Mean (±SE) shock scores and LIS at serial time points. (A-D) The shock score accounts for the level of vasopressor support (norepinephrine) needed to maintain the mean arterial pressure at a preset normal level for canines (mean 80 mm Hg).^1,28,29  (A,C) the shock score is plotted through time (x-axis) for animals receiving 42-day-old blood (A) or 7-day-old blood (C). The LIS in a previously published scoring system increases our ability to find the abnormalities in the lungs, which includes mean pulmonary artery pressure, alveolar-arterial oxygen gradient, plateau pressure, O₂ saturation, and respiratory rate.^1,28,29  (B,D) The LIS is plotted in the same fashion as the shock score for old and fresh blood. In each of these panels, unwashed blood is represented by a solid line and washed blood by a dashed line. The P value in each panel indicates differences between washed and unwashed blood (**) and the presence of qualitative interactions between age of blood and washing (*).