The Science Journal of the American Association for Respiratory Care

2007 OPEN FORUM Abstracts

VOLUME VARIANCES AT SET PRESSURES BETWEEN THE BEAR 150 JET VENTILATOR AND THE ACUTRONIC MISTRAL VENTILATOR

J. S. Wood1, J. D. Davies1, M. A. Gentile1, M. M. Wahidi1


Background: Our operating room utilizes two different models of jet ventilators during rigid bronchoscopy; the Bear 150 and the Acutronic Mistral. We noted a marked difference in ventilation of patients at similar set inspiratory pressures (IP) and respiratory rates (RR) as evidenced by serial arterial blood gas results. This prompted us to perform a bench study to examine the degree of variation in delivered tidal volumes between the two ventilators at set IP’s, RR’s, and I times (Ti).

Methods: We performed a bench evaluation using a double chambered test lung (TTL; Michigan Instruments, Grand Rapids, MI) and respiratory profile monitor (NICO, Respironics, Wallingford, CT). The Acutronic Mistral jet ventilator (Susquehanna Micro, Red Lion, PA) and Bear 150 jet ventilator (Viasys Healthcare, Palm Springs, CA) were connected to the test lung using different size endotracheal tubes sizes (9.0, 7.5, and 6.0 mm) designed to mimic the tracheobronchial tree. Tidal volume data were collected from each ventilator at settings of RR 60 and 120 bpm, IP of 20, 25, and 30 psi, and Ti of 25%, 35%, and 50%.

Results: All results represent tidal volumes

Conclusions: We conclude that there is a volume variance between the two ventilators at set pressures. Clinicians need to be aware of these variances due to the effect on overall patient minute ventilation.

 RR 60, Ti 25%   RR 120 Ti 25%   
 IP 20 IP 25 IP30 IP20 IP 25 IP 30
Bear 150 180 225 250 106 128 143
Mistral 155 200 240 90 110 130
 RR 60, Ti 35%   RR120, Ti 35%   
 IP 20 IP 25 IP 30 IP 20 IP 25 IP 30
Bear 150 240 284 320 132 148 162
Mistral 180 250 286 114 130 150
 RR 60, Ti 50%   RR 120, Ti 50%   
 IP 20 IP 25 IP 30 IP 20 IP 25 IP 30
Bear 150 280 320 360 140 160 174
Mistral 323 276 320 120 140 165



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