[Acid-base disturbances in surgical operation].

Metabolic acidosis immediately after surgical operation is followed by metabolic alkalosis. Hormonal change by surgical stress and anaerobic glucolysis due to tissue ischemia cause initial lactic acidosis. Later alkalosis may be caused by secondary aldosteronism and bicarbonate production from lactate and citrate supplied by massive infusion and transfusion. Postoperative complications, such as respiratory insufficiency, renal failure and hypovolemic or septic shock, cause acidosis. In the gastrointestinal surgery, acidosis can be caused by starvation and loss of bicarbonate contained in bile, pancreatic juice or intestinal fluid, and alkalosis can be caused by loss of HCl in gastric juice. Severe acidosis can be caused by extracorporeal circulation, hypothermia, low output syndrome or declamping shock in cardioaortic surgery.