Background In the context of acute respiratory distress syndrome (ARDS), the response to lung recruitment maneuvers (LRMs) varies considerably from one patient to another and so is difficult to predict. The aim of the study was to determine whether or not the recruitment-to-inflation (R/I) ratio could differentiate between patients according to the change in lung mechanics during the LRM. Methods We evaluated the changes in gas exchange and respiratory mechanics induced by a stepwise LRM at a constant driving pressure of 15 cmH 2 O during pressure-controlled ventilation. We assessed lung recruitability by measuring the R/I ratio. Patients were dichotomized with regard to the median R/I ratio. Results We included 30 patients with moderate-to-severe ARDS and a median [interquartile range] R/I ratio of 0.62 [0.42–0.83]. After the LRM, patients with high recruitability (R/I ratio ≥ 0.62) presented an improvement in the P a O 2 /F i O 2 ratio, due to significant increase in respiratory system compliance (33 [27–42] vs. 42 [35–60] mL/cmH 2 O; p < 0.001). In low recruitability patients (R/I < 0.62), the increase in P a O 2 /F i O 2 ratio was associated with a significant decrease in pulse pressure as a surrogate of cardiac output (70 [55–85] vs. 50 [51–67] mmHg; p = 0.01) but not with a significant change in respiratory system compliance (33 [24–47] vs. 35 [25–47] mL/cmH 2 O; p = 0.74). Conclusion After the LRM, patients with high recruitability presented a significant increase in respiratory system compliance (indicating a gain in ventilated area), while those with low recruitability presented a decrease in pulse pressure suggesting a drop in cardiac output and therefore in intrapulmonary shunt. Supplementary Information The online version contains supplementary material available at 10.1186/s13054-021-03876-z.
【저자키워드】 acute respiratory distress syndrome, mechanical ventilation, Respiratory mechanics, Recruitability, Recruitment maneuver, 【초록키워드】 ARDS, Ventilation, Gas exchange, Patient, Compliance, Respiratory system, predict, acute respiratory distress, Shunt, Lung recruitability, Ventilated, supplementary material, lung recruitment, significant increase, syndrome, significant decrease, pulse, driving, decrease, lung mechanics, Result, evaluated, median, determine, changes in, increase in, dichotomized, intrapulmonary, the median, 【제목키워드】 Patient, respiratory, acute respiratory distress, lung recruitment, syndrome, Effect,