Guide 5-INFUSION PUMP

Daniela&Oscar
29 abr 2018
4 Min. de lectura

Actualizado: 1 may 2018

Glossary

Pressure: Is defined as the force acting at right angles per unit area.

The force exerted a solid object on a surface is its weight, W.

W = mass x acceleration due to gravity = mg.

Sensors: Is a device which provides a usable output in response to a specified measurand.

A sensor acquires a physical quantity and converts it into a signal suitable for processing (e.g. optical, electrical, mechanical)
Nowadays common sensors convert measurement of physical phenomena into an electrical signal
Active element of a sensor is called a transducer.

Volume: Is a function of state and is interdependent with other thermodynamic properties such as pressure and temperature. For example, volume is related to the pressure and temperature of an ideal gas by the ideal gas law.

Time: Is a measured or measurable period, a continum that lacks spatial dimensions. Time is of philosophical interest and is also the subject of mathematical and scientific investigation.

Infuse: In medicine, to introduce a solution into the body through a vein. An infusion is the therapeutic introduction of a fluid other than blood into a vein. The infused fluid might, for example, be a saline (salt) solution.

Workshop:

By means of a peristaltic pump of 12 V, the control of an infusion pump was designed; Through the arduino program, Using related control, the user entered the machine an amount in milliliters and a time in minutes; The resolution handled by our infusion pump is 50 ml in 1 minute. all the variables to be controlled were related:

Pressure.
Volume.
Flow.
Weather.

Design

MOTOR

For the peristaltic engine in the first place, we designed to design one by means of the design tool .CAD Inventor to later adapt it to a DC motor; in this case there was a problem with the hose that would have to adapt to it.

We made a mounting for hold the reservoir bag and also for do the administration of the liquid and drip. The position of the mounting was the correct because it acted with the force of gravity.

Development

The <LiquidCrystal.h> library of the arduino board is used, to be able to use a 16x2 screen as a visualization interface, where it is shown:

-The name of the team: INFUSION PUMP.

-Menu for selection: A. Time. B. quantity.

-Process: time in which it is being carried out until its completion.

The coupling circuit of the screen to the arduino is the following, port D was used because it is where the lcd pins are best fitted, a 10k potentiometer was also used to adjust brightness:

2. Code for lcd use in arduino:

The keyboard library of the arduino board is used, to be able to select the different options that are shown on the LCD. Numerical values and float arrays will be used.

-Letras to enter the menu:

A. To be able to enter time.

B. To be able to enter amount.

#. To accept the values entered.

C. To return to the menu.

-Numbers to enter the corresponding values in which the dosage of the medication will be done.

The coupling circuit of the keyboard to the arduino is the following, port C was used because it is where the pins of the keyboard are best fitted, all digital.

Code for use of the keyboard in arduino:

Code for determination of rows, columns and result of pressing letters on the matrix keyboard:

MOTOR CHARACTERIZATION

Before carrying out the control code, the respective characterization of our peristaltic motor must be done; taking into account that the supply of medicines is done in milliliters is evaluated from one ml to one hundred ml at their respective times (min). The result of the characterization is one hundred ml in a min, the rest of this range is obtained one hundred ml in two min or ranges of fifty ml down in a min.

Peristaltic motor code

Previously we keep the values entered in time in the variable t and the values entered in quantity in q; because these terms would be string type it is necessary to convert them to integers as shown in the code.

The control that was generated consisted of the following steps:

1. Characterize the motor, in our case the motor has a resolution of 50 ml in 1 minute.

2. Therefore the resolution would be quantity entered over time.

3. Two times are determined:

to. On: resolution about 50ml.

b. Off: 1 less on.

As these times of turning on and off a numerical value and you want to have these times in value of seconds, each one is multiplied by 1000 ms; these values will be in the on and off delay respectively; To complete the process, a cycle for from 0 to the selected time is done.

ALARMS

Three alarms were fixed:

1. Bubble alarm: through a horseshoe sensor the alarm was designed to detect when no medication passes through that sector of the hose, located before entering the patient to avoid risks. The circuit that is implemented is as shown in the figure with a denier, while the medication is going to be kept off a led, when detecting light flow will turn on. Subsequently, through digitalRead read the sensor value and turn on the digital output a led.

2. Process alarm completed. At the end of the for cycle the DigitalWrite digital output of a led is turned on for 5 seconds to show that the process has been completed. Then the menu is shown again for another selection.

3. Occlusion alarm. It is necessary the use of this alarm, because in this type of procedures the patient can move the handle and place an occlusion in this which brings as a consequence the appearance of bubbles.

CONCLUSIONS

For proper administration of drugs in specific treatments, it is necessary to control different variables such as the amount and time of administration.
The accuracy in this type of pumps is due to the most important, because it is used in drip treatments to the patient, however, the peristaltic infusion pump is not as accurate as the linear.
If the volume limit is reached before the source of the cassette liquid ends, the vast majority of the pumps trigger an alarm and in turn continueinfusing liquid in a minimal infusion, with the aim of preventing the intravenous or intra-arterial cannula of the patient from being blocked by thrombi.