The comparison between capillary blood sampling and arterial blood sampling in an NICU

To study the correlation between the results of blood examination from arterial blood sampling via arterial puncture and capillary blood sampling via heel-stick, 33 premature infants with birthweights ranging from 635 grams to 2500 grams were enrolled in this study. The 33 paired samples of capillary blood sampling via heel-stick and simultaneous arterial blood sampling via arterial puncture were analysed within 3 minutes after collection for hemoglobin, hematocrit, sodium, potassium, chloride, calcium, glucose, lactate, osmolality, and blood gas. The average correlations between capillary and arterial samples were 0.92 for pH, 0.93 for PCO2, 0.87 for hematocrit, 0.88 for hemoglobin, 0.86 for sodium, 1.16 for calcium, 1.14 for glucose, 1.01 for lactate, 1.03 for base excess (BE), 1.05 for HCO3-, 0.91 for osmolality, 1.35 for PO2, 0.28 for O2 saturation, 0.67 for potassium, and 0.78 for chloride. We concluded that capillary blood sampling via heel-stick is a rapid, simple, less invasive, and reliable alternative to arterial blood sampling for the evaluation of hemoglobin, hematocrit, sodium, calcium, glucose, lactate, osmolality, and blood gas (pH, pCO2, HCO3-, BE) in premature infants.