Lactated Ringers, albumin and mannitol as priming during cardiopulmonary bypass reduces pulmonary edema in rats compared with hydroxyethyl starch

Abstract Background Endothelial disorders with edema formation and microcirculatory perfusion disturbances are common in cardiac surgery with cardiopulmonary bypass (CPB) and contribute to disturbed tissue oxygenation resulting in organ dysfunction. Albumin is protective for the endothelium and could be a useful additive to CPB circuit priming. Therefore, this study aimed to compare organ edema and microcirculatory perfusion in rats on CPB primed with lactated Ringers, albumin and mannitol (LR/albumin/mannitol) compared to 6% hydroxyethyl starch (HES). Results Male rats were subjected to 75 min of CPB primed with either LR/albumin/mannitol or with 6% HES. Renal and lung edema were determined by wet/dry weight ratio. Pulmonary wet/dry weight ratio was lower in rats on CPB primed with LR/albumin/mannitol compared to HES (4.77 [4.44–5.25] vs. 5.33 [5.06–6.33], p = 0.032), whereas renal wet/dry weight ratio did not differ between groups (4.57 [4.41–4.75] vs. 4.51 [4.47–4.73], p = 0.813). Cremaster microcirculatory perfusion was assessed before, during and after CPB with intravital microscopy. CPB immediately impaired microcirculatory perfusion compared to baseline (LR/albumin/mannitol: 2 [1–7] vs. 14 [12–16] vessels per recording, p = 0.008; HES: 4 [2–6] vs. 12 [10–13] vessels per recording, p = 0.037), which persisted after weaning from CPB without differences between groups (LR/albumin/mannitol: 5 [1–9] vs. HES: 1 [0–4], p = 0.926). In addition, rats on CPB primed with LR/albumin/mannitol required less fluids to reach sufficient flow rates (0.5 [0.0–5.0] mL vs. 9 [4.5–10.0], p