Ultrasonography: Applications in Critical Care PDF

13 April, 2023 Ultrasonography: Applications in Critical Care Amy Morris, MD, FCCP Conflict of Interest Disclosure No relevant financial or academic conflicts of interest How often do you use bedside ultrasound? A. Never B. I order someone else to do it C. Occasionally D. Several times per week E. D...

13 April, 2023 Ultrasonography: Applications in Critical Care Amy Morris, MD, FCCP Conflict of Interest Disclosure No relevant financial or academic conflicts of interest How often do you use bedside ultrasound? A. Never B. I order someone else to do it C. Occasionally D. Several times per week E. Daily F. I have a handheld device in my pocket right now Overview At the end of this talk you will be able to: Describe how ultrasound works Discuss principles of image interpretation Recognize 2D, M-mode, and color Doppler images List primary applications in the ICU Describe key normal thoracic, abdominal and cardiac ultrasound findings What is POC US? Procedural Diagnostic Does not replace comprehensive exams Focused (Dichotomous) Ultrasound Physics converse Piezoelectric effect Ultrasound Physics Piezoelectric effect Soft tissue Fluid Tissue Echogenicity Anechoic (fluid) Hypoechoic Hyperechoic (bone, gallstones, diaphragm, pericardium, gallstones) Depth Skin Surface IJ Carotid Gain Low Gain Optimal Gain High Gain Orientation Orientation Mark Effusion Lung cephalad Diaphragm Liver caudad Transducer Selection Skin Surface Basic Modes 2-D Basic Modes 2-D M-Mode Basic Modes 2-D M-Mode Color Doppler M-Mode Isolate a single line Follow changes over time M-Mode Isolate a single line Follow changes over time M-Mode Isolate a single line Follow changes over time Color Doppler US waves reflect off of objects (e.g. moving RBCs) Color Doppler US waves reflect off of objects (e.g. moving RBCs) Frequency of signal return indicates objects moving closer (frequency ↑) or away (↓) Color Doppler US waves reflect off of objects (e.g. moving RBCs) Frequency of signal return indicates objects moving closer (frequency ↑) or away (↓) A 76 year-old man with COPD and CHF presents with dyspnea and hypoxemia. A recent echo showed an ejection fraction of 30%, and his FEV1 is 30% predicted. He is tachypneic and tachycardic, O2 sat 90% on a nonrebreather mask. He has prominent wheezes and pitting lower extremity edema. His creatinine is 1.2; one month ago it was 1.0. Thoracic ultrasound looks like this in all fields: A 76 year-old man with COPD and CHF presents with dyspnea and hypoxemia. A recent echo showed an ejection fraction of 30%, and his FEV1 is 30% predicted. He is tachypneic and tachycardic, O2 sat 90% on a nonrebreather mask. He has prominent wheezes and pitting lower extremity edema. His creatinine is 1.3; one month ago it was 1.0. Thoracic ultrasound looks like this in all fields: What is the most appropriate therapy for the diagnosis suggested by this data? A. BiPAP and bronchodilators B. CPAP and diuresis C. Flutter valve or small-bore chest tube D. Thrombolytics Lung Ultrasound is Artifact Interpretation 1. 2. Ultrasound beams do not travel through air Lungs are mostly air Therefore: Normal lungs are not visible on ultrasound HOWEVER: Artifact patterns provide useful information about the lungs Thoracic Ultrasound: Anatomy Rib Rib Pleural Line Rib Shadow Normal Thoracic Artifacts Lung Sliding Presence confirms normal pleural apposition Alrajhi K. Chest 2012;141(3):703-708 Normal Thoracic Artifacts Lung Sliding Presence confirms normal pleural apposition Alrajhi K. Chest 2012;141(3):703-708 Lung Sliding Absent Diagnosis: Pneumothorax Disrupted pleural apposition Lung Sliding Absent Diagnosis: Pneumothorax Pleuridesis Inflammation Absence of lung sliding is nonspecific Disrupted pleural apposition OR movement 25 yo M with hypoxemia s/p CVC placement: uncertain lung sliding Does he need a chest tube? A. Yes B. No C. Insufficient data M-Mode 25 yo M s/p MVC, uncertain lung sliding Seashore Sign Normal 25 yo M s/p MVC, uncertain lung sliding Seashore Sign Normal Bar Code Sign Absent lung sliding Normal Thoracic Artifacts Lung Sliding A Lines Ultrasound beams do not pass through air!! Pleura Normal Thoracic Artifacts: A Lines Reverberation artifact Abnormal: B Lines Abnormal: B Lines B Lines Obliterate A Lines B Lines can be assessed quantitatively Volpicelli G. Intensive Care Med. 2012 Apr; 38(4):577-91 B Lines correlate with EVLW EVLW US Score *EVLW = Extravascular lung water Enghard. Crit Care 2015;19:36 Bilotta F. Eur J Anaesth 2013;30: 464-68 B Lines correlate are dynamic with EVLW Platz E. J Am Coll Cardiol HF 2019;7:849–58 B Lines correlate are not specific with EVLW Any alveolar filling or septal thickening can cause B lines: Edema ARDS Enghard. Crit Care 2015;19:36 Bilotta F. Eur J Anaesth 2013;30: 464-68 Interstitial Lung Disease… Back to case: Dyspneic man with CHF, COPD What is the most appropriate therapy for the diagnosis suggested by this data? A. B. X C. X D. X BiPAP and bronchodilators CPAP and diuresis Flutter valve or chest tube Thrombolytics Thoracic Ultrasound: Lower/Posterior Fields Orientation Orientation Mark Effusion Lung cephalad Diaphragm Liver caudad Normal finding at inferior posterior location Curtain Sign Normal: No effusion No consolidation Consolidation (“Hepatization”) + Pleural Effusion Focused Cardiac US: Essential Questions Is LV function normal or reduced? Is RV size/function normal? Is there a pericardial effusion? Are there gross valvular abnormalities? Spencer KT. J Am Soc Echocard. 2013;26:567-81 Via G. J Am Soc Echocard. 2014;27(7):683-e1 Focused Cardiac UltraSound: 4 Views Parasternal Long Axis (PLAX) Focused Cardiac UltraSound Parasternal Long Axis (PLAX) Focused Cardiac UltraSound Parasternal Long Axis (PLAX) Parasternal Short Axis (PSAX) Parasternal Short Axis (PSAX) Parasternal Short Axis (PSAX) Apical 4 Chamber (A4C) Apical 4 Chamber (A4C) Apical 4 Chamber (A4C) Subcostal Subcostal Subcostal: IVC IVC RA Subcostal: IVC IVC RA IVC RA Subcostal: IVC IVC RA IVC RA Will my patient respond to fluid? Ventilated, no spontaneous effort: Insp:exp variation of IVC diameter >12-33% Probably Breathing spontaneously: IVC 2.5cm, no inspiratory collapse Maybe Probably not Increased respiratory effort (large pressure swings) ¯\_(ツ)_/¯ Zhang Z. Ultrasound Med Biol. 2014 May;40(5):845-53 Abdominal POCUS Abdominal POCUS Probe Locations LUQ RUQ Pelvis (Bladder) accademia.org Right Upper Quadrant Hepatorenal recess (Morison’s Pouch) Paracolic gutter (liver tip) Subphrenic space +/- Pleural space PROBE POSITION: Mid-axillary line 8 to 10th rib Indicator cephalad TIP: rotate probe to align with intercostal space avoids rib shadow RUQ Hepatorenal Recess – Normal Hepatorenal Recess – Abnormal Left Upper Quadrant Splenorenal recess Paracolic gutter (spleen tip) Subphrenic space +/- Pleural space PROBE POSITION: Posterior axillary line 8 to 10th rib Indicator cephalad Hint: Rotate into intercostal orientation View is usually more posterior than you think View may improve with inspiration LUQ Splenorenal Recess 44 yo F with hx of ETOH cirrhosis Admitted with shock Hypotensive on two pressors Extremities warm Abdomen distended FCU hyperdynamic While waiting for labs you ultrasound her abdomen: POCUS for Ascites Hypotensive on two pressors Extremities warm Abdomen distended FCU hyperdynamic While waiting for labs you ultrasound her abdomen: POCUS for Ascites POCUS can identify complex ascites POCUS can identify complex ascites Doppler before paracentesis to avoid bleeding Abdominal POCUS Probe Locations LUQ RUQ Pelvis (Bladder) accademia.org Pelvis: Bladder Phased array transducer Just superior to pubic symphysis Indicator cephalad (long axis) and patient’s right (short axis) May be able to see uterus in women ?s [email protected]