Objective: To compare the individual effects of three recruitment maneuvers (RM) in children with congenital heart disease complicated by postoperation acute respiratory distress syndrome (ARDS).
Methods: A prospective single-blind randomized controlled trial was conducted. Thirty-two children with congenital heart disease complicated with ARDS after open-heart surgery undergoing mechanical ventilation were randomized into three groups, to whom three different RM was respectively performed, namely sustained inflation (SI), progressively increased positive end expiratory pressure (IP) and pressure control ventilation (PCV). Blood gas analysis was done every 6 hours, and the lung RM was performed if oxygenation index (OI) ≤ 300 mmHg (1 mmHg = 0.133 kPa). The OI, the dynamic lung compliance (Cdyn), as well as the parameters of hemodynamics before, during and after RM for 15, 30, and 60 minutes were recorded and analyzed before and after RM.
Results: During the treatment process, the OI was significantly increased during the process and 15, 30 or 60 minutes after RM compared with that before RM, with no statistical difference among groups (F value was 1.027, 0.403, 0.264, 0.172, 0.159, and P value was 0.367, 0.671, 0.769, 0.843, 0.853). The Cdyn at all time points in each group was also significantly increased, but there was no statistical difference among groups (F value was 0.009, 0.015, 0.206, 0.010, 0.389, and P value was 0.991, 0.985, 0.814, 0.990, 0.683). In the process of RM, the heart rate (HR) and mean arterial pressure (MAP) of the children were lowered compared with those before RM [ HR (bpm): 131.67 ± 9.56 vs. 138.93 ± 5.22 in SI group, 133.27 ± 9.54 vs. 140.33 ± 7.74 in IP group, 137.13 ± 7.39 vs. 142.40 ± 9.18 in PCV group, all P < 0.01; MAP (mmHg): 55.07 ± 4.43 vs. 65.87 ± 4.46 in SI group, 58.82 ± 6.04 vs. 64.02 ± 7.65 in IP group, 57.89 ± 4.71 vs. 65.36 ± 5.37 in PCV group, all P < 0.01], but it recovered immediately. CVP in all three groups was increased during RM [cmH₂O (1 cmH₂O = 0.098 kPa): 11.60 ± 0.99 vs. 5.53 ± 0.74 in SI group, 10.33 ± 1.35 vs. 5.40 ± 0.74 in IP group, 10.20 ± 0.94 vs. 5.80 0.68 in PCV group, all P < 0.01]. There was significant difference in CVP during RM among three groups (F = 7.327, P = 0.002), and CVP in SI group was higher than that of other two groups (both P < 0.05). CVP returned to the former level in 15 minutes after RM in IP and PCV groups, and recovered in 30 minutes in SI group.
Conclusions: All of the RM methods can effectively improve oxygenation and pulmonary compliance of the children with complication of ARDS, and they complement the inadequacy of lung protective ventilation. PCV and IP are more effective than SI in the uniform re-expansion of alveoli after RM and recovery of hemodynamics.