Determination of airway humidification in high-frequency oscillatory ventilation using an artificial neonatal lung model : Comparison of a heated humidifier and a heat and moisture exchanger

• Published in: Intensive care medicine 1999-09, Vol.25 (9), p.997-1002
• Main Authors: SCHIFFMANN, H, SINGER, S, SINGER, D, RICHTHOFEN, E. V, RATHGEBER, J, ZÜCHNER, K
• Format: Article
• Language: English
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Artificial Organs - statistics & numerical data; Biological and medical sciences; Compliance; Emergency and intensive respiratory care; Equipment Design - statistics & numerical data; Heat; High-Frequency Ventilation - instrumentation; High-Frequency Ventilation - methods; High-Frequency Ventilation - statistics & numerical data; Hot Temperature; Humans; Humidity; Infant, Newborn; Intensive care; Intensive care medicine; Lung; Measurement techniques; Medical sciences; Pediatrics; Pressure; Pressure transducers; Respiratory distress syndrome; Sensors; Temperature; Transducers, Pressure; Ventilators
• ISSN: 0342-4642; 1432-1238
• DOI: 10.1007/s001340050995

Thus far only few data are available on airway humidification during high-frequency oscillatory ventilation (HFOV). Therefore, we studied the performance and efficiency of a heated humidifier (HH) and a heat and moisture exchanger (HME) in HFOV using an artificial lung model. Experiments were performed with a pediatric high-frequency oscillatory ventilator. The artificial lung contained a sponge saturated with water to simulate evaporation and was placed in an incubator heated to 37 degrees C to prevent condensation. The airway humidity was measured using a capacitive humidity sensor. The water loss of the lung model was determined gravimetrically. The water loss of the lung model varied between 2.14 and 3.1 g/h during active humidification; it was 2.85 g/h with passive humidification and 7.56 g/h without humidification. The humidity at the tube connector varied between 34. 2 and 42.5 mg/l, depending on the temperature of the HH and the ventilator setting during active humidification, and between 37 and 39.9 mg/l with passive humidification. In general, HH and HME are suitable devices for airway humidification in HFOV. The performance of the ventilator was not significantly influenced by the mode of humidification. However, the adequacy of humidification and safety of the HME remains to be demonstrated in clinical practice.