Effect of increasing perfluorocarbon dose on VA/Q distribution during partial liquid ventilation in acute lung injury.
BACKGROUND
Although gas exchange during partial liquid ventilation (PLV) depends on perfluorocarbon liquid, the effect of perfluorocarbon dose on the ventilation-perfusion (VA/Q) distribution is not known. This study investigated how VA/Q distribution of an acutely injured lung is affected during PLV at increasing perfluorocarbon dose.


METHODS
In eight rabbits (3.2 +/- 0.1 kg), acute lung injury (ALI) was created by repeated saline lavage (arterial oxygen partial pressure/fraction of inspired oxygen, 37 +/- 11 mm Hg). Three different doses of perfluorodecalin (9 ml/kg = low dose; 13.5 ml/kg = medium dose; 18 ml/kg = functional residual capacity [FRC] dose) were applied in random order during PLV. VA/Q distribution at different doses was evaluated by multiple inert gas elimination technique.


RESULTS
Inert gas shunt (63 +/- 21% at ALI) decreased with increasing perfluorocarbon dose (43 +/- 21% at low dose, 29 +/- 10% at medium dose, 11 +/- 9% at FRC dose; P = 0.022). Compared with ALI (0%), the proportion of low VA/Q units was higher at all tested doses (19 +/- 10, 25 +/- 12, and 34 +/- 18%, respectively; all P < 0.05). Compared with ALI (27 +/- 14%), the proportion of normal VA/Q units was not increased at low or medium doses but was increased only at the FRC dose (45 +/- 13%; P = 0.027).


CONCLUSIONS
With increasing perfluorocarbon dose during PLV, shunt was reduced from a small dose. The majority shunt units were converted to units showing low VA/Q ratios rather than normal VA/Q ratios. The presence of considerable amount of low VA/Q units across the varying doses of perfluorocarbon suggested that additional measures are necessary during PLV to augment its effect on gas exchange.
Lim
C M
CM
Division of Pulmonary and Critical Care Medicine, University of Ulsan, Seoul, Korea. cmlim@www.amc.seoul.kr
Domino
K B
KB
Glenny
R W
RW
Hlastala
M P
MP
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005466:Fluorocarbons / Q000494:pharmacology*; D021061:Liquid Ventilation; D011659:Pulmonary Gas Exchange / Q000187:drug effects; D011817:Rabbits; D012128:Respiratory Distress Syndrome / Q000503:physiopathology*; D014692:Ventilation-Perfusion Ratio / Q000187:drug effects*
D005466:Fluorocarbons