Inconsistency between simultaneous blood pressure measurements in the arm, forearm, and leg in anesthetized children

Study Objective To determine the accuracy and precision of simultaneous noninvasive blood pressure (NIBP) measurement in the arm, forearm, and ankle in anesthetized children. Design Prospective, randomized study. Setting University medical center. Patients 101 ASA physical status 1 and 2 children (aged 1-8 yrs) scheduled for elective surgery with general anesthesia. Measurements Simultaneous NIBP measurements were recorded at the arm, forearm, and ankle at 5-minute intervals. Main Results The systolic blood pressure difference between the arm-forearm or the arm-ankle was within the ± 10% range in 63% and 29% of measurements, and within the ± 20% range in 85% and 67% of measurements, respectively. The diastolic blood pressure difference between the arm-forearm or the arm-ankle was within the ± 10% range in 42% and 44% and within the ± 20% range in 67% and 74% of measurements, respectively. In patients in whom the initial three NIBP measurements were within the ± 20% range between the forearm and arm, 86% of the subsequent measurements were also within that limit. Conclusions Forearm and ankle NIBP measurements are unreliable and inconsistent with NIBP measured in the arm of anesthetized children. These alternative BP measurement sites are not reliable in accuracy (comparison with reference "gold" standard) and precision (reproducibility).