Document created by Mateus Freitas on Jul 2, 2014
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Hypoxemia is a common clinical condition associated to several diseases that affect the respiratory system, including not only the lungs diseases, but also cardiac, neurological, neuromuscular and chest wall diseases. Its occurrence bring serious risks being essential its detection for appropriate treatment, and even to prevent the death of the patient.

Hypoxemia is defined as the low saturation of oxygen carried by the blood. The most efficient way to determine the oxygen saturation is the gasometry, an invasive method (through the collection of blood) which is able to determine the gases present in the blood as well as its relative amount, as well as other data related to the blood.

The Oximetry is a less effective method, but not least important, because of its practicality for not being an invasive method. Depending on the quality of the equipment, it can ensure very small variations with respect to the gasometry.

In some cases, the constant monitoring of oxygen saturation is required. The portable oximeters are useful in such cases due to their ease of use. For monitoring oxygen saturation in the blood and also the heart rate, the machine suitable for this purpose is the Pulse Oximeter. Such equipment can be easily purchased at a low cost, but requires an assisted operation for each measurement, by the user or another person.

This project proposed the development of a device capable of measuring blood oxygen saturation and heart rate. The data collected will be transmitted to a Smartphone, featuring an Android Application that displays the received data to the user and sends an automatic message to a health care center with the user's location in case of emergency. The project will also have sensors (accelerometers) to detect when the user has lost concience and fallen to the ground.

This device will help to people with a history of health problems such as hypertension, hypoxia, risk of heart attack, among other diseases, giving them more autonomy, since in case of any health problems, somebody will be informed. The mobile monitoring of vital signals will detect when these signals vary significantly out of a safe range, and upon such occurrance a message is sent to pre-registered telephone numbers informing the user's location, and that he needs help help.

The device will monitor the blood oxygen level and heart rate by measuring the change in the transparency of the blood through the presence of oxygen saturated hemoglobin is made. The measurement is taken by the emission of light at two wavelengths (red and infrared), where a sensor detects the intensity of light that is absorbed by hemoglobin, which depends on the degree of oxygen saturation. From the comparison between the received signals for each wavelength, it is possible to determine the degree of oxygen saturation in the blood.

The meter is controlled by a microcontroller to be selected for this project. There will be a Bluetooth module connected to the microcontroller in order to establish the communication between the device and a paired Smartphone.

An Android App will be developed to control the communicatin, display the user information sent by the device as well as send automatic voice messages to pre-registered telephones. The App will also reproduce additional messages played through the headphones to help the user in using the devices features, and also in case of emergency.