Important Diagnostic Tests and Procedures for Respiratory Disorders

1. Chapter 8 Other Important Tests and Procedures

2. Introduction • Additional important diagnostic studies include: • Sputum examination • Skin tests • Endoscopic examination • Lung biopsy • Thoracentesis • Hematology, blood chemistry, and electrolyte tests

3. Sputum Examination

4. Culture and Sensitivity Study • For a culture and sensitivity study, a single sputum sample is collected in a sterile container. • This test is performed to diagnose bacterial infection, select an antibiotic, and evaluate the effectiveness of antibiotic therapy. • The turnaround time for this test is 48 to 72 hours.

5. Gram Staining • The Gram staining of sputum is performed to classify bacteria into gram-negative and gram-positive types. • The results of the Gram stain tests guide therapy until the culture and sensitivity results are obtained.

6. The Acid-Fast Smear and Culture • The acid-fast smear and culture is performed to determine the presence of acid-fast bacilli (e.g., Mycobacterium tuberculosis). • Three early morning sputum samples are tested.

7. Cytology • Cytology entails the collection of a single sputum sample in a special container with fixative solution. • The sample is evaluated under a microscope for the presence of abnormal cells that may indicate a malignant condition.

8. Box 8-1. Common Organisms Associated With Respiratory Disorders

9. Skin Test • Skin tests are commonly performed to evaluate allergic reactions or exposure to tuberculous bacilli or fungi. • Skin tests entail the intradermal injection of an antigen.

10. Skin Test (Cont’d) • Positive test result • Exposure to antigen • Negative test result • No exposure to antigen

11. Endoscopic Examinations

12. Bronchoscopy • The bronchoscope is a flexible fiberoptic bronchoscope that allows direct visualization of the upper airways. • Nose • Oral cavity and pharynx • Larynx • Vocal cords • Subglottic area • Trachea, bronchi, lobar bronchi, and segmental bronchi

13. Bronchoscopy (Cont’d) • Diagnostic bronchoscopy • Abnormal x-rays • Persistent atelectasis • Excessive bronchial secretions • Therapeutic bronchoscopy • Suctioning of excessive secretions • Removal of foreign bodies • Selective lavage

14. Figure 8-1. Fiberoptic bronchoscope. A, The transbronchoscopic balloon-tipped catheter andthe flexible fiberoptic bronchoscope. B, The catheter is introduced into a small airway and the balloon inflated with 1.5 to 2 mL of air to occlude the airway. (A from Lewis SM, Heitkemper MM, Dirksen SR: Medical-surgical nursing: assessment and management of clinical problems, ed 6,St Louis, 2004, Mosby; B from Meduri GU, Beals DH, Maijub AG, Baselski V: Protected bronchoalveolar lavage, Am Respir Dis 143:855, 1991.)

15. Mediastinoscopy • A mediastinoscopy is the insertion of a scope through a small incision in the suprasternal notch; the scope is then advanced into the mediastinum. • The test is used to inspect and biopsy lymph nodes in the mediastinal area.

16. Lung Biopsy • A lung biopsy specimen can be obtained by means of a transbronchial needle biopsy or an open-lung biopsy. • A transbronchial lung biopsy entails passing forceps or a needle through a bronchoscope to obtain a specimen.

17. Lung Biopsy (Cont’d) • An open lung biopsy involves surgery to remove a sample of lung tissue. • An incision is made over the area of the lung from which the tissue sample is to be collected.

18. Insert Figure 8-2 here Figure 8-2. Transbronchial needle biopsy. The diagram shows a transbronchial biopsy needle penetrating the bronchial wall and entering a mass of subcarinal lymph nodes or tumor. (Redrawn from DuBois RM, Clarke SW: Fiberoptic bronchoscopy in diagnosis and management, Orlando, 1987, Grune and Stratton.)

19. Video-Assisted Thoracoscopy (VATS) • Insertion of thoracoscope through thechest wall • Results displayed on a video monitor • Helpful in the diagnosis of: • Tuberculosis • Mesothelioma • Metastatic cancer

20. Thoracentesis • Thoracentesis is a procedure in which excess fluid accumulation (pleural effusion) between the chest cavity and lungs (pleural space) is aspirated through a needle inserted through the chest wall. • A diagnostic thoracentesis may be performed to identify the cause of a pleural effusion.

21. Figure 8-3. Thoracentesis. A catheter is positioned in the pleural space to remove accumulated fluid. Pleural fluid is seen as the dark shadow at the base of the left lung. (From Lewis SM, Heitkemper MM, Dirksen SR: Medical-surgical nursing: assessment and management of clinical problems, ed 6, St Louis, 2004, Mosby.)

22. Pleurodesis • Pleurodesis is performed to prevent the recurrence of a pneumothorax or pleural effusion. • A pleurodesis is achieved by injecting any number of agents (called sclerosing agents or sclerosants) into the pleural space through a chest tube. • Common sclerosant chemicals include a slurry of talc, bleomycin, nitrogen mustard, doxycycline, povidone iodine, and quinacrine.

23. Pleurodesis (Cont’d) • The instilled sclerosing agents cause irritation and inflammation (pleuritis) between the parietal and the visceral layers of the pleura. • This action causes the pleurae to stick together and thereby prevents subsequent gas or fluid accumulation.

24. Pleurodesis Risks • Infection • Bleeding • Acute respiratory distress syndrome • Collapsed lung (pneumothorax), and respiratory failure

25. Pleurodesis Risks (Cont’d) • Complications may be specific for each sclerosant. • Talc and doxycycline can cause fever and pain. • Quinacrine can cause low blood pressure, fever, and hallucination. • Bleomycin can cause fever, pain, and nausea.

26. Hematology, Blood Chemistry, and Electrolyte Findings

27. Hematology • The most frequent laboratory hematologic test is the complete blood count (CBC). • The CBC provides important information about the patient’s diagnosis, prognosis, response to treatment, and recovery.

28. Table 8-1. Red Blood Cell Indices

29. Table 8-1. Red Blood Cell Indices

30. White Blood Cell Count (WBC) • The major functions of the WBCs (leukocytes) are to: • Fight against infection • Defend the body by phagocytosis against foreign organisms • Produce (or at least transport and distribute) antibodies in the immune response

31. Box 8-2. Normal Differential White Blood Cell Count

32. Table 8-2. Common Causes of WBC Increase

33. Platelet Count • Platelets are the smallest of the formed elements in the blood. • They are round or oval, flattened, and disk-shaped in appearance. • Platelets are produced in the bone marrow and possibly in the lungs. • Platelet activity is essential for blood clotting. • The normal platelet count is 150,000 to 350,000/mm3.

34. Table 8-3. Blood Chemistry Tests Commonly Monitored in Respiratory Care

35. Table 8-4. Electrolytes Commonly Monitored in Respiratory Care

36. (Cont’d) Table 8-4. Electrolytes Commonly Monitored in Respiratory Care—cont’d