Tag Archives: venous access

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)

Straight Suture Safety

finger bandage 300x271 Straight Suture SafetyHopefully you are using ultrasound to guide your insertion of central venous catheters. Once they are in, you still have to suture them at some point. Straight suture needles are often used to secure arterial and venous catheters to the skin. These types of suture needles have been demonstrated to be more dangerous than curved or blunt suture needles, with up to seven times higher rate of injury for health care workers. By utilizing the plastic needle sheath present in most central venous line kits as a “thimble,” counter pressure and skin puncture may be achieved without bringing the fingers near the sharp end of the suture. Here’s an image from Bret Nelson’s article on the technique.

Straight Sutre Safe 500x213 Straight Suture Safety

Panel A shows counter-pressure being applied with the cap to direct the tip of the needle. Panel B shows the needle tip safely sheathed within the cap.

The video below demonstrates this technique in real time:

 

Safety technique for straight suture needle from Sinai EM Ultrasound on Vimeo.

 

Other authors have illustrated alternative techniques to reduce the risk of self-injury when using straight suture needles.  Steven Bauer uses a 5-mL syringe to ensconce the emerging straight needle. This can provide even more distance, and he also uses it to guide tying an ‘air knot’ when needed!

syringe needle cap Bauer Straight Suture Safety

Haney Mallemat has just posted a video where he demonstrates using the paper envelope the suture is packaged in to distance the needle tip from your fingers.

Keep in mind NONE of these techniques has been studied- there is no evidence that they reduce needlesticks. We DO know that using curved, blunt-tip suture needles used with needle drivers and forceps is safer than using straight sutures. Whichever method you use please be careful!

References

  • Nelson BP. Making straight suture needles a little safer: a technique to keep fingers from harm’s way. J Emerg Med. 2008 Feb; 34(2):195-7. Epub 2007 Oct 1. (PMID: 18282537)
  • Bauer S, Tauferner D, Carlson D. Improving straight needle safety: an alternate method. J Emerg Med. 2011 Jul; 41(1):e19-20. Epub 2009 Sep 17. (PMID: 19765943)
  • Centers for Disease Control and Prevention. Evaluation of blunt suture needles in preventing percutaneous injuries among healthcare workers during gynecologic surgical procedures—New York City, March 1993–June 1994. MMWR Morb Mortal Wkly Rep 1997;46:25–9. (PMID: 9011779)
  • Edlich RF, Wind TC, Hill LG, Thacker JG, McGregor W. Reducing accidental injuries during surgery. J Long Term Eff Med Implants 2003;13:1–10. (PMID: 12825744)

 

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

Tips and Tricks: Probe Rotation

Probe 500x312 Tips and Tricks: Probe Rotation

Probe Manipulation – Rotation from Sinai EM Ultrasound on Vimeo.

How do you obtain that nice long image of the peripheral blood vessel for a longitudinal approach? It is easy to say ‘rotate the probe 90 degrees from the transverse view,’ but there are many subtleties to probe rotation. Many times when we rotate the probe, we do not get the desired longitudinal view, but rather the vessel is seen in part, or obliquely sectioned. Also, the vessel may appear on the left side of the screen or the right side and further fine rotation often makes the vessel disappear. How do we correct for this?

The trick is to understand the many different axes of probe rotation. See the video for an example of :

(i) probe rotation along an axis that goes through the proximal end of the probe (incorrect)

(ii) probe rotation along an axis through the distal end of the probe (incorrect)

(iii) CORRECT probe rotation along an axis through the central portion of the probe (through the transducer wire)

In order to move from a transverse to longitudinal view of a blood vessel without losing track of it, you must:

  1. Visualize the vessel in the center of the screen (thus, directly beneath the center of the probe)
  2. Rotate the probe on its CENTRAL axis (through the wire)
  3. Watch as the vessel transitions from a circle (transverse) to an ellipse (oblique) to two parallel lines (longitudinal)

Go try this on a phantom and with some practice, everyone can get that nice elongated view of the vessel.

Hot Topics in Emergency Medicine for the Physician Assistant

The annual Sinai PA Conference took place on 9/12/2009. The division of Emergency Ultrasound ran a course on peripheral line placement under ultrasound.

Screen shot 2009 09 26 at 12.03.09 PM1 300x200 Hot Topics in Emergency Medicine for the Physician Assistant
Attendees were enthusiastic and placed angiocaths under ultrasound guidance using our vessel phantoms. In fact, some were so eager that they were absolutely covered in gel by the end of the conference. Next year we will remember to bring towels.