Feasibility study of continuous non-invasive blood pressure measurement in critically ill children

Introduction

Arterial finger blood pressure can be measured continuously and non-invasively using the Finapres method. There are numerous studies on the absolute blood pressure levels and tracking of blood pressure changes in adults [1]. The accuracy and precision of Finapres are according to the standards of the Association for the Advancement of Medical Instrumentation. Recently BMEYE developed finger cuffs specifically designed for the pediatric population. We present the first feasibility study comparing the blood pressure measurements of a pediatric prototype device (PFINAP) with intra-arterial blood pressure (IAP) in critically ill children.

Methods

Thirty-six mechanically ventilated and sedated children, with a median age of 4 months (4 days-10 years) and a median body weight of 5 kg (2–22 kg) were included. The IAP and PFINAP were recorded simultaneously for a period of 10 min. Both signals were stored with a 200 Hz sample rate. Standardized intervals of 30 s were used for further analysis. The two methods were compared using the Bland-Altman method.

Results

One hundred and thirty-seven out of 144 non-invasive blood pressure measurement (95%) signals were obtainable. The bias for systolic, diastolic and mean arterial pressures was -15.9 mmHg (SD 9.8), -8.0 mmHg (SD 5.9) and -10.5 mmHg (SD 5.6), respectively (Fig. 1). Repeatability for the bias of MAP (1.96 × SD of the difference between repeated measurements) was 6.9 mmHg. The use of vasoactive drugs or a low temperature of the hand did not influence the bias.

Figure 1

Conclusion

The bias and precision found in this study are comparable with the results of previous studies in adults. In adults, accuracy and precision strongly improves after reconstruction of finger blood pressure [2]. A similar software adjustment for the pediatric population is under construction.