Introduction to NIBP Monitoring
Non-invasive blood pressure (NIBP) monitoring has become a vital practice in healthcare for detecting hypertension at an early stage. However, subtle differences in NIBP monitor designs can lead to inconsistencies in their blood pressure readings. This highlights the critical importance of thoroughly testing and validating the accuracy of NIBP monitors before clinical use. The importance of hypertension management is highlighted by the stringency of thresholds for high BP in recent clinical guidelines. Recent clinical guidelines have tightened the thresholds defining high blood pressure, highlighting the need for accurate measurement.
The BPA700 is an advanced NIBP simulator uniquely designed to assess the performance of NIBP monitors and ensure they provide precise, reliable blood pressure measurements. This application note provides an overview of the critical need for rigorous NIBP monitor testing and demonstrates how the specialized capabilities of the BPA700 enable robust, standardized testing procedures.
The Need for NIBP Monitor Testing
Most NIBP monitors utilize oscillometric techniques to calculate blood pressure values. This involves analyzing the pressure oscillations generated within an occluding cuff to determine systolic and diastolic values as Figure 1 shown. However, subtle variations in proprietary algorithms for interpreting the oscillometric waveform can lead different NIBP monitors to calculate inconsistent blood pressure readings from the same input data. Comprehensive testing across the clinical pressure range is thus essential to verify accurate readings of both normal and hypertensive pressures.
Figure 1: Blood pressure oscillometric waveform and NIBP waveform (Source)
Advanced NIBP Testing Solution- BPA700
A noteworthy advancement in BPA700 serves as a specialized non-invasive blood pressure simulator designed to assess the performance of electronic non-invasive blood pressure monitors and physiological blood pressure monitors. The BPA700 boasts a high-precision pressure sensor and an inflation pump, endowing it with a wide array of testing capabilities. It can perform static pressure testing, dynamic pressure testing, leakage testing, and overpressure testing, all in compliance with the specific standards outlined in ISO/IEC/YY regulations. This device assumes a pivotal role as an indispensable tool for assuring the precision and dependability of blood pressure monitoring equipment, thereby making a significant contribution to the quality of care delivered to patients within clinical environments.
The BPA700 consists of a static pressure source with pump and a dynamic pressure generated by an advanced step motor, which passes through an air chamber to deliver air to ports. At the same time, the built-in manometer displays the pressure value in real time. BPA700 is equipped with an electromechanically operated valve for controlling the pressure port output.
Figure 2: Internal Diagram of BPA700
● A high-precision pressure sensor paired with an inflation pump and step motor generates accurate static (0-400mmHg) and dynamic pressure (10-300mmHg) waveforms across a wide clinical range.
● Sophisticated waveform simulation mimics patient physiological signals to assess NIBP algorithm accuracy.
● Electromechanical valves enable automated pressure control for standardized leak, overpressure and additional safety tests.
● A built-in manometer displays real-time pressures while an external interface allows graphing waveforms.
Testing NIBP Monitors with BPA700
Testing an NIBP monitor involves using a simulator which can mimic the oscillometric waveforms that the monitor would typically detect from a patient. The simulator is connected to the NIBP monitor, and it generates signals that represent various blood pressure levels. The monitor's readings are then compared with the known values generated by the simulator to verify its accuracy.
The BPA700 connects to the NIBP monitor through designated ports, and the testing should include:
1. Configuring the BPA700 to generate a specific blood pressure
2. Running the NIBP monitor to acquire a reading
3. Comparing the monitor's reading to the BPA700's set value
4. Repeating across the clinical pressure range
The accuracy of the NIBP monitor is determined by comparing its readings with the known values generated by the simulator. If the readings are within the acceptable error range, the monitor is considered accurate. Otherwise, it may need to be calibrated or serviced.
Configuration of Connecting BPA700 with the NIBP monitor
Figure 3: Configuration of Blood Pressure Monitor Connecting to BPA700
The BPA700 device features three essential output ports: Port 1, Port 2, and the Air reservoir, each serving a distinct function in the system as Figure 3 has shown. The cuff connects to the air reservoir port, meanwhile the blood pressure monitor device connects to port 1. A USB cable also links the BPA700 to a computer for real-time waveform visualization and data monitoring during testing.
Proper tubing configuration is critical for the BPA700. The wrist cuff and NIBP monitor must be separated from the main BPA700 unit. Dedicated tubing then connects each externally to the corresponding ports per the diagram.
Following this port connection scheme and tubing setup allows the BPA700's pressure waveforms to be accurately acquired from the monitor and displayed. It enables seamless pressure data transmission for complete testing and analysis.
Features and Benefits of BPA700
The BPA700 is a device that can test the performance and accuracy of non-invasive blood pressure (NIBP) monitors.
It has the following features:
• Standard assistant software: It conforms to the IEC 80601-2-30 standard, which is an international standard for the safety and essential performance of NIBP monitors. This standard specifies the methods and criteria for testing the accuracy and repeatability of NIBP measurement. By complying with this standard, the BPA700 ensures that the test results are consistent and reliable. (This part refers to the next chapter of the application note)
Figure 4: Assistant Software compliance with IEC 80601-2-30
• Pulse envelope: It allows users to adjust the pulse envelope, which is the shape of the pressure pulse amplitude variation with cuff pressure. The pulse envelope reflects the physiological characteristics of blood pressure and pulse, and different NIBP monitors use different algorithms to interpret it and calculate the blood pressure values. By adjusting the pulse envelope, users can simulate different blood pressure conditions and test how different NIBP monitors respond to them (This part refers to the next chapter of the application note).
Figure 5: Custom waveform adjustable to fit the manufacturer's algorithm
• Wide test range: It can simulate a wide range of dynamic blood pressure (10-300 mmHg) and static pressure (20-400 mmHg), covering the normal and abnormal blood pressure levels. Dynamic blood pressure is the blood pressure that changes with time, such as during a cardiac cycle or a measurement cycle. Static pressure is the constant pressure that is applied to the cuff or the artery. By simulating different levels of dynamic and static pressures, users can test the functionality and accuracy of NIBP monitors under various scenarios.
• Pressure - Time graph: It displays the pressure-time graph with cursors and automatic measurements, which helps users to analyze the test results and compare them with the target values. The pressure-time graph shows how the cuff pressure changes over time during a measurement cycle. The cursors allow users to select a specific point or segment on the graph and see the corresponding pressure value. The automatic measurements show the peak, as well as the leak rate on the main graph. These features enable users to easily evaluate the performance of NIBP monitors.
Figure 6: Blood pressure monitor pressure waveform shown in the graph
