Do bolus doses of UFH contribute to increased bleeding risks in children?
Abstract number: PP-WE-437
Newall1 F.H., Ignjatovic2 V., Johnston3 L., Lane4 G., Monagle1 P.
11Paediatrics 22Murdoch Childrens Research Institute, The University of Melbourne, Parkville, Australia 33School of Nursing and Midwifery, Queens University, Belfast, Ireland 44Cardiology, Royal Childrens Hospital, Parkville, Australia
How-to-cite Newall FH, Ignjatovic V, Johnston L, Lane G, Monagle P. Do bolus doses of UFH contribute to increased bleeding risks in children?. Journal of Thrombosis and Haemostasis 2009; Volume 7, Supplement 2: Abstract PP-WE-437
Clinical reports suggest UFH-related major bleeding rates of up to 24% in children. Current recommendations for UFH therapy recommend a 75–100 IU/kg bolus followed by an age-dependent continuous infusion rate. This recommendation is based on a study that first measured UFH response 6 h post commencement; at that time, 39% of patients achieved a minimum level APTT (> 55 s). We evaluated laboratory response to a single UFH bolus dose of 75–100 u/kg in children < 16 years of age (n = 64) to determine the independent impact of UFH bolus on anticoagulation levels in children. Venous blood was collected from a dedicated IV at 15, 30, 45 and 120 mins post UFH dose. APTT and anti-Xa assays were performed. The upper limit of the APTT assay was modified to measure time to clot formation up to 999 s. APTT and anti-Xa results for samples collected at 15 and 120 mins post bolus are presented in the table.
Table for PP-WE-437
| ||15 mins Post-UFH||120 mins Post-UFH|
|Anti-Xa (mean, 95% CI)||0.88 (0.84–0.91) N = 55||0.63 (0.58–0.68) N = 43|
|APTT (mean, 95% CI)||586 (394–778) N = 14∗||250(200–300) N = 41^|
|∗43 results > 999 s; ^2 results > 999 s.|
67% of all APTT assays performed at 15, 30 and 45 mins post bolus were > 999 s. Current bolus recommendations give very high anticoagulant effect out to 120 mins post bolus dose, without concurrent continuous infusion. Despite very high APTT and anti-Xa levels, there were no major bleeding events. Lack of target APTT range achievement in previous paediatric studies may reflect the need for modified continuous infusion doses. Further study of reduced bolus dose UFH therapy may be worthwhile.
Disclosure of interest: none declared.
To cite this abstract use the following format:
Journal of Thrombosis and Haemostasis 2007; Volume 5, Supplement 2: abstract number
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