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

Background: Adequate humidification in long-term jet ventilation is a critical aspect in terms of clinical safety.

      Aim:
      To assess a prototype of an electronic jet-ventilator and its
			humidification system.
    
    
      Methods:
      Forty patients with respiratory insufficiency were randomly
			allocated to one of four groups. The criterion for inclusion in this study was
			respiratory insufficiency exhibiting a Murray score above 2. The four groups of
			patients were ventilated with three different respirators and four different
			humidification systems. Patients in groups A and B received superimposed
			high-frequency jet ventilation (SHFJV) by an electronic jet-ventilator either
			with (group A) or without (group B) an additional humidification system.
			Patients in group C received high-frequency percussive ventilation (HFPV) by a
			pneumatic high-frequency respirator, using a hot water humidifier for warming
			and moistening the inspiration gas. Patients in group D received conventional
			mechanical ventilation using a standard intensive care unit respirator with a
			standard humidification system. SHFJV and HFPV were used for a period of 100 h
			(4days).
    
    
      Results:
      A significantly low inspiration gas temperature was noted in
			patients in group B, initially (27.2 ± 2.5°C) and after 2 days
			(28.0 ± 1.6°C) (P < 0.05). The percentage of relative
			humidity of the inspiration gas in patients in group B was also initially
			significantly low (69.8 ± 4.1%; P < 0.05) but rose to an average
			of 98 ± 2.8% after 2 h. The average percentage across all four groups
			amounted to 98 ± 0.4% after 2 h. Inflammation of the tracheal mucosa was
			found in patients in group B and the mucosal injury score (MIS) was
			significantly higher than in all the other groups. Patients in groups A, C and
			D showed no severe evidence of airway damage, exhibiting adequate values of
			relative humidity and temperature of the inspired gas.
    
    
      Conclusion:
      The problems of humidification associated with jet ventilation can
			be fully prevented by using this new jet-ventilator. These data were sustained
			by nondeteriorating MIS values at the end of the 4-day study period in groups
			A, C and D.