The agreement between oscillometric and intra‐arterial technique for blood pressure monitoring in the lower extremities for infants and toddlers undergoing aortic coarctation repair

OBJECTIVE: Anesthetic management for patients undergoing surgical repair of aortic coarctation (CoA) should include constant blood pressure monitoring of the right upper extremity and a lower extremity. The delayed or absent pulse in the lower limbs often leads to unsuccessful arterial cannulation in infants and the oscillometric technique used for blood pressure measurement. The aim of this study was to evaluate the agreement between the oscillometric method and intra-arterial technique for blood pressure monitoring in the lower limbs of infants undergoing CoA. METHODS: A total of 45 infants diagnosed with isolated CoA were initially enrolled in this study and five were excluded because of cannulation failure. Thus, 40 patients had their blood pressure measured simultaneously by both oscillometric technique on the thigh and femoral artery catheterization. After induction and intubation, five pairs of blood pressure readings from each patient were collected in an interval of 3 min. Statistical analysis was accomplished by revised Bland-Altman analysis. RESULTS: There was a strong correlation between oscillometric and invasive blood pressure measurements [systolic blood pressure (SBP) r = 0.771, diastolic blood pressure (DBP) r = 0.704 and mean artery pressure (MAP) r = 0.850]. The mean difference and 95% limits of agreement (95% LOA) between oscillometric and femoral artery blood pressure readings was 3.830 mmHg (-19.297, 26.957) for SBP, -8.725 mmHg (-26.236, 8.786) for DBP, and -3.235 mmHg (-18.842, 12.372) for MAP. There were only one pair of MAP (1/40) and two pairs of SBP readings (2/40) out of range (95% LOA), and all of paired DBP readings were within 95% LOA. CONCLUSION: There was a good agreement between oscillometric and invasive blood pressure measurements of lower extremities in infants with isolated CoA statistically. However, the oscillometry-measured SBP showed a tendency to overestimate the intra-arterial blood pressure reference, while oscillometry-measured DBP underestimated its reference. MAP measurement provided the most accurate and reliable results in this study.