Comparison of Non-Invasive Oscillometric and Intra-Arterial Blood Pressure Measurements in Children Admitted to the Pediatric Intensive Care Unit

Intra-arterial blood pressure (IABP) measurement, although considered the gold standard in critically ill children, is associated with certain risks and lacks widespread availability. This study was conducted to determine the differences and agreements between oscillometric non-invasive blood pressure (NIBP) and invasive IABP measurements in children. Inclusion criteria consisted of children (from 1 month to 18 years) admitted to the pediatric intensive care unit (PICU) of a teaching hospital who required arterial catheter insertion for blood pressure (BP) monitoring. The comparison between IABP and NIBP was studied using paired t-test, Bland–Altman analysis, and Pearson's correlation coefficient. In total, 4,447 pairs of simultaneously recorded hourly NIBP and IABP measurements were collected from 65 children. Mean differences between IABP and NIBP were −3.6 ± 12.85, −4.7 ± 9.3, and −3.12 ± 9.30 mm Hg for systolic, diastolic, and mean arterial BP, respectively (p < 0.001), with wide limits of agreement. NIBP significantly overestimated BP (p < 0.001) in all three BP states (hypotensive, normotensive, and hypertensive), except systolic blood pressure (SBP) during hypertension where IABP was significantly higher. The difference in SBP was most pronounced during hypotension. The difference in SBP was significant in children <10 years (p < 0.001), with the maximum difference being in infants. It was insignificant in adolescents (p = 0.28) and underweight children (p = 0.55). NIBP recorded significantly higher BP in all states of BP except SBP in the hypertensive state. SBP measured by NIBP tended to be the most reliable in adolescents and underweight children. NIBP was the most unreliable in infants, obese children, and during hypotension.