Bedside ultrasonography is a quick noninvasive method for assessing a critically ill patient's condition. There are four views that are used—the parasternal long axis, the parasternal short axis, the subcostal 4-chamber, and the apical 4-chamber. The subcostal 4-chamber view is often the easiest to obtain in the ICU because lung expansion with mechanical ventilation can obscure the views obtained with the probe on the patient’s chest. Intraluminal bowel gas and pneumoperitoneum can interfere with the subcostal view. It makes sense to learn the different views, because often in the ICU you can only get one good view.
The major purpose of using ultrasound is to see if this is the kind of shock that needs fluids (hypovolemic, distributive) or drugs (cardiogenic, distributive after fluid resuscitation). It can also guide you with fluid management. Ultrasound is also great at diagnosing causes of obstructive shock. A pericardial effusion that’s collapsing the right atrium suggests tamponade. A dilated right ventricle with an underfilled, hyperdynamic left ventricle suggests pulmonary embolism. The absence of sliding lung should make you think of pneumothorax.
The best way to learn ultrasound is to practice. Take a look at these videos, courtesy of Sonosite. Learn the technique and what to look for, and then grab the ultrasound and use it as much as you can in the MICU. Your attendings should be able to help you master the technique.
bedside ultrasound in the ICU
subcostal 4-chamber view
parasternal long axis view
parasternal short axis view
ultrasound for pneumothorax
Videos are courtesy of Sonosite, which is an awesome product. Check out their education site here.