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An in vitro evaluation of the influence of neonatal endotracheal tube diameter and length on the work of breathing
Author(s) -
Miyake Fuyu,
Suga Rika,
Akiyama Takahiro,
Namba Fumihiko
Publication year - 2018
Publication title -
pediatric anesthesia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.704
H-Index - 82
eISSN - 1460-9592
pISSN - 1155-5645
DOI - 10.1111/pan.13366
Subject(s) - medicine , endotracheal tube , breathing , work of breathing , tube (container) , anesthesia , intubation , mechanical ventilation , composite material , materials science
Summary Background Neonates, particularly premature babies, are often managed with endotracheal intubation and subsequent mechanical ventilation to maintain adequate pulmonary gas exchange. There is no consensus on the standard length of endotracheal tube. Although a short tube reduces resistance and respiratory dead space, it is believed to increase the risk of accidental extubation. There are not entirely coherent data regarding the effect of endotracheal tube length on work of breathing in infants. Aim The aim of this study was to evaluate the impact of neonatal endotracheal tube diameter and length on the work of breathing using an infant in vitro lung model. Method We assessed the work of breathing index and mechanical ventilation settings with various endotracheal tube diameters and lengths using the JTR100 in vitro infant lung model. The basic parameters of the model were breathing frequency of 20 per minutes, inspiratory—expiratory ratio of 1:3, and positive end‐expiratory pressure of 5 cmH 2 O. In addition, the diaphragm driving pressure to maintain the set tidal volume was measured as the work of breathing index. The JTR 100 was connected to the Babylog 8000plus through the endotracheal tube. Finally, we monitored the peak inspiratory pressure generated during assist‐control volume guarantee mode with a targeted tidal volume of 10‐30 mL. Results The diaphragm driving pressure using a 2.0‐mm inner diameter tube was twice as high as that using a 4.0‐mm inner diameter tube. To maintain the targeted tidal volume, a shorter tube reduced both the diaphragm driving pressure and ventilator‐generated peak inspiratory pressure. The difference in the generated peak inspiratory pressure between the shortest and longest tubes was 5 cmH 2 O. Conclusion In our infant lung model, a shorter tube resulted in a lower work of breathing and lower ventilator‐generated peak inspiratory pressure.