Focus on POCUS
As part of our ultrasound curriculum, interns undergo an anesthesia/ultrasound rotation that consists of intubations in the OR in the morning, followed by ultrasounds in the ED in the afternoon. During this four week rotation, some residents log over 250 ultrasound exams! We started the series off with Scaff's Scans, and today we will be sharing some incredible ultrasound cases from Dr. Bruce Grattan. Take a look at his images and video clips!
- Shyam Murali, MD, Editor-in-Chief
By Bruce J. Grattan Jr, DO, MS, RD, PGY-2
21 year old female presents to the ED with complaint of cramping abdominal pain. PMH is significant for cirrhosis, crack cocaine use, alcohol abuse, hepatitis C, hepatitis B, and IVDA. Patient also has a history of a tricuspid valve replacement and recent pericardial effusion requiring drainage. On exam, the patient appears uncomfortable and is complaining of abdominal pain and an inability to keep food down. HR 87, RR 18, BP 112/68, afebrile. A bedside echo is performed showing the following.
What pathology is seen on the echo?
Large pericardial effusion
What is the classic triad associated with the finding seen on echo?
Beck’s triad: hypotension, JVD, and muffled heart sounds. This was not seen on exam. However, it is well-known that seeing all three components of Beck's triad even in cardiac tamponade is rare. One study had the following results:
"None of the patients with pericardial effusion or pericardial tamponade had all of the elements of Beck’s triad. The sensitivity of Beck’s triad was found to be 0 (0%–19.4%). The sensitivity for one finding of Beck’s triad to diagnose pericardial tamponade was 50% (28.0%–72.0%)." (Stolz 2017)
What EKG finding would be anticipated based on this Echo?
Electrical alternans. Interestingly this was not seen on this patient's ECG; this was attributed to the fibrous tract, resulting from a prior pericardiocentesis several weeks earlier, which stabilized the heart and likely prevented electrical alternans.
47 year old male, PMH significant for tobacco abuse (2ppd x 25 years) and HTN well-controlled on medications, presents to the ED with chest tightness radiating to his back associated with SOB. Symptoms were sudden in onset when he was getting on the bus to go to work; however, he decided to go home and take a nap instead. Symptoms persisted when he woke up an hour later, so he came to ED for evaluation. BP on the right arm 130/85, BP on the left arm 124/77. Bedside ultrasound was obtained which showed the following.
What pathology is seen on this ultrasound?
Absent lung sliding and absent comet tail artifacts indicate the presence of a pneumothorax.
What is the treatment for this condition?
Chest tube for large pneumothoraces (greater than 3cm distance to apex). Although controversial, a small diameter pigtail catheter can be placed at the bedside or by interventional radiology for spontaneous pneumothoraces. In traumatic pneumothoraces, a larger chest tube is required (24 to 36 French). Small pneumothoraces (less than 3cm distance to apex) can be treated with high flow oxygen, which causes nitrogen washout and re-expansion of the lung.
What condition can occur after chest tube placement if there is aggressive re-inflation or the chest tube is placed to high suction?
Re-expansion pulmonary edema:
Characterized by rapidly progressive respiratory failure and tachycardia after intercostal chest drainage.
Probably related to histological changes of the lung parenchyma and reperfusion-damage by free radicals leading to an increased vascular permeability. It is often often self-limiting and treatment is supportive.
Fatal in 20% of cases
A subsequent chest x-ray demonstrated a large right pneumothorax, so a 24F chest tube was placed and the patient was admitted to this hospital for further monitoring.
74 year old male comes to the ED with a chief complaint of chest pain and shortness of breath. His PMH includes CAD s/p multiple stents and s/p CABG, HTN, HLD, COPD, CHF, Type 2 Diabetes. Pt is stable on exam. Bedside ultrasound was performed which demonstrated the following.
What pathology is seen?
Heart failure with grossly reduced ejection fraction
How can one estimate ejection fraction with bedside ultrasound?
EPSS (E-Point Septal Separation). EPSS can be measured by direct ultrasound visualization of the heart in parasternal long axis. Using M-mode, the marker is placed over the most distal tip of the anterior mitral leaflet.
A normal, healthy anterior mitral valve leaflet may come in contact with the septum creating zero distance of E-point separation (Massie, 1977). As a strained heart begins failing to pump against an elevated systolic afterload, the left ventricle expands. This expansion results in decreased contractile forces, the consequences of which is a reduced ejection fraction – the original observation made by the early LVEF studies (Massie, 1977; Strunk, 1975; Ahmadpour, 1983). These same research studies demonstrated an inverse correlation between EPSS distance and ejection fraction – i.e., as the left ventricle size expands to compensate for decreased stroke volume, the mitral valve flow fails to keep pace, causing an increased space, or separation, between the valve and septum (Massie, 1977; Ahmadpour, 1983). Specifically, it was demonstrated that a EPSS >7mm was 87% sensitive (75% specific) at identifying reduced LVEF (<50%) compared to other studies (Ahmadpour, 1983). 7mm has since been accepted as the general cut-off for abnormal EPSS.
Stolz L et al. Clinical and Historical Features of Emergency Department Patients With Pericardial Effusions. World Journal of Emergency Medicine 2017. PMID: 28123617.