Acute Normovolemic Hemodilution (ANH) in Complex Cardiac Surgery

Brief Summary

Detailed Description

Adult patients undergoing complex heart surgery will be randomized to 1 of 2 groups using block randomization: the intervention arm receiving acute normovolemic hemodilution (ANH) or the control arm receiving standard of care. As day of surgery hemoglobin (Hgb)/hematocrit (Hct) is critical to the final determination for study participation, patients will be randomized to control or intervention arms after the first intraoperative arterial blood gas (ABG) is obtained. The Hb/Hct obtained from this ABG is used to determine the postdilutional hematocrit using specific pre-ANH and post-ANH equations. Patients with pre-ANH or post-ANH postdilutional Hct lower than 22-24 will not be eligible for inclusion in the ANH arm of the study. For the Study Group: Using sterile techniques, ANH is performed by removing 8-10cc/kg of whole blood with a maximum of 700cc, from the patient in the OR prior to incision. Whole blood will be collected and stored at room temperature. Hemodynamics are assessed during whole blood removal to ensure adequate stability. ANH will be discontinued if the patient becomes hemodynamically unstable (i.e. significant hypotension greater than 20% reduction from pre-ANH, unstable arrhythmia, evidence of myocardial ischemia or evidence of worsening myocardial function). After whole blood removal, the patient is hydrated to maintain isovolemia with an equivalent volume of crystalloid and/or colloid given, and the blood is stored in the OR at room temperature. After cardiopulmonary bypass (CPB) is complete, the whole blood is returned to the patient. Whole blood stored at room temperature will be transfused within 8 hours of initial collection. After 8 hours, ANH whole blood will be considered expired and will be transfused back to the patient prior to expiration and not discarded. Laboratory coagulation and ROTEM studies (assess blood clotting) will be resent after the ANH blood is returned to the patient. Transfusion requirement will be continuously reassessed based upon laboratory values and surgical assessment of clinical bleeding. For the Control Group: Blood conservation will not be performed in the OR. Coagulation labs (i.e. platelet count, fibrinogen level and ROTEM studies) are sent while the patient in on bypass. After separation from bypass, coagulation laboratory studies and clinical bleeding are assessed in collaboration with the surgeon. Based on laboratory values and surgical assessment, allogenic transfusions (donor/recipient not the same person) occur in a targeted fashion (i.e. clinical bleeding with platelet count less than 150 x10E3/uL and a ROTEM results indicative of inadequate clot strength will result in platelet transfusion). Transfusion requirements are continuously reassessed based upon updated laboratory values and surgical assessment of clinical bleeding. Data will also be collected and recorded from the medical record for both groups.

Primary Outcomes

Secondary Outcomes

• 24 Hour Prothrombin time (PT)(24 hours)
• 72 Hour Hemoglobin (Hgb)(72 hours)
• 24 Hour Chest Tube Output(24 Hours)
• Acute Kidney Injury (AKI)(72 hours)
• Maximum Intraoperative Vasoactive-Inotropic Score(Conclusion of intraoperative procedure)
• Maximum 72 Hour Vasoactive-Inotropic Score(72 hours)
• 72 Hour Activated Partial Thromboplastin time (aPTT)(72 hours)
• Maximum 48 Hour Vasoactive-Inotropic Score(48 hours)
• 72 Hour Prothrombin time (PT)(72 hours)
• 24 Hour Activated Partial Thromboplastin time (aPTT)(24 hours)
• 48 Hour Platelet Count(48 hours)
• 24 Hour Hemoglobin (Hgb)(24 hours)
• Maximum 24 Hour Vasoactive-Inotropic Score(24 hours)
• 72 Hour Chest Tube Output(72 Hours)
• 24 Hour International Normalized Ratio (INR)(24 hours)
• 48 Hour International Normalized Ratio (INR)(48 hours)
• 72 Hour International Normalized Ratio (INR)(72 hours)
• 48 Hour Activated Partial Thromboplastin time (aPTT)(48 hours)
• 48 Hour Hematocrit (Hct)(48 hours)
• 48 Hour Chest Tube Output(48 Hours)
• 48 Hour Prothrombin time (PT)(48 hours)
• 48 Hour Fibrinogen(48 hours)
• Platelets (PLT)(72 hours)
• 24 Hour Fibrinogen(24 hours)
• 24 Hour Hematocrit (Hct)(24 hours)
• 72 Hour Hematocrit (Hct)(72 hours)
• Rotational Thromboelastometry FIBTEM Maximum Clot Firmness (FIBTEM MCF)(During intraoperative period)
• Rotational Thromboelastometry HEPTEM Clotting Time (HEPTEM CT)(During intraoperative period)
• Mortality(An average of 5-10 days until discharge from the hospital, whichever came first)
• Fresh frozen plasma (FFP)(72 hours)
• Cryoprecipitate (cryo)(72 hours)
• 72 Hour Fibrinogen(72 hours)
• 24 Hour Platelet Count(24 hours)
• 72 Hour Platelet Count(72 hours)
• 48 Hour Hemoglobin (Hgb)(48 hours)
• Rotational Thromboelastometry EXTEM Clotting Time (EXTEM CT)(During intraoperative period)
• Post-cardiopulmonary bypass HEPTEM/EXTEM MCF(In the operating room (OR) during surgery.)
• Cerebral oximetry using near infrared spectroscopy derived tissue oxygenation as a marker of perfusion(In the OR during surgery.)
• Change in mixed venous oxygen saturation as a marker of perfusion(72 hours)
• Delirium(Two times per day for up 72 hours post-op or until discharge from the ICU, whichever came first)
• Number of patients with infection/sepsis(72 hours post-op or until discharge from the ICU, whichever came first)
• Rotational Thromboelastometry EXTEM Clotting Time (EXTEM A20)(During intraoperative period)
• Rotational Thromboelastometry HEPTEM/EXTEM Maximum Clot Firmness (HEPTEM/EXTEM MCF)(During intraoperative period)
• Perfusion markers (lactate)(72 hours)