Anesthesiology
Thank you Brian, this seems to be a nice approach. Do you use any method to improve the crit before the procedure – like HuEPO, iron reposition, danazol, or sth like that? claudia 2006/3/14, Brian Woodcock <bwudcock@med.umich.edu>: > I think that using acute normovolemic hemodilution may not actually be > worthwhile in reducing blood transfusion, mathematically you have to be > extreme to have a chance of reducing transfusion. > > Consensus conference on autologous transfusion. Acute normovolaemic > haemodilution. Transfusion. 36(7):640-3, 1996 Jul. > > “ANH is a relatively cheap and logistically straightforward method of > autologous transfusion which is attractive in that it may be applied to > a wide cross-section of patients, many of whom will not be suitable for > pre-deposit. There are, however, concerns about the safety of the > procedure, and doubts have been expressed about its efficacy in reducing > allogeneic transfusion requirements and, therefore, its > cost-effectiveness. Assessment of the value of the procedure is hampered > by the lack of large scale prospective, controlled trials. In the > present state of knowledge it seems that ANH is most likely to be safe, > efficacious and cost-effective when undertaken aggressively (target > haematocrit < 0.20) in otherwise healthy, young patients undergoing > elective surgery with large expected blood losses. [References: 45]” > > Does acute normovolemic hemodilution reduce perioperative allogeneic > transfusion? A meta-analysis. The International Study of Perioperative > Transfusion. Anesthesia & Analgesia. 86(1):9-15, 1998 > > “The objective of this study was to systematically review the > literature and to statistically summarize the evidence evaluating acute > normovolemic hemodilution (ANH). Prospective, randomized, controlled > trials of ANH that reported either the proportion of patients exposed to > allogeneic blood or the units of allogeneic blood transfused were > included. All types and languages of publication were eligible. Of 1573 > identified publications, 24 trials (containing a total of 1218 patients) > were included in the meta-analysis. When all trials were pooled, ANH > reduced the likelihood of exposure to allogeneic blood (odds ratio [OR] > 0.31, 95% confidence interval [CI] 0.15, 0.62) and the total units of > allogeneic blood transfused (weighted mean difference [WMD] -2.22 U, 95% > CI -3.57, -0.86). However, there was marked heterogeneity of the > results. In trials using a protocol to guide perioperative transfusion, > ANH failed to reduce either the likelihood of transfusion (OR 0.64, 95% > CI 0.31, 1.31) or the units administered (WMD -0.25 U, 95% CI -0.60, > 0.10). Adverse events were incompletely reported. It is possible that > biased experimental design is, in part, responsible for the reported > efficacy of this technique. Implications: after a systematic literature > review, 24 randomized trials examining the role of acute normovolemic > hemodilution were identified, pooled, and summarized using statistical > techniques. Many studies reported an impressive reduction in blood > transfused. Closer examination suggests that these reductions in blood > exposure may be due to flawed study design.” > > However, WARNING; unsubstantiated personal observations approaching (I > seem to be doing this a lot recently), we do ANH for massive cardiac ops > where major bleeding is anticipated, particularly aortic reconstruction > involving the ascending and arch, or descending thoracic repairs. So we > give the blood back immediately after the protamine, so they get their > own platelets which have not been wrecked by passing through the CPB > pump. > > Our protocol is to take 2 units from the 9 french introducer in the > neck, this goes into a blood bag with 60ml of CPD, I usually try to get > good sized units 600 – 650 ml. You can weigh them to see how much you > have. I watch the hemodynamics while it comes off, if they look > hypovolemic I’ll speed up the peripheral IV with crystalloid, or colloid > if necessary. If it is a big patient with a good crit I might take 3 > units. > > You can predict the final crit by estimating blood volume (70ml/kg) > then new crit = (EBV-volume taken off) x crit/EBV. If the predicted > crit will be too low to go on CPB (they get further hemodiluted) then we > will give PRBC peripherally during or after the blood harvest. Remember > we are not trying to reduce transfusion by ANH, we are harvesting good > platelets to give back after CPB. > > Brian > > Brian Woodcock MB ChB, MRCP, FRCA
I’ve been using normovolemic hemodilution quite a bit in the last years and I think it can be very usefull especially if the procedure is at high risk of bleeding and the starting hematocrit is over 36. My collegues, who think that a cardio patient has to be dry, take from 350 to 450 ml of blood before heparinization and give maximum of 500ml of colloids insted. I think an the other way that the cardiac output has to be mantained and a cardiac patient has not to be dry and so I give 3 times the volume of blood drawn away of cristalloides or the double of the amount of blood of colloides. Advantages: it lowers the risk of transfusion, and of bleeding (coagulation is better with fresh whole blood). And thinking about eythropietin and iron: Probably erithropoietin would be ok even if expensive (I stopped using it becouse the advantages/costs ratio was in my opinion not so high and becouse usually we see the patients just the day before the procedure); on the other side I would not use iron since it is one of the elements responsible of the reperfusion injury. Guido Panduri Anesthesiologist Ancona – Italy
Sedation with volatile anesthetics (J Crit Care 2009;inpress soukup j, state of the art: sedation concepts with volatile) including the AnaConDa
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