Summary of abstractsThroughout history, mankind has been obsessed with blood. Who, we ask ourselves, are we to try and change this? Decreasing red blood cell transfusion - Audit and GuidelinesAn interesting study aiming to compare the changes in transfusion practices by applying simple protocols and auditing the results. The authors compared their anaesthetists' practices and opinions in 1996 and 1998 with regard to:
In 1996 they found that the majority of their staff used estimated blood loss as a transfusion trigger. In 1998 the staff had to measure a haemoglobin pre-transfusion. No limit was set as a transfusion guide. Hb of 8 – 9 was reported as the level at which most of their staff felt it was appropriate to transfuse blood. They attempted to calculate the patient's actual Haemoglobin at the end of the procedure and proved that using estimated blood loss as a trigger resulted in a rise in Hb by the end of surgery, whereas using Hb as a trigger for transfusion resulted in a Hb lower than pre-operatively. This is a major flaw in this study as estimating blood loss is notoriously difficult and I feel this final value should have been a measured Hb , not a calculated value from an estimate. So I feel one should not try to even interpret this set of results. Other results show remarkable changes in actual practice…..
This shows a significant decrease in the amount of blood transfused by the introduction of a simple protocol that still allows the individual anaesthetist the autonomy to decide on the patients management. An interesting aside from this audit is a ratio calculated using the number of units of blood cross matched for each unit transfused.
Plasma protects mechanically stressed red cells!
Aim of the study – Does the prime or dilutent fluid used in cardiopulmonary bypass make a difference to red blood cell (RBC) haemolysis? Method 10 units of blood had 4 x 65ml samples removed. 65ml samples were diluted with
Sample was then run through a Bypass pump for 2 hours and haemolysis was measured at 30 minute intervals using free Hb and LDH levels. Results:
Conclusions The trial is well standardised, with blood coming from the same unit, experiencing the same trauma and significant results being produced. The conclusion is that Gelofusin and albumin have erythrocytic protection properties. The postulate for the protective properties is that The negative charge on Albumin and Gelofusin coats RBCs, something that does not occur with the neutrally charged solutions Normal saline and HES.
Normovolaemic haemodilution Vs Controlled HypotensionA well constructed trial where blood pressure reduced to a mean of 50mmHg by the use of Sodium Nitroprusside was compared to normovolaemic haemodilution where 15ml per Kg of blood was removed and replaced with Gelatin. Blood was transfused at a Hb of 7.
There was no difference in the coagulation profiles ( PTT, AT III, D Dimers & aPTT) between the groups. There were no strokes or neurological sequelae in any patient. Troponin T levels were similar in all groups. Proof that deliberate hypotension causes less bleeding and blood transfusion! BUT is this practice safe in all patients, especially using a mean arterial blood pressure of 50mmHg?
& now 4 somEthiNg cOmpletEly diFferenT !
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| Date of First Publication : 2000-12-20 | Date of Last Update : 2006/10/23 | Web page author: Click here |