Focused Cardiac Ultrasound

Image-Based Resuscitation of the Hypotensive Patient

with Cardiac Ultrasound: An Evidence-Based Review

J Trauma Acute Care Surg. 2016;80:511-518.

Point-of-care cardiac ultrasound does not require advanced technology. It can be performed with a simple 2D ultrasound machine. It is performed at the bedside by any treating clinician, emergency physicians, residents, paramedics, and even medical students.International guidelines that suggest term Focused Cardiac Ultrasound (FoCUS) should be a core competency among all critical care providers.

The diagnostic targets of this simplified examination are gross cardiac contractility and anatomy (LV and RV size and function) as well as volume status and presence of a pericardial effusion ± tamponade.

Summary of the Terminology Used to Describe Point-of-Care Cardiac Ultrasound

Undifferentiated hypotensive patient protocol. 2001, RoseFocused assessment with trans-thoracic echocardiography, 2004, JensenBedside limited echocardiography by the emergency physician. 2004, PershadGoal-directed transthoracic echocardiography. 2005, ManasiaFocused echocardiographic evaluation in resuscitation. 2007, BreitkreutzGoal-oriented hand-held echocardiography. 2007, VignonCardiovascular limited ultrasound examination. 2007, KimuraFocused critical care ultrasound study. 2007 BeaulieuRapid assessment with cardiac echocardiography. 2007, SeppeltIntensivist bedside ultrasound. 2007, CarrBedside echocardiographic assessment in trauma. 2008 GunstFocused cardiovascular ultrasound. 2009, CowieFocused intensive care echocardiography. 2009, FletcherAbdominal and cardiac examination with sonography in shock. 2009, AtkinsonFocused echocardiographic evaluation in life support. 2010, BreitkreutzRapid ultrasound in shock. 2010, PereraFocused rapid echocardiographic examination. 2011, FerradaLimited transthoracic echocardiography. 2011, FerradaGoal-directed echocardiography. 2012, Schmidt

TechniqueM mode: to examine structures that are in motion such as the cardiac walls or the walls of the vena cava

1. Subcostal long axis (SLAX)2. Subcostal inferior vena cava (SIVC)3. Parasternal long axis (PLAX)4. Parasternal short axis (PSAX)5. Apical 4 chamber (A4CH)

SLAX and SIVC viewsFAST

PLAX and PSAXleft lateraldecubitus position

LV LVOT

RVRV

LV

A4CHleft lateral decubitus positionsupine position

RA LA

RV LV

Clinical ApplicationDifferentiate between different types of shockDetermine the need and the quantity of fluid or resuscitation required in hypotensive patients

Volume StatusDiagnostic of hypovolemia in hypotensive patients: empty heart or flat IVCIn hypovolemia, the ventricular walls will come together or ‘‘kiss,’’ or in cardiologist lingo, an ejection fraction >70%Flat IVC: IVC collapses >50% during the respiratory cycle

The Significance of the IVC in Volume Status

The overall size of the vessel is not as important as the variability. Increasing the intra-thoracic pressure would result on an increased IVC size but might not change the variability. A small IVC on a hypotensive ventilated patient is diagnostic of hypovolemia, but a full IVC does not rule out this diagnosis.

1. Subxiphoid; 2. Middle clavicular line; 3. Midaxillary line.

GLOBAL HEART FUNCTION AND VENTRICULAR SIZE

Visual estimations of cardiac function are equivalent to more detailed measurements, decreased LV function can be diagnosed by novice providers with minimal training.For the non-cardiologist, one only needs to be able to detect if there is a decrease in global cardiac activity.

The American Society of Echocardiography current recommendation to assess LV function on the short-axis view at the level of the mitral valve.Assessment of global cardiac function: – the inward motion of the endocardium– the presence of thickening of the myocardium– the longitudinal motion of the mitral annulus– the overall geometry of the ventricle

In hypotensive patients, evaluation of the function and the size of the RV can be very useful in diagnosis and treatment for pulmonary embolism.RV enlargement in the presence of a massive pulmonary embolus is predictive of poor outcome.

Pericardial EffusionFAST: subcostal viewCardiac tamponade: right heart compression

Lung and Pleura Ultrasound in the Deteriorating Patient

A lines are horizontal, regularly spaced hyper-echogenic lines representing reverberations of the pleural line. These are motionless and are artifacts of repetition. B lines are vertical narrow lines arising from the pleural line to the edge of the ultrasound screen. ‘‘comet tails ’’

Assessing pulmonary interstitial fluid allows clinicians to recognize a cardiogenic cause of respiratory failure. When evaluating for fluid status, predominance of B lines should discourage the clinician for further fluid resuscitating since it is indicative of interstitial lung edema.

Pneumothorax: absence of ‘‘lung sliding.’’The lung point: an interface between normal lung and pneumothorax.Hemothorax is identified in the lateral position and sometimes in the FAST.

Q & A