Respiratory system diagnostic tests
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
In medicine, the respiratory examination is performed as part of a physical examination, or when a patient presents with a respiratory problem (dyspnea (shortness of breath), cough, chest pain) or a history that suggests a pathology of the lungs.
Respiratory system diagnostic tests
Sputum examination
- Appearance, color, presence of blood, and smell
- Colorless (Bronchitis)
- Green (pulmonary infection)
- Red (carcinoma)
- Frothy pink (pulmonary edema)
- Black (pollutants)
- Order tests - Routine microscopy (gram and ZN stain), cytology, culture
Peak expiratory flow
- Maximal forced expiration through peak flow meter.
- Used to estimate airway caliber in COPD, and asthma
Pulse oximetry
- Quick, non-invasive way of measurement of peripheral oxygen saturation
- Its alarm is usually set on 90%
- A decrease of oxygen saturation below 80% needs attention.
- In some cases for instance, COPD, an oxygen saturation below 80% is normal and patient is compensated
- False results may be due to:
- Skin pigmentation
- Nail paints
- Carbon monooxide poisoning
- Dyshemoglobulinemia
- Poor perfusion
Arterial blood gas
- Heparinized blood from peripheral arteries like radial, brachial, and femoral
- Measure pH, PaO2, PaCO2, and FiO2 (percent of inspired oxygen)
- For interpretation of ABG click here