RIGHT LUNG VENTILATION IN A PORCINE OPEN-CHEST SHOCK MODEL

Objective: To determine the effect of selective right lung ventilation on gas exchange and hemodynamics when compared with bilateral lung ve ntilation in a porcine open-chest shock model. Methods: A randomized, controlled laboratory investigation was performed using a static hemor rhagic shock model in 12 adult swine undergoing thoracotomy. The anima ls were subjected to a fixed 40% circulating blood volume hemorrhage o ver 20 minutes. Each animal was then assigned to either a tracheal (co ntrol) or a right mainstem (experimental) intubation group. Minute ven tilation was held constant in both groups and tidal volumes were decre ased by 33% in the right mainstem intubation group. Following intubati on and left lateral thoracotomy, another 20% fixed-volume hemorrhage w as instituted simultaneously with IV crystalloid and whole blood resus citation for both groups over 30 minutes. Heart rate, blood pressure, and arterial blood gases were measured at 5-minute intervals. Results: There was no significant difference between the control and experimen tal groups for any of the measured variables, including mean arterial pressure, pH, partial arterial pressure of CO2 (Paco(2)), and Pao(2), over time. All animals survived the study protocol. Conclusion: Select ive right lung ventilation has no detrimental effect on gas exchange o r hemodynamics when compared with standard bilateral lung ventilation in a porcine open-chest shock model.