Patient with history of hypertension presents periumbilical abdominal pain radiating to the back. Minimal abdominal tenderness, no rebound or guarding, thoughÂ a pulsatile mass is felt.
The following ultrasound is obtained:
As the title suggests, the patient was diagnosed with an abdominal aortic aneurysm and vascular surgery was consulted.
We’re experimenting a bit with the GMEP.org system. It’s a great educational collaborative run by the folks who brought you Life in the Fast Lane. Worth checking out.
As you may know, we have a Vimeo channel with a growing video archive as well. Our goal is to make this site and its content as helpful and accessible a possible, so please let us know how we can improve!
When evaluating for possible elevation in intracranial pressure, it has been shown that optic nerve sheath diameter (ONSD)Â measurements correlate with elevated intracranial pressures.(1,2) Â The optic nerve attaches to the globe posteriorly and is wrapped in a sheath that contains cerebral spinal fluid.Â The optic nerve sheath is contiguous with the dura mater and has a trabeculated arachnoid space through which cerebrospinal fluid slowly percolates.
ONSD Normal Ranges
< 5 mm
Children >1 yr
< 4.5 mm
Infants < 1 yr
The ONSD is measured 3 mm posterior to the globe for both eyes.Â A position of 3 mm behind the globe is recommended because the ultrasound contrast is greatest. Â It is best to average two measurements of each eye.Â An average ONSD greater than 5 mm is considered abnormal and elevated intracranial pressure should be suspected.
In severe cases of elevated ICP, one can see anÂ echolucentÂ circle within the optic nerve sheath separating the sheath from the nerve due to increased subarachnoid fluid surrounding the optic nerve. Â Ophthalmologists refer to this as theÂ crescent sign.
Â The Case
40 yo female patient presents with several months of frontal headache associated with photophobia and blurry vision. Â Symptoms have gotten much worse over the last few days and she has had difficulty reading and watching TV because of her visual symptoms. Â She denies fevers, chills, nausea, vomiting, or focal weakness. Â Pt is hypertensive 170/100. Â Her vital signs are otherwise normal.
This patient had enlarged ONSD (measurements were 6 mm bilaterally) as well as papilledema(arrow).
Lumbar puncture was performed. Â Opening pressure was 44. Â 30 cc’s of CSF was drained and the closing pressure was 11. Â The patient’s headache and visual symptoms improved . Â She was started on acetazolamide and admitted to the neurology service. Â MRI brain prior to lumbar puncture showed posterior scleral flattening bilaterally with protrusion of the optic nerve in the the globes bilaterally consistent with increased ICP.
This patient’s papilledema and increased ONSD correlated with a markedly increased opening pressure during lumbar puncture and suggests that ocular ultrasound may play a role in the ED management of patients with suspected pseudotumor cerebri.
Elevated intracranial pressure in the abscence of intracranial mass lesion.Â Most common in young, over weight women. If the diagnosis is missed, persistently elevated intracranial pressure can lead to optic atrophy and blindness.
Lumbar puncture to drain CSF to a normal opening pressure.
Medical:Â Diomox (acetazolamide), high dose steroids
The ability to diagnose papilledema using bedside sonography is useful to emergency physicians, as manyÂ non-ophthalmologistÂ clinicians do not feel confident in their ability to perform an accurate nondilated fundoscopic examination. (3) Â Ultrasound provides a useful alternative means of determining the presence or absence of papilledema in a patient in whom fundoscopy cannot be adequately performed.
 Geeraerts T, Launey Y, Martin L, et al. Ultrasonography of the optic nerve sheath may be useful for detecting raised intracranial pressure after severe brain injury. Intensive Care Med 2007;33(10):1704-11 [electronic publication 2007 Aug 1].Â PMID:Â 17668184
 Kimberly HH, Shah S, Marill K, Noble V. Correlation of optic nerve sheath diameter with direct measurement of intracranial pressure. Acad Emerg Med 2008;15(2):201-4.Â PMID:Â 18275454
 Wu EH, Fagan MJ, Reinert SE, Diaz JA. Self-confidence in and perceived utility of the physical examination: a comparison of medical students, residents, and faculty internists. J Gen Intern Med 2007;22 (12):1725-30 [electronic publication 2007 Oct 6]. Â PMID:Â 17922165
We already know it is helpful to use ultrasound to guideÂ placementÂ 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?):
Blood gas drawn through central venous catheter port
Pressure transduction (quantitative- manometry)
Pressure transduction (qualitative- attach IV tubing and checkÂ heightÂ 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. Â When done rightÂ should look something like this :
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 pushÂ necessaryÂ for the bubble test. SomeÂ peopleÂ have used this angiocatheter during ACLSÂ situationsÂ 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.
Prekker ME, Chang R, Cole JB, Reardon R. Â â€œRapid confirmation of central venous catheter placement using an ultrasonographic “Bubble Test.â€Â Acad Emerg MedÂ 2010;17(7):e85-6. (PMID:Â 20653578)
We 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.
Emergency physician, intensivist, and Mount Sinai Emergency Ultrasound Fellowship graduate Dr. Robert Arntfield is making news at his new home, London Health Sciences Center (LHSC) in Ontario, Canada. Dr. Arntfield and his department have set up a hardware and software infrastructure for bedside ultrasound which allows for electronic data storage and retrieval, robust QA, teaching and research.
LHSC’s website has this to say:
Dr. Rob Arntfield, an ED physician and intensivist at LHSC, recently completed a year-long fellowship at The Mount Sinai Hospital in New York, learning and integrating cutting edge point-of-care ultrasound applications into the care of the critically ill patient. Since his return to LHSC, Arntfield has been working with Dr. Drew Thompson, also an LHSC ED physician, to develop new quality assurance training standards to enhance residentsâ€™ knowledge and use of this important patient care technology