Blood gas analysis, liquid heparin, pre-analytic error
Citation Information :
Sharma R, Goyal P, Chhapola V, Kumar S. Use of liquid heparin for blood gas sampling in pediatric intensive care unit: A comparative study of effects of varying volumes of heparin on blood gas parameters. Indian J Crit Care Med 2013; 17 (6):350-354.
Background and Aims: Pre-analytical errors in sample collection affect the reliability of blood gas (BG) analysis. Amount of liquid heparin as anticoagulant in samples for BG can affect results by its dilutional direct binding and compositional effects. The aim of this study was to examine the effect of varying amounts of heparin in blood samples on results. Materials and Methods : The prospective study was conducted on 15 children at a pediatric intensive care unit (PICU). Three different heparinized syringes were used containing minimal, 60 IU and 120 IU of heparin. A total volume of 1 ml blood in each syringe was taken and was analyzed by blood gas analyzer. Statistical analysis used related samples Friedman′s test and Wilcoxon signed ranks test for paired comparisons. The observed bias was also compared with the desirable bias according to specifications by Ricos et al. Results: There was a significant difference (P < 0.05) in values of pH, pCO 2, HCO3−, Hb and Na + in the three syringes. The pCO 2, HCO3− and Na + levels decreased with the increasing amount of heparin. The observed percentage bias was more than desirable percentage bias specifications for pCO 2, HCO3−, Hb, Na +, K + and Cl− levels. Conclusions: Syringes with minimal liquid heparin are most appropriate for studying BG parameters as they have the least effect on these parameters. There is a need to standardize the procedure of syringe preparation for BG analysis. Further studies are needed to compare minimal amounts of heparin with commercially available dry balanced heparin syringes.
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