below target but not <85%, and time with SpO₂ above target.
Results: Twenty patients were randomized and 19 completed the study. Mean age was 72.4 years and mean FEV₁ was 0.72 L (33% of predicted). Patients with O2matic-controlled treatment were within the SpO₂ target interval in 85.1% of the time vs 46.6% with manually controlled treatment (P <0.001). Time with SpO₂ <85% was 1.3% with O2matic and 17.9% with manual control (P =0.01). Time with SpO₂ below target but not <85% was 9.0% with O2matic and 25.0% with manual control (P =0.002). Time with SpO₂ above target was not significantly different between treatments (4.6% vs 10.5%, P =0.2). Patients expressed high confidence and a sense of safety with automatic oxygen delivery.
Conclusion: O2matic was able to effectively control SpO₂ for patients admitted with an exacerbation of COPD. O2matic was significantly better than manual control to maintain SpO₂ within target interval and to reduce time with unintended hypoxemia.
Keywords: oxygen therapy, oxygen saturation, hypoxia, hyperoxia, closed-loop

摘要视频链接：Automated oxygen control with O2matic^®