Tonometric Condition of Cellular Polypropylene Film Sensors in Measuring Arterial Pressure Waveform

Tonometric continuous measurement of arterial pressure becomes feasible using a cellular polypropylene (Cellular PP) film sensor. A pulsatile arterial vascular phantom model was used to find the range of optimal tonometric conditions and the responsiveness to dynamic pressure changes. The optimal tonometric condition was assessed by the correlation coefficient between the hydraulic pressure and the Cellular PP output using two different types of tubes (the latex tube and the hydrogel tube) to simulate arteries. With a setting of the normal blood pressure range, the output of Cellular PP correlated strongly with the level of hydraulic pressure, 0.998 and 0.989 in the latex tube and the hydrogel tube, respectively. For maintaining the optimal tonometric condition, the depressed depths of the latex and the hydrogel tube were less than 1.2 and 0.6 mm, respectively. The phantom model also demonstrated that the Cellular PP sensor followed changes in a hydraulic pressure dynamically under the optimal tonometric conditions. The present results demonstrated the Cellular PP film sensor is applicable to the arterial tonometry in measuring the instantaneous blood pressure while the sensor is adjusted to maintain the minimal flatness of the underlying arterial wall.Clinical Relevance— To understand the physiological characteristics of blood pressure and arterial system, the instantaneous measurement of blood pressure is necessary. The present study suggests that Cellular PP films are applicable to peripheral arteries tonometrically to obtain simultaneously the respective blood pressure waveforms.