Controversies in transfusion medicine. Perioperative hemodilution: pro

Hemodilution can obviate the need for allogeneic transfusion in some patients. However, it is only one component of a comprehensive blood conservation program and should be combined with other techniques whenever possible. While most often employed in teenagers and healthy young adults, ANH has been used in small children, the elderly, and patients of all ages who are undergoing cardiac surgery. Extreme caution should be exercised if ANH is used in patients with coronary artery disease or aortic stenosis who are undergoing noncardiac surgery, because their normal compensatory mechanisms are impaired. What usually is a safe and relatively simple procedure can become a disaster if employed in inappropriately selected patients. Careful hemodynamic monitoring and maintenance of normovolemia are critical.     

Controversies in transfusion medicine. Alanine aminotransferase screening of blood donors: pro

In my opinion, independent, carefully conducted scientific studies indicate that an accurate, rapid, relatively sensitive, and inexpensive laboratory test substantially reduces the major long-term risk of blood transfusion in the United States; donor ALT has emerged as one of the most effective laboratory determinants for reducing the incidence of NANB PTH. Despite its nonspecificity and limited predictive value, ALT screening may prevent up to 30 percent of cases, one-half of which would progress to chronic liver disease and then possibly to cirrhosis and hepatocellular carcinoma. Blood donors appear to understand and accept the testing rationale as a reasonable precaution. Admittedly, ALT screening is not a perfect solution. It has not been validated by prospective studies and probably never will be. Determination of the proper cutoff value remains controversial. However, the risk of PTH progresses with increasing ALT levels, so that the real issue is not whether to test, but how best to configure the test to exclude the fewest false-positive donors while detecting the most true-positive donors. It is undesirable and expensive to discard safe units of blood, but the primary responsibility of blood collectors is to ensure an adequate supply of safe components. Some still consider the ALT assay technically too demanding for routine use. However, technical concerns regarding performance and interpretation are not insurmountable, and both quality control and proficiency testing are being addressed at the national level. The assay is capable of great precision, and a system employing a national standard and single cutoff has already been described and tested with excellent results. Circumstances have changed since donor screening with ALT was widely implemented in 1986. More thorough screening and testing have eliminated many high-risk donors. Public expectations have changed as well. While it is neither reasonable nor responsible to promise the public blood transfusions without risk, neither is it prudent to propose any major change in management of the blood supply without compelling evidence that such a change will not impair transfusion safety. It is hard to defend discontinuing the ALT screen at this time, especially when the costs of retaining it are minimal and the benefits clearly greater than those of screening for HTLV-I and for Treponema pallidum (in the United States) or HIV-2 (in West Germany). A first-generation assay specific for antibody to hepatitis C will probably be available within a year.(ABSTRACT TRUNCATED AT 400 WORDS)     

自体输血也要三思而后行

输血在外科领域中广泛应用的同时也带来了一些不良反应甚至严重的并发症，特别是在某些紧急情况下输入他人血液(异体输血)时，可能会感染肝炎、艾滋病等血液传播疾病，即使在血液管理较规范、供血较安全的发达国家也不能完全避免。而现在备受青睐的自体输血，被认为是最安全可靠的输血方式。所谓自体输血，是在术前条件允许的情况下或手术中收集病人自身的血液以备手术需要之用。