Control system for continuous positive airway pressure

INTRODUCTION: Continuous Positive Airway Pressure (CPAP) is a mode of non-invasive mechanical ventilation commonly used in neonatology. The incorporation of new therapeutic and technological advances may impact the survival of very low birth weight preterm infants. However, one of the difficulties faced is the high cost of this device and its numerous add-on functions, such as Apnea Hypopnea Index (AHI), flow limitation, among others. Thus, in this study, we aim to address the design and construction of a CPAP device prototype to be used in a Neonatal Intensive Care Unit (NICU). METHODS: In order to design the experimental CPAP device with sensory instrumentation for providing data to a micro-controlled system, electro-pneumatic circuits and signal conditioning boards of sensors have been fitted to achieve optimized CPAP function with low energy consumption. While running this setup, a metrological study was carried out to evaluate the sensors' performance. The methodology employed for the study was the IDOV (Identify, Design, Optimize, and Validate) method, a variant of six sigma, to minimize the failure rates. It is expected that it works under valve activation to maintain positive pressure in the airways of the patient (neonate). RESULTS: The whole system performs satisfactorily (low noise level) for each assessed module. Additionally, it is emphasized that software development for application control has resulted in a significant improvement of hardware functions. CONCLUSION: In this work, a system that performs the CPAP function was obtained; the research has shown that, by adopting a specific purpose, it may create a better understanding of Assistive Technology.

Dispositivo para determinaçäo da impedância mecânica do sistema respiratório por oscilaçöes forçadas / Device for mechanical impedance determinaton of the respiratory system for forced oscillations

O método de oscilações forçadas, proposto por Dubois em 1956, permite a determinação da impedância mecânica do sistema respiratório. O sistema em desenvolvimento é baseado em microcomputador PC AT 486, serão realizadas medidas na faixa de 2 a 48 Hz em mono freqüência e multi freqüência, o gerador de pressão e realizado a partir de alto-falante. O software será implementado em C++. O sistema será testado em um sistema utilizando um modelo físico RI, bem como em testes clínicos no HU.

The forced oscillations method proposed by Dubois in 1956, makes possible to determine the mechanical impedance of the respiratory system. The developing system makes use of a PC A T 486 microprocessor. The measurements will be made in a 2 to 48 Hz range in mono and multi frequency adjustments, the pressure generator is based on a loudspeaker. The software will be implemented in C++ language. The system will be tested in a physical RL model system, as well as clinicai measurements at HU.

Gerador de pressäo para a determinaçäo da impedância mecânica de pacientes ventilados artificialmente / Pressure generator for determination of mechanical impedance of the artficialy ventilated patients

Para se determinar a impedância mecânica de pacientes intubados e ventilados artificialmente em UTI, o gerador de pressão senoidal deverá ser capaz de suportar pressões produzidas pelo ventilador, e gerar pressões de amplitudes de 2 a 4 hPa pico a pico. Para a implementação do gerador uma simulação numérica foi realizada tendo como objetivo encontrar a melhor montagem que satisfizesse as condições para tal aplicação. O gerador implemantado foi testado em um sistema RIC.

To determine the mechanical impedance of the intubated and artificialy ventilated patients in Intensive Carte Unit (ICU), the sinusoidal pressure generator must be capable of supporting the pressure generated by the ventilator and to generate a pressure amplitude from 2 to 4 hPa peak to peak. To make the generator assembly, a numerical simulation has been realized, to obtain the best assembly which could satisfy the requirements for such application. The implemented generator has been tested in RIC model system.