Figure 2

EVLWI and PaO₂/FiO₂ per volume of resuscitation fluid. (a) Extravascular lung water index (EVLWI) and partial pressure of arterial oxygen (PaO₂)/fraction of inspired oxygen (FiO₂) as a function of resuscitation volume over the entire study. Linear regression analysis reveals a larger increase in EVLWI in the normal saline (NS) group as compared with the lactated Ringer's solution (LR) group. An increase of 1 ml/kg of EVLWI occurred at a resuscitation volume of 55.6 ± 6.3 ml/kg for normal saline and 76.9 ± 12.1 ml/kg for LR (p = 0.02). A significant change in oxygenation defined as a drop in PaO₂/FiO₂ of 100 or more (roughly corresponding to a drop in arterial oxygen saturation below 90% on room air) did not occur until more than 250 ml/kg of either fluid had been administered. (b) EVLWI and PaO₂/FiO₂ as a function of resuscitation volume of 250 ml/kg or less. To examine fluid type-specific effects we examined changes in oxygenation and EVLWI at similar total volumes of resuscitation. A limit of 250 ml/kg was chosen as none of the LR animals required more than this volume to maintain goal mean arterial pressure (MAP) and to allow examination of the effects of fluid type early in the resuscitation at similar volumes. Linear regression analysis revealed a larger increase in EVLWI in the NS group as compared with the LR group at similar volumes infused as shown by differences in the slopes of the regression lines (p = 0.027). An increase of 1 ml/kg of EVLWI occurred at a resuscitation volume of 68.6 ± 5.2ml/kg for NS and 81.3 ± 8.7 ml/kg for LR (p = 0.027). A significant change in PaO₂/FiO₂ (≥ 100) was not seen over this range of volume.