tailieunhanh - Báo cáo y học: "Management of acidosis: the role of buffer agents"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học General Psychiatry cung cấp cho các bạn kiến thức về ngành y đề tài: Management of acidosis: the role of buffer agents. | Weil and Tang Critical Care 1997 1 51 http c CRITICAL CARE COMMENTARY Management of acidosis the role of buffer agents Max Harry Weil 1 Wanchun Tang2 52cc-1-2-051 Full text For more than 50 years continuing up to about 1980 sodium bicarbonate was used for the treatment of metabolic acidosis. The rationale was that administration of an alkaline fluid would correct an acidotic state. However the potential value of sodium bicarbonate was called into question when more recent studies demonstrated that it induced venous hypercarbia and decreases in tissue and cerebrospinal fluid pH as well as provoking tissue hypoxia circulatory congestion hypernatremia and hyperosmolality with consequent brain damage 1-6 . Bicarbonate buffers may intensify rather than ameliorate cellular acidosis because sodium bicarbonate generates CO2 and thereby increases intracellular hypercarbic acidosis 7 . Sodium bicarbonate administered to patients with diabetic ketoacidosis failed to favorably alter the clinical course or outcome. More specifically the survival rate was similar in patients who did not receive bicarbonate 8 . During hypoxic lactic acidosis sodium bicarbonate produced a decline in both systemic arterial pressure and cardiac output without improvement in outcome 9 . The declines in arterial pressure and cardiac output were associated with the hypertonicity of buffer agents which produced arterial vasodilation 10 . Several other agents have been investigated for the treatment of lactic acidosis. The intent was to increase blood pH during hypoxic states without reducing oxygen delivery or increasing blood and tissue CO2. Among the most promising are the organic buffers including TRIS THAM and a mixture of equimolar concentrations of sodium carbonate and bicarbonate named Carbicarb. Both of these agents are CO2-consuming rather than CO2-generating bicarbonate buffers. In animal studies both THAM and Carbicarb appeared to have advantages over sodium bicarbonate in the .