Ultrasound Case of the Month
Cases of the month from January, 2017
Case # 1: Submitted by Dr. Michael Wilk
This is an 84 year old male, who presents to the ED with multiple complaints, including shortness of breath. A bedside ultrasound was performed and the lungs were evaluated.
Discussion:
This image is taken with the curvilinear probe in the RUQ, in a coronal plane, with the probe marker pointed to the patient’s head. This is the same location where we place the probe in a FAST exam, to evaluate Morrison’s pouch. Place the probe at the level of the xiphoid process in the mid-axillary line. Consider obliquing slightly so that the probe is parallel to the ribs and you decrease the amount of interference from rib shadow. Remember, if you are doing a FAST there are 4 areas you need to investigate in the RUQ: 1) Morrison’s pouch 2) tip of the liver/inferior pole of the kidney 3) under the diaphragm and 4) over the diaphragm. When evaluating for a pleural effusion, we just look above the diaphragm.
Normally, the lung is filled with air. Air does not transmit the ultrasound beam well, so you cannot visualize the spine in the chest. It is normal to see the spine below the diaphragm (in the abdomen), but we are normally not able to visualize the spine above the diaphragm through normal lung. If you do visualize the spine above the diaphragm, there is something abnormal in or around the lung, i.e. NOT air, that is allowing the ultrasound beam to travel all the way to the spine. Often times, this is caused by a pleural effusion, which can be seen as anechoic (black) fluid above the diaphragm. Fluid, in contrast to air, allows for easy transmission of the ultrasound wave, enabling visualization of the spine in the chest. This is ABNORMAL and is referred to as the Spine Sign.
The spine sign on ultrasound was found to have a sensitivity of nearly 74% and specificity of 93% for identifying a pleural effusion. This is superior to chest x-ray, which has only sensitivity of 69% and specificity of 54% as compared to gold standard CT scan.
Additional resources:
http://5minsono.com/pleuraleffusions/
https://www.youtube.com/watch?v=X1E7OgOLzw0
Case # 2: Submitted by Dr. Chana Rich
This is a 71-year-old male with a complicated past medical history, who presents to the ED as a transfer from an outside hospital after ROSC following PEA arrest. Patient had a femoral line placed at the outside hospital prior to transfer. There was some concern about whether the line was in the artery or in the vein, so the ultrasound team was called in to help.
Discussion:
**Please note, limited views were obtained on this patient, so the findings on the ultrasound are subtle. Please see the 5-minute sono podcast below for another, more obvious, example of this. You can watch the whole video (only 5 minutes) or you can fast forward to minute 2 and just see the bubbles
Ultrasound can be used for rapid central venous catheter placement confirmation by visualizing bubble artifact in the right side of the heart. To do this, inject agitated saline into the CVC. At the same time, place your cardiac probe on the patient's chest and obtain a view of the heart. As you rapidly inject the agitated saline through the central line, watch for artifact from the bubbles in the right heart. If you see “bubbles” in the right side of the heart, you know that your CVC must be in the right place!
Additional Resources:
The Bubble Study: Ultrasound confirmation of central venous catheter placement. Am J Emerg Med. 2015 Mar;33(3):315-9.
http://5minsono.com/cvc_confirm/
Case # 3: Submitted by Dr. Alisa Anderson
This is a 41 year old female who presents with left lower abdominal, back pain, and vaginal bleeding for 5 hours. The patient has had no prior pregnancies and no history of STIs. The patient had a positive pregnancy test in the ED.
Discussion:
This patient has evidence of a gestational sac outside of the uterus on the bedside ultrasound. There is no clear fetal pole is visualized. A small amount of free fluid can be seen in the cul de sac. This patient's bHCG was 2500.
Any patient with a positive pregnancy test and abdominal pain or vaginal bleeding should be evaluated for an ectopic pregnancy. On a bedside ultrasound, a gestational sac alone is not adequate for diagnosis of IUP. In addition, you need to see either a yolk sac or a fetal pole. A gestational sac can be visualized as early as 4 weeks gestation. At about 5 weeks you may begin to see a yolk sac as well. If located in the endometrium, this is adequate to rule in an IUP. In patients undergoing fertility treatment, make sure you consider a heterotopic pregnancy as well.
This patient was transferred to an outside hospital specializing in Ob/Gyn care for further management of this ectopic pregnancy. She ultimately went to the OR and was found to have a ruptured ectopic pregnancy.
Additional Resources:
http://www.sonoguide.com/obgyn.html
http://www.ultrasoundpodcast.com/?s=ectopic