Design and Development of Low cost spirometer with pc Interface

The primary test of lung function is called Spirometry. Spirometry parameters are derived from pressure and/or flow measurements. The spirometer records exhaled air volume, and produces graphic and numeric information in the form of spirometric parameters and tracings that can depict and describe the mechanical properties of the lung. Some possible measurements are like Pressure and gas flows behave during one respiratory cycle in volume controlled. Patient Spirometry measures airway pressures, flow, volumes, compliance, and airway resistance breath-by-breath at the patient’s airway. The flow of gas is measured, and the inspiratory and expiratory concentrations of oxygen and carbon dioxide analyzed. All parameters are measured through a single, lightweight flow sensor and gas sampler, placed at the patient’s airway. The “close to the patient” measurement is a sensitive and continuous reflector of patient’s ventilator status, obtained independently of the ventilator used. The breath-by-breath measurement of pulmonary gas exchange is technically very demanding and requires sophisticated compensation and data processing algorithms to achieve the accuracy required in\ud the clinical use. Measurement of respiratory gas flow continuously is associated with several problems, such as the effects of humidity, alternating gas composition, secretions, and the dynamic response of the flow sensors. Medical technologies have enabled accurate measurement of respiratory gas exchange in a wide variety of clinical conditions. The clinical applications range from assessment of energy requirements to comprehensive analysis of ventilation and oxygen transport in patients with complex cardio respiratory problems. Obstructive disorders, which are much more common than restrictive abnormalities include asthma and COPD.\ud Asthmatic bronchitis, chronic bronchitis, and emphysema are included in COPD. These diseases can be identified by a low FEV / FVC ratio or an FEV that is lower than predicted. Spirometric data have been presented as exhaled volume over time. These volume-time curves are easy to visualize and allow physicians to identify FEV, FVC, and expiratory time at a glance. The flow transducer permits physicians to visualize peak flow and timed peak flow. Which is a check of patients’ efforts FEV, FVC, and FEV, FVC ratio are expressed in terms of lower limit of normal.\ud Here the FEV1/FVC ratio is about the same as (i.e., 57% vs. 59%), but the absolute FEV, is only 66% of predicted. Spirometric measurements can be as fundamental to medicine as are pulse, blood pressure. Temperature, height and weight measurements and therefore could be considered in the physical examination as important vital signs