Patient Simulation Support
Advice and support for users of Rigel’s patient simulators
Get the most out of your Rigel patient simulators and find the answers to your questions with our FAQs.
FAQs and Articles
Why perform patient simulations?
Vital signs are crucial in communicating a patient’s condition and severity of a disease to health care clinicians. Patient monitors observe these vital signs continuously and provide warnings in the case of a serious event. It’s important any anomalous vital sign values alert clinicians, and to some extent, provide direct physiological input data to control connected life support devices.
A surge in patient flow and reduction in clinicians has increased the demand for patient monitors worldwide; which has led to an increase in the overall number of performance testing being implemented.
Patient simulation is a key part of performance test procedures, ensuring that patient monitoring devices are measuring correctly and accurately, by conforming to the manufacturer’s specifications and international standards.
Why do we test each parameter? What’s its significance?
NIBP (Blood pressure measurement)
- To determine transducer linearity and static pressure is within specification.
- Leaks can occur within the cuff or pressure system so leakage tests required.
- An overpressure test to ensure the pop off valve safeguards against a build-up of pressure.
IBP (Blood pressure measurement)
- To test pressure transducer performance for its linearity
- Dynamic pressure testing for blood pressure variations (hypotension/hypertension)
SpO2 (Oxygen saturation measurement)
- Testing for faulty probes. i.e LED degradation, contaminated lenses or damage to wiring
- Ensuring accurate calibration of SpO2 monitor
- Verifying the audible alarms
ECG (Heart rate measurement)
- Linearity test for heart rate amplitude and frequency
- Determining correct arrhythmia recognition
- Gain change sensitivity test
Temperature
- Linearity testing of temperature measurement
- Ensuring the correct temperature sensor is selected (YSI400/YSI700)
Respiration
- Accurate detection of sleep apnoea and verifying alarms
- Linearity testing of respiration rates
How to perform patient simulations?
Patient simulation is implemented by following performance verification procedures from medical device manufacturer service manuals. Ideally, a multi-parameter patient simulator is used to test a device in one test sequence, which provides a practical approach to the biomedical technicians. Each parameter has a different method for performance testing.
NIBP measurement principles primarily rely on the oscillometric method. It determines systolic, diastolic and mean arterial values by detecting the vibrations in the arterial wall at various pressure points by means of an inflated cuff. Testing the monitor accuracy involves both static and dynamic pressure simulations at specific values. System leak and over pressure tests are also part of the procedure, executed through the use of a manometer and a built-in pump, to ensure patient safety.
IBP is an invasive form of blood pressure measurement and uses a liquid filled catheter, which is placed in an artery. The arterial pressure is converted by a pressure transducer into an electrical signal. This is typically 5µV/mmHg. Testing the monitor for its linear sensitivity is essential in determining its accuracy. Patient simulation is performed by outputting defined DCV values.
SpO2 estimates the amount of oxygen in the blood by analysing the absorption of light by haemoglobin across two different wavelength LEDs (RED/IR). If more red than infrared light is being absorbed there are less oxygenated blood cells. SpO2 simulation is often implemented using optical simulation “fingers”. These devices provide variable attenuation to light in the red and IR wavelengths.
ECG measures tiny electrical signals from the heart using ECG leads placed on various parts of the body. These signals are amplified, measured and displayed on a patient monitor. ECG simulations are electrically generated cardiac arrhythmias or performance waveforms with pre-set amplitudes and frequencies.
Respiration utilizes the ECG leads to measure transthoracic impedance. As the thoracic cavity expands during inspiration, the impedance of the chest increases. During expiration the impedance of the chest decreases. Simulating respiration involves set baseline impedances with delta impedances providing respiration rates.
Temperature measurements in patient monitors are primarily carried out using NTC thermistors. This means that when temperature increases the resistance of the thermistor decreases. Temperature simulation is provided through a set number of resistances depending on the type of sensor (YSI400/YSI700).
What is patient simulation?
The primary vital signs are clinical measurements that are displayed and recorded across the biomedical field; predominantly on patient monitors. Patient simulation provides accurate mimicking of physiological vital signs to calibrate and test these devices, ensuring patient safety. There are five crucial vital signs that are regularly simulated:
- Blood pressure
- Oxygen saturation
- Heart rhythm
- Respiratory rate
- Temperature
Patient simulation is a fundamental part of service tests for patient monitors, which are required at regular service intervals. Service testing consists of a wide range of checks for each function or parameter.
The first tests are usually visual and electrical safety tests. This is followed by performance testing and includes:
- Integrity testing (Leak checks, over pressure testing)
- Performance accuracy (Patient simulation)
- Printer checks (Speed, amplitude
- Alarm checks (Pitch, frequency, volume)
- Physiological simulations (Patient simulation)
Or tell us what you’re looking for
Stay in the know
Sign up to our mailing list today to stay up to date with the latest industry news and information from Seaward.
Part of the GMC Group
Part of GMC Instruments
Contact us
Email: sales@rigelmedical.com
Switchboard: +44 (0) 191 586 3511
Phone: +44 (0) 191 587 8730
