The Ventilatory Effect of Intratracheal Pulmonary Ventilation in Rabbits with Acute Respiratory Failure

Lee, Kook Hyun; Cho, Byoung Woo; Lee, Sang Chul

Abstract

BACKGROUND
New methods of ventilation are devised to minimize airway pressure increase because high pressure ventilation might result in barotrauma and hemodynamic compromise. Intratracheal pulmonary ventilation(ITPV) was developed to allow a decrease in physiological dead space during mechanical ventilation. ITPV can be applied broadly when it combined with pressure controlled ventilation(PCV) to make a hybrid ventilation(HV). We intended to compare the respiratory effect of HV with volume controlled ventilation(VCV) and PCV.
METHODS
Oleic acid of 0.06 ml/kg was injected to induce acute respiratory failure in rabbits. To reduce anatomic dead space, a reverse thrust catheter(RTC) was introduced into an endotracheal tube(ETT) through an adapter and positioned just above the carina inside the ETT. VCV and PCV were compared with HV by measuring peak inspiratory pressure(PIP) and dead space(VD) at various respiratory rates(RR) from 20 breaths/min to 120 breaths/min. Gas flowed through the RTC at the flow rate of 1 liter/min during HV.
RESULTS
The values of VD of VCV were 37+/-10 ml, 29+/-11 ml, 23+/-5 ml, and 18+/-3 ml at respiratory rate of 20 breaths/min, 40 breaths/min, 80 breaths/min and 120 breaths/min, respectively. The values of VD of PCV were 33+/-6 ml, 28+/-7 ml, 23+/-5 ml, and 18+/-3 ml, respectively. The values of VD of HV were 25+/-13 ml, 15+/-8 ml, 9+/-5 ml, and 8+/-4 ml, respectively. The VD of HV were significantly lower than those of VCV and PCV at the same RR. The PIP was lower in HV than in VCV and PCV at the same RR.
CONCLUSION
It can be concluded that HV, as a modification of ITPV, can be applied to acute respiratory failure in rabbits to minimize airway pressures and dead space of mechanical ventilation.