ICU Radiography Diseases that Develop Within 24 hrs and Longer in Critical Care Patients Tyler Andrews OHSU-MS4 September ...
Major Considerations <ul><li>Aspiration:  OFTEN  to blame for fever </li></ul><ul><li>Atelectasis:  NOT  to blame for feve...
Identify the Abnormality (click for a hint) Air Bronchogram ETT Ill-defined, focal consolidation (not “prominent vasculatu...
… 12 hours later Progression to ill-defined, patchy consolidation  < 24 hrs Aspiration
Aspiration Pneumonitis <ul><li>There are usually two requirements to produce aspiration pneumonitis: </li></ul><ul><ul><li...
<ul><li>… But don’t ETTs protect the airway? </li></ul><ul><ul><li>No! –  Patients still aspirate 24/7 </li></ul></ul><ul>...
Did this Patient Aspirate? Absolutely! Foreign body (tooth) aspirated into  R. mainstem bronchus during laryngoscopy
Identify the Abnormality (click for a hint) RUL Collapse Lack of air bronchograms Atelectasis (post obstructive) Bronchosc...
Atelectasis <ul><li>Refers to collapse or loss of lung volume </li></ul><ul><li>Results from a number of causes: </li></ul...
Do You Perform a Thoracentesis? No…This is obstructive ateletasis secondary to mucous plugging Pleural effusion  would shi...
Would bronchoscopy  help in this patient? No…airways are patent Tightly “packed” air-bronchograms Diffuse, ground-glass op...
Atelectasis Versus Aspiration Both demonstrate dependent, ground-glass opacities with air-bronchograms … however Atelectat...
Does Atelectasis Cause Fever? <ul><li>Postoperative fever occurs in many patients </li></ul><ul><ul><li>Causes include inf...
<ul><li>Lansing et al. </li></ul><ul><ul><li>1963 - Made early attempts at elucidating a mechanism of how atelectasis caus...
<ul><li>Bottom Line </li></ul><ul><ul><li>Atelectasis  does not  cause fever, if anything, it is inversely correlated with...
Infectious Pneumonia:  >24 Hours
Infectious Pneumonia <ul><li>> 20% of nosocomial infections are acquired in ICUs </li></ul><ul><li>Ventilator Associated P...
Pulmonary Edema <ul><li>Divided into two major forms </li></ul><ul><ul><li>Hydrostatic Edema  (CHF) – develops and resolve...
Identify the Abnormality (click for a hint) Dependent, ground-glass opacities bilaterally Vascular  indistinctness Enlarge...
Cardiogenic (Hydrostatic) Edema <ul><li>Results from increased pressure in pulmonary capillaries    left ventricular fail...
Hydrostatic Edema – CHF (comparison film is your best friend) … Again, note vascular indistinctness Soft tissue edema Wide...
…Hydrostatic Edema Continued Lateral projection is best for detection of…? Kerley-A’s Kerley-B’s
Identify the Abnormality (click for a hint) Diffuse, patchy areas of consolidation … with sparing of  the lower lobes SGC ...
Noncardiogenic (Capillary Leak) Edema <ul><li>Results from disruption of the  capillary endothelium  with leakage of plasm...
ARDS/Diffuse Alveolar Damage Same patient…compare lung volumes Peripheral distribution of opacification Decreased complian...
ARDS/Diffuse Alveolar Damage <ul><li>Considered the severest form of capillary leak edema, in which  alveolar epithelial  ...
Identify the Abnormality Visceral Pleura Absence of vascular markings Little or no mediastinal shift noted Pneumothorax (s...
Pneumothorax <ul><li>Refers to gas in the pleural space and can be divided into several types: </li></ul><ul><ul><li>Simpl...
Same patient…what happened? “ One-way” valve  placed backwards Flattening of R hemidiaphragm R. visceral pleura, mediastin...
Same patient…proper valve placement
Simple or Tension Pneumothorax? Neither    Skin fold Take a closer look (next slide)
Line vs. stripe interface (see next slide) Skin Fold Try to follow vasculature to the periphery
Which patient just bought a chest tube? Pneumothorax Skin fold Note the opaque edge of the visceral pleura Line vs. Stripe...
Identify the Abnormality Enlarged cardiac silhouette “ Superior pericardial border” sign Hint…patient is s/p CABG surgery ...
Pericardial Effusion – Lateral View Enlarged cardiac silhouette “ Oreo” sign Retrosternal fat Epicardial fat Pericardial e...
Pericardial Effusion <ul><li>Should be considered with unexplained new radiographic cardiomegaly without pulmonary congest...
References <ul><li>Chastre, J, Fagon, JY.  Ventilator-associated Pneumonia.   Am J Respir Crit Care Med  2002; 165:867. </...
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ICU Radiography

  1. 1. ICU Radiography Diseases that Develop Within 24 hrs and Longer in Critical Care Patients Tyler Andrews OHSU-MS4 September 20, 2004 Skeena River, BC
  2. 2. Major Considerations <ul><li>Aspiration: OFTEN to blame for fever </li></ul><ul><li>Atelectasis: NOT to blame for fever </li></ul><ul><li>Pulmonary Edema: hydrostatic vs. capillary leak vs. diffuse alveolar damage </li></ul><ul><li>Infectious Pnuemonia </li></ul><ul><li>Pneumothorax </li></ul><ul><li>Pericardial Effusion </li></ul>
  3. 3. Identify the Abnormality (click for a hint) Air Bronchogram ETT Ill-defined, focal consolidation (not “prominent vasculature”) ”)
  4. 4. … 12 hours later Progression to ill-defined, patchy consolidation < 24 hrs Aspiration
  5. 5. Aspiration Pneumonitis <ul><li>There are usually two requirements to produce aspiration pneumonitis: </li></ul><ul><ul><li>Compromise in the usual defenses that protect the lower airway including glottic closure, cough reflex, and other clearing mechanisms </li></ul></ul><ul><ul><li>An inoculum deleterious to the lower airways by a direct toxic effect, stimulation of inflammatory response, or obstruction </li></ul></ul><ul><li>Predisposing conditions seen in the ICU: </li></ul><ul><ul><li>Reduced consciousness/altered mental status </li></ul></ul><ul><ul><li>GERD, upper airway/esophageal surgery </li></ul></ul><ul><ul><li>Protracted vomiting, nasogastric feeding, recumbent position </li></ul></ul><ul><ul><li>Mechanical disruption of the glottic closure </li></ul></ul><ul><ul><ul><li>Tracheostomies, endotracheal tubes, bronchoscopy </li></ul></ul></ul>
  6. 6. <ul><li>… But don’t ETTs protect the airway? </li></ul><ul><ul><li>No! – Patients still aspirate 24/7 </li></ul></ul><ul><ul><li>Aspiration is a common event even in healthy individuals and usually resolves w/o detectable sequelae </li></ul></ul><ul><li>Clinical features that should raise suspicion </li></ul><ul><ul><li>Abrupt onset of symptoms, prominent dyspnea </li></ul></ul><ul><ul><li>Fever, usually low-grade </li></ul></ul><ul><ul><li>Cyanosis and diffuse crackles upon auscultation </li></ul></ul><ul><ul><li>Severe hypoxemia despite oxygen supplimentation </li></ul></ul><ul><li>Quick onset  Quick resolution </li></ul><ul><ul><li>Radiographic changes can often be noted within two hours of the aspiration event </li></ul></ul>
  7. 7. Did this Patient Aspirate? Absolutely! Foreign body (tooth) aspirated into R. mainstem bronchus during laryngoscopy
  8. 8. Identify the Abnormality (click for a hint) RUL Collapse Lack of air bronchograms Atelectasis (post obstructive) Bronchoscopy should be performed to remove mucous plug Elevated, convex minor fissure
  9. 9. Atelectasis <ul><li>Refers to collapse or loss of lung volume </li></ul><ul><li>Results from a number of causes: </li></ul><ul><ul><li>Obstructive – mucous plugging, inflammatory debris, foreign body </li></ul></ul><ul><ul><li>Nonobstructive </li></ul></ul><ul><ul><ul><ul><li>Compressive – pleural effusions </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Adhesive – lack of surfactant (ARDS/DAD) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Cicitrization – radiation, necrotizing pneumonia </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Relaxation – pleural effusion, pneumothorax </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Replacement – alveoli of an entire lobe are replaced by tumor </li></ul></ul></ul></ul>
  10. 10. Do You Perform a Thoracentesis? No…This is obstructive ateletasis secondary to mucous plugging Pleural effusion would shift the trachea to the R.
  11. 11. Would bronchoscopy help in this patient? No…airways are patent Tightly “packed” air-bronchograms Diffuse, ground-glass opacification of LLL Atelectasis (non-obstructive)
  12. 12. Atelectasis Versus Aspiration Both demonstrate dependent, ground-glass opacities with air-bronchograms … however Atelectatic air- bronchograms are often compacted together … while aspiration air-bronchograms are often more wide-spread
  13. 13. Does Atelectasis Cause Fever? <ul><li>Postoperative fever occurs in many patients </li></ul><ul><ul><li>Causes include infection, hematoma, pulmonary embolism, malignant hyperthermia, and drug fever  however… often times atelectasis, if present, may be blamed </li></ul></ul><ul><li>Engoren et al. </li></ul><ul><ul><li>Studied 100 consecutive postoperative cardiac surgery patients admitted to the ICU through the second postoperative day with portable CXR’s and continuous bladder thermometry </li></ul></ul><ul><ul><li>Radiographs were read by the same, blinded observer </li></ul></ul><ul><ul><li>Results: </li></ul></ul><ul><ul><ul><li>daily incidence of atelectasis increased from 43  69  79% </li></ul></ul></ul><ul><ul><ul><li>However, incidence of fever (temp > 38.0 degrees C) fell from 37  21  17% </li></ul></ul></ul>
  14. 14. <ul><li>Lansing et al. </li></ul><ul><ul><li>1963 - Made early attempts at elucidating a mechanism of how atelectasis caused fever </li></ul></ul><ul><ul><ul><li>Cotton plugs (non-sterile) were placed in the left-main bronchus of 30 dogs. Animals became febrile within 12 hours. Distal to the plug, the bronchial tree was found to be “filled with a thick mucopurulent exudate.” </li></ul></ul></ul><ul><ul><ul><li>6 animals were treated with penicillin/streptomycin at the time of bronchial plugging. “Only very slight rises in temperature” were seen in these animals. </li></ul></ul></ul><ul><ul><ul><li>Authors concluded that fever, but not atelectasis was prevented by antibiotics…why? </li></ul></ul></ul><ul><ul><ul><li>Atelectasis was not responsible for the fever  it was post-obstructive pneumonia! </li></ul></ul></ul>
  15. 15. <ul><li>Bottom Line </li></ul><ul><ul><li>Atelectasis does not cause fever, if anything, it is inversely correlated with fever. </li></ul></ul><ul><ul><li>While atelectasis may cause pulmonary shunting and hypoxemia and require treatment for these reasons, attributing fever to atelectasis may lead to missing infection or to inappropriate therapy. </li></ul></ul><ul><ul><li>Look elsewhere! </li></ul></ul>
  16. 16. Infectious Pneumonia: >24 Hours
  17. 17. Infectious Pneumonia <ul><li>> 20% of nosocomial infections are acquired in ICUs </li></ul><ul><li>Ventilator Associated Pneumonia (VAP) </li></ul><ul><ul><li>Infection of lung tissue that develops 48 hours or more after intubation in mechanically ventilated patients. </li></ul></ul><ul><ul><li>Mechanical ventilation increases the risk of developing pneumonia 7 to 21%  ETTs are not protective! </li></ul></ul><ul><ul><li>Risk factors </li></ul></ul><ul><ul><ul><li>Age > 60, chronic lung disease (COPD), ARDS, duration of ventilation, aspiration, paralytics, nasogastric tube, delay in extubation of patients who meet criteria </li></ul></ul></ul><ul><ul><li>Radiographically similar to aspiration or atelectasis </li></ul></ul><ul><ul><ul><li>The key is the duration to onset  > 24 hours </li></ul></ul></ul>
  18. 18. Pulmonary Edema <ul><li>Divided into two major forms </li></ul><ul><ul><li>Hydrostatic Edema (CHF) – develops and resolves quickly, often with no radiologic lag. In fact, radiologic findings often precede clinical symptoms </li></ul></ul><ul><ul><li>Capillary Leak Edema (ARDS) – Also develops quickly, but tends to resolve much slower due to alveolar epithelial damage </li></ul></ul><ul><li>These forms do not look alike and often can be distinguished on the chest radiograph </li></ul>
  19. 19. Identify the Abnormality (click for a hint) Dependent, ground-glass opacities bilaterally Vascular indistinctness Enlarged cardiac silhouette Hydrostatic Edema (CHF)
  20. 20. Cardiogenic (Hydrostatic) Edema <ul><li>Results from increased pressure in pulmonary capillaries  left ventricular failure, volume overload, etc. </li></ul><ul><li>Edema can manifest as indistinctness of vessels, subpleural thickening along interlobar fissures, peribronchial cuffing, and septal (Kerley A/B) lines. </li></ul><ul><li>If hydrostatic edema is severe enough to flood the alveoli, it usually has a central or basilar distribution. </li></ul><ul><li>Duration of edema also affects distribution </li></ul><ul><ul><li>Initially, edema is distributed evenly  eventually it may clear peripherally but persist centrally (~ 1 week) </li></ul></ul><ul><ul><li>Redistribution (cephalization) only occurs in the setting of chronic pulmonary venous hypertension (mitral stenosis, etc.) </li></ul></ul>
  21. 21. Hydrostatic Edema – CHF (comparison film is your best friend) … Again, note vascular indistinctness Soft tissue edema Wide vascular pedicle (volume overload)
  22. 22. …Hydrostatic Edema Continued Lateral projection is best for detection of…? Kerley-A’s Kerley-B’s
  23. 23. Identify the Abnormality (click for a hint) Diffuse, patchy areas of consolidation … with sparing of the lower lobes SGC reads 20 mmHG … do you believe it? “ Aztec sign of death” (defibrillator pad) 35% false positive rate Non-Cardiogenic Edema
  24. 24. Noncardiogenic (Capillary Leak) Edema <ul><li>Results from disruption of the capillary endothelium with leakage of plasma into the surrounding lung tissue. </li></ul><ul><li>Much more common than cardiogenic edema </li></ul><ul><li>Causes include sepsis, pneumonia, hypotension, trauma, burns, DIC, pancreatitis, transfusion reactions, air embolism, and toxic inhalation </li></ul><ul><li>Two other pulmonary disorders may be confused with capillary leak edema: </li></ul><ul><ul><li>Diffuse alveolar hemorrhage – should be considered in association with an unexplained drop in hemoglobin concentration </li></ul></ul><ul><ul><li>Cancer dissemination – rarely occurs in the ICU setting </li></ul></ul>
  25. 25. ARDS/Diffuse Alveolar Damage Same patient…compare lung volumes Peripheral distribution of opacification Decreased compliance = Decreased lung volume Identify the Abnormality Hint…this patient will Require intubation very soon
  26. 26. ARDS/Diffuse Alveolar Damage <ul><li>Considered the severest form of capillary leak edema, in which alveolar epithelial injury is the determining factor. </li></ul><ul><li>Pathological findings are divided into 3 stages: </li></ul><ul><ul><li>Exudation – edema, hemorrhage, hyaline membranes </li></ul></ul><ul><ul><li>Proliferation – organization </li></ul></ul><ul><ul><li>Fibrosis </li></ul></ul><ul><li>Radiographic findings </li></ul><ul><ul><li>Peripheral distribution and lack of effusion favors ARDS </li></ul></ul><ul><ul><li>Serial exams may be helpful  ARDS clears very slowly </li></ul></ul><ul><ul><li>Is the patient intubated?  with ARDS, even mild lung opacification is almost always associated with severe enough hypoxia to require mechanical ventilation </li></ul></ul>
  27. 27. Identify the Abnormality Visceral Pleura Absence of vascular markings Little or no mediastinal shift noted Pneumothorax (simple)
  28. 28. Pneumothorax <ul><li>Refers to gas in the pleural space and can be divided into several types: </li></ul><ul><ul><li>Simple – pleural pressure becomes slightly more positive, but still remains subatmospheric </li></ul></ul><ul><ul><li>Tension – intrapleural pressure exceeds atmospheric pressure resulting in a “check valve” mechanism, which promotes the inspiratory accumulation of gas. As a result, the diaphragm may be depressed and the mediastinum shifted to the contralateral side. </li></ul></ul><ul><ul><li>Don’t be fooled by skin folds! Beware of the classic stripe pattern and vasculature that extend beyond the alleged pneumothorax. </li></ul></ul>
  29. 29. Same patient…what happened? “ One-way” valve placed backwards Flattening of R hemidiaphragm R. visceral pleura, mediastinum shifted to contralateral side Conversion to Tension Pneumothorax
  30. 30. Same patient…proper valve placement
  31. 31. Simple or Tension Pneumothorax? Neither  Skin fold Take a closer look (next slide)
  32. 32. Line vs. stripe interface (see next slide) Skin Fold Try to follow vasculature to the periphery
  33. 33. Which patient just bought a chest tube? Pneumothorax Skin fold Note the opaque edge of the visceral pleura Line vs. Stripe interface Vs. the stripe pattern seen with skin folds
  34. 34. Identify the Abnormality Enlarged cardiac silhouette “ Superior pericardial border” sign Hint…patient is s/p CABG surgery Pericardial Effusion
  35. 35. Pericardial Effusion – Lateral View Enlarged cardiac silhouette “ Oreo” sign Retrosternal fat Epicardial fat Pericardial effusion
  36. 36. Pericardial Effusion <ul><li>Should be considered with unexplained new radiographic cardiomegaly without pulmonary congestion, particularly in the ICU setting. </li></ul><ul><li>Risk factors: </li></ul><ul><ul><li>Myocardial infarction, cardiac surgery, or an invasive cardiac diagnostic or interventional procedure </li></ul></ul><ul><li>Contrary to common teaching, pericardial effusion can be diagnosed on history, physical exam and radiography alone  echocardiography is not required. </li></ul><ul><li>Radiographic signs: </li></ul><ul><ul><li>Increased cardiac silhouette </li></ul></ul><ul><ul><li>“ Superior pericardial border” sign </li></ul></ul><ul><ul><li>“ Oreo” sign – blood/cardiac fat interface </li></ul></ul>
  37. 37. References <ul><li>Chastre, J, Fagon, JY. Ventilator-associated Pneumonia. Am J Respir Crit Care Med 2002; 165:867. </li></ul><ul><li>Ketai, L, Godwin, J. A New View of Pulmonary Edema and Acute Respiratory Distress Syndrome. Journal of Thoracic Imaging 1998; 13:147-171. </li></ul><ul><li>Engoren, M. Lack of Association Between Atelectasis and Fever. Chest Jan 1995:81-84. </li></ul><ul><li>Daffner, R. Diagnostic Radiology – The Essentials (2 nd Edition). Lippincott Williams and Wilkins 1999. </li></ul>N. Umpqua River, OR

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