Summary of Ultrasound Indications: Class 1 Clinical Indications For Goal-Directed Sonography in the Critically Ill
Adapted from: the ACC/AHA Guidelines on the Clinical Applications of Echocardiography,1 the Surviving Sepsis Guidelines,2 recommendations of the Agency for Healthcare Research and Quality (AHRQ),3 and emergency medicine, surgery, and critical care literature.
Class I: Conditions for which there is evidence and/or general agreement that a given procedure or treatment is useful and effective.
Pericardial Disease: Patients at risk for or suspected of having pericardial disease that may be of an effusion, constrictive, or constrictive-effusive nature. Think penetrating trauma with hypotension, hypotension days after a myocardial infarction, or hypotension in the patient with end stage renal disease.
Acute Myocardial Infarction: Bedside echocardiography can assess for any complication of acute myocardial infarction (including free wall rupture, septal wall rupture, tamponade, aneurysm formation, and thrombus formation).
Severe Valvular Disease: Especially aortic regurgitation and stenosis as well as mitral regurgitation.
Cardiomyopathy, Congestive Heart Failure, and Assessment of Left Ventricular Function: The assessment of LV systolic function is described as the most common recommendation for echocardiography. Evaluate for hypertrophic, dilated, restrictive cardiomyopathy; systolic and diastolic dysfunction fall under this category.
Aortic Dissection: Although TTE may visualize the intimal flap in patients with aortic dissection, TEE is more sensitive in detecting massive pulmonary embolism and thoracic aortic abnormalities. It is especially helpful when TTE is non diagnostic or is technically limited due to mechanical ventilation/ lung interference.
Pulmonary Embolism: Echocardiography has aided a diagnosis of central pulmonary artery thromboembolic disorders, especially in patients with severe or massive pulmonary embolism. It has a low sensitivity and specificity for detecting pulmonary peripheral emboli. With larger pulmonary emboli, TEE may detect thrombus in the main portion and proximal branches of the pulmonary artery. Massive embolism may be detected by the presence of pulmonary hypertension and RV dilatation and dysfunction.
Palpitations: Cardiac asynchrony (arrhythmias) can occur as a purely electrophysiological problem or as a sequel to and/or in association with an underlying structural heart disease. Think SVT that may easily respond to adenosine or another AV nodal blocking agent; however, the diagnosis of hypertrophic septal hypertrophy may usher in a consideration of myomectomy. See the April 2008 Emergency Medicine Practice issue, “An Evidence-Based Approach To Supraventricular Tachydysrhythmias.”
Serious Blunt Trauma or Juxtacardiac Penetrating Trauma: TTE, when compared to subxiphoid pericardiotomy, is very accurate, specific, and sensitive in detecting pericardial fluid in juxtacardiac penetrating chest wounds.
ACLS and ATLS: Guidelines urge the rapid recognition of several dangerous and time-sensitive diagnoses in the cardiopulmonary arrest or injured patient. Severe hypovolemia and low CVP states direct the clinician to search for occult fluid loss/accumulations in the thorax and peritoneum using enhanced FAST principles. See the January 2007 Pediatric Emergency Medicine Practice issue, “Use Of Bedside Ultrasound In The Pediatric Emergency Department” for a detailed description of FAST principles as well as sample images.
Pulmonary: One of the most commonly encountered causes of low cardiac output and obstruction is high pressure pneumothorax. Supine chest x-rays may miss this finding. The sliding pleural sign is more sensitive and specific than the portable CXR and more immediately available than the CT of the thorax.
Abdominal Aortic Aneurysm: The rapid and accurate detection of AAA is well established.
Vascular Access: This can be even more challenging in the critically ill patient. Indirect or direct sonographic guidance can be used in central and peripheral venous cannulation and other procedures.