FAST ExamFAST Exam

Erin CarnesErin Carnes

September 27, 2007September 27, 2007

FAST ExamFAST Exam IntroductionIntroductionUltrasound PhysicsUltrasound PhysicsTechniqueTechnique Indications for FAST examIndications for FAST examPerforming a FAST examPerforming a FAST examLimitationsLimitationsQuestionsQuestions

What is the FAST exam?What is the FAST exam?

FFocused ocused AAssessment by ssessment by SSonography in onography in TTraumarauma Focused exam using ultrasound to diagnose Focused exam using ultrasound to diagnose

hemorrhage in a trauma settinghemorrhage in a trauma setting Ideally takes < 3 minIdeally takes < 3 min 4 primary views4 primary views

RUQRUQ LUQLUQ SubxiphoidSubxiphoid SuprapubicSuprapubic

Basic Ultrasound PhysicsBasic Ultrasound Physics Ultrasound is a spectrum of sound frequencies Ultrasound is a spectrum of sound frequencies

above the human hearing range. above the human hearing range. Molecules must be present for sound to exist.Molecules must be present for sound to exist. Every object has an echogenicity. When sound Every object has an echogenicity. When sound

waves hit the object some are transmitted waves hit the object some are transmitted through and some bounce back.through and some bounce back.

Every substance will respond differently to the Every substance will respond differently to the sound waves striking it’s surface. This occurs at sound waves striking it’s surface. This occurs at every sound-to-sound interface and the every sound-to-sound interface and the reflection of sound waves can be used to create reflection of sound waves can be used to create and image.and image.

TechniqueTechnique Goal: to identify blood in Goal: to identify blood in

body cavities where it is body cavities where it is not supposed to benot supposed to be Unclotted blood appears Unclotted blood appears

black on USblack on US Clotted blood appears grayClotted blood appears gray

Abdominal probe with Abdominal probe with small footprint (between 1- small footprint (between 1- 3 cm) with range of 3 cm) with range of frequency between 2.0 Hz frequency between 2.0 Hz and 5.0 Hzand 5.0 Hz

Scan 4 areasScan 4 areas RUQRUQ SubxiphoidSubxiphoid LUQLUQ SuprapubicSuprapubic

IndicationsIndications

Blunt thoracoabdominal traumaBlunt thoracoabdominal traumaPenetrating thoracoabdominal traumaPenetrating thoracoabdominal traumaSuspected pericardial tamponadeSuspected pericardial tamponadeTrauma patient with hypotension on Trauma patient with hypotension on

unknown etiologyunknown etiologyThoracoabdominal trauma in a pregnant Thoracoabdominal trauma in a pregnant

patientpatient

Right Upper QuadrantRight Upper Quadrant Sagittal view obtained by Sagittal view obtained by

placing probe either in the placing probe either in the midclavicular line on the midclavicular line on the lower rib cage or below lower rib cage or below the right costal marginthe right costal margin

May have to move probe May have to move probe laterally to avoid gas in laterally to avoid gas in hepatic flexurehepatic flexure

Air-filled lung creates Air-filled lung creates reflection artifact in which reflection artifact in which lung appears to be lung appears to be composed of liver composed of liver parenchymaparenchyma

Scan for black fluid in Scan for black fluid in potential spacespotential spaces

Normal RUQNormal RUQ

Abnormal RUQAbnormal RUQ

SubxiphoidSubxiphoid

Probe placed under Probe placed under xiphoid almost parallel xiphoid almost parallel with skin surface directed with skin surface directed towards patient’s left towards patient’s left shouldershoulder

Parasternal view may be Parasternal view may be used when supxiphoid used when supxiphoid unable to be obtained unable to be obtained

Consider pnuemothorax Consider pnuemothorax when unable to obtain when unable to obtain images of heart and no images of heart and no apparent reasonapparent reason

Normal SubxiphoidNormal Subxiphoid

Abnormal SubxiphoidAbnormal Subxiphoid

Left Upper QuadrantLeft Upper Quadrant

Most technically Most technically difficult to obtaindifficult to obtain

Probe placed parallel Probe placed parallel with ribs in posterior with ribs in posterior axillary lineaxillary line

Scan potential spaces Scan potential spaces between diaphragm between diaphragm and spleen and and spleen and spleen and kidney for spleen and kidney for free fluidfree fluid

Normal LUQNormal LUQ

Abnormal LUQAbnormal LUQ

SuprapubicSuprapubic

Entire pelvis should be Entire pelvis should be scanned from top to scanned from top to bottom with transducer in bottom with transducer in transverse place and them transverse place and them side to side with side to side with transducer in sagittal planetransducer in sagittal plane

Pouch of Douglas is the Pouch of Douglas is the most dependent site in most dependent site in peritoneal cavityperitoneal cavity

First sign of blood is often First sign of blood is often two small black triangles two small black triangles on either side of rectumon either side of rectum ““Bow tie sign”Bow tie sign”

Normal SuprapubicNormal Suprapubic

Abnormal SuprapubicAbnormal Suprapubic

LimitationsLimitations

Retroperitoneal bleedingRetroperitoneal bleeding Inadequate volume of fluidInadequate volume of fluid Not enough time elapsed since trauma to Not enough time elapsed since trauma to

demonstrate bleedingdemonstrate bleeding Solid organ trauma with encapsulated bleedingSolid organ trauma with encapsulated bleeding Image quality dependent on quality of US Image quality dependent on quality of US

machine and probe, body habitus of patient, machine and probe, body habitus of patient, physical injuriesphysical injuries

Scan and interpretation are operator dependentScan and interpretation are operator dependent

Questions?Questions?