Adding air leakage at the expiratory port decreases CO2 rebreathing during helmet-based ventilatory support with single-circuit and conventional ICU mechanical ventilators.

Le résumé fourni par la source

Background: Helmet-based ventilatory support (HBVS) uses CPAP (H-CPAP) or mechanical ventilators (H-NIV). Carbon dioxide (CO₂) rebreathing is a concern, mainly with H-CPAP. We hypothesized that adding intentional leaks to the ELMO helmet’s expiratory port would enhance CO₂ washout and reduce rebreathing during H-CPAP and H-NIV with leak-compensating ventilators. Objectives: Assess the impact of intentional leakage on CO₂ rebreathing in four HBVS setups: 1) H-CPAP with flow-generator and PEEP valve, 2) H-CPAP with single-circuit portable ventilator, 3) H-NIV with single-circuit portable ventilator, and 4) H-NIV with double-circuit ICU ventilator. Methods: A randomized crossover study with 10 healthy volunteers. Leakage was titrated at the helmet’s expiratory port. CPAP: 10cmH₂O; H-NIV: 12cmH₂O pressure support and 10cmH₂O PEEP. Primary: inhaled CO₂ (PiCO₂); secondary: transcutaneous CO₂ (TcCO₂), respiratory patterns, intra-helmet pressures, and discomfort. Results: Max leak flows: 50.0, 58.9, 55.3L/min, and 84.3% for setups 1–4. After 20min, PiCO₂ dropped from 5.3 to 1.3mmHg (H-CPAP portable), 5.0 to 2.0mmHg (H-NIV portable), and 5.4 to 0.3mmHg (H-NIV ICU), while stable in H-CPAP with flow-generator. TcCO₂ stayed normal. H-NIV ICU had the lowest respiratory rate, longest expiratory time, and minimal CO₂ rebreathing. Intra-helmet pressure decreased in all setups. H-NIV portable had least discomfort. Conclusions: Intentional leakage reduced CO₂ rebreathing, improved breathing patterns, and slightly decreased intra-helmet pressure. H-NIV ICU minimized CO₂ rebreathing, while H-NIV portable offered greatest comfort.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.