Oscillometric and intra-arterial blood pressure in children post-kidney transplantation: Is invasive blood pressure measurement always needed?

Abstract

Objective: Blood pressure (BP) monitoring in children immediately after kidney transplantation is ideally performed with an arterial line. Accurate measurement of BP is necessary for optimal management. However, during the first days postoperative, the arterial line is removed and BP measurement is switched to a non-invasive device. The aim of this study was to determine the accuracy and reliability of the automated oscillometric device compared to invasive arterial BP (IBP) monitoring in patients after renal transplantation in pediatric intensive care unit (PICU). Method: We analyzed all simultaneously measured BPs in children with a kidney transplant in the Amalia Children's Hospital Radboud University Medical Center between January 1, 2012, and January 1, 2016. BP measurements were performed according to the hospital protocol. Agreement between invasive and non-invasive methods was assessed using Bland-Altman plots. Results: A total of 29 patients were included in this retrospective study. The majority of children were male (59%), and median age was 11 years (range 1-17 years). Totally, 80 BP measurements were recorded during the first days post-kidney transplantation. The correlation coefficients (R) of systolic, diastolic, and MAP of non-invasive (NIBP) and IBP measurements were 0.84, 0.76, and 0.77, respectively (P < 0.01). Overall, the average MAP (7.5 ± 1.2 mm Hg; P < 0.05) NIBP values were lower compared to IBP. In hypertensive patients, MAP (10.4 ± 10.0 mm Hg; P < 0.05) BP values were significantly lower using the NIBP device. Clinically relevant difference of >10 mm Hg was found in 51% (41/80) of measurements and mainly observed in hypertensive measurements. Conclusions: IBP measurement is considered the golden standard for monitoring BP in patients immediately after kidney transplantation. NIBP values showed a good agreement with invasive reading, but the variability of NIBP mainly in hypertensive patients is high as it is the number of clinically relevant differences to IBP. We conclude that IBP remains the golden standard to monitor BP in children directly postoperatively.