Improved arterial oxygenation with biologically variable or fractal ventilation using low tidal volumes in a porcine model of acute respiratory distress syndrome.
We compared biologically variable ventilation (V (bv); n = 9) with control mode ventilation (V (c); n = 8) at low tidal volume (VT)--initial 6 ml/kg--in a porcine model of acute respiratory distress syndrome (ARDS). Hemodynamics, respiratory gases, airway pressures, and VT data were measured. Static P-V curves were generated at 5 h. Interleukin (IL)-8 and IL-10 were measured in serum and tracheal aspirate. By 5 h, higher Pa(O(2)) (173 +/- 30 mm Hg versus 119 +/- 23 mm Hg; mean +/- SD; p < 0.0001 group x time interaction [G x T]), lower shunt fraction (6 +/- 1% versus 9 +/- 3%; p = 0.0026, G x T) at lower peak airway pressure (21 +/- 2 versus 24 +/- 1 cm H(2)O; p = 0.0342; G x T) occurred with V (bv). IL-8 concentrations in tracheal aspirate and wet:dry weight ratios were inversely related; p = 0.011. With V (c), IL-8 concentrations were 3.75-fold greater at wet:dry weight ratio of 10. IL-10 concentrations did not differ between groups. In both groups, ventilation was on the linear portion of the P-V curve. With V (bv), VT variability demonstrated an inverse power law indicating fractal behavior. In this model of ARDS, V (bv) improved Pa(O(2)) at lower peak airway pressure and IL-8 levels compared with V (c).
Boker
Abdulaziz
A
Department of Anesthesiology, University of Manitoba, Winnipeg, Canada.
Graham
M Ruth
MR
Walley
Keith R
KR
McManus
Bruce M
BM
Girling
Linda G
LG
Walker
Elizabeth
E
Lefevre
Gerald R
GR
Mutch
W Alan C
WA
D000704:Analysis of Variance; D000818:Animals; D016207:Cytokines / Q000378:metabolism; D017709:Fractals; D006439:Hemodynamics; D008170:Lung Compliance; D011659:Pulmonary Gas Exchange; D011897:Random Allocation; D012121:Respiration, Artificial / Q000379:methods*; D012128:Respiratory Distress Syndrome / Q000628:therapy*; D013552:Swine; D013990:Tidal Volume
D016207:Cytokines