Objectives Basic principles of lung ultrasound Key lung - PDF document

10/9/2019 Point of Care Ultrasound Lung Ultrasound Stephanie Conner MD October 20, 2019 Objectives • Basic principles of lung ultrasound • Key lung ultrasound findings • Brief overview of thoracentesis windows 2 1

10/9/2019 Objectives • Basic principles of lung ultrasound • Key lung ultrasound findings • Brief overview of thoracentesis windows 3 Probe Selection Linear Phased array • Superficial depth • Deeper depth • High resolution • Lower resolution • Ideal for evaluating the • Ideal for evaluating a- pleural line, lung sliding lines, b-lines, consolidations, and effusions 4 2

10/9/2019 Patient Position: Ambulatory Chest. 2011;140(5):1332-1341. doi:10.1378/chest.11-0348 5 Hospitalized Patient Technique 3

10/9/2019 Anatomy of Lung Ultrasound Skin & soft tissue Ribs Pleural line Intercostal space Key Learning Point Ultrasound cannot visualize through bone or air. Therefore, everything we see in lung ultrasound is either: Artifact or Abnormal - A-lines - B-lines - Consolidation - Rib shadow - Pleural Effusion 4

10/9/2019 Lung scatter & A-lines Ultrasound scatters in air, so you can’t see through it Rib shadowing Rib shadow Ultrasound cannot penetrate through bone, so you can’t visualize deep to it. 5

10/9/2019 Key Learning Point Ultrasound cannot visualize through bone or air. Therefore, everything we see in lung ultrasound is either: Artifact or Abnormal - A-lines - B-lines - Consolidation - Rib shadow - Pleural Effusion Objectives • Basic principles of lung ultrasound • Key lung ultrasound findings (5) • Brief overview of thoracentesis windows 12 6

10/9/2019 A-lines (1 of 5) Reverberations between the highly reflective pleura and transducer Can be seen in any LZ DDx: • Normal • If no lung sliding: PTX • If hypoxic/dyspneic: asthma, COPD, PE 13 A- vs. B-lines 14 7

10/9/2019 B-lines (2 of 5) Propogation of US waves through the lungs 2/2 widening of the interlobular septa Differential diagnosis: • Pulmonary edema • Pneumonia • ILD • ARDS >3 b-lines in >2 zones bilaterally = interstitial syndrome . • 94% sensitivity, 92% specificity for pulmonary edema Features of B-lines • Arise from the pleural line • Obliterate a- lines • Move with lung sliding • Extend >12cm • Abnormal >3 in one LZ 8

10/9/2019 Clinical Correlation of B-lines Liteplo et al. Real-time resolution of sonographic B-lines in a patient with pulmonary edema on CPAP. AJEM (2010) • Case: Hx CHF, ESRD, dyspnea, orthopnea • Initial US: Diffuse B-lines • After CPAP x 3.5hrs: A-lines 17 Alveolar Consolidation (3 of 5) • “Hepatization of lung” • Ddx: PNA vs atelectasis • Clinical correlation, other POCUS signs (shred sign, air bronchograms) needed * Real world note: probably the most challenging application of lung US 18 9

10/9/2019 Case: 50 y/o male with cough & fever Liver 19 Pleural Effusion (4 of 5) • Identification of a hypoechoic or echo-free space surrounded by typical anatomic boundaries • Costophrenic angles bilaterally (LZ 4) • Simple vs complex 10

10/9/2019 RUQ/Perihepatic view: Normal Morison’s Pouch Diaphragm Costophrenic Recess 21 Typical anatomic boundaries: • Diaphragm (and abdominal organs) • Chest wall • Ribs • Visceral pleura • Lung Spine sign Pleural Effusion 11

10/9/2019 Simple vs complex effusions Pleural Effusion US more sensitive than XR or exam: • Exam > 300mL • CXR >200mL Liver • US > 20 mL Effusion Scan dependent zones Fluid is hypoechoic (black) Lung Spine sign 24 12

10/9/2019 Lung Findings Summary • US for B-lines, consolidation, and pleural effusion = more sensitive than physical exam or CXR • Faster to acquire than CXR • Less radiation 25 Pneumothorax (5 of 5) 26 13

10/9/2019 Key Principle: Lung Sliding Movement of visceral pleura against parietal pleura with respiratory motion Linear probe B- and M-mode Findings: Syndrome Lung sliding? A-lines? B-lines? Normal √ √ Pneumothorax √ Pneumonia ± √ Is Pleural Sliding Present? 28 14

10/9/2019 Pneumothorax Is Pleural Sliding Present? When in doubt… M-mode 29 Normal M-mode of Lung Soft Ocean Tissue Normal Beach Lung 30 15

10/9/2019 Abnormal M-mode: PNEUMOTHORAX Soft Tissue Ocean / Barcode Abnormal Lung 31 The Lung Point Interface of normal lung sliding and absent lung sliding • Sensitivity: 0.66 • Specificity: 1.00 (Lichtenstein 233 ICU pts vs CT) 32 16

10/9/2019 Summary: US in pneumothorax • Outperforms CXR in supine patients • Much higher sensitivity, similar specificity • Lower specificity in critically ill ICU patients • False positives with pleural scarring, TB, ARDS (specificity 60-91%) • Lung Point: 100% specificity 33 Summary of Findings in Dyspnea/Hypoxia Findings Diagnosis A lines Asthma, COPD, PE Cardiogenic Diffuse B lines pulmonary edema Loss of pleural line, Pneumonia consolidation, focal B lines A lines without pleural Pneumothorax sliding, lung point 17

10/9/2019 Objectives • Basic principles of lung ultrasound • Key lung ultrasound findings • Brief overview of thoracentesis windows 35 Thoracentesis 36 18

10/9/2019 37 US Guidance in Thoracentesis • Find fluid on ultrasound • Establish landmarks for safe needle insertion with adequate depth • Usually not done under direct US guidance • Check for lung sliding before AND after the procedure 38 19

10/9/2019 Safe for thoracentesis? 39 Safe for thoracentesis? 40 20

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