Welcome to Med e-News.

Med e-News is the electronic newsletter from Transfusion Medicine Services at the Australian Red Cross Blood Service, allowing us to keep you up to date with our news and important issues in clinical transfusion practice.

If any of your colleagues would like to receive Med e-News and Medilink, please contact us at lreid@arcbs.redcross.org.au

“In stable, critically ill children a haemoglobin threshold of 7g per decilitre for red cell transfusion can decrease transfusion requirements without increasing adverse outcomes.” (Lacroix et al, p1609)

This was the conclusion of the TRIPICU Study published in April this year in the New England Journal of Medicine.

The non-inferiority trial included 637 paediatric intensive care patients in Belgium, United Kingdom, United States and Canada. Patients were randomly assigned a threshold for red cell transfusion of 7g per decilitre or 9.5g per decilitre (restrictive or liberal, respectively). All red cells were leucocyte depleted before storage.

Significantly, the restrictive group of children received 44% less transfusions and were far more likely to receive no transfusions at all (54% of the restrictive group as compared with 2% of the liberal group received no transfusions of red cells).

The primary outcome of multi-organ dysfunction was not different between the 2 groups (risk reduction 0.4% [95% confidence interval -4.6 to 5.5]). Secondary outcomes included death, length of ICU stay, nosocomial infections, mechanical ventilation and transfusion reactions. No significant differences were found.

In an editorial, Corwin and Carson (2007, p1669) comment that there is an increasing body of evidence to support a trigger of a haemoglobin of 7g per decilitre for red cell transfusion.

These results support the premature infants in need of transfusion (PINT) study findings. Kirpilani et al (2006, p301) found no evidence of benefit when extremely low birth weight infants (<1000g) were maintained at higher haemoglobin levels.

These studies also support the findings of Wells et al in their TRICC (transfusion requirements in critical care) trial. They found a restrictive strategy was at least as effective as, and possibly superior to, a liberal transfusion strategy in critical care patients (except possibly those with unstable angina and acute myocardial infarction).

References
Corwin, H. Carson, J. Blood Transfusion – When is More Really Less? NEJM 19 April 2007, 356(16): 1667-1669.

Lacroix J, Hebert P, Hutchison, et al. Transfusion Strategies for Patients in Paediatric Intensive Care Units. NEJM 19 April 2007, 356(16): 1609-1619.

Kirplani H, Whyte R, Anderson C, Asztalos E , Heddle N, Blaichman M, Peliowski A,  Rios A,  LaCorte M,  Connelly R, Barrington K,  Roberts R,  The Premature Infants in Need of Transfusion (PINT) Study: A Randomized, Controlled Trial of a Restrictive (Low) Versus Liberal (High) Transfusion Threshold for Extremely Low Birth Weight Infants. J. Pediatr. Sept 2006; 149(3): 301-307.

Hebert P,  Wells G,  Blacjchman M, Marshall J,  Martin C, Pagliarello G,Tweeddale M, Schweitzer I,  Yetisir E,  A Multicenter, Randomized, Controlled Clinical Trial of Transfusion Requirements in Critical Care. NEJM 11 February  1999, 340(6): 409-417.

Transfusion support plays an integral role in the management of trauma patients, however, specific data on prognostic indicators and outcome in massively transfused trauma patients are limited.

A recently published Australian study from a major metropolitan trauma centre summarises their experience with massive transfusion (defined as 5 or more units of red cells in the first 4 hours) in trauma resuscitation.

The group describes a retrospective analysis of 119 trauma patients over a 26 month period:

• Most patients were male, and injured in motor vehicle accidents (n=86) or as pedestrians (n=12);
• Mean time to reach hospital was 118 + 64 minutes; and
• The median number of red cell units transfused during the first four hours was 8 (inter-quartile range 6 -14 units).

Initial clinical features and injuries associated with a larger red cell transfusion requirement included hypotension, pelvic fractures, renal injuries, acidosis and thrombocytopenia.

The overall mortality was 27.7%; predictors of death were the severity of injuries (by Injury Severity Score), coagulopathy and presence of head injuries.

Interestingly, the absolute volume of blood transfused during trauma was not found to be an independent predictor of mortality. The authors noted the importance of prompt diagnosis and intervention to prevent and manage hypothermia, acidosis and coagulopathy.

They concluded that prospective studies into transfusion practice and clinical features of patients during the trauma resuscitation phase are needed to establish evidence-based guidelines for massive transfusion.

Reference:
Mitra B, Mori A, Cameron PA et al: Massive Blood Transfusion and Trauma Resuscitation. (in press) 10.1016/j.injury, 21 March 2007.

Why are albumin solutions sometimes green?

Albumin solutions that are straw-coloured or green are normal and safe to use.

CSL Bioplasma uses chromatographic fractionation techniques to manufacture albumin products with >99% purity.(1)

CSL Bioplasma’s albumin products, consistent with other commercially available products, may vary in colour from a pale straw to amber to a greenish tint (2,3) depending on the proportions of bilirubin and its degradation products - lumirubin and biliverdin.

In the human body, erythrocytes are destroyed in the reticulo-endothelial system (spleen, lymph nodes, bone marrow) after the termination of their normal life span. This process releases haemoglobin, which is processed to bilirubin which then binds to albumin and is transported to the liver.

The majority of this bilirubin is then conjugated and excreted via the bile duct in the liver. Bilirubin is sensitive to light and degrades predominantly to lumirubin, which has a yellow pigment and also results in the generation of small amounts of biliverdin which is green.(4)

References:
1. Che Y, Wilson F, Bertolini J, Schiff P, Maher D.W. Impact of Manufacturing Improvements on Clinical Safety of Albumin: Australian Pharmacovigilance Data for 1988-2005. Critical Care & Resuscitation 8[4], 334-338. 2007. 
2. Product Information (various), commercially prepared Albumin.
3. British Pharmacopeia.
4. Onishi S, Itoh S, Isobe K, Ochi M, Kunikata T, Imai T. Effect of the Binding of Bilirubin to either the First Class or the Second Class of Binding Sites of the Human Serum Albumin Molecule on its Photochemical Reaction. Biochem J. 1989 Feb 1;257(3):711-4.

Australian & New Zealand Haemophilia Conference -
October 4 – 7, Canberra, Australia

HSANZ/ANZSBT/ASTH Annual Scientific Meeting –
October 14 – 17, Gold Coast, Australia

AABB Annual Meeting & TXPO – October 21 – 24, Anaheim, USA

ISBT Regional Conference, Asia – November 10 – 13, Hanoi, Vietnam