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The pressure drop across the endotracheal tube in mechanically ventilated pediatric patients
Author(s) -
Spaeth Johannes,
Steinmann Daniel,
Kaltofen Heike,
Guttmann Josef,
Schumann Stefan
Publication year - 2015
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.12595
Subject(s) - medicine , endotracheal tube , mechanical ventilation , ventilation (architecture) , airway , anesthesia , peak inspiratory pressure , tracheostomy tube , intubation , tidal volume , respiratory system , mechanical engineering , engineering
Summary Background During mechanical ventilation, the airway pressure (P aw ) is usually monitored. However, P aw comprises the endotracheal tube ( ETT )‐related pressure drop (∆ P ETT ) and thus does not reflect the pressure in the patients’ lungs. Therefore, monitoring of mechanical ventilation should be based on the tracheal pressure (P trach ). We systematically investigated potential factors influencing ∆ P ETT in pediatric ETT s. Methods In this study, the flow‐dependent pressure drop across pediatric ETT s from four manufacturers [2.0–4.5 mm inner diameter ( ID )] was estimated in a physical model of the upper airways. Additionally, ∆ P ETT was examined with the ETT s shortened to 75% of their original length and at different curvatures. In nine healthy mechanically ventilated children (aged between 9 days and 29 months), P trach was compared to P aw . Results ∆ P ETT was nonlinearly flow dependent. Low ID s corresponded to high ∆ P ETT . Differences between ETT s from different manufacturers were identified. Shortening of the ETT s’ length by 25% reduced ∆ P ETT on average by 14% of the value at original length. Ventilation frequency and tube curvature did not influence ∆ P ETT to a relevant extent. In the pediatric patients, the root mean square deviation between P aw and P trach was 2.3 cm H 2 O. Conclusion P aw and P trach differ considerably (by ∆ P ETT ) during mechanical ventilation of pediatric patients. The ETT s’ ID , tube length, and manufacturer type are significant factors for ∆ P ETT and should be taken into account when P aw is valuated. For this purpose, P trach can be continuously calculated with good precision by means of the Rohrer approximation.