Efficacy of Spontaneous Deep Breathing Technique with Pressure Support / Continuous Positive Airway Pressure during Preoxygenation: A Randomized Controlled Trial

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Raweeporn Laopakdee


Background: Preoxygenation with deep breathing technique for 1 minute is accepted for emergency situations. Pressure support (PS) and continuous positive airway pressure (CPAP) combined with tidal volume breathing for 3-5 minutes provides more rapidly increasing and achieved higher end-tidal oxygen (ETO2). The aim of this study was to determine the efficacy of deep breathing technique with PS/CPAP in term of ETO2.

Methods: Randomized controlled trial study was conducted in patients ASA I and II, aged 18-65 years old, undergoing elective surgery under general anesthesia. Control (C) group was preoxygenated by using deep breathing technique. Pressure (P) group used deep breathing technique combined with PS 4 cmH2O and CPAP 4 cmH2O. The ETO2 and respiratory discomfort scores were recorded at 1 minute.

Results: Forty-five patients were included for each group. The mean end-tidal oxygen (ETO2) at the end of 1 minute in P group and C group were 86.67 ± 3.91% and 83.98 ± 5.62% respectively. Mean difference between group was 2.69 ± 1.02 (95% CI 0.66-4.72, p = 0.01). Thirty-five patients (77.8%) in P group and twenty-one patients (46.7%) in C group got ETO2 ≥ 85% in 1 minute which were significantly different (p = 0.002). Respiratory discomfort scores were not significantly difference (p = 0.971) in both groups.

Conclusion: Application of PS and CPAP combined with deep breathing technique for one-minute preoxygenation provides higher ETO2.

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