CHAPTER 13

2. CHAPTER 13 Diagnostic Procedures

3. Objectives • After studying this chapter, you will be able to: • Apply knowledge of anatomy and physiology to determine which diagnostic examinations will be useful • Indicate the sources of patient data • Compare and contrast techniques used to establish the diagnosis

4. Objectives (cont’d.) • Determine which diagnostic procedures will require surgical intervention • Recognize the major indications for surgical intervention

5. Sources of Patient Data • Obtained several ways • History and physical examination • Diagnostic imaging • Laboratory findings • Electrodiagnostic studies • Endoscopic studies • Pulmonary diagnosis • Plethysmography and phleborheography

6. History and Physical Examination • First step in determining the etiology of a patient’s condition • Gathering medical, social, and psychological information about the patient and, if applicable, the patient’s family • Physical examination should be performed • Symptoms and signs • Several tools and methods are available

7. Diagnostic Imaging • Various techniques • Now available for producing images of the human body • Radiography (roentgenography) • X-rays • Mammography • Myelography

8. Diagnostic Imaging (cont’d.) • Fluoroscopy • Utilizes X-rays to project images of body structures onto a monitor • Many intraoperative applications • Angiography and cholangiography • Retrograde urography • Aid in bone realignment and prosthesis placement • Verification of catheter placement and lead introduction • To direct instrumentation

9. Diagnostic Imaging (cont’d.) • Computed axial tomography (CT or CAT scan) • Use of a specialized X-ray machine that produces pictures of a body part in “slices” for evaluation by a radiologist • CT scanner is adjustable to make the slices as thick or thin as desired • Refer to Figure 13-7

10. Diagnostic Imaging (cont’d.) • Positron emission tomography (PET scanning) • Combines CT and radioisotope brain scanning • Helps to identify how different areas of the brain function by highlighting chemical or metabolic activity

11. Diagnostic Imaging (cont’d.) • Magnetic resonance imaging (MRI) • Uses two different forms of energy • Spinning hydrogen atom is placed into a magnetic field, forcing the atoms to line up and “spin” • Applied radio waves force the hydrogen atoms to cycle in phase • Atoms release a radio wave of the characteristic frequency that is measured and transformed into an image • MRI uses these radio waves in a strong magnetic field to form pictures of parts of the body

12. Diagnostic Imaging (cont’d.) • Ultrasonography • High-frequency sound waves are directed into the body and reflected from the tissues to a recording device for diagnostic purposes • Echocardiography • Provides a two-dimensional image of the heart by directing beams of ultrasonic waves from a sonar-like device through the chest wall

13. Diagnostic Imaging (cont’d.) • Doppler ultrasonography • Doppler monitor measures blood flow that transmits the sound of moving red blood cells to the transducer • Used in the OR to determine the patency of arterial anastomosis

14. Diagnostic Imaging (cont’d.) • Isotope scanning • Involves intravenous injection of a radioactive isotope into the patient prior to the imaging study • Refer to Figure 13-10 • Radiation therapy • Use of radiation to kill cells by interfering with metabolic activity

15. Laboratory Reports • Laboratory or pathology department • Responsible for countless types of examinations on every type of body fluid and tissue that exists • Findings are extremely valuable in sorting out what may be normal for one patient and abnormal for another

16. Laboratory Reports (cont’d.) • Important studies and tests • Hematologic studies: refer to Tables13-1 and 13-2 • Urinalysis: refer to Table 20-3 • Bacteriologic tests (e.g., Gram strain, spinal tap, and thoracentesis): refer to Table 13-3

17. Electrodiagnostic Studies • Body consists of cells that contain polarized molecules • Communication systems of the body are bioelectrical or biochemical • Microelectrical impulses can be measured and provide useful diagnostic information

18. Electrodiagnostic Studies (cont’d.) • Electrocardiography • Electrocardiogram (ECG) is a valuable tool for detection and evaluation of all forms of heart disease: refer to Figure 13-12 • Electrocardiography is performed by placing a number of electrodes in predetermined locations on the skin of the arms, legs, and torso to record the electrical activity of the heart

19. Electrodiagnostic Studies (cont’d.) • Electroencephalography (EEG) • Display and recording of the electrical activity of the brain by measurement of changes in electric potentials • Electromyography (EMG) • Study and recording of the electrical activity of skeletal muscle

20. Pulmonary Diagnosis • Respiratory status and severity of pulmonary conditions is evaluated in several ways • Pulse oximetry: measures oxygen saturation in percentages • Capnography: estimates arterial levels of carbon dioxide • Spirometry: provides information about lung capacity, resistance, and ventilatory pressure

21. Endoscopy • Endoscopes • Can be used preoperatively or intraoperatively to directly visualize internal structures for diagnostic purposes • Refer to individual procedural chapters for specific endoscopic procedures

22. Plethysmography and Phleborheography • Plethysmography • Useful in patients with diffuse small vessel arterial disease, especially diabetics • Plethysmograph • Instrument for determining and registering variations in the volume of an extremity and in the amount of blood present in the extremity or passing through it

23. Plethysmography and Phleborheography (cont’d.) • Phleborheography • Plethysmographic technique • Rhythmic changes in venous volume in the legs associated with respiration are recorded

24. Summary • This chapter reviewed: • Diagnostic examination data • Sources of patient data • Diagnosis techniques • Indications of surgical intervention