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65 Cards in this Set
- Front
- Back
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The four general principles for pulmonary function
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Test specificity, sensitivity, validity, reliability
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accuracy
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how well it measures a known reference value
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capacity
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range or limits of how much it can measure
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error
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difference between reference values and measured values
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resolution
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smallest detectable measurement, instruments with high resolution can measure smallest flow, volume, etc
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linearity
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accuracy of instrument over its entire range of measurement or capacity
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helium diluation
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measures lung volume using a closed, rebreathing circuit - get initial amount of helium, let it diffuse in lungs and then get final helium reading at equilibrium
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nitrogen wash
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uses a nonrebreathing or open circuit - based on 78% N2 in lungs and when patient breaths in 100% O2, O2 replaces N2 in lungs
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plethysmography
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applies Boyles law and uses measurements of volume and pressurechanges to determine lung volume, assuming temp is constant – measures volume of incompressible gas in the thorax, including gas trapping behind airway obstructions or pleural space
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diffusing capacity
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Measures ability of lungs to transfer gases across alveolar-capillary membrane
CO is gas used to measure diffusing capacity of lung (DL) DLCO is difference between the volume of CO inhaled and the volume of CO exhaled |
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single breathe technique
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– most common because it is quick and reproducible
Patient exhales RV, rapidly inspires VC of gas mixture containing 0.3% CO and an inert tracer gas such as He in air, maintains breathe for 10 sec, and then exhales rapidly at least 1 L and sample of alveolar gas is collected and analyzed for expired CO and He |
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factors that decrease DLCO
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o Anemia
o Carboxyhemoglobin o Pulmonary embolism o Diffuse pulmonary fibrosis o Pulmonary emphysema |
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factors that increase DLCO
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o Polycythemia
o Exercise o Congestive heart failure |
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air
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Absorbs the least energy and appears virtually black on film (radiolucent)
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Fat
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Absorbs slightly small amount of x-ray energy than soft tissue and appears just slightly darker than soft tissue
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soft tissue
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Absorbs small amount of x-ray beam and is usually seen as medium gray shadow
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Bone
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Absorbs large amount of x-ray beam and is seen nearly as white (radiopaque)
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Radiolucent
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– appears virtually black on film
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Radiopaque
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– seen as nearly white
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What are the clinical indications for outpatient chest radiographs?
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o Unexplained dyspnea
o Severe persistent cough o Hemoptysis o Fever and sputum production o Acute severe chest pain o Positive TB skin test |
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What are the clinical indications for inpatient chest radiographs?
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oPlacement of endotracheal tube
oPlacement of pulomonary artery catheter oPlacement of central venous pressure catheter o Sudden onset of dyspnea or chest pain o Elevated platuea pressure during mechanical ventilation o Sudden drop in SPO2 |
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ask questions on how to evaluate radiograph
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o Is the film labeled appropriately?
o Is the film PA with lateral or is it an AP portable film? o Is the entire chest imaged on film? o Was the patient properly positioned on film? o Were the optimal settings for the x-ray beam selected when the film was taken (penetration or exposure on film) |
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PA chest film
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o Patient puts his or her back to the x-ray source and the chest against the film
o Performed in radiology dept with standardized equipment o Taking film anterior chest closest to film minimizes magnification of heart |
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AP chest film
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o Taken with portable radiography machine
o Puts x-ray source in front of patient with film behind patients back o Film much closer so variances between patient distance o Less quality |
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Anatomical structures on radiograph
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•Bones (ribs, clavicle, scapulae, vertebrae)
•Soft tissues (chest wall, upper abdomen and lymph nodes) •Lungs (including trachm bronchi, tissue or parenchyma) •Pleura (membranous covering of lung including visercal pleura (part attached to lungs), the parietal pleura (part lining inside of chest wall), space between is pleural space) •Heart, greater vessels and mediastimun (tissues between lungs in center of chest, bordered by sternum and vertebral column in AP dimension and by thoracic inlet (where trach enters thoraz and diaphragm in cephalocaudal direction) •Upper abdomen •Lower neck |
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Pleura
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o Outer membrane that adheres to inside of chest wall, upper surface of diaphragm, and lateral aspect of mediastinum – parietal pleura
o Inner membrane that closely adheres to surface of each lung |
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Hydrothorax (Pleural effusion)
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o FIGURE 20-6
o Accumulation of excessive fluid within the pleural space o When the costophrenic angle is rounded rather than sharp indicates hydrothorax o Formed when 175 to 200 ml have accumulated |
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Hydropneumothorax
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o FIGURE 20-7
o Air-fluid level in the pleural space o When air wan fluid are contained within same space, the interface between air and fluid will form a soft tissue density with straight, level border that has air density above it o Interface may have small meniscuc on both sides |
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Intrafissural fluid
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o FIGURE 20-8
o Fluid occupies unusual position such as within an interlobar fissure o Most commonly seen in minor fissure, which is between the right middle lobe and right upper lobe |
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Empyema
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o FIGURE 20-9
o Elliptical pleural fluid collection with thickening and enhancement of surrounding pleura o Presence of gas bubbles within the fluid without prior surgery or needle insertion establishes diagnosis of empyema |
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Deep sulcus pneumothorax
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o Deep sulcus sign
- FIGURE 20-11 - Air accumulating anteriorly and outlining the heart border below the dome of the diaphragm |
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Tension pneumothorax
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air within the pleural space may be under pressure or tension
- FIGURE 20-12 - Tear in the pleura (which allows air to leave the lung and enter pleural space) opens on inspiration but closes on expiration - Air continues to accumulate in pleural space and can compress the heart and adjacent lung - Chest film shows hemidiaphragm pushed down or mediastinum shifted towards opposite lung |
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Alveolar disease
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material other than air that fills alveoli
- Pulmonary edema – alveoli are flooded with watery fluid that contains few blood cells - Bacterial pneumonia – alveoli contain WBC (pus) - Pulmonary hemorrhage – filled with blood - Pulmonary alveolar proteinosis – alveoli filled with fat-rich material derived from pulmonary surfactant |
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Air-bronchograms
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(FIGURE 20-13)
• Shadows often have lecent tubular visible structures running through • Infiltrates that fill alveoli (air space disease) • No contrast between air in airways and air in lungs |
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pulmonary edema
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• Caused by vascular congestion, loss of intergrity of pulmonary capillaries or combo
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Cardiogentic pulmonary edema – seen in changes of films
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• Pressure in pulmonary veins rises
• Rising pressure can be seen in blood vessels to apex of lung enlarge • Blood vessels to apex of lung are same size or larger than blood vessels to base, vessels are cephalize (pulmonary blood flow is often caused by left sided heart failure) • (FIGURE 20-15) |
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Peribronchial cuffing
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• When fluid builds up high venous pressure, thickening bronchial walls and edema in the septa sparate the lung lobules become evident
• FIGURE 20-15) • Thickened septa are most clearly seen as thin lines against the pleural edge that fun perpendicualry away from pleural edge called Kerley B lines |
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pulmonary edema
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- Bats wing – predominace of edema in hilar region of both lungs with progessivley less edema in more peripheral areas of lungs
- FIGURE 20-17 |
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Interstital lung disease
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- Represents part of lung that frames the air spaces and supports the vessels and bronchi as they travel through the lung
- Interstitial lung disease is a group of diseases that involve the lower respiratory tract - Usually has diffuse, bilateral infiltrates – may look nodular, reticular (scattered lines) or honeycombing which is development of cystic spaces with well-defined walls seen in periphery of lung and resembling honey comb (FIGURE 20-18) |
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Table 20-1
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- Pneumothorax – cause of disease by lymnphangioeiomyomatosis, eosinophilic granuloma of lung
- Pleural effusion – cause of disease rheumatoid arthritis, systemic lupus erythematosus - Dilated esophagus – caused by scleroderma, CREST syndrome - Erositve arthropathy (shoulder joints, clavicles) – caused by rheumatoid arthritis - Medistinal adenopathy – caused by sarcoidosis, scleroderma, metastatic disease - Soft tissue calcification – caused by dermatomyositis, scleroderma - Pleural plaque – caused by asbestosis |
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Atelectasis
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- common abnormality on chest radiographs, and the location and extent of volume of loss produce characteristic chest radiograph patterns
- Occurs after abdominal or thoracic surgery, with pleurisy or following pleural irritation from rib fracture or pulmonary infarction |
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Plate atelectasis –
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- associated with ventilator disturbance, including restricted diaphragmetaic motion, sometimes with resultant alveolar hypoventilation, retained secretions, producing small airway obstruction, and diminished surfactant production
- (FIGURE 20-19) |
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Hyperinflation
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- Occurs when more than seven anterior ribs are visible about diaphragm
- Obstructive pulmonary disease is classically associated with increased lung volumes |
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Mediastinum
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– consists of heart, greater vessels, trachea and other soft tissue structures that lie between the lungs, divided into anterior, middle, posterior (FIGURE 20-3)
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abnormalities
Anterior mediastinum |
- Thyroid or parathyroid mass
- Thymic lesions - Lymphoma - Pericardial cyst/fat pad - Teratoma - Morgagni hernia - Ventricular aneurysm |
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abnormalities middle mediastinum
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- Aortic aneurysm (ascending/arch)
- Lymphadenopathy - Bronchogenic cyst - Tracheoespophageal masses - Hiatal hernia |
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abnormalities posterior mediastinum
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- Aortic aneurysm (descending)
- Neurogenic tumors - Lymphoma - Neuroenteric cyst - Bochdalek hernia |
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Pneumomediastinum
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- Form of barotraumas, may result from movemtn of air in mediastinum and may also be seen in cases of esophageal rupture
- FIGURE 20-30 |
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Endotracheal tube
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- radiopaque, received at bedside after intubation for correct lining
- 5-7 cm from carnia when neck is neutral position • FIGURE 20-31 |
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Tracheostomy tubes
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– should be 2/3 diamter of trachea and should project within borders of trachea on radiograpn and tip should extend beyond half the distance of stoma to carina
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Central lines
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CVP catherter is placed via internal jugular veins of subclavian veins
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Pulmonary artery (Swan-Ganz) catheters
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– measures hemodynamic and central pressure variables such as pulmonary artery occlusion pressure
• Placed at bedside • FIGURE 20-32 |
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chest tube
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- small to large bore tubes placed into pleural space from outside of chest wall
• Should be within pleural space and is radiopaque |
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Intraaortic balloon pump
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- counterpulsation device that is used to improve cardiac output and blood pressure in the patients cardiogenic shock
• Inserted via femoral artery, is 26 cm long, radioopaque, inflates during diastole and deflates during systole to enhance perfusion of coronary arteries and cardiac output |
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Alveolar (air space disease) features
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o Air bronchograms
o Fluffy opacities o Rapid coalescence o Acinar nodules o Segmental/lobar distributions |
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Inertial impaction occurs when suspended particles in motion collide with and are deposited on a surface
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• Primary particles larger than 5 um
o Because of mass and velocity, the higher the flow of gas stream, the greater the tendency for particles to impact and be deposited in airways o -Particles that are 5 to 10 um are deposited in oropharynx and hypopharx |
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• Sedimentation
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occurs when aerosol particles settle out of suspension and are deposited owing to gravity
o The greater the mass of particle, the faster it settles o Particles 1-5 um |
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Diffusion
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o Primary mechanism for deposition of small particles (less than 3 um), mainly in respiratory region where bulk gas flow ceases and most aerosol particles reach the alveoli by diffusion
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Tail off
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• When not have a counter like pMDI, after label doses were administered, there appears to be 20-60 doses which may deliver little or no medication as the doses tail-off
• Tail-off effect is variability of the amount of drug dispensed toward the end of the life of the canister • Result of tail-off is swings from normal to almost no dose emitted from one breath to next with no reliable indicator to user • FDA requires new pMDI to have counter |
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the “cold Freon effect” and how it is corrected.
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• In spacers and holding chambers
• Retention of larger droplets in the spacer, and evaporation of propellants prior to entering the airway, the cold Freon effect which causes many children to stop inhaling, is reduced as is the foul taste asspciated with some of the drugs aerosols |
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factors that affect SVN
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• Design
o Baffle, fill volume, residual drug volume, nebulizer position, continuous versus intermittent nebulization, reservoirs and extensions, vents, valves, and gas entrainment, tolerances in manufacturing within lots • Gas pressure • Gas density • Medication characteristics o Viscosity, surface tension, homogeneity |
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• Breath-enhanced neb
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o Entrain air through the nebulizer during inspiration
o Generate aerosol continuously, utilizing a system of vents and oneway valve system can be used to minimize aerosol waste o Ex. Pari LC Jet Plus |
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•Small volume ultrasonic neb
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o Can be used with wide range of bronchodilators to anti-inflammatory agents and antibiotics
o Convenience in mobility o But high cost and poor reliability o Have minimal residual volumes and treatment time is reduced |
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77. What is the recommended age for use of each aerosol device?
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(Rule of thumb p. 829)
• SVN – neonate • pMDI - > 5 years old • valved chamber with mouthpiece - > 4 years old • valved chamber with mask – Neonate/infant/toddler • endotracheal tube – neonate • breath-actuated - > 5 years old • DPI - > or equal to 6 years old |
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80. Discuss factors associated with reduced aerosol drug deposition in the lung (Box 36-6).
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• Mechanical ventilation
• Artificial airways • Reduced airway caliber (infants, babies) • Severe airway obstruction • Poor patient compliance of technique • Limitation of specific delivery device |
