Friday, February 1, 2013

The Effect of Packed Red Blood Cell Transfusion of Anaemic Dogs on Venous Oxygen Content, Lactate Concentration and Objective Clinical Assessment

The Effect of Packed Red Blood Cell Transfusion of Anaemic Dogs on Venous Oxygen Content, Lactate Concentration and Objective Clinical Assessment
WSAVA/FECAVA/BSAVA World Congress 2012
C. Kisielewicz; T. Parkin; R. Bell
University of Glasgow, School of Veterinary Medicine, Glasgow, Scotland, UK

Packed red blood cell (pRBC) transfusion improves blood oxygen carrying capacity and oxygen delivery to tissues in anaemic dogs; however, parameters of oxygenation, such as blood oxygen content and lactate concentration, are not commonly assessed when transfusing dogs. There is no standardised approach in determining when anaemic dogs require pRBC transfusion.
This prospective study aimed to evaluate changes in venous oxygen content (CvO2), lactate concentration and objective clinical assessment in response to pRBC transfusion and assess whether these corresponded to changes in haemoglobin.
Haemoglobin, CvO2 (calculated from values acquired through anaerobic venous blood gas analysis) and lactate concentration were measured (using overspill blood) prior to and following pRBC transfusion in anaemic client-owned dogs. A canine anaemia objective clinical assessment score was designed rating six parameters: mucous membrane colour, pulse quality, heart rate, respiratory rate and mentation / exercise tolerance giving pre- and post-transfusion scores. Increasing numerical score (maximum of 12) represented increasingly severe clinical condition. Dogs were excluded if receiving supplemental oxygen, dyspnoeic, hypovolaemic/dehydrated or if a transfusion reaction occurred. Statistical analyses were performed using paired t-tests, Wilcoxin signed rank tests, Spearman rank correlation and receiver-operator characteristic curves.
Haemoglobin, CvO2, lactate concentration and clinical assessment were determined in 15 dogs. Haemoglobin and CvO2increased with pRBC transfusion (P < 0.001, mean increase 3.2 g/l, P < 0.001, mean increase 9.95% and P = 0.002, mean increase 2.5 ml/dl respectively). Lactate concentration did not decrease significantly (P = 0.05, mean decrease 0.54 mmol/l). Each score parameter decreased significantly with transfusion; total score decreased by median of 4 (P = 0.001). Heart rate and respiratory rate decreased by a mean of 49.5 beats/minute (P < 0.001) and 22.5 breaths/ minute (P = 0.001) respectively. Changes in lactate concentration, score parameters, heart and respiratory rates were independent of pRBC volume or haemoglobin administered per kilogram bodyweight; however, haemoglobin, haematocrit and CvO2 were positively correlated with both pRBC volume and haemoglobin administered per kilogram bodyweight. Dogs with haemoglobin < 7.1 g/l were 12.24 times more likely to require transfusion (sensitivity 94.12%, specificity 92.31%) and those with CvO2 < 6.1 ml/dl were 11.47 times more likely to require transfusion (sensitivity 88.24%, specificity 92.31%). All dogs requiring transfusion had a clinical assessment score ≥ 5.
Conclusions and Clinical Relevance
Haemoglobin and CvO2 increase and the canine anaemia objective clinical assessment score decreases significantly with pRBC transfusion. The combination of these parameters may be used to objectively determine whether anaemic dogs require transfusion.
Speaker Information
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C. Kisielewicz
University of Glasgow
School of Veterinary Medicine
Glasgow, Scotland, UK