NMS. Surgery

17

Chapter 1 ♦ Principles of Surgical Physiology

II. Electrolyte disturbances A. Hyperkalemia: Lysed cells can cause hyperkalemia. B. Hypocalcemia: Citrate in stored blood can bind calcium. III. Coagulopathy: Packed red blood cells (pRBCs) do not contain clotting factors or platelets. IV. ABO incompatibility A. Etiology: Intravascular immune reaction, leading to clumping and lysis of red cells with mismatched blood. B. Signs and symptoms: Hemoglobinuria, fever, coagulopathy, renal failure, and shock. V. Delayed hemolytic reaction: Usually takes 3–7 days to manifest. A. Signs and symptoms: Fever, malaise, hyperbilirubinemia, and decreasing hematocrit, usually related to minor antibody systems (e.g., Rh system). B. Usually but not always preventable with recipient antibody screening. C. Treatment: Hydration and supportive care. VI. Disease transmission: Many viruses are transmitted by blood. A. HIV: Risk of transmission estimated to be 1:2,000,000. B. Hepatitis C: Risk of transmission estimated to be 1:2,000,000. C. Hepatitis B: Risk of transmission estimated to be 1:2,000,000. D. Others: Risks less known but have been described, including human t-lymphotropic virus (HTLV) 1 and 2, West Nile virus, and Creutzfeldt– Jakob disease; overall risk of viral transmission may be as high as 1:50,000. VII. Immunosuppression: A. Increased infectious complications, including ventilator-associated pneumonia. B. Possible increase in cancer recurrence following potentially curative surgery. C. Increased mortality in ICU patients. Transfusion Indications I. Acute coronary disease: Standard trigger is 8 g/dL. II. Trauma patients: Exsanguinating patients should be given blood as resuscitation. A. Hgb measurement may still be high acutely, but they are losing blood and its attendant oxygen-carrying capacity. B. Blood/FFP ratios are being currently studied, but resuscitate with 1:1:1 ratio of blood/FFP/ platelets. III. ICU patients: Oxygen delivery and extraction can help to guide transfusion therapy. IV. Non-ICU patients: If symptomatic (e.g., tachycardia, tachypnea, confusion, lethargy, and acidosis), then transfuse.