ultrasound - university of florida · fast focused assessment with sonography in trauma rohit...

UltrasoundFAST

Focused Assessment with Sonography in Trauma

Rohit Patel, MDUniversity of Florida Health

Director, Critical Care Ultrasound Surgical ICUCenter for Intensive Care

Gainesville, Florida

Wednesday, June 1, 16

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


IntroductionFirst 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, 2001Wednesday, June 1, 16

FAST and E-FASTFAST 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. 1995.Stengel, D. Radiology. 2005.


History of FAST

Focused assessment with sonography in trauma

Focused abdominal sonography in trauma


Focused QuestionsIs there free fluid in the abdomen?

Is there fluid in the pericardium?

Extended FAST:

Is there fluid in the thorax?

Is there a pneumothorax?


AnatomyRight 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


Probe selection and locationPhased array 5 MHz or Abdominal probes (bigger footprint)

Noble et al. Textbook. Manual of Emergency and Critical Care Ultrasound.Wednesday, June 1, 16

Right upper quadrant


Kidney


KidneyDiaphragm-->


Right upper quadrant

Kidney

<--free fluidpleural fluid-->

diaphragm-->


Left upper quadrant

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

More Posterior and Superiorthan RUQ


Left upper quadrant


Suprapubic


The heart


Back to the pump


Pericardial fluid ------->

Pleural fluid-------->


Effusion around the pumpTamponade 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



Pericardial fluid -------> RV

<-------


FAST and e-FASTIf 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. 2007.Sisley, AC. J Trauma. 1998


pleural fluid (could be hemothorax in trauma setting)

------->


Ultrasound for pneumothorax

Kirkpatrick, J Trauma 2004

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



Zhang M. Crit Care. 2006Lichtenstein. Chest. 1995

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



Lichtenstein D. Intensive Care Med. 2000

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


Lung SlidingParietal 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


Pleural line with sliding ------->


Pleural line without sliding

<--------

optimal depth to evaluate is 3-7 cm

------------>


Focused QuestionsIs there free fluid in the abdomen?

Is there fluid in the pericardium?

Extended FAST:

Is there fluid in the thorax?

Is there a pneumothorax?


ultrasound - university of florida · fast focused assessment with sonography in trauma rohit...

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