Long-term Blood Pressure Measurement Research Articles

Silk nanofibrous iontronic sensors for accurate blood pressure monitoring

Continuous and cuff-less blood pressure (BP) monitoring based on pulse transit time has been extensively explored in wearable electronics. However, both the accuracy and wearing comfort are impeded by the limited sensitivity, skin conformability and breathability of conventional pulse sensors. Here, silk nanofibrous iontronic pressure sensors made entirely of biocompatible materials were demonstrated for accurate, skin-friendly and long-term BP measurement. The sensor achieved a high sensitivity (138.5 kPa−1) by incorporating ionic deep eutectic solvents (DES) and engineering micro-structured electrodes, which enables the accurate measurement of pulse waveforms. High flexibility and gas-permeability (2056 g m-2h−1) of the sensor render a conformal contact with the skin and prevent the signal deterioration by sweat, thus improving the signal accuracy and stability during long-term on-skin BP monitoring. Together with the electrocardiogram, both systolic and diastolic BPs could be estimated with mean ± standard deviation of 0.6 ± 3.57 mmHg and 0.7 ± 3.72 mmHg, respectively, meeting the standard of Association for the Advancement of Medical Instrumentation.

Continuous Non-Invasive Blood Pressure Measurement Using Pulse Transit Time in Children and Adolescents

As an alternative to ambulatory 24-h blood pressure monitors, the continuous, non-invasive blood pressure recording using pulse transit time (PTT) was compared with both oscillometric and intra-arterial measurement. In 144 pediatric patients (9.4±5.2 years) acute blood pressure was determined using three different methods of measurement. In 57 patients (11.4±4.9 years) of the pediatric normal ward, the blood pressure was simultaneously determined continuously by means of PTT compared to the intermittent oscillometric long-term measurement. In 9 patients (9.8±6.8 years) of the pediatric intensive care unit with continuous intra-arterial blood pressure measurement, the blood pressure was measured in parallel by means of PTT. Compared to the gold standard sphygmomanometry, mean systolic blood pressure values were comparable to 2 different oscillometric devices, but in the case of diastolic pressure measurement the pressure values were significantly lower or higher than with sphygmomanometry and auscultation. The results of the non-invasive comparative long-term measurements showed better correlations for systolic rather than diastolic pressure. Similar results were obtained comparing the direct intra-arterial blood pressure measurement with the SOMNOtouch™ NIBP device which measures blood pressure using the PTT. Continuous, indirect blood pressure recording using pulse transit time provides good correlations to the reference measurements for long-term measurement of blood pressure in children and adolescents and appears to be a usable method to measure the blood pressure of children especially at rest.

Validation of a telemetry system for long-term measurement of blood pressure.

We have used an implanted telemetry system to continuously monitor blood pressure (BP) in three dogs for durations ranging from 28 to 75 wk after implantation. Measurements of BP obtained by telemetry were compared every 3-12 wk, with measurements of BP recorded with a manometer-tipped catheter that was inserted into a femoral artery. Over a wide range of both physiological and pharmacologically manipulated pressures (40-200 mmHg), the values of BP obtained by the two methods were highly correlated (all r > 0.966; all P < or = 0.0001). However, the mean differences between the values obtained by the two systems were different from zero (range +29.6 to -1.5 mmHg; P < or = 0.0001), indicating an offset in the BP values recorded from the implanted system. Furthermore, this offset was dependent on the absolute level of the BP. The findings indicate that, for a period of at least 28 wk and up to 75 wk after implantation, the telemetry system accurately measures acute changes in BP and can reliably measure absolute BP provided that the system is properly validated.

Radial nerve palsy in a premature infant following long-term measurement of blood pressure

Radial nerve palsy in a premature infant following long-term measurement of blood pressure