EUS: Pyloric Stenosis, Early Pregnancy, Serratus Plane block

brownsound 2
Brown Ultrasound Tape Review – 11:19:15
At this week’s BUTR, we again reviewed some great ultrasound images that were scanned over the past week.
Resident reviewer: Dr. Mike Hunihan
Faculty reviewers: Drs. Erika Constantine and Otto Liebmann
————————————————————————————————————
PYLORIC STENOSIS
When to suspect pyloric stenosis:
– Onset between 3-5 weeks old, but can occur up to 12 weeks old.
– More commonly affects males.
– Risk factors include family history of pyloric stenosis, maternal smoking, macrolide antibiotics administered to infant, and bottle-feeding.
– Classic presentation is “hungry vomiter”; postprandial forceful non-bilious vomiting.
How to diagnose: 
– “Olive-shaped” mass that can be palpated along the R rectus sheath is pathognomonic, but rarely found.
– Ultrasound is the gold standard test when done by an experienced ultrasonographer.
– Additional studies, when ultrasound and exam are nondiagnostic, include barium swallow and upper endoscopy.
Ultrasound diagnostic criteria: 
Pyloric Muscle Thickness = >3mm
Pyloric Muscle Length = >14mm
Helpful mnemonic to remember this: Pi =3.14 (PYloric stenosis, >3mm thick, >14mm long)
Screen Shot 2015-11-30 at 12.26.58 PM Screen Shot 2015-11-30 at 12.27.12 PM
Abnormal findings: (Upper) Channel length (Lower) Muscle wall thickness
Another component of the US exam is to watch for passage of gastric contents through the pylorus. If you visualize passage of gastric contents, this is reassuring that there is no pyloric stenosis. However, sometimes you can get passage of small volumes of liquid through a tight pylorus and still have pyloric stenosis – it’s called the string sign with barium studies.
The other pertinent signs of pyloric stenosis:
1. Antral Nipple Sign: Redundant pyloric mucosa that protrudes into gastric antrum resembling a nipple.
 image
2. Target Sign: Hypertrophied hypoechoic muscle surrounding echogenic mucosa layer, visualized in short axis.
target sign
www.radiopaedia.org
3. Cervix Sign: Indentation of the pylorus into the fluid filled antrum. image (1)
In 2013, there was a prospective observational trial of PEM fellows performing bedside US for diagnosis of pyloric stenosis. They had a convenience sample of patients who were suspected to have pyloric stenosis based on history and physical exam, and who were ordered to have a formal ultrasound in the radiology department. The PEM fellows also performed bedside ultrasound on those same patients and compared their results to the radiology results. They enrolled 67 patients into their study, of which, 10 patients (15%) were found to have pyloric stenosis. The results of their study showed a 100% sensitivity and 100% specificity for PEM fellows performing bedside ultrasound. They had zero false positives or false negatives. This study suggests that bedside ultrasound for evaluation of pyloric stenosis is feasible for our residents, fellows, and attendings in the ED.
Sivitz, Adam B., Cena Tejani, and Stephanie G. Cohen. “Evaluation of hypertrophic pyloric stenosis by pediatric emergency physician sonography.”Academic Emergency Medicine 20.7 (2013): 646-651.
—————————————————————————————————————–
EARLY PREGNANCY

We also discussed the use of ultrasound in early pregnancy patients. From the ED perspective, our main question should be: IUP or no IUP?  If we cannot visualize a definitive IUP (gestational sac + yolk sac) then we need to be concerned about ectopic pregnancy.
But what about heterotopic pregnancy?
-A heterotopic pregnancy is the presence of both an IUP AND an ectopic pregnancy at the same time!
– In females who become pregnant by natural means, the chance is 1 in 10,000.
– In females who have assisted reproduction (IVF or even just hormone therapy) that chance increases to 1 in 1,000.

Moral of the story: When performing ultrasound in early pregnancy be sure to take a good history of any assisted reproduction techniques used for that pregnancy 
 
In addition to determining the location of an early pregnancy, we discussed the diagnostic criteria for non-viable IUP. A helpful review article in NEJM by Doubilet et al reviews the topic at length. 
 
Important measurements on US that are diagnostic for nonviable pregnancy: 
CRL >7mm with no heartbeat 
GS diameter >25mm with no embryo 
 
image (2)
Doubilet, Peter M., et al. “Diagnostic criteria for nonviable pregnancy early in the first trimester.” New England Journal of Medicine 369.15 (2013): 1443-1451.

——————————————————————————————————————–
SERRATUS NERVE BLOCK
Finally, we discussed a novel serratus plane nerve block that could be useful for anesthesia for axillary abscesses, rib fractures, or even chest tube placement. The aim is to block the thoracic intercostal nerves and provide anesthesia to the lateral hemithorax. The images below show the two options for serratus nerve plane block; injecting superior or inferior to the serratus anterior.
image (3)
 image (4)
Although this study gave the initial description of a serratus nerve plane block, there is still further studies to be performed. Something to keep an eye out for!
Blanco, R., et al. “Serratus plane block: a novel ultrasound‐guided thoracic wall nerve block.” Anaesthesia 68.11 (2013): 1107-1113.

Overly Traumatic: A Teenager Elbowed in the Stomach

Link

Overly Traumatic: A Teenager Elbowed in the Stomach

Case: 

A 17 yo healthy M presents with abdominal pain and a syncopal episode several hours after getting elbowed in the stomach at a soccer game.

PMH: Intermittent asthma

ROS: Sore throat, cough and fatigue x 1 week.

Physical Exam:

VS: T 98.3 °F | HR 90 | BP 129/60 | RR 16 | SpO2 100%

Pale but comfortable and alert. Abdomen diffusely tender, guarding in the upper quadrants. Exam otherwise unremarkable.

FAST exam: 

RUQ: Free fluid in Morrison’s pouch & at the tip of the liver

LUQ: Free fluid in splenorenal recess & bowel floating in free fluid

Transverse Bladder: Large amount of fluid & clotted blood anterior to the bladder

Click ahead to reveal diagnosis

Continue reading

ROCKstars – Case 1: US-Guided Central Venous Access (CIV)

brownsound 2

An elderly patient is in the RIH Critical Care bay with severe sepsis and needs central access.  Luckily, Drs. Adam “Hyperechoic” Haag and Eddie “Rule ‘Em Out” Ruhland are on shift.  They settle on the right Internal Jugular vein, but traditional sternocleidomastoid muscle (SCM) and clavicular bone landmarks are not apparent.  So a linear-array probe is correctly placed transversely over the triangle formed by the bifurcation of the SCM, to where the IJ and Carotid are seen in parallel…but there is some sort of hyperechoic, noncompressible mass…

They identify the thrombus, and instead find the Femoral vein, where CIV access is successfully achieved on the first attempt with no immediate complications.  The use of US to guide this procedure changed this patient’s course and potentially saved a complication.  

But exactly how much safer, faster, and more reliable is US-guided CIV placement?

THE ISSUE

  • Vascular access is critical in emergent situations
  • Body habitus, dehydration, poor perfusion, anatomical abnormalities, or history of IVDU can cause difficulties and delays when using landmark-based techniques
  • Complications of CIV placement include arterial puncture, excessive bleeding, vessel laceration, pneumothorax, hemothorax, and necessitation of multiple attempts
  • US guidance was identified in 2001 by United States Agency for Healthcare Research and Quality as one of the top 11 means of increasing patient safety, but this was based on one study of subclavian lines at one large urban center (1)

The “SOAP-3” Trial (2005)

  • A concealed, randomized, controlled study of 201 patients
  • Studies dating back to the 1990s in EM and Anesthesia (4) had demonstrated the efficacy of ultrasound-guidance, but this was the first study in the ED setting comparing the anatomical landmark method, the static “quick look” US-guided method, and dynamic “real time” US-guided method
  • In the “quick look” group, US was used to identify landmarks, the skin was marked, and the catheter was placed without real-time US guidance
  • EM residents and Attendings passed a 1h training course, then placed 10 CIVs with dynamic US guidance to qualify to participate

RESULTS

Dynamic

US Guidance

Static

US Guidance

Anatomical Landmarks Method
Overall Success 98% 82% 64%
First-Attempt Success

(OR vs LM)

5.8 3.4
Avg # of Attempts 1.7 1.6 3.2
Avg Total Sec 30 20 150
Complications 2 2 8

DISCUSSION

  • Dynamic guidance is superior but requires the most training
  • Static guidance is vastly superior to Landmark, and while slightly inferior to Dynamic, it requires less training
  • 10% of the study patients had “extremely narrow” (<5mm) IJs bilaterally, which could explain the inferior performance of the LM technique, even with experienced practitioners
  • All the complications were arterial punctures, and these were not statistically significant

References

  1. Agency for Health Care Research and Quality (AHRQ). Evidence Report/Technology Assessment: Number 43. Making Health Care Safer. A Critical Analysis of Patient Safety Practices: Summary 2001. 2007.
  1. Milling, et al. Randomized, controlled clinical trial of point-of-care limited ultrasonography assistance of central venous cannulation: The Third Sonography Outcomes Assessment Program (SOAP-3) Trial.  Critical Care Medicine, 2005, Aug;33(8); 1764-9.
  1. Sulek et al.  A Randomized Study of Left versus Right Internal Jugular Vein Cannulation in Adults.  J Clin Anesth, 2000, Mar; 12(2): 142-5
  1. www.sonoguide.com/line_placement.html

Nerve Blocks Rule

Jon and I did this awesome ultrasound-guided superficial cervical plexus nerve block the other day for a R IJ central line placement– taught to us by none other than the amazing Dr. Otto Liebmann.

It was so neat we made a video about it. Check it out!