Respiratory metrics of neonatal positive pressure ventilation on different ventilatory rates: A simulation study

Effective ventilation is the core of neonatal resuscitation (NR). T-piece resuscitators (TPR) and self-inflating bags (SIB) are the two most widely utilized resuscitation devices. Nevertheless, limited information is available regarding the respiratory metrics during NR with these devices.

This study aimed to evaluate the respiratory metrics at different ventilatory rates (VR) using a TPR or SIB during NR training.

An observational, simulation study was conducted during a NR training course. The participants were instructed to perform positive pressure ventilation at predetermined pressures and varying rates using TPR and SIB. They were subsequently grouped into three categories based on their actual VR: 20-40 breaths per minute (bpm) (SlowVR), 40-60 bpm (StdVR), and 60-80 bpm (FastVR). Respiratory metrics were recorded and analyzed using a neonatal active lung model (NALM).

Of the 71 participants in the training course, data from 66 were validated by analyzing 198 ventilations. In general, the participants manipulated the TPR slightly slower than the SIB. Notably, the positive end-expiratory pressure (PEEP) detected via TPR in the NALM was substantially higher, whereas the tidal volume (Tv) and minute volume (MV) with TPR were significantly smaller than those with SIB (p < 0.05). A significant decrease in the peak alveolar pressure (palva) was observed with faster TPR ventilation (p < 0.001), whereas no such reduction was observed with SIB (p = 0.103). Additionally, faster VR correlated positively with higher PEEP levels for both TPR (F = 7.543, p = 0.002) and SIB (F = 7.720, p = 0.002) and inversely with smaller Tv for both TPR (F = 19.239, p < 0.001) and SIB (F = 14.937, p < 0.001). However, no significant differences in MV were observed across the different VR for either TPR or SIB (both p > 0.05).

Faster VR were inversely associated with smaller Tv but increased PEEP in both devices. Despite the guidelines of NR, VR exceeding 60 bpm with TPR might sometimes be used, was associated with excessive PEEP in TPR, which may not be a safe in clinical practice. The effect of varying VR on MV was relatively minor for both TPR and SIB.