A blood pressure sensor for long-term implantation
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Published on: May 17, 2016
E Bullister1, S Reich, P D'Entremont
1APEX Medical, Inc; and EDG, Inc., East Walpole, Massachusetts 02032, USA.
Abstract:
An implantable flow-through blood pressure sensor prototype has been developed for use with an implantable left ventricular assist device (LVAD). This sensor incorporates a flat pressure-sensing diaphragm that is designed to be integral with the wall of a titanium tube that may be placed in the inlet or the outlet flow path of any LVAD. The interior tube flow geometry is transitioned from a round to a D-shape such that flow separation is eliminated. Bench testing of 3 sensors was performed to characterize the sensor. The worst-case results showed a maximum nonlinearity of 0.64 mm Hg, a maximum hysteresis of 0.87 mm Hg, and a maximum nonrepeatability of 0.87 mm Hg. Long-term drift studies of 2 sensors at 193 days and 112 days resulted in a projected annual drift rate of 1.4 and 2.0 mm Hg, respectively. The APEX pressure sensors were evaluated in 5 ventricular assist acute calf experiments in which the sensor outputs were compared with Millar pressure catheter sensors. Pressure output comparisons showed similar pressure tracings. No visible evidence of thrombus formation was found on the APEX sensor compared with thrombus formation found on the Millar catheter at the entrance to the flow path. Tests demonstrated that the blood pressure sensor can accurately measure blood pressure and indicate that it has long-term stability.
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Equipments Used To Measure Blood Pressure
This invasive approach involves cannulating a peripheral artery. During each cardiac contraction, pressure generates mechanical motion within the catheter, transmitted through rigid, fluid-filled tubing to a transducer. This transducer converts mechanical motion into electrical signals displayed as waveforms on a monitor. An automatic flushing system prevents blood backflow. Due to the potential risk of unexpected arterial blood loss, this method is primarily used in intensive...
Measurement of Blood Pressure
Special considerations while measuring blood pressure
Monitoring Both Arms:
Monitoring BP in both arms during the initial assessment is advisable, as the systolic value may differ by five to ten mm Hg between arms. For subsequent BP assessments, use the arm with the higher reading.
Sites for measuring blood pressure
The Brachial Artery: Primary Site for Blood Pressure Measurement
Assessing Blood pressure using a doppler ultrasound
Pre-Procedural Guidelines for Doppler Ultrasound Blood Pressure Assessment:
Preparation of Equipment:
Pre-Procedural Guidelines for Assessing Blood Pressure
