Caroline M Mann1, Paul A Baker1, David M Sainsbury1, Richard Taylor2. 1. Department of Paediatric Anaesthesia, Starship Children's Hospital, Auckland, New Zealand. 2. Department of Otorhinolaryngology and Cardiac Anaesthesia, Auckland City Hospital, Auckland, New Zealand.
Abstract
BACKGROUND: Pediatric emergency front of neck airway guidelines recommend oxygenation via cannula cricothyroidotomy or tracheotomy. AIM: The primary aim was to measure test lung pressures and volumes generated by cannula insufflation devices recommended for emergency front of neck airway compared with a pressure limit of 50 cm H2 O and volume limit of 20 ml/kg. The secondary aim was to calculate pressure and volume variability. The primary end point was test lung expansion. METHOD: Adult, child, and infant airway models, each with three degrees of upper airway obstruction, were oxygenated using six cannula insufflation devices: 3-way stopcock, Rapid-O2 , Manujet, Enk oxygen flow modulator, Ventrain, and self-inflating bags. Test lung pressures and volumes were recorded. RESULTS: Pressures and volumes from all devices were highly variable, despite oxygen flow calibration and strict adherence to oxygen insufflation protocols. With upper airway occlusion, pressures >50 cm H2 0 were produced by Rapid-O2 and Enk oxygen flow meter in adult and infant lungs, 3-way stopcock in adult and child lungs, and Manujet in all lung sizes. Ventrain produced acceptable pressures <35 cm H2 O in all models. Test lung volumes >20 ml/kg were recorded in airway models with fully obstructed proximal airways using Rapid-O2 and Enk oxygen flow meter in infant lungs, and Manujet in all lung sizes. Rapid-O2 produced lung volumes >20 ml/kg in the infant model with partially obstructed and open upper airways. Test lung volumes >20 ml/kg were produced by the 3-way stopcock in adult, child, and infant models. Insufflation was unsuccessful with the self-inflating bag. Ventrain produced acceptable volumes <7 ml/kg in all airway models. CONCLUSION: Rapid-O2 , Enkoxygen flow meter, Manujet, and 3-way stopcock oxygenation devices produced highly variable and excessive airway pressures and volumes in models with obstructed upper airways. Self-inflating bag insufflation was unsuccessful. Ventrain was the only device that insufflated oxygen with acceptable pressures and volumes in adult, child, and infant airway models with any degree of airway obstruction.
BACKGROUND: Pediatric emergency front of neck airway guidelines recommend oxygenation via cannula cricothyroidotomy or tracheotomy. AIM: The primary aim was to measure test lung pressures and volumes generated by cannula insufflation devices recommended for emergency front of neck airway compared with a pressure limit of 50 cm H2 O and volume limit of 20 ml/kg. The secondary aim was to calculate pressure and volume variability. The primary end point was test lung expansion. METHOD: Adult, child, and infant airway models, each with three degrees of upper airway obstruction, were oxygenated using six cannula insufflation devices: 3-way stopcock, Rapid-O2 , Manujet, Enk oxygen flow modulator, Ventrain, and self-inflating bags. Test lung pressures and volumes were recorded. RESULTS:Pressures and volumes from all devices were highly variable, despite oxygen flow calibration and strict adherence to oxygen insufflation protocols. With upper airway occlusion, pressures >50 cm H2 0 were produced by Rapid-O2 and Enk oxygen flow meter in adult and infant lungs, 3-way stopcock in adult and child lungs, and Manujet in all lung sizes. Ventrain produced acceptable pressures <35 cm H2 O in all models. Test lung volumes >20 ml/kg were recorded in airway models with fully obstructed proximal airways using Rapid-O2 and Enk oxygen flow meter in infant lungs, and Manujet in all lung sizes. Rapid-O2 produced lung volumes >20 ml/kg in the infant model with partially obstructed and open upper airways. Test lung volumes >20 ml/kg were produced by the 3-way stopcock in adult, child, and infant models. Insufflation was unsuccessful with the self-inflating bag. Ventrain produced acceptable volumes <7 ml/kg in all airway models. CONCLUSION: Rapid-O2 , Enkoxygen flow meter, Manujet, and 3-way stopcock oxygenation devices produced highly variable and excessive airway pressures and volumes in models with obstructed upper airways. Self-inflating bag insufflation was unsuccessful. Ventrain was the only device that insufflated oxygen with acceptable pressures and volumes in adult, child, and infant airway models with any degree of airway obstruction.
Authors: J Adam Law; Laura V Duggan; Mathieu Asselin; Paul Baker; Edward Crosby; Andrew Downey; Orlando R Hung; Philip M Jones; François Lemay; Rudiger Noppens; Matteo Parotto; Roanne Preston; Nick Sowers; Kathryn Sparrow; Timothy P Turkstra; David T Wong; George Kovacs Journal: Can J Anaesth Date: 2021-06-18 Impact factor: 5.063