Comparison of the effects of heat and moisture exchangers and heated humidifiers on ventilation and gas exchange during non-invasive ventilation

Byline: Samir Jaber (1), Gerald Chanques (1), Stefan Matecki (2), Michele Ramonatxo (2), Bruno Souche (1), Pierre-Francois Perrigault (1), Jean-Jacques Eledjam (1) Keywords: Heat and moisture exchanger Heated humidifier Non-invasive ventilation Abstract: Abstract Objective. To compare the short-term effects of a heat and moisture exchanger (HME) and a heated humidifier (HH) during non-invasive ventilation (NIV). Design. Prospective, clinical investigation. Setting. Intensive care unit of a university hospital. Patients. Twenty-four patients with acute respiratory failure (ARF). Intervention. Each patient was studied with a HME and a HH in a random order during two consecutive 20min periods of NIV. Measurements and results. Respiratory rate (RR), expiratory tidal volume (VTe) and expiratory minute ventilation (VE) were measured during the last 5 min of each period and blood gases were measured. Mean pressure support and positive end-expiratory pressure levels were, respectively, 15+-4 and 6+-2 cm[H.sub.2]O. VE was significantly greater with HME than with HH (14.8+-4.8 vs 13.2+-4.3 l/min p Conclusion. During NIV the increased dead space of a HME can negatively affect ventilatory function and gas exchange. The effect of HME dead space may decrease efficiency of NIV in patients with ARF. Author Affiliation: (1) Unite de Reanimation et de Transplantation-Departement d'Anesthesie-Reanimation 'B', CHU de Montpellier Hopital Saint Eloi, 80 avenue Augustin Fliche, 34295 Montpellier Cedex, France (2) Service central de Physiologie Clinique, CHU de Montpellier Hopital Arnaud de Villeneuve, 371 avenue du Doyen Gaston Giraud, 34295 Montpellier cedex 5, France Article History: Received Date: 28/11/2001 Accepted Date: 16/07/2002 Article note: Electronic Publication