JPH0472553B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an infusion pump used for medical purposes. (Prior Art) As is well known, in an infusion pump, it is dangerous if air bubbles are mixed into the tube for infusion, so a detector is installed to detect air bubbles mixed into the tube. The time interval of the operation of the detector provided in the conventional infusion pump was constant regardless of the infusion rate. And since the moving speed of any air bubbles that may pass through the set position of the detector is the same as the infusion rate, it is short enough to detect air bubbles when infusion is performed at the highest infusion rate. The detector was set to operate at time intervals. In this way, if you give the detector an operating time interval value that allows it to detect air bubbles when injecting at the highest speed, all other infusion speeds are lower than the highest, so it is possible to is sufficient as the operating time interval value for air bubble detection when infusion is occurring at a rate of . FIG. 5 shows an operational flowchart of a conventional infusion pump. After turning on the power (S ₀ step), stop the pump operation (S ₁ step) and stop the 1ms timer (S ₂ step). Then, the input infusion rate is stored in the input memory x (S ₃ steps), and the pump start key is pressed.
In response to turning on (S ₄ steps),
Input 9 (m seconds) to counter T (S ₅ steps). Thereafter, the 1 ms timer is started (step _S6 ) and the pump operation is started (step _S7 ). When the stop key is not turned on (S ₈ steps), the detector is operated every time the flag becomes 1 (S ₉ steps) (S ₁₀ steps). As _{shown in FIG} .
is subtracted by 1, and when the count value of the counter T becomes 0, 1 is set in the flag. Therefore, bubble detection is performed every 9 msec. Air bubble detection is performed in step _S10 , and the presence or absence of air bubbles in the tube is determined (step _S11 ). When bubbles are present, an alarm is generated (step _S12 ), the operation of the detector is stopped (step _S13 ), and the process returns to step _S1 . On the other hand, when there are no bubbles, the operation of the detector is stopped (step _S14 ), the flag is set to 0 (step _S15 ), and the process returns to step _S8 . (Problems to be Solved by the Invention) As in the past, if the operating time interval of the detector is set to the shortest in order to accommodate all infusion rates, the operating time of the detector will inevitably become longer. This may lead to a deterioration in the life of the detector itself or an unnecessarily increased power consumption. (Means for solving the problem) Considering that when an infusion pump is actually used, it is relatively rare to perform infusion at the maximum speed, and it is often performed at a medium speed or lower speed. The present invention is an infusion pump that detects air bubbles mixed in a tube, and includes an infusion rate setting means for setting a rate at which an infusion is delivered from the tube, and a rate set by the infusion rate setting means. operation interval timing generating means for calculating an interval of operation time during which air bubbles can be detected according to the infusion rate determined; This is an infusion pump consisting of a bubble sensor for monitoring. (Function) With this configuration, according to the present invention, the operating time interval of the detector (bubble detection sensor) is changed according to the infusion rate, thereby preventing unnecessary deterioration of the detector and wasting power consumption. It can be omitted. (Example) Hereinafter, the configuration of the present invention will be described with reference to the drawings. FIG. 1 shows the use of an infusion pump according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a drug bag containing a drug solution for injection, and the drug solution in the drug solution bag 1 is transported through a tube 2, and is passed through a human body (in most cases It is injected into the body's veins) 4. An infusion pump 5 is set to control the amount of infusion. The tube 2 is installed in a pump head 6 for infusion provided in the infusion pump 5 and a detector (bubble detection sensor) 7 for detecting air bubbles in the tube 2. The pump head section 6 applies pressure to the tube 2 from the outside, and can control the amount of drug flowing through the tube 2, that is, the infusion rate, by increasing, decreasing, or moving the pressure value. The detector 7 is for detecting air bubbles 8 before they enter the human body 4, if air bubbles 8 are mixed in the chemical liquid flowing in the tube 2. The infusion pump 5 generates a visual or audible alarm upon detection by the detector 7, and also stops the operation of the pump head 6 to stop the flow of the drug solution in the tube 2. Injection of the air bubbles 8 into the human body 4 is prevented. FIG. 2 shows a block diagram representing the system of the infusion pump of this embodiment. The infusion pump of this embodiment receives an instruction to set the infusion rate from the infusion rate setting section 9 before starting infusion. Then, the central processing unit 10 controls the amount of rotation of the motor 11 according to the set infusion rate, and performs infusion at the pump head unit 12 (corresponding to 6 in FIG. 1). At the same time, based on the infusion rate, the operating time interval of the detector that matches the infusion rate is calculated. The operation time interval determined by the calculation is sent to the timing generation section 13, which instructs the operation time interval. Reference numeral 14 in the figure denotes a detector (corresponding to 7 in FIG. 1) for detecting air bubbles, and the detector 14 monitors air bubbles in the tube at operating time intervals according to instructions from the timing generator 13. When the detector 14 detects air bubbles, it notifies the alarm generator 15 that air bubbles have occurred. As a result, the alarm generator 15 generates a visible or audible alarm and instructs the motor 11 to stop rotating. Doctors, nurses, etc. respond to the alarm and take appropriate measures immediately. The detector 14 is, for example, an ultrasonic sensor that emits ultrasonic waves and utilizes the fact that the reception level on the receiving side is different depending on the chemical liquid and air, or the difference in the refractive index of light between the chemical liquid and air. An optical sensor or the like that performs detection by . FIG. 3 shows an operational flowchart of the infusion pump of this embodiment. The flowchart in the same figure is for an infusion pump in which the set value of the drug solution infusion rate is 1 ml/hour to 999 ml/hour, and the infusion rate is divided into five stages, and the maximum infusion rate in each category is Figure 2 illustrates the operation of a detector (bubble detection sensor) designed to detect air bubbles at sufficient operating time intervals to detect air bubbles at speeds. The table below shows the infusion speed divided into five stages and the operation time interval at which air bubbles can be detected at the highest speed among each division.

[Table] We will explain how to rank the infusion rate according to the set speed and operate the detector at the operating time interval according to each rank. See Figure 3a. In the figure, x is an input memory for a set infusion rate, and M is a memory for inputting different operation time intervals depending on the infusion rate. The flowchart includes a 1ms timer routine and a counter T for time measurement. The operating time interval set in the memory M is input to the counter T in an initial state, and the count value of the counter T is decremented by 1 each time an interrupt occurs in the 1 msec timer routine. When the power is turned on (S ₀ step), the operation of the infusion pump is stopped (S ₁ step). Next, stop the 1ms timer (S ₂ steps),
The infusion rate input by the operator is set in the input memory x (step _S3 ). Then, it is determined whether the infusion rate set in the _input memory ₅ steps). On the other hand, if x<700, proceed to step _S6 , and this time the infusion rate set in the input memory x is
Determine whether it is 400 (ml/hour) or more (S ₆ steps),
If x≧400, set the memory M18 (m/sec) (step _S7 ). On the other hand, if x<400, proceed to step _S8 , and this time the infusion rate set in the input memory x is
Determine whether it is 200 (ml/hour) or more (S ₈ steps),
If x≧200, 36 (m seconds) is set in the memory M (step _S9 ). On the other hand, if x<200, proceed to step _S10 , and this time the infusion rate set in the input memory x is 100.
(ml/hour) or more (S ₁₀ steps), x
If ≧100, 63 (m seconds) is set in the memory M (step _S11 ). On the other hand, if x<100, proceed to step _S12 and set 92 (ml/hour) in the memory M. After the operation time interval is set in the memory M as described above, it is detected that the pump start key is turned ON (step _S13 ), and after the detection, the set value of the memory M is stored in the counter T ( S ₁₄ steps). Then, a 1-second timer is started at step _S15 , and at the same time, pump operation is started at step _S16 . After that, the detector ₍ bubble detection sensor) starts operating (step S 19) on condition that the stop key is not operated (step S ₁₇ ) and that the flag described later is 1 (step S ₁₈ ). . The detector determines whether or not air bubbles are present in the tube (step S ₂₀ ), and if air bubbles are detected, generates an alarm (step S ₂₁ ) and stops the operation of the detector. (S ₂₂ steps).
When the processing of step _S22 is completed, the process returns to step _S1 . On the other hand, if no bubbles are detected, the operation of the detector is stopped (step _S23 ) and the flag is set to 0 (step _S24 ). When the process of step _S24 is completed, the process moves to step _S17 . If the stop key is in the OFF state in step _S17 , the process advances to step _S18 , and since the flag is set to 1 here, the process returns to step _S17 . This S ₁₈ steps →
Each time the _S17 step is repeated, the contents of the counter T are decremented by 1, and when the count value of the counter T reaches 0, the flag becomes 0, and the process proceeds from the _S18 step to the _S19 step again. ,
Air bubble detection is performed. Note that the stop key is turned on in step _S17 above.
If it is determined that the operation has been performed, the process returns to step _S1 . Figure 3a shows the case where the main operation routine is implemented using, for example, a microprocessor, but as shown in figure 3b, when an interrupt occurs by an internal timer etc., An interrupt routine may be provided to operate. FIG. 4 shows an operation flowchart of an infusion pump according to another embodiment of the present invention. In this embodiment, a stepping motor (pulse motor) is used as the motor for rotating the pump head, and the stepping motor receives pulse output from a microprocessor or the like. The rotational movement of the stepping motor is given by a change in the phase of the pulse output. In other words, when the infusion rate is set high (size), the interval between motor output timings becomes shorter,
On the other hand, when the infusion rate is set slow (small), the interval between motor output timings becomes longer, and therefore in this example, the detector (air bubble detection sensor)
The operation time interval is created by the motor output timing. The flowchart shown in FIG. 2A will be explained. After turning on the power ( _S0 step), the pump operation is temporarily stopped ( _S1 step), and the input infusion rate is stored in the input memory x ( _S2 step).
Now, the infusion rate 1 to 999 is stored in the input memory x.
(ml/hour) is set. Then, in step _S3 , the motor output timing y is obtained from the function y=(x). Specifically, this function can be y=a/x (a is a constant) y=(a/x)+b (a, b are constants), etc. If the set infusion rate x is a large value, that is, When the infusion is performed quickly, y is set to a small value in order to generate pulses at short time intervals; on the other hand, when the set infusion rate In order to generate pulses at intervals, a formula in which y is set to a large value is used. Then, in response to the pump start key being turned ON (step S ₄ ), the constant stored in the constant memory M is input to the counter T (step S ₅₎ .
step). Next, start pump operation (S ₆ steps). Thereafter, the detector (bubble detection sensor) is operated (step S ₉ ) on the condition that the stop key is OFF (step S ₇ ) and the flag is 1 (step S ₈ ). The detector detects whether or not there are bubbles in the tube, and if there are bubbles, an alarm is generated (step _S11 ) and the operation of the detector is stopped (step _S12 ). When the processing of step _S12 is completed, the process returns to step _S1 . On the other hand, if the presence of bubbles is not detected by the detector, the process proceeds to step _S13 , and the operation of the detector is stopped. Next, in step _S4 , the flag is set to 0, and the process returns to step _S7 . This embodiment has a configuration in which motor pulses are output at y time intervals, and an internal interrupt operation is used in a microprocessor program. That is, as shown in FIG. 4b, the routine for motor output timing is operated independently of the main routine shown in FIG. 4a. In this embodiment, constants are stored in the memory M, and
In step _S5 , the counter T is initialized with the constant of the memory M. In other words, the detector performs bubble detection operation once every M times of motor pulse output, and the operation time interval t=My
is given by Of course, by giving the value of M as a function of x other than a constant, the counter value can be changed depending on the speed of the motor. The present invention is not limited to the above two embodiments, but may include means for changing (lengthening or shortening) the operating time interval of the detector (bubble detection sensor) according to the infusion rate. In other words, the scope of rights extends. (Effects) As described above, according to the present invention, there is provided an infusion pump that detects air bubbles mixed in a tube, which includes an infusion rate setting means for setting the rate at which the infusion is delivered through the tube, and an operation interval timing generating means for calculating an interval of operation time during which air bubbles can be detected according to the infusion rate set by the speed setting means, and an operation interval calculated by the operation interval timing generating means; Since a bubble sensor is provided to monitor the bubbles in the tube,
Conventionally, bubble detection was performed at all infusion speeds at the bubble detection time interval required when infusion was performed at the highest speed, which shortened the life of the detector and increased power consumption. However, the present invention improves this problem and prevents the detector from deteriorating more than necessary and from wasting power.

[Brief explanation of drawings]

FIG. 1 is an overall structural diagram of an infusion pump according to an embodiment of the present invention, FIG. 2 is a block circuit diagram of the infusion pump, FIGS. 3a and 3b are operational flowcharts of the infusion pump, and FIG. 4a and 4b are operational flowcharts of an infusion pump according to another embodiment of the present invention, and FIGS. 5a and 5b are operational flowcharts of a conventional infusion pump. 1...Medical solution bag, 2...Tube, 3...Injection needle, 4...
Human body, 5... Infusion pump, 6... Pump head, 7... Detector (bubble detection sensor), 8... Air bubbles,
9... Infusion rate setting unit, 10... Central calculation unit, 11...
Motor, 12... Pump head section, 13... Timing generating section, 14... Detector, 15... Alarm generating section.

Claims (1)

[Scope of Claims] 1. An infusion pump that detects air bubbles mixed in a tube, comprising: an infusion rate setting means for setting a rate at which an infusion is delivered from the tube; and an infusion rate setting means for setting a rate at which the infusion rate is set by the infusion rate setting means. operation interval timing generating means for calculating an interval of operation time during which air bubbles can be detected according to the infusion rate determined; and the air bubbles in the tube at the operation interval calculated by the operation interval timing generation means. An infusion pump characterized in that it is comprised of a bubble sensor that monitors.