Air change rate (ACH) and purging flow rate (PFR) are adopted as evaluation indices of ventilation efficiency.
The indices of ventilation efficiency express quantitatively the ability to deliver fresh upper-tier wind to the lower tiers of void spaces and dilute pollutants emitted therein.
GS performed all computer simulations and calculations of the indices of ventilation inhomogeneity.
We collected ventilatory and EIT parameters and, by offline analysis, we calculated the increase of EELV at higher PEEP and the EIT-based indexes of ventilation heterogeneity (VtHetend-insp) and of the regional homogeneity of ventilation/perfusion matching (HA/P).
The other parameters of the lung function tests, including TV, respiratory rate, TPTEF, TE, and indices of ventilation inhomogeneity, were also comparable between both groups after adjustment (Table 2).
Functional residual capacity (FRC), tidal volume (TV), respiratory rate, time to peak tidal expiratory flow (TPTEF), total expiratory time (TE), and indices of ventilation inhomogeneity (lung clearance index, first and second moment ratios) were measured during normal tidal breathing using a tracer gas (4 % SF6) and the multiple-breath washout technique.
Our results showed that lung volume and indices of ventilation inhomogeneity in very preterm infants receiving conservative management for PDA were comparable to those of very preterm infants without PDA at discharge, although the infants with PDA had a higher percentage of BPD than those without PDA.
Regional ventilation distributions moved significantly towards dorsal regions during ATC100% ( EIT-based index center of ventilation, AC vs. ATC: 46.2 ± 5.8 vs. 51.7 ± 6.5, p < 0.001).
It has indeed been proposed that ΔPP (and other indices of ventilation-induced stroke volume variations) may not apply in patients breathing spontaneously [ 6, 7], but this has never been shown.
