A new prototype of an electronic jet-ventilator and its humidification system

摘要

Background:Adequate humidification in long-term jet ventilation is a criticalaspect in terms of clinical safety.Aim:To assess a prototype of an electronic jet-ventilator and itshumidification system.Methods:Forty patients with respiratory insufficiency were randomlyallocated to one of four groups. The criterion for inclusion in this study wasrespiratory insufficiency exhibiting a Murray score above 2. The four groups ofpatients were ventilated with three different respirators and four differenthumidification systems. Patients in groups A and B received superimposedhigh-frequency jet ventilation (SHFJV) by an electronic jet-ventilator eitherwith (group A) or without (group B) an additional humidification system.Patients in group C received high-frequency percussive ventilation (HFPV) by apneumatic high-frequency respirator, using a hot water humidifier for warmingand moistening the inspiration gas. Patients in group D received conventionalmechanical ventilation using a standard intensive care unit respirator with astandard humidification system. SHFJV and HFPV were used for a period of 100 h(4days).Results:A significantly low inspiration gas temperature was noted inpatients in group B, initially (27.2 ± 2.5°C) and after 2 days(28.0 ± 1.6°C) (P < 0.05). The percentage of relativehumidity of the inspiration gas in patients in group B was also initiallysignificantly low (69.8 ± 4.1%; P < 0.05) but rose to an averageof 98 ± 2.8% after 2 h. The average percentage across all four groupsamounted to 98 ± 0.4% after 2 h. Inflammation of the tracheal mucosa wasfound in patients in group B and the mucosal injury score (MIS) wassignificantly higher than in all the other groups. Patients in groups A, C andD showed no severe evidence of airway damage, exhibiting adequate values ofrelative humidity and temperature of the inspired gas.Conclusion:The problems of humidification associated with jet ventilation canbe fully prevented by using this new jet-ventilator. These data were sustainedby nondeteriorating MIS values at the end of the 4-day study period in groupsA, C and D.