Comparison of tidal volume and airway pressure during neonatal resuscitation in mask leaks

Abstract

Background: Providing positive-pressure ventilation (PPV) to the lungs is essential for neonatal resuscitation. Accurate PPV requires a precise measurement of tidal volume and airway pressure, with airway obstruction and mask leakage being the primary concerns for ineffective ventilation. This study aimed to investigate the differences between tidal volume and airway pressure measured by a respiratory function monitor (RFM) and the actual values delivered to the lungs in scenarios involving mask leaks, using a system comprising a PPV device, a face mask, and an artificial lung model.

Methods: Three experiments were conducted to assess mask leakage (1) under varying lung conditions, (2) under different ventilation rates, and (3) using different PPV devices. Two RFMs were used, one in the test lung and the other in the mask. Trends in those data were assessed by means of a correlation graph.

Results: Mask leakage resulted in an underestimation of the actual tidal volume, with the effect intensifying as the leak percentage increased. PPV devices using a compressed gas source demonstrated less reduction in lung tidal volume (from 15 to 12 mL) owing to mask leaks compared with those without such a source (from 16 to 5 mL).

Conclusions: Significant discrepancies were observed between RFM readings and test lung values for tidal volume. These findings highlight the importance of accurate monitoring to prevent lung injury caused by excessive tidal volume, particularly in the presence of mask leaks. Accurately measuring tidal volume in the presence of mask leaks presents a significant challenge for the future.

Keywords: infant newborn; positive‐pressure respiration; resuscitation.

FIGURE 1

(a) A schematic diagram of the experimental environment. RFM (shown on the right) monitors tidal volume and airway pressure at the test lung. RFM (shown on the left) monitors tidal volume and airway pressure at the mask. The automated machine replicates the PPV technique. Thin plate was placed between the mask and the block. (b) A picture of the experimental environment.

FIGURE 2

(a) Tidal volume and peak inspiratory pressure results at different mask leaks by lung condition. VTE delivered to the normal lung was 44 mL, whereas it was only 15 mL for the RDS lung when there was a 0%leak. The tidal volume measured at the mask and test lung began to diverge as the percentage of mask leakage increased. R means Pearson's correlation, and bold text indicates measured at test lungs, and thin text indicates measured at mask. (b) Tidal volume and peak inspiratory pressure results at different mask leaks by ventilation rate. As the mask leakage increased, both tidal volume and airway pressure decreased. This was particularly noticeable at higher ventilation rates and with more significant differences. R means Pearson's correlation, and bold text indicates measured at test lungs, and thin text indicates measured at mask. (c) Tidal volume and peak inspiratory pressure results at different mask leaks by PPV devices. T‐piece resuscitator did not reduce tidal volume as much as the SIB as mask leaks increased. The SIB showed a more significant decrease in airway pressure than the T‐piece resuscitator with increasing mask leaks. R means Pearson's correlation, and bold text indicates measured at test lungs, and thin text indicates measured at mask.

FIGURE 3

Volume, pressure, and flow waveforms for each PPV device with and without mask leaks. The flow waveform of the T‐piece resuscitator showed a positive offset at the baseline during mask leaks, resulting in a more significant error than SIB.