231 - Validation and reconstruction of intra-arterial blood pressure measurement with catheter-manometer systems in critically ill neonates

Poster Number: 231
Publication Number: 231.221

Lotte R. Hazeleger, Radboudumc Amalia Children's Hospital, Nijmegen, Gelderland, Netherlands; Berend E. Westerhof, Amsterdam University Medical Centers, Amsterdam, Noord-Holland, Netherlands; Tim Antonius, Amalia Children's Hospital, Radboudumc Nijmegen, Nijmegen, Gelderland, Netherlands; Willem-Pieter de Boode, Radboudumc Amalia Children's Hospital, Nijmegen, Gelderland, Netherlands

Background: Adequate blood pressure (BP) measurement, as part of comprehensive hemodynamic monitoring, is important to assess the circulation in critically ill neonates. Continuous BP measurement via an intra-arterial catheter-manometer system (CMS) is the gold standard method in neonatal care. However, validity of these measurements may be affected by the dynamic response (DR), a characteristic of the CMS. Inadequate DR of the system may lead to under- or overestimation of BP values and changes in waveshape.

Objective: The aim of this study was twofold: to assess the validity of intra-arterial BP measurement in neonatal intensive care and to propose and evaluate a method for the reconstruction of distorted intra-arterial BP measurement.

Design/Methods: Newborns admitted to the neonatal intensive care unit (NICU) with an umbilical or peripheral arterial line were included. During routine catheter flushing, we attempted to calculate DR from the pulse exercised on the system by closure of the flush. Computer simulations of neonatal BP measurement with CMS were performed to assess the effect of varying DR on BP values and waveshape. We created a measurement-specific method for waveform reconstruction based on DR of the CMS. The corrections for distortions in the signal were validated in the computer simulations. We simulated CMS distortions in high-fidelity waveforms, on which we exercised a simulated pulse to calculate DR. Using the DR, the distorted BP signals were reconstructed and compared with the original high-fidelity signals.

Results: To measure DR at the NICU, 8 patients with a total of 10 arterial lines were included from which 314 flush moments were recorded and DR could be calculated in[WB(1]  74% of the cases. Computer simulations showed patient-specific effects of DR on BP values, particularly systolic pressure, and the waveshape. 26 high-fidelity signals were used to validate the reconstruction method. Application of the reconstruction method improved validity of the distorted BP signal. The systolic pressure error between the original and distorted signal (2.4±3.0 mmHg, p < 0.001), and the original and reconstructed signal (0.8±0.8 mmHg, p< 0.001) were significantly different (1.6±2.2 mmHg, p=0.003).Conclusion(s): Validity of intraarterial BP measurement via CMS in critically ill neonates can be considerably affected by the CMS’ dynamic response, which can be easily measured in routine care. From the DR, we created a measurement-specific reconstruction method to distorted BP signals, leading to more valid intra-arterial BP measurements in critically ill neonates.
Curriculum Vitae LR HazelegerCV_LRHazeleger_EN.pdf