TY - CHAP M1 - Book, Section TI - Fluid Management & Blood Component Therapy A1 - Butterworth IV, John F. A1 - Mackey, David C. A1 - Wasnick, John D. PY - 2022 T2 - Morgan & Mikhail’s Clinical Anesthesiology, 7e AB - KEY CONCEPTS While the intravascular half-life of a crystalloid solution is 20 to 30 min, most colloid solutions have intravascular half-lives between 3 and 6 h. Patients with a normal hematocrit should generally be transfused only after losses greater than 10% to 20% of their blood volume. The timing of transfusion initiation is based on the patient’s procedure, comorbid conditions, and rate of blood loss. The most severe transfusion reactions are due to ABO incompatibility; naturally acquired antibodies can react against the transfused foreign antigens, activate complement, and result in intravascular hemolysis. In anesthetized patients, an acute hemolytic reaction is manifested by a rise in temperature, unexplained tachycardia, hypotension, hemoglobinuria, diffuse oozing in the surgical field, or a combination of these findings. Allogeneic transfusion of blood products may diminish immunoresponsiveness and promote inflammation. Immunocompromised and immunosuppressed patients (eg, premature infants, organ transplant recipients, patients with cancer) are particularly susceptible to severe transfusion-related cytomegalovirus (CMV) infections. Ideally, such patients should receive only CMV-negative units. The most common cause of nonsurgical bleeding following massive blood transfusion is dilutional thrombocytopenia. Clinically important hypocalcemia, causing cardiac depression, will not occur in most normal patients unless the transfusion rate exceeds 1 unit every 5 min, and intravenous calcium salts should rarely be required in the absence of measured hypocalcemia. Once normal tissue perfusion is restored, any metabolic acidosis typically resolves and metabolic alkalosis commonly occurs as citrate and lactate contained in transfusions and resuscitation fluids are converted to bicarbonate by the liver. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accessanesthesiology.mhmedical.com/content.aspx?aid=1190611192 ER -