Capillary blood gases in a pediatric intensive care unit

Objective: To determine if samples obtained from arterial and capillary sources are comparable in children with diverse pathologic conditions during their stay in a pediatric intensive care unit. Study Design: Prospective, descriptive study in patients admitted to a multidisciplinary pediatric intensive care unit. Interventions: Seventy-five simultaneous paired samples (arterial and capillary) were obtained from patients with different degrees of capillary reperfusion, hemodynamic stability, blood pressure, and temperature. Both samples were analyzed ≤5 mins after collection. Measurements and Main Results: The average correlations between arterial and capillary samples were 0.87 for pH, 0.86 for CO₂, and 0.65 for oxygen. Neither poor perfusion nor low temperature altered the correlation for pH or CO₂. The only condition that significantly affected the correlation was hypotension. Conclusion: Capillary blood sampling is a useful alternative to gasometric evaluation of critically ill children, even in the presence of hypothermia or hypoperfusion, provided that hypotension is not present.