Purpose: The aim of this study was to determine whether the relative change in the end-expiratory lung volume (EELV) obtained by the recruitment maneuver (RM) can serve as an indicator of the change in the P/F ratio.
Materials and methods: The effects of the intermittent stepwise increases in the RM (peak inspiratory pressure, 45, 50, and 55 cm H2O) were compared in 21 patients with atelectasis under mechanical ventilation. The EELV, the ratio of arterial oxygen concentration to the fraction of inspired oxygen P/F ratio, and relative change rate (Δ) in these parameters were evaluated after each RM.
Results: A greater improvement in the EELV (1157 ± 344 mL vs 1469 ± 396 mL) and P/F ratio (250 ± 99 vs 320 ± 92) was observed after the RM. The ΔEELV was correlated with the ΔP/F ratio (ρ = 0.73, P < .01) and was identified as an accurate predictor of the improvement of the ΔP/F ratio by the receiver operating characteristic curve (the area under the curve, 0.93; P < .01).
Conclusions: These results suggest that the ΔEELV obtained by intermittent stepwise RM can serve as an indicator of the change in the P/F ratio.
Keywords: Atelectasis; End-expiratory lung volume; Functional residual capacity; Recruitement maneuver; Respiratory therapy.
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