Tag Archives: echo

Bubble test

bubbles 300x225 Bubble testWe already know it is helpful to use ultrasound to guide placement of central venous catheters.

How can we use ultrasound to help confirm proper placement of an internal jugular catheter?

There are several methods which have been described:

  • Visualize the needle entering the vein (optimally in the long axis)
  • Visualize the guide wire in the vein
  • Visualize the tip of the triple lumen catheter in the right atrium, then pull back 2 cm
  • Bubble test (more on this below)

In addition there are non-ultrasound-related methods to confirm placement (but who cares about those?):

  • Chest x-ray
  • Blood gas drawn through central venous catheter port
  • Pressure transduction (quantitative- manometry)
  • Pressure transduction (qualitative- attach IV tubing and check height of blood column)

So let’s get back to that bubble test. In order to confirm that the catheter has been placed in the superior vena cava, inject 5-10 cc normal saline through the catheter while visualizing the right heart on a subxiphoid 4-chamber view.  When done right should look something like this :

Saline flush right heart from Sinai EM Ultrasound on Vimeo.

So this is a neat trick after the catheter is in, but the horse is out of the barn at that point. Ideally you should confirm proper venous placement prior to dilating the vessel and placing the central line. You could do this while the needle is in the vessel, but that’s a bit unstable. Instead consider using the long angiocatheter found in most central line kits to puncture the internal jugular vein.

After the flash (and ultrasound confirmation of venous puncture) advance the catheter and remove the needle. You then have an angiocatheter in the central venous system, which can be used for manometry, blood gas analysis, or the saline push necessary for the bubble test. Some people have used this angiocatheter during ACLS situations to administer a few doses of code medications in a shorter time than it would take to complete a “full” central line.

Once proper venous placement is confirmed, you can advance the guide wire through the angiocatheter and continue the procedure as normal.

For a great overview of central venous catheterization, check out this post by Haru Okuda and Scott Weingart at EMCrit.org.

Further Reading

Prekker ME, Chang R, Cole JB, Reardon R.  “Rapid confirmation of central venous catheter placement using an ultrasonographic “Bubble Test.” Acad Emerg Med 2010;17(7):e85-6. (PMID: 20653578)

Ultrasound education at MSSM

VscandemoBretNelson2 500x375 Ultrasound education at MSSMThe Mount Sinai School of Medicine recently welcomed its incoming first-year class in its traditional White Coat Ceremony. In a day filled with inspirational talks by prominent faculty and medical leaders, students don their new white coats and receive a stethoscope at a special ceremony attended by family, friends and faculty members.

This year, Sinai’s medical students were also introduced to a new curriculum in point-of-care ultrasound:

“First-year medical students traditionally learn about the human body by dissecting the cadavers and eventually by examining the patients, and the examination ranges from inspection and palpation to listening with the help of a stethoscope and interpreting the sounds of the heart, lungs and blood vessels,” says Jagat Narula, MD, PhD, who is the principal investigator of this research study and the director of the cardiovascular imaging program at Mount Sinai School of Medicine. “With handheld ultrasound, our medical students will have the ability to see live images of inside the body projected onto a handheld screen in real time.  It’s an innovative educational concept that can modernize medical education.”

As part of an educational research study, GE Vscan ultrasound machines will be distributed to groups of medical students who will learn to use the technology to image the heart, lungs, and abdomen. Mount Sinai is the first school in New York to initiate such a curriculum.

David Muller, MD, dean of medical education at Mount Sinai School of Medicine, says of the research study, “First-year medical students will learn how to identify and assess the anatomical structures within cardiac, thoracic and abdominal applications. We are excited to incorporate the portable ultrasound in our curriculum as we strive to revolutionize the way medicine is taught.”

The curriculum will augment what is being taught in the Art and Science of Medicine course, which is the students’ introduction to physical examination.

Bret Nelson, MD, RDMS, FACEP, associate professor and director of emergency ultrasound in the department of emergency medicine at Mount Sinai, will be leading the new curriculum with Dr. Narula. Says Dr. Nelson, “Point-of-care ultrasound represents a distinct skill set beyond physical examination. Te increased penetration of sonography through a variety of clinical practice environments means students will need to understand this technology to excel in patient care through their careers.”

vscanGroup 500x375 Ultrasound education at MSSM

FROM LEFT: Jagat Narula, MD, PhD; David Muller, MD; Mike Harsh, Vice President and Chief Technology Officer, GE Healthcare; Dennis S. Charney, MD, Anne and Joel Ehrenkranz Dean, Mount Sinai School of Medicine and Executive Vice President for Academic Affairs, The Mount Sinai Medical Center; Tom Gentile, President and Chief Executive Officer, GE Healthcare; Bret Nelson, MD; and Lisa Kennedy, Director, Strategic Marketing, healthmagination

“Today, we are thrilled to play a part in this important research project by providing Mount Sinai’s first-year medical students with the power of portable ultrasound technology, as they take the first step towards becoming our next generation of doctors,” says Tom Gentile, president and CEO of GE Healthcare Systems. “Tools like Vscan have the ability to help transform the physical exam and today’s announcement reaffirms GE Healthcare’s commitment to research and improving patient care by helping enhance the physician’s ability to quickly and accurately diagnose patients.”

For the full story, please check out the October 1 edition of Inside Mount Sinai.

Ponte Vedra Ultrasound Course 2012

hero.inn and club 500x178 Ponte Vedra Ultrasound Course 2012We are pleased to present our annual critical care ultrasound pre-conference course at the Clinical Decision Making in Emergency Medicine symposium in Ponte Vedra, Florida on Wednesday, June 20. Each year this intensive, hands on course features ultrasound faculty from across the country working in small groups with live models and plenty of hands-on scanning time.

The course is held at the beautiful and historic Ponte Vedra Inn and Club.

Please visit here for Registration information

Highlights of the four-hour course include:

  1. Cardiac ultrasound
  2. Thoracic ultrasound
  3. Ultrasound for venous access
  4. Assessment of the hypotensive patient

Faculty for this year’s course include:

  • Bret Nelson, MD, RDMS (course director)
  • Petra Duran, MD
  • Joseph Wood, MD, JD, RDMS

Emergency and Critical Care Ultrasound Course 2012

CME2011 7 Emergency and Critical Care Ultrasound Course 2012On March 22, 2012 the Division of Emergency Ultrasound will host its annual hands-on CME course at Mount Sinai. Targeted at clinicians in emergency and critical care settings, the course consists of presentations by national faculty and plenty of hands-on scanning with live models.

Course highlights:

  • Basic to advanced topics covered
  • Organ system-based approach to bedside ultrasound use
  • Faculty with international experience in ultrasound education
  • Diagnostic applications as well as procedure guidance covered

Both experienced sonographers and neophytes will benefit from small group sizes and an interactive course design.

Additional information is available on the CME Course Page, or download our Mount Sinai Ultrasound CME course brochure 2012.

Registration for the course is open!

CME2011 3 Emergency and Critical Care Ultrasound Course 2012

Cardiac tamponade

One of the major indications for bedside cardiac ultrasound is the detection of pericardial effusion and its extreme form, cardiac tamponade. You may remember that Beck’s Triad (hypotension, jugular venous distension, and muffled or distant heart sounds) is pathognomonic for cardiac tamponade. You should also remember (to say to your colleagues who recite that tamponade is a clinical diagnosis) that the triad is present in about one-third of cases.

If you can spot tamponade clinically in a hypotensive, tachycardic patient with muffled heart tones and JVD, congratulations! You may pass your boards, save a simulated patient, or impress a junior medical student. But how does one diagnose this condition a bit earlier in its natural history?

Pulsus parodoxus is not as hard to assess as it sounds- inflate a blood pressure cuff as you normally would. Slowly deflate the cuff and listen for Korotkoff sounds. If they are present during inspiration and expiration, there is no pulsus parodoxus and you are done. If you only hear Korotkoff sounds during expiration, note the pressure reading and keep slowly deflating until they are present throughout the respiratory cycle. What is the pressure difference between sounds during expiration only and sounds throughout the entire cycle? If it is greater than 10 mmHg, pulsus paradoxus is present.

But you read this far down because you want to know how to find tamponade using ultrasound, right? There are some earlier findings of cardiac tamponade which are detectable with ultrasound before hemodynamic instability ensues. They are:

  1. Pericardial effusion
    • Hard to have tamponade without this
  2. Diastolic collapse of right atrium and right ventricle
    • Ideally diastole can be recognized with EKG monitoring on ultrasound, or using M-Mode
  3. Inferior Vena cava plethora
    • Dilated IVC with loss of respiratory variation
  4. Atrio-ventricular valve Doppler inflow velocities
    • If these words are unfamilar, use the first three findings instead! Respiratory variation in inflow across the atrioventricular valves (like a valvular pulsus parodoxus) can be a sign of early tamponade physiology. However this is an advanced technique.

The video below shows the first three findings nicely:

Large Pericardial Effusion from Sinai EM Ultrasound on Vimeo.

Note the subxiphoid view with large effusion, followed by the parasternal long axis view. Finally, a transverse view of the IVC demonstrates dilatation and loss of respiratory variation.

 Further Reading:

  • Schairer JR, Biswas S, Keteyian SJ, et al. A systematic approach to evaluation of pericardial effusion and cardiac tamponade. Cardiol Rev. 2011 Sep-Oct;19(5):233-8.
  • Nagdev A, Stone MB. Point-of-care ultrasound evaluation of pericardial effusions: does this patient have cardiac tamponade? Resuscitation. 2011 Jun;82(6):671-3.