Will Carson et al.’s study be the garlic that deters the most blood thirsty colleagues? The image is CC by Gaviota Paseandera.

As I have a weakness for studies that challenge the dogma, I was ecstatic when I stumbled upon Carson et al.’s bold study on blood transfusions. In their study they selected 2000 patients with cardiovascular disease that were undergoing surgery due to hip fracture. Interestingly, there was no difference in 3-year mortality when randomizing between transfusion Hemoglobin thresholds of 100 g/L or 80 g/L!

The study is a multicenter RCT based upon 47 centers throughout the US and Canada. Note that the lower threshold of 80 g/L was also supplemented with transfusion if the patient experienced symptoms of anemia:

• chest pain thought to be cardiac in origin
• symptoms and signs of congestive heart failure
• hypotension, tachycardia unresponsive to fluid challenge

The study was elegantly designed with random block size for the randomization, both short and long-term follow-up, and well-defined selection criteria. In their short-term follow-up (30 and 60-day) they also reported lack of difference regarding hospital stay, function and infections. The latter was slightly higher in the liberal transfusion group, although not significant due to generally low numbers. This supports though the general view that transfusions are immunosuppressive and increase risk of infections (see Hill et al’s meta-analysis).

On a side note

I was recently invited to hold the “journal club“ with the surgeons here at Danderyd, interestingly they asked me to go through Villanueva et al.’s similar article. With almost 900 patients they showed an improve 45-day survival with a restrictive approach (< 70 g/L). While it seems a little gutsy to suggest an improved survival (there are also some issues with the study) – the restrictive approach has definitely a broad scientific support, see Carless et al’s Cochrane review.

Summary

It seems that questioning liberal blood transfusions has a good scientific foundation. We can both reduce costs and possibly improve outcomes.

J. L. Carson, F. Sieber, D. R. Cook, D. R. Hoover, H. Noveck, B. R. Chaitman, L. Fleisher, L. Beaupre, W. Macaulay, G. G. Rhoads, B. Paris, A. Zagorin, D. W. Sanders, K. J. Zakriya, and J. Magaziner, “Liberal versus restrictive blood transfusion strategy: 3-year survival and cause of death results from the FOCUS randomised controlled trial,” The Lancet, vol. 385, no. 9974, pp. 1183–1189, Apr. 2015.

C. Villanueva, A. Colomo, A. Bosch, M. Concepción, V. Hernandez-Gea, C. Aracil, I. Graupera, M. Poca, C. Alvarez-Urturi, J. Gordillo, C. Guarner-Argente, M. Santaló, E. Muñiz, and C. Guarner, “Transfusion Strategies for Acute Upper Gastrointestinal Bleeding,” New England Journal of Medicine, vol. 368, no. 1, pp. 11–21, Jan. 2013.

P. A. Carless, D. A. Henry, J. L. Carson, P. P. Hebert, B. McClelland, and K. Ker, “Transfusion thresholds and other strategies for guiding allogeneic red blood cell transfusion,” Cochrane Database Syst Rev, no. 10, p. CD002042, 2010.

G. E. Hill, W. H. Frawley, K. E. Griffith, J. E. Forestner, and J. P. Minei, “Allogeneic blood transfusion increases the risk of postoperative bacterial infection: a meta-analysis,” J Trauma, vol. 54, no. 5, pp. 908–14, May 2003.