Skip to Main Content

++

Hemodynamic insufficiency, presenting as hypotension and shock, is a common presentation in both the emergency and critical care setting. The etiology of hypotension may be easily identifiable in such cases as massive hemorrhage, profound dehydration, sepsis, or severe cardiac dysrhythmia. More often, there is ambiguity as to the cause of a patient's hypotension, especially when no good history is available and the physical examination and laboratory values are unrevealing. In the patient with hypotension and no identifiable cause, appropriate initial management may be delayed. In this situation, the physician may use bedside ultrasonography to rapidly assess the patient for various causes of shock, possibly leading to immediate life-saving interventions.

++

The usefulness of bedside ultrasound in the hypotensive patient is based on the principles already discussed in previous chapters. A bedside ultrasound is performed rapidly by the physician taking care of the patient, and interpreted immediately while performing the scan. This allows the treating physician to expedite the patient's diagnosis and definitive care. In addition, a hypotensive patient is usually too hemodynamically unstable to leave the department, and performing an ultrasound at the bedside may help obviate the need for further testing and transport out of the department. Consultant-performed ultrasound is still not always available in every hospital setting and testing may be delayed. This stresses the importance of needing an ultrasound machine available in both the emergency and critical care department and adequately training physicians to use the equipment properly. Along with using ultrasound to search for the cause of a patient's instability, it is useful for procedures needed to treat the condition, such as central line placement. Finally, a bedside ultrasound can be repeated as necessary to assess response to therapy, evolution of disease, and to search for new problems.

++

The causes of shock can be divided into various categories that help to generate a differential diagnosis for a patient's instability. These categories help to design an ultrasound approach at the bedside tailored to the patient's presenting complaint and most likely diagnosis.

++

Obstructive Shock

++

Etiologies of obstructive shock are either due to intrinsic or extrinsic factors. Common causes include pericardial tamponade, tension pneumothorax, right ventricular (RV) outflow impedance (ie, pulmonary embolism, high ventilator pressures, auto PEEP), and intraabdominal compartment syndrome. Rare causes of obstructive shock include tamponade from massive pleural effusion and intracardiac obstruction (ie, myxoma or massive valvular vegetation).

++

Ultrasonography permits rapid assessment for obstructive shock. An echo can be performed to evaluate for pericardial effusion and signs of tamponade, including right ventricular (RV) diastolic collapse. The inferior vena cava (IVC) size can also be evaluated, which will appear plethoric with minimal or no respiratory variability.

++

An echo can be used to look for evidence of RV outflow impedance, showing a dilated chamber size consistent with acute cor pulmonale and pulmonary embolism. A lower extremity ultrasound can also be used to identify deep venous thrombosis (DVT) ...

Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.

Ok

About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

AccessAnesthesiology Full Site: One-Year Subscription

Connect to the full suite of AccessAnesthesiology content and resources including procedural videos, interactive self-assessment, real-life cases, 20+ textbooks, and more

$995 USD
Buy Now

Pay Per View: Timed Access to all of AccessAnesthesiology

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.