Abstract
BACKGROUND: The Oxylator is an automatic resuscitator, powered only by an oxygen cylinder, with no electricity required, that could be used in acute respiratory failure in situations where standard mechanical ventilation is not available or feasible. We aimed to assess the feasibility and safety of mechanical ventilation using this automatic resuscitator in an animal model of Acute Respiratory Distress Syndrome (ARDS).
METHODS: Randomized experimental study in a porcine ARDS model with twelve pigs randomized to Oxylator or Control group (6 per group) and ventilated for 4 hours. with the Oxylator, peak pressure set at 20 cmH2O in all pigs, and Positive End-Expiratory Pressure (PEEP) set at the lowest observed respiratory rate during a decremental PEEP titration. Control pigs were ventilated with a conventional ventilator, using protective settings and PEEP at the crossing point of collapse and overdistension, as indicated by electrical impedance tomography. Our endpoints were feasibility and safety, as well as respiratory mechanics, gas exchange and hemodynamics.
RESULTS: After lung injury, mean respiratory system compliance and PaO2/FiO2 were 13±2 mL/cmH2O and 61±17 mmHg. Mean total PEEP was 10±2 cmH2O and 13±2 in the Control and Oxylator groups respectively (p=0.05). The mean plateau pressure was kept below 30 cmH2O in both groups. In the Oxylator group, tidal volume was transiently higher than 8 mL/kg but was 6±0.4 mL/kg at 4 hours, while respiratory rate increased from 38±4 to 48±3 breaths per minute (p<0.01). There was no difference in driving pressure, compliance, PaO2/FiO2, and pulmonary shunt between groups. PaCO2 was higher in the Oxylator group after 4 hours, 74±9 mmHg versus 58±6 mmHg (p<0.01). There were no differences in hemodynamics between groups, including blood pressure and cardiac output.
CONCLUSIONS: Short-term mechanical ventilation using an automatic resuscitator (Oxylator) and a fixed pressure setting in an ARDS animal model is feasible and safe.
- artificial respiration
- mechanical ventilators
- respiratory insufficiency ventilator-induced lung injury
- respiratory distress syndrome
- rescue ventilation
Footnotes
- Correspondence
: laurent.brochard{at}unityhealth.to
- Received June 28, 2022.
- Accepted November 3, 2022.
- Copyright © 2022 by Daedalus Enterprises
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