Original

Intensive Care Medicine

, Volume 24, Issue 2, pp 138-146

First online:

A novel method of evaluation of three heat-moisture exchangers in six different ventilator settings

  • N. ÜnalAffiliated withSurgical Intensive Care Unit, University Hospital RotterdamDepartment of Anesthesiology and Reanimation, Medical Faculty, University of Ankara
  • , J. K. K. KanhaiAffiliated withSurgical Intensive Care Unit, University Hospital Rotterdam
  • , S. L. C. E. BuijkAffiliated withSurgical Intensive Care Unit, University Hospital Rotterdam
  • , J. C. PompeAffiliated withSurgical Intensive Care Unit, University Hospital Rotterdam
  • , W. P. J. HollandAffiliated withSurgical Intensive Care Unit, University Hospital Rotterdam
  • , I. GültinaAffiliated withDepartment of Anesthesiology, University Hospital Rotterdam
  • , C. InceAffiliated withDepartment of Anesthesiology, Academic Medical Centre, University of Amsterdam
  • , B. SayginAffiliated withDepartment of Anesthesiology and Reanimation, Medical Faculty, University of Ankara
  • , H. A. BruiningAffiliated withSurgical Intensive Care Unit, University Hospital Rotterdam Email author 

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Abstract

Objective: The purpose of this study was to assess and compare the humidification, heating, and resistance properties of three commercially available heat-moisture exchangers (HMEs). To mimic clinical conditions, a previously validated, new, realistic experimental setup and measurement protocol was used.

Design: Prospective, comparative experimental study.

Setting: Surgical Intensive Care Unit, University Hospital of Rotterdam.

Materials: An experimental set-up consisting of a patient model, measurement systems, and ventilator and three different HME types.

Interventions: The air flow, pressure in the ventilation circuit, pressure difference over the HME, and partial water vapour pressure and temperature at each side of the HMEs were measured. Measurements were repeated every 30 min during the first 2 h and every hour up to 24 h for each HME at six different ventilator settings. The mean inspiratory and maximum expiratory resistance, flow-weighted mean absolute humidity and temperature outputs, and humidification and heating efficiencies of HMEs were calculated.

Measurements and results: The Dar Hygroster had the highest humidity output, temperature output, humidification efficiency, and heating efficiency values throughout the study (32.8 ± 21. mg/l, 32.2 ± 0.8 °C, 86.3 ± 2.3 %, and 0.9 ± 0.01 %, respectively) in comparison to the Humid-Vent Filter (25.3 ± 3.2 mg/l, 31.9 ± 0.8 °C, 72.2 ± 5.3%, 0.9 ± 0.02 %, respectively) and the Pall Ultipor BB100 breathing circuit filter (23.4 ± 3 mg/l, 28.3 ± 0.7 °C, 68.8 ± 5.9 %, 0.8 ± 0.02 %, respectively). The inspiratory and expiratory resistance of the HMEs remained below clinically acceptable maximum values (2.60 ± 0.04 and 2.45 ± 0.05 cmH2O/l per s, respectively). Conclusion: The Dar Hygroster filter was found to have the highest humidity and temperature output of all three HMEs, the Humid-Vent filter had a satisfactory humidity output only at low tidal volume flow rate and minute volume settings, whereas the Pall Ultipore BB100 never achieved a sufficient humidity and temperature output.

Key words

Humidity Heat and moisture exchangers Mechanical ventilation Temperature Resistance