Gas exchange and lung mechanics during high frequency ventilation in the perflubron-treated lung.
OBJECTIVE
To identify the effect of perflubron on gas exchange and lung mechanics during high frequency oscillatory ventilation in an animal model.


METHODS
Prospective randomized animal trial.


METHODS
Eighteen Yorkshire swine.


METHODS
Three groups of six animals each were investigated: control (high frequency oscillatory ventilation alone), low dose perflubron (high frequency oscillatory ventilation plus perfluoro-octyl bromide [PFOB]-Lo, 1.5 mL/kg), and high dose perflubron (high frequency oscillatory ventilation plus PFOB-Hi, 3 mL/kg). Lung injury was induced with repeated saline lavage and amplified for 1 hr using large tidal volumes. Perflubron (Alliance, CA) or a sham dose (room air) was administered with bronchoscopic guidance. The animals were transitioned to high frequency oscillatory ventilation starting at a mean airway pressure of 15 cm H2O. Mean airway pressure was increased (inflation phase) by 5 cm H2O every 15 mins to a maximum mean airway pressure of 40 cm H2O. During the deflation phase, mean airway pressure was reduced by 5 cm H2O every 15 mins to a mean airway pressure of 15 cm H2O.


RESULTS
Oxygenation was improved and pulmonary shunt fraction was reduced for PFOB-Hi compared with the control group only at a mean airway pressure of 15 and 20 cm H2O. At a maximal mean airway pressure of 40 cm H2O, oxygenation was not different between the groups, but pulmonary artery pressures were elevated in both PFOB-groups compared with the control group. During the deflation phase, oxygenation, pulmonary shunt fraction, and pulmonary artery pressures were adversely affected by PFOB-Hi and PFOB-Lo.


CONCLUSIONS
Although PFOB-Hi compared with the control group improved oxygenation and reduced pulmonary shunt fraction only during the first pressure steps of a formal stepwise recruitment maneuver during high frequency oscillatory ventilation, this effect was not sustained during maximal recruitment. During the deflation phase, both PFOB groups were associated with worse gas exchange compared with the control group. PFOB also produced significant pulmonary hypertension in comparison with the control group.
Division of Critical Care Medicine, Department of Anesthesia, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA. gerhard.wolf@childrens.harvard.edu
Gerhard K
GK
Wolf
Padraig
P
Sheeran
David
D
Heitz
John E
JE
Thompson
John H
JH
Arnold
D000818:Animals; D005466:Fluorocarbons / Q000494:pharmacology*; D006612:High-Frequency Ventilation; D006842:Hydrocarbons, Brominated; D008168:Lung / Q000187:drug effects / Q000502:physiology*; D023421:Models, Animal; D011659:Pulmonary Gas Exchange / Q000187:drug effects; D011897:Random Allocation; D015656:Respiratory Mechanics / Q000187:drug effects; D013552:Swine
D005466:Fluorocarbons; D006842:Hydrocarbons, Brominated; C003072:perflubron