Comparing the Liquid Heparin Syringe with Dry Bound Heparin Syringe for Blood Gas Analysis

Abstract

Background Blood gas (BG) analysis is routine today for patient management in intensive care units. Accurate analysis of different parameters in the BG is essential for managing critical patients. Errors in BG analysis can happen at many levels, with one of them being at sampling and heparinization. We compared self-prepared heparinized syringes rinsed with liquid heparin (LH) and the standard commercially available syringes with dry bound heparin (DBH) for arterial BG analysis of postoperative cardiac surgical patients. Methods This prospective observational study was conducted in 100 consecutive adult cardiac surgical patients in the cardiac surgical intensive care unit. Paired samples were collected, analyzed immediately, and statistically compared for pH, partial pressure of arterial oxygen (pO2), partial pressure of arterial carbon dioxide (pCO2), oxyhemoglobin saturation (SaO2), HCO, Na+, K+, Cl–, Ca2+, Mg2+, base excess (BE), hemoglobin (Hb), hematocrit, glucose, and lactate. Paired parameters were compared and agreement was evaluated using Bland–Altman difference plots. The 95% limits of absolute agreement (LOA) were compared with total allowable error (TEa). Results The BG parameters analyzed by two types of heparinized (LH and DBH) syringes were found to be comparable with a negligible mean difference and had an agreement outside the TEa of 8% for pO2, pCO2, and hematocrit, 7% for BE, 6% for Mg2+, 5% for K+, Ca2+, and lactate, 4% for HCOand Na+, 3% for pH, Cl–, Hb, and glucose, and zero for SaO2. The two types of syringes did not show clinically relevant discrepancies among many different parameters as per LOA and TEa limits. Conclusion In this study, we found that the BG parameters—respiratory, metabolic, and electrolytes—were comparable between the two types of syringes used for sampling. Unlike some previous studies, we did not find statistically significant differences among these analytes, which might have been due to appropriate self-preparation of heparin syringes.

Comparison of arterial blood gas results obtained using two types of Heparinized Syringes

“…However, some studies differed in their findings. A study conducted by Sahu et al did not find any significant difference in any of the blood gas parameters under study 15 . Similarly, another study by Sezik et al also found no significant difference between the blood gas results obtained using liquid heparin or dry heparin 16 .…”

“…This could have be possible because of efficient blood sampling, ensuring appropriate ratio of heparin and whole blood and efficient heparinization technique along with rapid analysis. Studies conducted by Borabadi et al and Shabani et al highlighted the importance of appropriate heparin concentration in minimizing the effects of liquid heparin on blood gas results [13][14][15][16][17] . Low concentration (1000 U/L) heparin caused less difference in results.…”

The Effect of Heparin Concentration on Results of Venous Blood Gas of Patients admitted to Cardiac Intensive Care Unit: A double-blind clinical Trial

“…According to the results of the study by Sandler et al, the sodium ion group in the heparin (5000 IU/mL) was less affected than heparin (1000 IU/mL), which is probably due to the higher sodium concentration added to the sample from liquid sodium heparin, and this error is exacerbated at higher liquid heparin concentrations [ 41 ]. Kumar Sahoo and Hooper, excess liquid heparin due to its dilution and combination effects leads to a decrease in the measurement of positively charged ions such as potassium, calcium, and, on the other hand, there is almost no potassium in liquid sodium heparin and dilution of heparinized blood samples can lead to a significant reduction in potassium levels [ 18 , 38 ]. In general, the liquid heparin concentration should not exceed 10 units per milliliter of blood, unless specialized heparin is used to eliminate the effect of heparin-binding activity of calcium [ 31 ].…”

“…Adding too much liquid heparin (sodium or calcium) to the blood sample can lead to positive bias by binding to positive ions and lead to negative bias by increasing the acidity level of the blood gases and the diluting blood sample [ 12 , 15 , 16 ]. Electrolytes and partial pressure of carbon dioxide (PCO2) seem to be dilution-sensitive variables, while the logarithm of the hydrogen ion concentration (pH) and the partial pressure of oxygen (PO2) are not significantly affected [ 17 , 18 ]. Ionized calcium is more affected by the binding of heparin salts, although sodium and potassium may also be affected [ 19 – 21 ].…”

“…The Clinical and Laboratory Standards Institute (CLSI) and American Association for Respiratory Care (AARC) have published guidelines for the BG analysis that do not state the collection of blood in liquid heparinized syringes; however, they do warn the dilution and chemical effects of liquid heparin in BG tests [ 18 , 22 , 23 ]. Moreover, despite all these releases, non-standard BG sampling using liquid heparin (especially different sizes of syringes, needles and collecting different blood samples) is used to ensure patient comfort, it's easier use or unawareness of its effects [ 18 , 24 ].…”