Intravenous infusion is a commonly used method of administration in clinical treatment. In clinical practice, the speed of infusion may directly affect the treatment effect, and may even affect the safety of care. infusion pump is an instrument that can accurately control the number of infusion drops or infusion flow rate, ensure that the drug can be evenly velocied, the dosage can be accurate and safe into the patient's body, and it is an intelligent infusion device, the infusion speed is not affected by the back pressure of the human body and the operator, the infusion is accurate and reliable, which helps to reduce the intensity of clinical nursing work and improve the accuracy of infusion. safety and quality of care.

Infusion pumps have a variety of product models and different performance. According to its working characteristics, it can be divided into three categories: peristaltic controlled infusion pumps, constant volume controlled infusion pumps and syringe micro-injection infusion pumps.

1. The basic structure and working principle of the infusion pump

The infusion pump system is mainly composed of a microcomputer system, a pump device, a monitoring device, an alarm device and an input and display device. The microcomputer system is the "brain" of the whole system, which intelligently controls and manages the whole system, and processes the detection signal, generally using a single-chip microcomputer system. The pump unit is the "heart" of the whole system and is the power source for delivering liquids medical infusion pumpGenerally, a finger-shaped peristaltic pump is used as the power source. The finger peristaltic pump (the peristaltic part shown in the figure below) uses a roller to rotate to squeeze a certain part of the infusion pump pipeline to produce peristalsis, thereby pushing the liquid forward flow. Finger peristaltic pumps are the most widely used due to their small size, light weight, accurate quantification, and convenient loading and unloading of infusion tubes. This type of pump has a camshaft with multiple cams that move at different angles, each connected to a finger-shaped slide.

When working, the camshaft is driven by the stepper motor to rotate, so that the slider moves up and down in a certain order and movement law, and squeezes the intravenous infusion tube in turn like a wave, so that the liquid in the infusion tube flows in a certain speed directionally. The finger peristaltic pump is more accurate and can control the total amount and speed of infusion in a wide range; When the number of "fingers" exceeds 8 (generally 12), the linearity of the pump is good, and it is not easy to pulsate during infusion, so that the infusion pump has a safety and stability monitoring device is mainly composed of a variety of sensors, and the infusion pump is equipped with an infrared drop number sensor, a pressure sensor and an ultrasonic bubble sensor, etc., which are respectively used for the detection of liquid flow rate and flow, blocking pressure and leakage and bubbles.

The alarm system is that the signal sensed by the sensor is processed by the microcomputer to obtain the alarm control signal, and then the alarm device responds to attract people's attention and carry out correct processing at the same time. It has the functions of photoelectric alarm and sound alarm, which can alarm abnormal situations such as power failure, pump door not closed, low temperature, completion of infusion, battery undervoltage, pipeline blockage and bubbles in the pipeline during the infusion process. The input part of the input and display device is responsible for setting the various parameters of the infusion, such as the infusion volume and infusion speed. The display section is responsible for displaying the parameters and the current working status.

2. Verification and quality control of the main performance of the infusion pump

In order to ensure the safe and normal operation of the infusion pump and try to avoid failures, it is necessary to conduct regular testing and quality control. According to the requirements of the calibration specification of JJF1259-2010 " medical Syringe pumps and infusion pumps", the quality inspection of infusion pumps is mainly divided into two aspects: electrical safety testing (patient leakage current) and performance testing.

1) Preparation before testing

The instrument to be tested should be placed smoothly on the workbench ( syringe pump) or on the infusion stand (infusion pump), and the syringe or infusion tube used in the testing process should be suitable for the instrument under test, and the syringe or infusion tube matched with the syringe pump or infusion pump to be tested should generally be used. The medium used for testing should be distilled water or deionized water that meets the requirements of GB/T6682-2008 "Specifications and Test Methods for Analytical Laboratory Water".

2) Patient leakage current check

The infusion pipeline is filled with normal saline (0.9% sodium chloride solution), the output end connected with the patient is immersed in a container filled with normal saline, and the leakage current tester is used to measure the patient leakage current between the output end of the infusion pump and the ground of the external power supply and between the output end of the infusion pump and the internal power supply. The allowable values of the patient's leakage current were 0.01 mA for AC and DC, respectively.

3) Door opening alarm function check

During the working process of the infusion pump, when the door is opened without stopping, the infusion pump should generate the corresponding sound and light alarm.

4) Bubble alarm function check

During the working process of the infusion pump, the infusion pipeline is used to inject bubbles larger than the size specified by the manufacturer with a microsampler, and when the bubbles pass through the infusion pump, the infusion pump should produce the corresponding sound and light alarm.

5) Functional check of the alarm after the infusion is completed

Set the infusion volume before the infusion pump works, and when the infusion volume reaches the set value, the infusion pump should stop and alarm.

6) Functional check of power cord falling off alarm

Turn on the AC power supply of the infusion pump (with built-in power supply or standby power supply), and the instrument is in the working state of AC power supply, and disconnect the power cord at this time, which should automatically switch the built-in power supply or standby power supply and alarm.