Background: Weaning from mechanical ventilation is associated with the presence of asynchronies between the\npatient and the ventilator. The main objective of the present study was to demonstrate a decrease in the total\nnumber of patient-ventilator asynchronies in invasively ventilated patients for whom difficulty in weaning is\nexpected by comparing neurally adjusted ventilatory assist (NAVA) and pressure support ventilation (PSV) ventilatory\nmodes.\nMethods: We performed a prospective, non-randomized, non-interventional, single-center study. Thirty patients\nwere included in the study. Each patient included in the study benefited in an unpredictable way from both modes\nof ventilation, NAVA or PSV. Patients were successively ventilated for 23 h in NAVA or in PSV, and then they were\nventilated for another 23 h in the other mode. Demographic, biological and ventilatory data were collected during\nthis period. The two modes of ventilatory support were compared using the non-parametric Wilcoxon test after checking\nfor normal distribution by the Kolmogorovââ?¬â??Smirnov test. The groups were compared using the chi-square test.\nResults: The median level of support was 12.5 cmH2O (4ââ?¬â??20 cmH2O) in PSV and 0.8 cmH2O/Ã?¼volts (0.2ââ?¬â??3 cmH2O/Ã?¼volts)\nin NAVA. The total number of asynchronies per minute in NAVA was lower than that in PSV (0.46 vs 1,\np < 0.001). The asynchrony index was also reduced in NAVA compared with PSV (1.73 vs 3.36, p < 0.001). In\nNAVA, the percentage of ineffective efforts (0.77 vs 0.94, p = 0.036) and the percentage of auto-triggering\nwere lower compared with PSV (0.19 vs 0.71, p = 0.038). However, there was a higher percentage of double\ntriggering in NAVA compared with PSV (0.76 vs 0.71, p = 0.046).\nConclusion: The total number of asynchronies in NAVA is lower than that in PSV. This finding reflects\nimproved patient-ventilator interaction in NAVA compared with the PSV mode, which is consistent with\nprevious studies. Our study is the first to analyze patient-ventilator asynchronies in NAVA and PSV on such\nan important duration. The decrease in the number of asynchronies in NAVA is due to reduced ineffective\nefforts and auto-triggering.
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