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 cmH(2)O. VE was significantly greater with HME than with HH (14.8+/-4.8 vs 13.2+/-4.3 l/min; p<0.001). This increase in VE was the result of a greater RR for HME than for HH (26.5+/-10.6 vs 24.1+/-9.8 breaths/min; p=0.002), whereas the VT for HME was similar to that for HH (674+/-156 vs 643+/-148 ml; p=0.09). Arterial partial pressure of carbon dioxide (PaCO(2)) was significantly higher with a HME than with a HH (43.4+/-8.9 vs 40.8+/-8.2 mmHg; p<0.005), without significantly changing oxygenation. 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.
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 cmH(2)O. VE was significantly greater with HME than with HH (14.8+/-4.8 vs 13.2+/-4.3 l/min; p<0.001). This increase in VE was the result of a greater RR for HME than for HH (26.5+/-10.6 vs 24.1+/-9.8 breaths/min; p=0.002), whereas the VT for HME was similar to that for HH (674+/-156 vs 643+/-148 ml; p=0.09). Arterial partial pressure of carbon dioxide (PaCO(2)) was significantly higher with a HME than with a HH (43.4+/-8.9 vs 40.8+/-8.2 mmHg; p<0.005), without significantly changing oxygenation. 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.
Authors: Antonio M Esquinas Rodriguez; Raffaele Scala; Arie Soroksky; Ahmed BaHammam; Alan de Klerk; Arschang Valipour; Davide Chiumello; Claude Martin; Anne E Holland Journal: Crit Care Date: 2012-02-08 Impact factor: 9.097
Authors: Sean P Keenan; Tasnim Sinuff; Karen E A Burns; John Muscedere; Jim Kutsogiannis; Sangeeta Mehta; Deborah J Cook; Najib Ayas; Neill K J Adhikari; Lori Hand; Damon C Scales; Rose Pagnotta; Lynda Lazosky; Graeme Rocker; Sandra Dial; Kevin Laupland; Kevin Sanders; Peter Dodek Journal: CMAJ Date: 2011-02-14 Impact factor: 8.262