Accuracy of oscillometric noninvasive blood pressure compared with intra-arterial blood pressure in infants and small children during neurosurgical procedures

BACKGROUND: General anaesthesia in children results in a significant decrease of arterial pressure. Hypotension in neonates and infants reduces cerebral perfusion; therefore, an accurate arterial pressure measurement is of utmost importance. Although arterial pressure measured via an arterial catheter is considered to be the gold standard, in most children undergoing anaesthesia, arterial pressure is monitored by an upper arm cuff using an oscillometric technique. Data on the accuracy of these devices in such young patients are rare. OBJECTIVE: The aim of this study was to assess the accuracy of oscillometric blood pressure measurement compared with intra-arterial measurement. DESIGN: An observational comparison study. SETTING: A single-centre study, conducted in a German university hospital from November 2015 to January 2018. PATIENTS: Twenty-five children of 2 years old or less (median age 6 [IQR, 5 to 11]) months undergoing neurosurgical procedures requiring invasive arterial pressure determination. MAIN OUTCOME MEASURES: Arterial pressure was measured invasively and also oscillometrically by an upper arm cuff every 10 min. Simultaneously measured pairs of mean arterial pressures were analysed by the Bland-Altman method; the correlation coefficient, percentage error and concordance were calculated. RESULTS: Data from 21 children were analysed. Mean, (standard deviation) and [range] of invasive and noninvasive mean arterial pressures were 54 (8) [30 to 94] and 57 (8) [40 to 108] mmHg, respectively. The overall bias between invasive and noninvasive arterial pressure was -3 (7) mmHg, with 95% limits of agreement from -17 to +10 mmHg. The correlation coefficient, percentage error and concordance were 0.65, 25% and 0.77, respectively. For hypotensive invasive arterial pressure values below 45 mmHg, the mean bias (invasive arterial pressure - noninvasive arterial pressure) was -9 (5) mmHg. CONCLUSION: Arterial pressure derived by the oscillometric device showed acceptable levels of agreement. However, during hypotension, a clinically relevant overestimation of arterial pressure occurred when measured by an upper arm cuff.