Submitted on October 16, 2003
Accepted on December 10, 2003
Continuous tracheal gas insufflation during partial liquid ventilation in juvenile rabbits with acute lung injury
Guangfa Zhu1*, Thomas H Shaffer2, and Marla R Wolfson3
1 Department of Respiratory Medicine, Shanghai First Peoples Hospital, Shanghai, China; Department of Physiology, Temple University School of Medicine, Philadelphia, PA, USA
2 Department of Physiology, Temple University School of Medicine, Philadelphia, PA, USA; Nemours Research Lung Center, AI duPont Hospital, Wilmington, DE, USA
3 Department of Physiology, Temple University School of Medicine, Philadelphia, PA, USA
* To whom correspondence should be addressed. E-mail: gzhu{at}temple.edu.
To examine the hypothesis that combined treatment with tracheal gas insufflation (TGI) and partial liquid ventilation (PLV) may improve pulmonary outcome relative to either treatment alone in acute lung injury (ALI), saline lavage lung injury was induced in 24 anesthetized, ventilated juvenile rabbits that were then randomly assigned to receive (n = 6/group): (1) conventional mechanical ventilated alone (CMV), (2) continuous TGI at 0.5 L/min (TGI), (3) PLV with perfluorochemical liquid (PLV), (4) combined TGI and PLV (TGI+PLV), and subsequently ventilated with minimized pressures and tidal volume (VT) to keep PaO2 >100 mmHg and PaCO2 45-60 mmHg for 4 hrs. Gas exchange, lung mechanics, MPO, IL-8, and histomorphometry (including expansion index: EI) were assessed. The CMV group showed no improvement in lung mechanics and gas exchange; all treated groups had significant increases in compliance, PaO2, ventilation efficacy index (VEI) and EI, and decreases in PaCO2, oxygenation index (OI), physiological dead space to VT ratio (VD/VT), MPO and IL-8, relative to the CMV group. TGI resulted in lower peak inspiratory pressure (PIP), VT, VD/VT and greater VEI vs. PLV group; PLV resulted in greater compliance, PaO2 and EI vs. TGI. TGI+PLV resulted in decreased PIP, VT, VD/VT and increased VEI compared to TGI, improved compliance and EI compared to PLV, and a further increase in PaO2 and OI, and decrease in PaCO2 vs. either treatment alone. These results indicate that combined treatment of TGI and PLV results in improved pulmonary outcome than either treatment alone in this animal model of ALI.
