Examination of Respiratory System — OmpathStudy

Continued from $1. TOPIC 5: EXAMINATION OF THE R SYSTEM – PROCEDURES AND INVESTIGATIONS OBJECTIVES At the end of the session the learner should be able to 1. Interpret findings in critical investigations in chest diseases 2. Perform basic diagnostic and therapeutic procedures 6.0 INTRODUCTION There are several important therapeutic and diagnostic procedures in the respiratory system as well as important investigations. 7.0 INVESTIGATIONS 7.1. Chest X-ray Use the ABCDEFGH mnemonic 7.1.1. Chest X-ray - Systematic Approach ✓ Reading a chest X-ray (CXR) requires a systematic approach. 7.1.2. The "right film for the right patient" ✓ Check that the film bears the patient's name, age or hospital number too ✓ The label may also tell features such as anteroposterior (AP) projection or supine position ✓ Check the date of the film to ascertain which one you are viewing 7.1.3. Technical details ✓ Check the position of the side marker (left or right) against features such as the apex of the heart and air bubble in the stomach. A misplaced marker is more common than dextrocardia or situsinversus. ✓ Most films are a poster anterior (PA) projection. The usual indication for AP is a patient who is confined to bed. ✓ AP vs PA Views o Look at the relationship of the scapulae to the lung margins o A PA view shows the scapulae clear of the lungs whilst in AP projection they always overlap o Vertebral endplates are more clearly visible in AP and laminae in PA. This is important because the heart looks bigger on an AP view. ✓ Lateral films o A lateral view may have been requested or performed on the initiative of the radiographer or radiologist. As an X-ray is a two-dimensional shadow, a lateral film helps to identify a lesion in 3 dimensions. The usual indication is to confirm a lesion seen on a PA film. o The heart lies in the anteroinferior field. Look at the area anterior and superior to the heart; this should be black because it contains aerated lung. Similarly, the area posterior to the heart should be black right down to the hemidiaphragms. The degree of blackness in these two areas should be similar, so compare one with the other. If the area anterior and superior to the heart is opacified, it suggests disease in the anterior mediastinum or upper lobes. If the area posterior to the heart is opacified there is probably collapse or consolidation in the lower lobes. ✓ The normal posture for films is erect. Supine is usually for patients confined to bed. In an erect film, the gastric air bubble is clearly in the fundus with a clear fluid level but, if supine, in the antrum. In a supine film, blood will flow more to the apices of the lungs than when erect. ✓ Rotation should be minimal. It can be assessed by comparing the medial ends of the clavicles to the margins of the vertebral body at the same level. Oblique chest films are requested to look for achalasia of the cardia or fractured ribs. ✓ CXR should be taken with the patient in full inspiration but some people have difficulty holding full inspiration (except when seeking a small pneumothorax as this will show best on full expiration) A CXR in full inspiration should have the diaphragm at the level of the 6th rib anteriorly and the liver pushes it up a little higher in the right than on the left. ✓ Penetration o Is affected by both the duration of exposure and the power of the beam o More kV gives a more penetrating beam o A poorly penetrated film looks diffusely light (an x-ray is a negative) and soft tissue structures are readily obscured, especially those behind the heart o An over-penetrated film looks diffusely dark and features such as lung markings are poorly seen. Airway ✓ Trace the lucency from the neck down towards the carina ✓ Should be midline and you should be able to see two bronchi splitting from it Bones and soft tissues ✓ Look at the shoulder joint and trace out each rib contour to check for fractures or other abnormalities such as lytic lesions ✓ Are both breast shadows present ✓ Attention may be merited to apices, periphery of the lungs, under and behind the hemidiaphragms and behind the heart Cardiac ✓ Check the cardio-thoracic ratio (CTR) o The width of the heart should be no more than half the width of the chest o About a third of the heart should be to the right and two thirds to the left of centre o Note: the heart looks larger on an AP film and thus you cannot comment on the presence or absence of cardiomegaly on an AP film. Diaphragm (e.g. flat or elevated hemidiaphragm) ✓ Ascertain that the surface of the hemidiaphragms curves downwards, and that the costophrenic and cardiophrenic angles are not blunted ✓ Blunting suggests an effusion ✓ Extensive effusion or collapse causes an upward curve ✓ Check for free air under the hemidiaphragm - this occurs with perforation of the bowel but also after laparotomy or laparoscopy Edges (borders) of the heart ✓ The left border of the heart consists of the left atrium above the left ventricle ✓ The right border