- Sputum may be obtained for evaluation of gross appearance, microscopic examination, Gram's stain, culture, acid-fast bacillus, and cytology.
- The direct smear shows presence of white blood cells and intracellular (pathogenic) bacteria and extracellular (mostly nonpathogenic) bacteria.
- The sputum culture is used to make a diagnosis, determine drug sensitivity, and serve as a guide for drug treatment (ie, choice of antibiotic).
- Cytology examination identifies abnormal and possibly malignant cells.
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Nursing and Patient Care Considerations
- Patients receiving antibiotics, steroids, and immunosuppressive agents for prolonged time may have periodic sputum examinations, because these agents may give rise to opportunistic pulmonary infections.
- It is important that the sputum be collected correctly and that the specimen be sent to a laboratory immediately. Allowing it to stand in a warm room will result in overgrowth of organisms, making identification of pathogen difficult; this also alters cell morphology.
- Sputum can be obtained by various methods:
- Deep breathing and coughing
- Obtain early morning specimen- yields best sample of deep pulmonary secretions from all lung fields.
- Have patient clear nose and throat and rinse mouth- to decrease contamination by oral and upper respiratory flora.
- Instruct patient to take several deep breaths, exhale, and perform a series of short coughs.
- Have patient cough deeply and expectorate the sputum into a sterile container.
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- Ultrasonic or hypertonic saline nebulization
- Patient inhales through mouth slowly and deeply for 10 to 20 minutes.
- Nebulization increases the moisture content of air going to lower tract; particles will condense on tracheobronchial tree and aid in expectoration.
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- Tracheal suction- aspiration of secretions through endotracheal (ET) or tracheostomy tube
- Bronchoscopic removal- provides sputum sampling by aspiration of secretions; brushing through a sterile catheter; bronchoalveolar lavage; and transbronchial biopsy
- Gastric aspiration (rarely necessary since advent of ultrasonic nebulizer)
- Nasogastric tube is inserted into the stomach to siphon out swallowed pulmonary secretions.
- Useful only for culture of tubercle bacilli, but not for direct examination
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- Transtracheal aspiration involves passing a needle and then a catheter through a percutaneous puncture of the cricothyroid membrane. Transtracheal aspiration bypasses the oropharynx and avoids specimen contamination by mouth flora.
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