A cohort study assessing the impact of small volume blood tubes on diagnostic test quality and iatrogenic blood loss in a cohort of adult haematology patients.

BACKGROUND/AIM: To estimate the reduction in blood volume loss and impact on diagnostic test quality associated with introduction of small volume blood tubes in a cohort of haematology inpatients compared to a historical comparator group. METHODS: Prospective cohort study of haematology inpatients admitted to a tertiary referral hospital in Adelaide. Small volume blood tubes were used in an intervention cohort admitted between 2012 and 2013 and compared to a control cohort admitted between 2009 and 2010 where standard volume blood tubes had been used. The diagnostic test quality, specimen integrity and total reduction in blood loss associated with small volume blood tubes were estimated. RESULTS: Small volume blood tubes demonstrated acceptable collinearity on commonly assayed haematological and biochemical parameters. Small volume tubes were associated with a 42% reduction in blood volume loss equating to a saving of 8.5 mL per patient per day or 180 mL of blood loss over a 3-week admission. Small volume blood tubes were associated with a slight but significantly increased rate of fibrin contamination of ethylenediaminetetraacetic acid samples (0.2-0.5% of specimens). CONCLUSION: Small volume blood tubes are associated with a substantial reduction in total blood volume collected per day in haematology inpatients. They have similar diagnostic validity and sample integrity to that of standard volume containers.

Warming blood prior to transfusion using latent heat.

OBJECTIVE: Major trauma is associated with blood loss and hypothermia. It is common to replace lost fluid with red cells stored at 2-6°C, and/or colloid/crystalloid fluid stored at ambient temperature, thus increasing hypothermia risk. At trauma and medical retrieval sites, mains electricity powered fluid warmers cannot be generally used. Latent heat provides an alternate practical method of portable temperature-controlled intravenous fluid warming. This work investigates the safety and efficacy of a fluid warmer powered by latent heat. METHODS: Twenty-five haematology patients received red cell transfusions, one through a fluid warmer, using latent heat from a super-cooled liquid and one without warming. Temperature of donor red cell units was measured after passing through fluid warmers. Blood samples were collected from red cell units and patients, prior and after each transfusion. These were tested for haemolysis markers (plasma haemoglobin, potassium, lactate dehydrogenase, bilirubin) and for traces of super-cooled liquid. Patient physiological parameters (oxygen saturation, pulse, temperature, blood pressure, respiration) were monitored during each transfusion. RESULTS: Patient's physiological signs remained stable and no transfusion reactions were observed during warm transfusions. Latent heat fluid warmers increased the temperature of red cell units to approximately 35°C. There were no significant differences in haemolysis markers following warmed and unwarmed transfusions, and no contamination of red cell units by super-cooled liquid was detected. CONCLUSION: The latent heat fluid warmer was shown to safely warm transfused blood in a controlled clinical setting.