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Jody Lester


Background: Recent developments in non-invasive positive pressure ventilation have led to the production of adaptive servo-ventilation devices that examine an individual’s breathing characteristics and adjust pressure levels via a product specific algorithm. We evaluated two adaptive servo-ventilation devices, the Respironics BiPAP® auto SV™ and ResMed VPAP™ Adapt SV to lung simulator generated central and obstructive sleep apneic episodes.

Methods: Each system was adjusted to the following settings: EPAP minimum 4 cmH2O, IPAP maximum 15 cmH2O, adaptive modes, 15 breaths per minute. Each system was tested using its own brand of ventilation circuit and face mask (Respironics Comfort Gel ™Full and Mirage Quattro). The masks were fitted to a Laerdal SimMan® version 2 mannequin and demonstrated minimal leak levels. The SimMan® was connected to a Hans Rudolph Electronic Breathing Simulator (HR 1101) which generated 15 normal breaths followed by central and obstructive apenic episodes. The lung simulator scripts were constructed with the following parameters: compliance 40 cmH2O, amplitude 20 cmH2O, resistance ramped from 5 to 200 L/sec during obstructive apnea simulation and compliance 40, amplitude 0 and resistance of 50 during central apnea simulation.

Results: During simulated obstructive apnea the VPAP™ Adapt SV delivered an average pressure of 7.53 cmH2O and an average Vt of 299.7 ml. Max/Min pressures were 11.148 cmH2O and 5.104 cmH2O. The BiPAP® auto SV™ delivered an average pressure of 6.41 cmH2O with an average delivered Vt of 257.2 ml. Max/min pressures were 11.8 cmH2O and 3.18 cmH2O. During simulated central apnea the VPAP™ Adapt SV delivered an average pressure of 8.95 cmH2O and an average Vt of 354.4 ml. Max/min pressures were 14.5 cmH2O and 5.08 cmH2O . The BiPAP® auto SV™ delivered an average pressure of 7.04 cmH2O and average Vt of 280.06 ml. Max/Min pressures were 11.81 cmH2O and 3.22 cmH2O.

Conclusion: Each system responded adequately to both types of apnea however, some differences were recognized. The VPAP™ Adapt SV has more clinician definable parameters and our observations were that it performed better in tests simulating central apenic episodes. We observed that the BiPAP® auto SV™ performed better during obstructive apenic episodes. Initially the BiPAP® auto SV™ demonstrated a long rise time and delivered smaller volumes when respiratory rate was set on “auto”; using a set rate of 15 alleviated this discrepancy.


This research was also published in the December 2009 issue of the Respiratory Care Journal.