Ultrasound. FAST Focused Assessment with Sonography in Trauma

Transcription

1 Ultrasound FAST Focused Assessment with Sonography in Trauma Rohit Patel, MD University of Florida Health Director, Critical Care Ultrasound Surgical ICU Center for Intensive Care Gainesville, Florida

2 A few points about didactic lectures Hands on instruction better explained in Bedside Videos Reading material important to cover aspects not discussed in this lecture portion Important to mix hands on Active Learning with the reading/didactic material to best learn ultrasound application

3 Introduction First used in Europe 1970's, ATLS since 1997, later incorporated into surgery and emergency medicine residency curriculums Objective: detect free fluid in pericardium and intraperitoneal in the setting of trauma Alternatives: CT, DPL, OR, Observation; ultrasound has higher specificity for therapeutic laparotomy than DPL Combination algorithmic approach seems best McKenney, Journal of Trauma, 2001

4 FAST and E-FAST FAST exam and pleural fluid assessment Coined at international consensus conference in 1996 to describe an integrated, goal directed, bedside examination to detect fluid FAST detects fluid as low as 100 ml but commonly cited as 250 to 620 ml Sensitivity 79% Specificity 99% Branney, SW. J Trauma Stengel, D. Radiology

5 History of FAST Focused abdominal sonography in trauma Focused assessment with sonography in trauma

6 Focused Questions Is there free fluid in the abdomen? Is there fluid in the pericardium? Extended FAST: Is there fluid in the thorax? Is there a pneumothorax?

7 Anatomy Right paracolic gutter - Morrison's pouch to pelvis Left paracolic gutter - not as deep as right and phrenocolic ligament blocks fluid movement Morrison's pouch (hepatorenal recess) - space between Glisson's capsule on liver and Gerota's fascia of kidney Splenorenal recess - between spleen and Gerota's fascia Rectovesicle pouch - pocket formed by reflection of peritoneum from rectum to bladder; pouch of Douglass in female

8 Probe selection and location Phased array 5 MHz or Abdominal probes (bigger footprint) Noble et al. Textbook. Manual of Emergency and Critical Care Ultrasound.

9 Right upper quadrant Noble et al. Textbook. Manual of Emergency and Critical Care Ultrasound.

10 Right upper quadrant Noble et al. Textbook. Manual of Emergency and Critical Care Ultrasound.

11 Kidney

12 Kidney

13 Diaphragm--> Kidney

14 Right upper quadrant Kidney diaphragm--> pleural fluid--> <--free fluid

15 Left upper quadrant More Posterior and Superior than RUQ Noble et al. Textbook. Manual of Emergency and Critical Care Ultrasound.

16 Left upper quadrant Noble et al. Textbook. Manual of Emergency and Critical Care Ultrasound.

17 Suprapubic Noble et al. Textbook. Manual of Emergency and Critical Care Ultrasound.

18 Suprapubic Noble et al. Textbook. Manual of Emergency and Critical Care Ultrasound.

19 The heart Noble et al. Textbook. Manual of Emergency and Critical Care Ultrasound.

20 Back to the pump

21 Pericardial fluid > Pleural fluid >

22 Pericardial fluid > Pericardial fluid >

23 Effusion around the pump Tamponade or not? Hallmark: RV free wall inversion, best recognized during diastole Right atrial inversion during systole (more common and early finding) Increased respiratory variation of mitral or aortic inflow velocities (greater than 25%) Dilated inferior vena cava with decreased inspiratory collapse ASE Committee Recomendations. Am Soc Echocardiography. 2005

24 Pericardial fluid >

25 Pericardial fluid > RV < Pericardial fluid >

26 FAST and e-fast If fluid found, move up one or two costal spaces, lung sometimes seen floating in pleural fluid Sensitivity 92% and Specificity 100% in detecting hemothorax in the Emergency Department, can detect 20 ml of pleural fluid VS supine CXR needs 175 ml Head slightly elevated can help accumulate fluid just above diaphragm McEwan K. Emerg Med J Sisley, AC. J Trauma. 1998

27 pleural fluid (could be hemothorax in trauma setting) >

28 Ultrasound for pneumothorax First described in a horse in 1986 In a normal lung, the visceral and parietal pleura are closely associated, and ultrasound shows shimmering or sliding at the pleural interface during respiration; absence of this indicates a pneumothorax In trauma, US shown to be more than twice as sensitive for detecting occult pneumothorax with similarly high specificity (98%) Comet tails are ultrasound artifacts that arise when ultrasound encounters a small air fluid interface Kirkpatrick, J Trauma 2004

29 Ultrasound for pneumothorax Chest radiography? US relies on fact that free air is lighter than normal aerated lung tissue, accumulates in nondependent areas of thoracic cavity Multiple studies show ultrasound to be more sensitive than supine chest radiography (CT gold standard) Sensitivity 86 to 100% Specificity 92 to 100% Negative predictive value of 100% (Lichtenstein study) Zhang study: sensitivity 86% vs 27% AND time to obtain study 2.3 minutes vs 19.9 minutes Zhang M. Crit Care Lichtenstein. Chest. 1995

30 Ultrasound for pneumothorax Supine High frequency linear array best Midclavicular line at third through fifth intercostal space to ID pleural line, but should look through several intercostal spaces Lung point: area where pneumothorax interfaces with chest wall Lichtenstein D. Intensive Care Med. 2000

31 Lung Sliding Parietal and visceral pleura can be seen sliding to each other Graphically depicted using M-mode Absence can also be seen in COPD bleb, consolidated pneumonia, atelectasis, main stem intubation

32 Pleural line with sliding >

33 Pleural line without sliding < optimal depth to evaluate is 3-7 cm >

34 Focused Questions Is there free fluid in the abdomen? Is there fluid in the pericardium? Extended FAST: Is there fluid in the thorax? Is there a pneumothorax?