British Journal of Anaesthesia, 2004, Vol. 92, No. 4 601
© 2004 The Board of Management and Trustees of the British Journal of Anaesthesia
Correspondence |
Intraoperative blood transfusions
1 Christchurch, New Zealand 2 Changigarh, India
Editor—I would like to comment on the paper by Niraj and colleagues.1 I have also been involved in audits on blood use in elective surgery and found inappropriate use and excessively high cross-match:transfusion ratios to be widespread. The authors chose a postoperative haemoglobin concentration of greater than 11 g dl–1 as their standard for an inappropriate transfusion. Recent guidelines2 3 suggest that values of 8 or 10 g dl–1, depending on the patients’ co-morbidity, would have been more appropriate. The proviso to this comment is that the decision to transfuse must be based on the unique clinical setting rather than a number. The authors rightly emphasize the occasional difficulty in assessing the clinical setting, in particular estimation of the intra-operative blood loss. They mention the problem of the dilutional effects of crystalloid therapy but then appear to contradict themselves by promoting greater reliance on intraoperative haemoglobin measurement. In order to clarify this situation, I believe it is useful to determine the maximum allowable blood loss (MABL) using Gross’s4 formula before surgery. Combining knowledge of the patient’s physiological reserve, the individualized MABL (based on weight, body habitus and preoperative haemoglobin), an intraoperative haemoglobin, the estimated blood loss and any ongoing loss, the decision to transfuse or not intraoperatively may be made with more certainty.
R. Seigne
Christchurch, New Zealand
Editor—In assessment of intraoperative blood use we did consider 8 and 10 g dl–1 (depending on the presence of comorbidities) as the requisite trigger thresholds in deciding the appropriateness of transfusion.1 There are difficulties in placing excessive reliance on a single intraoperative haemoglobin estimate given the dynamic effects of fluid shifts, dilutional crystalloid therapy, ongoing surgical losses, and so on. We therefore chose also to measure postoperative haemoglobin (when we expected that these effects would have diminished), and a more correct estimate of the true haemoglobin concentration was possible. A postoperative haemoglobin value of 11 g dl–1 was chosen as the cut-off in deciding on the inappropriateness of transfusions.5 Had we chosen a lower cut-off we would arguably have ended up designating some transfusions as ‘inappropriate’, when the intraoperative haemoglobin estimate would actually have warranted blood use.
We appreciate the utility of Gross’s simplified formula4 to estimate the maximal allowable blood loss and apply it in our own work. Our main contention is that intraoperative haemoglobin together with other clinical data can reduce further the inappropriate use of blood. This was validated by our observations that inappropriate transfusions were fewer in patients in whom this estimate was made and that, over time, using the estimate routinely led to fewer, more appropriate transfusions.
G. D. Puri
G. Niraj
D. Arun
V. Chakravarty
J. Aveek
P. Chari
Chandigarh, India
References
1 Niraj G, Puri GD, Arun D, Chakravarty V, Aveek J, Chari P. Assessment of intraoperative blood transfusion practice during elective non-cardiac surgery in an Indian tertiary care hospital. Br J Anaesth 2003; 91: 586–9
2 NHMRC. In: http://www.nhmrc.gov.au.
3 ASA. Practice guidelines for blood component therapy. Anesthesiology 1996; 84: 732–47[CrossRef][Web of Science][Medline]
4 Gross J. Estimating allowable blood loss: corrected for dilution. Anesthesiology 1983; 58: 277–9[Web of Science][Medline]
5 Tartter PI, Barron DM. Unnecessary blood transfusion in elective colorectal cancer surgery. Transfusion 1985; 25: 113–15[Medline]
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