Effects of citrated whole blood transfusion in response to hemorrhage

Background and Purpose: Standard treatment for massive hemorrhage in dogs i s infusion of whole blood or of packed red blood cells with fresh frozen pl asma if whole blood is not available. Although most whole blood is collecte d using a citrate-based anticoagulant, knowledge of citrate's relevant non- anticoagulant effects is not widespread. Citrate's anticoagulant activity i s achieved through chelation of divalent metal cations (e.g., magnesium, ca lcium), which may exacerbate cardiovascular and metabolic insults attributa ble to hemorrhage, Methods: Blood pressures, gas tensions, metabolites, and electrolytes; myoc ardial metabolites, pressures, and contractility; cardiac output; and left cranial descending and circumflex coronary artery flows were measured in 21 anesthetized dogs after hemorrhage was induced by collection of blood into a citrated reservoir to mean arterial pressure of 45 mm Hg for approximate ly 60 min (until arterial lactate concentration was 7.0 mmol/L), followed b y a l-h transfusion and 2 h of maintenance. Results: Arterial ionized calcium concentration, total peripheral resistanc e, and myocardial function decreased significantly during hemorrhage. All a forementioned responses but myocardial function continued to decrease durin g the initial 20 min of transfusion, then began to recover. Total periphera l resistance and end-systolic elastance were the only factors significantly related to calcium concentration. Conclusion: Transfusion with citrated whole blood may significantly alter c alcium concentration, negatively affecting myocardial and vascular function .