Context: The Paratrend monitor provides continuous arterial blood gas monitoring after insertion through a ≥20-gauge arterial cannula. Objective: To determine the correlation of arterial blood gas values and the Paratrend monitor placed through a peripheral intravenous catheter. Design: Prospective, open-label evaluation. Setting: University-based pediatric intensive care unit. Patients: Infants and children with respiratory failure and arterial access. Results: The cohort included 23 infants and children. A total of 100 sample sets (Paratrend/ABG PCO2 and pH values) were collected. The absolute difference between the arterial and Paratrend PCO2 was 2.9 ± 1.8 mm Hg (range 0 to 9 mm Hg). Linear regression analysis of Paratrend PCO2 versus arterial PCO2 resulted in r = 0.97 and r2 = 0.9479 (P < .001). Bland-Altman analysis of PCO2 values demonstrated a bias ± precision of - 2.1 ± 2.7 mm Hg. The absolute difference between arterial and Paratrend pH was 0.04 ± 0.02 units (range 0 to 0.15 units). Linear regression analysis of Paratrend pH versus arterial pH resulted in r = 0.83 and r2 = 0.7016 (P < .0001). Bland-Altman analysis of pH values revealed a bias ± precision of 0.03 ± 0.03 units. Conclusions: Inserted through a peripheral intravenous cannula, the Paratrend monitor can be used to provide an accurate estimation of arterial blood gas values in children with respiratory failure.