maintaining adequate hepatic perfusion

Planning the anesthetic must take into account the surgical procedure, type and severity of liver disease, and alterations to hepatic blood flow due to anesthetics. Meticulous attention must be paid to maintaining adequate hepatic perfusion and oxygen delivery. Both general and regional anesthesia techniques can decrease total hepatic blood flow. Episodes of perioperative hepatic ischemia (due to surgical manipulation or anesthetics) can exacerbate preexisting liver disease. Hypotension, hemorrhage, and vasopressors can compromise hepatic oxygenation delivery, resulting in increased postoperative hepatic dysfunction. Surgical traction and patient positioning can compromise hepatic blood flow. Positive-pressure ventilation and positive end-expiratory pressure may cause deleterious effects in hepatic venous pressure, resulting in decreased cardiac output and total hepatic blood flow. Hyperventilation should be avoided because hypocarbia can independently reduce hepatic blood flow.