Mechanical Ventilator

GLOSSARY

DEVELOP

Operating principle

A mechanical ventilator is a machine or equipment that helps breathing when a patient cannot breathe in a sufficient measure by their own means. It is used in order to bring oxygen to the lungs and to the organism, to help the lungs to get rid of carbon dioxide. Also, to facilitate breathing: in some cases, the patient can breathe, but it is very difficult.

For its operation, the equipment is first connected to the patient through an endotracheal tube (ET) that is placed inside the mouth or nose and inside the trachea. In some patients, a hole is made in the neck by a surgical procedure and a tracheostomy tube is connected there. The ventilator then blows gas (fresh air, as needed) into the patient's lungs. It can handle one hundred percent of the breath or only help the patient's breathing.

The ventilator can deliver higher oxygen levels than a mask or other types of device. It may also offer a pressure (PEP pressure) that helps keep the lungs open so that the pulmonary alveoli do not collapse. The tube in the trachea makes it easier to remove mucus in case of a mild cough.

The differences between the different types of ventilation:

Some ventilation modes are:

CPAP (Continuous Positive Airway Pressure): It is a continuous spontaneous ventilatory mode in inspiration and exhalation, applied by means of positive pressure systems, mechanical and non-mechanical. Its fundamental parameters are:

• Pressure
• flow
• Others: oxygen / additional medical air, humidification systems

BIAPAP (Bilevel Positive Airway Pressure): This ventilated mode enhances the patient's inspiration. For the inspiratory aid, the trigger signal is activated by the patient, which is the beginning of inspiratory pressure.

PSV / NIPSV (Pressure Support Ventilation): This mode is limited by pressure and cycled by flow, each inspiration is initiated by the patient overcoming the established level of tirgger.

PAV (Proportional assisted ventilation)

For the design of a mechanical ventilator, takes into account the circuit diagram and the block diagram basic.

Figure 1. Represents fan control diagram with microprocessor

Figure 2. Block diagram

For the maintenance of this equipment, the following must be taken into account:

RESULTS

In the block diagram implemented to make a model of a mechanical ventilatord you can see the following details, for the front panel is a friendly interface, the system allows you to select the respiratory rate at which you want the patient to make the process of mandatory breath which was determined to be with an I: E ratio of 1: 2.

Figure 3. Friendly interface in lABVIEW

Likewise, on the front panel were the PMV and VMV graphs. One of the characteristics of the system was its self-test, which activated the entire system and, through time and thresholds, presented the messages corresponding to the current state of the mechanical fan systems.

Figure 4. Diagram when the self-test is false

Figure 5. Diagram when the self-test is true

A 3-way solenoid valve and a compressor were used, both at 12 volts, to manage the pulse from Arduino a power circuit was implemented shown in figure 6, it uses an opto-coupler, a bjt transistor and a tip 31 that connects to a 12v relay to operate the components.

Figure 6. Power circuit

The project also made use of a mpx5700 pressure sensor and from its formula found in the datasheet found the corresponding pressure delivered by the compressor and delivered through the solenoid valve when the inspiration and expiration of the system was performed .

The operation that can be observed in the video, corresponds to a test to blow a lung (represented by a blue elastic pump), through one way of the compressor and the other way was directed to the pressure sensor, the compressor all the time was on to send a constant flow and the change of I: E was achieved with help of the solenoid valve.

CONCLUSIONS

It is possible to conclude that for the design of a mechanical ventilator we must differentiate nuy well which are the control modes to be used; In addition the alarms must be raised very well since these must be visible and audible to the person who is using the equipment. In the part of acquisition of the signal emitted by the sensor one must keep in mind its linearization and the equation that allows us to graph our ventilatory mode that is contained in the Datasheet of the sensor used.