Even Fewer Central Lines? - US Guided IVs

The Gist:  Patients in the ED often need venous access for fluid resuscitation or medication but may have poor peripheral venous access due to a myriad of reasons.  Ultrasound guided peripheral IV placement reduces the need for central venous catheters (and may also spare patients undue pain).

Doesn't sound that exciting, why should I care?  A patient presented with the clinical picture of sepsis - febrile, hypotensive, tachycardic, headache, visual changes and a possible source of cellulitis on his leg.  It was incredibly easy to order initiation of an early goal directed protocol; however, implementation was another story since we were unable to establish venous access.  The patient was morbidly obese and clearly intravascularly depleted, as evidenced by his very collapsed IVC on US.  The IV team eventually established access, but by that point, greater than one hour had elapsed.  The patient ended up doing well, but I think would have been better served had we begun fluid resuscitation, IV antibiotics, and the battery of lab tests more quickly.  The family and the patient were frustrated by the multiple unsuccessful attempts, and all interventions were dependent upon that access (no, he did not want an intraosseous line).    

The paper:  Au A, Rotte M, Grzybowski R, Ku B, Fields J.  Decrease in central venous catheter placement due to use of ultrasound guidance for peripheral intravenous catheters.  Am J of Emergency Medicine.  Online first 15 July 2012.

Methods

• 100 patients enrolled after meeting the following criteria:  after "multiple" failed peripheral attempts, nurse and physician discussed need for IV access and, if necessary, the physician attempt at external jugular placement must have been unsuccessful.  Physicians only enrolled patients who they thought would need a central venous catheter if peripheral access were unsucessful.
• Patients then underwent attempted cannulation with a 20g with single-operator US by a resident or attending

Results

• 88% of US guided peripheral IVs successful, of which, 11 eventually ended up with a CVC (1 with a central line, 10 with a PICC).
• 1 patient with a central catheter had a line infection requiring antibiotics.
• 12% of initial US guided peripheral IVs were unsuccessful.  7 of these underwent successful US guided IV in the ED and another 4 received a central line in the ED. 

This study builds upon other evidence that US guided IV access reduces time and number of attempts to successful cannulation (1,2, 3), although there has been a study demonstrating no difference (4).  This small study certainly has limitations:

• Not randomized 
• Some of the junction points in the study are subjective.  For example, patient or operator "fatigue" is variable.
• US guided IV only performed by physicians, not nurses or technicians
• Further attempts at standard IV access may have been abandoned earlier than usual due to availability of US (this is not a bad thing, especially from the patient perspective)
• No standard number of attempts prior to use of US.

Where to from here?

• Excessive attempts on pediatric patients seems brutal and studies demonstrate US works well for IV access in this population (6).  It's a study about ultrasound so, of course, I must mention something from the Ultrasound Podcast.  These guys are offering an incredible opportunity for US IV access education under the event "Not A Pin Cushion."  Check out their personal, touching story, which will inspire one to use US for difficult IVs.  There are many local programs and resources throughout the country that promote US guided IVs by physicians and nurses.  Here's a link to some FAQ regarding nurse placement of US guided peripheral lines from the "Stone's Side" of the Ultrasound Podcast.  Get on it. 
• There are two things I never argue "for," but I don't think this case fits either one. 
• Procedures that encourage providers to rely upon technology.  As someone with first hand disaster experiences following natural disasters, I'm fearful of dependence on things that require being "plugged in" (being without electricity for a month will instill this in one) and of becoming lazy.  I think that US is a great adjunct in the IV process for patients who fail initial attempts, thus could serve as an augmentation aid in difficult scenarios rather than foster dependence.
• Fewer procedures (unless it's actually in the patient's best interest, which turns out to not be infrequently).  Some patients will need a central line, period, perhaps for pressors or due to failure of peripheral access.  However, the risks associated with central lines including infection, probably the most common, are not negligible.  When indicated, central lines are still the way to go, US guided IV just reduces the number of unnecessary central lines (by up to 85% in the abovementioned study).

If it's a family member or friend, I'm breaking out the US even earlier.

References:
1.  Costantino TG, Parikh AK, Satz WA, Fojtik JP.  Ultrasonography-guided peripheral intravenous access versus traditional approaches in patients with difficult intravenous access.Ann Emerg Med. 2005 Nov;46(5):456-61.

2.  Doniger SJ, Ishimine P, Fox JC, Kanegaye JT. Randomized controlled trial of ultrasound-guided peripheral intravenous catheter placement versus traditional techniques in difficult-access pediatric patients.  Pediatr Emerg Care. 2009 Mar;25(3):154-9.

3.  Bauman M, Braude D, Crandall C.  Ultrasound-guidance vs. standard technique in difficult vascular access patients by ED technicians.  Am J Emerg med. 2009 Feb; 27(2)135-40.
4.  Stein J, George B, River G, Hebig A, McDermott D.  Ultrasonographically guided peripheral intravenous cannulation in emergency department patients with difficult intravenous access: a randomized trial.  Ann Emerg Med. 2009 Jul;54(1):33-40. 
5.  Dargin JM, Rebholz CM, Lowenstein RA, Mitchell PM, Feldman JA.  Ultrasonography-guided peripheral intravenous catheter survival in ED patients with difficult access. Am J Emerg Med. 2010 Jan;28(1):1-7.
6.  Benkhadra M, Collignon M, Fournel I, Oeuvrard C, Rollin P, Perrin M, Volot F, Girard C.  Paediatr Anaesth. 2012 May;22(5):449-54.  Ultrasound guidance allows faster peripheral IV cannulation in children under 3 years of age with difficult venous access: a prospective randomized study.

Out of Control: CT Scans in Renal Colic

The Gist:   Patient's don't keep track of their imaging and often underestimate the amount of radiation they've been exposed to through medical imaging.  Renal colic patients are at a high risk of cumulative radiation exposure so consider beginning the diagnostic evaluation other modalities, such as renal ultrasound (US), in relatively high risk populations.  CT scans aren't bad, but should probably used in series after US and with consideration.

Who should I really worry about?  If the imaging is absolutely necessary, then a theorized risk doesn't outweigh the potential harm from not performing the scan.  Period.  Also, younger people are more radiosensitive so imaging the geriatric population is less of an issue from the radiation standpoint.  For a review of radiation in medical imaging, check this out.

Patients with multiple medical problems.  Many patients, if not most patients, have no idea how much imaging they've had.  A study by Baumann et al in Annals of EM surveyed patients regarding their perception of radiation in medical imaging.  

• In this study (n=1,168), 365 of participants reported no previous CT scan, of these 39% had at least one documented CT scan in that medical system (2). As radiation is additive, how can one estimate a patient's radiation risk with no idea of exposure?  

Patients with renal colic.  Presently, the "gold standard" diagnostic modality for renal colic exists as the CT scan.  A retrospective chart review published by Broder, et al provides insight into the magnitude of the problem of radiation exposure in evaluation of 356 patient encounters (n=306 patients) for suspected renal colic over 10 month period.   

• 74% got a CT (n=262)
• Many got more than one CT scan in that period:
• Nearly half of the patients (49.3%, n=151) had 2 CT scans during the time period
• 15% had 3 CT scans  (n=46) 
• 4.9% had 4 CT scans  (n=15) 
• 1% (n=3) had 7 CT scans
• 1.6% (n=5) had >9 CT scans
• Three patients had excessive scans:  28 y/o female had 14 CTs, a 53 y/o male had 25 CT scans, and a 42 y/o female had 22 CT scans. 
• 38% of CTs were normal and only 2% (6 scans) showed an urgent or emergent cause of symptoms
• 21% (n=56) of CT scans showed complicated urolithiasis
• Only 6% of those who had a CT scan underwent a procedure

A typical single detector unenhanced CT in suspected renal colic exposes a patient to approximately 6.5 mSv (8.5 mSv for multidetector unenhanced CT) (3).  For simplicity sake, suppose scans were single detector CT limited protocol (not complete abdomen/pelvis scans) then the cumulative dose for some of the patients reached near 50 mSv.  If there's a 1 in 1000 risk of cancer caused by radiation per 10 mSv, then at least half of the patients in this cohort tip that balance.  Some of the patients received over 100 mSv of radiation within this short time frame.  Additionally, the mean age in this study was 38.9 years, placing these patients in a more radiosensitive category than their geriatric peers.

Also, keep in mind that the above Broder, et al study was conducted in 2003.  Another review, published in Academic Emergency Medicine demonstrated that between 1996-2007, CT usage for flank pain 4% to 42.5%, a 10-fold increase.  Thus, the Broder study may actually underestimate the radiation exposure for this population.  Unfortunately, this increase didn't result in an increase in the diagnosis of the badness that emergency physicians look for (therefore, likely not imparting a significant patient benefit) (1).

There is a solution...ultrasound and common sense.  For the former, Mike and Matt come through on Ultrasound Podcast, a podcast filled with great visual examples of hydronephrosis for practice.  SonoSpot, a relatively new blog, also has a great entry on renal ultrasound.

• Curvilinear or phased array low frequency probe 
• Placing the probe in the right and left mid-axillary line at the lower rib cage
• Slowly fan up and down to evaluate the longitudinal view of the kidney for dilation of the collecting system and renal pelvis
• Rotate 90 degrees to see the transverse view of the kidneys and slowly fan
• Look at the bladder
• Consider administering a 500 mL bolus of fluid before US
• Add an aorta US in older patients with higher suspicion for AAA
• Do a U/A
• Get a CT if needed

I'm looking...how do I interpret what I see?  The name of the game is hydronephrosis, which correlates to nephrolithiasis as stones are poorly visualized in US.

• Sensitivity 73-97%; Specificity 73-83%
• Study with highest sensitivity administered 500 mL fluid bolus prior to US

The statistics listed below are from an excellent review article (abstract here). 
Mild: renal pelvis dilation.

• 88% stones < 5 mm  (95% CI 79.2-92.3).  Almost all of these stones pass spontaneously (76.7%)
• Treat clinically and D/C with follow up if improved.
• If fail medical management, get CT scan

Moderate: renal pelvis and calyces dilated

• 69.8%  stones <5 mm (95% CI 54.9-81.4)
• Consider treating clinically and D/C with follow up if improved.
• If fail medical management, get CT scan.

Severe hydronephrosis: effacement of entire collecting system

• 80%  stones > 5mm (95% CI 37.6-96.4).  These stones are less likely to pass spontaneously. 
• CT scan/urology consult  

1. 1.  
2.  Westphalen A,
3.  Hsia R, 
4. Maselli J, 
5. Wang R, 
6. Gonzales R.  
Radiological Imaging of Patients With Suspected Urinary Tract Stones: National Trends, Diagnoses, and Predictors Academic Emergency Medicine Volume 18, Issue 7, pages 699–707, July 2011

1. 2.  Sharyn I. Katz1,2, 
2. Sanjay Saluja1, 
3. James A. Brink1 and
4. Howard P. Forman.  
Radiation Dose Associated with Unenhanced CT for Suspected Renal Colic: Impact of Repetitive Studies AJR Am J Roentgenol. 2006 Apr;186(4):1120-4.

Clinical Confidence Through Ultrasound

The Gist:  A small (n=74), yet promising study demonstrates the perceived decision-making utility of bedside ultrasonography (U/S) in managing septic patients using IVC diameter, IVC collapsibility index, and cardiac echo.  This may prove particularly useful for those of us (students) with limited clinical experience and confidence

The Ultrasound Podcast guys make U/S exciting and hip, yet I'm occasionally frustrated by the paucity of good data to sate the small scientific portion of my brain.  I often encounter ED physicians who don't believe that U/S really adds much to clinical practice.  If Drs. Mike Mallin and Matt Dawson can't convince them, perhaps journal articles can achieve that feat (although I remain suspect of anyone not excited about U/S after the 'name that 'stauche game' on the duo's echo episode). 

Results:

• Primary outcome achieved.  Treatment plan changed in 53% of the patients (n=39)
• A change in the volume resuscitation plan in 45% of patients (n=33).
• The decision to give pressors changed in 4 patients
• Physicians were more confident of their assessment of deranged vital signs after viewing the U/S.
• Sure, they're just treating numbers in this case, but this may point towards better understanding of the patient's physiological state (although what impact that makes on the patient is not addressed in this study).
• Only 10% of treating physicians found that the U/S data didn't contribute to patient management

The Good:

• Prospective
• Clinicians were initially blinded to the U/S results 
• Demonstrates bedside U/S is do-able by clinicians.  With minimal training, clinicians were nearly always able to obtain the necessary U/S data.
• U/S can actually change our ED management, adding to our clinical skill set and cushioning our certainty.

The Bad:

• Convenience sampling - no randomization
• Lack of generalizability - Most of the patients had sepsis or severe sepsis and very few had the scary elevated lactates, one tertiary facility
• Small cohort
• Power? No a priori calculation, so statistical significance for the primary outcome is not evaluated
• An average time of 138 minutes elapsed before the U/S was performed and an average of 160 minutes before the U/S was viewed by the clinician. 
• I think this may be missing some of the critical time in sepsis...perhaps the "early" in Early Goal-Directed Therapy
• Also, most shops I've been in obtain and interpret bedside U/S in real time
• Changes in interventions doesn't necessarily translate into a change in patient outcomes.

References:

Haydar S, Moore E, Higgins G, et al.  Effect of Bedside Ultrasonography on the Certainty of Physician Clinical Decisionmaking for Septic Patients in the Emergency Department.  Annals of Emergency Medicine Article in Press, 24 May 2012.  

I See Right Through You - Intro to EM Ultrasound

The Gist:  Within the Emergency Medicine (EM) realm, ultrasound (US) is gaining an incredible amount of momentum.  Once relegated solely to use in FAST (focused assessment with sonography for trauma) exams, obstetrics, and placement of vascular catheters, US use and its application are growing in EM.  Keep up by using US often, getting this application, and learning from these guys.

Radiology is boring so why should I care about US?  It takes too much time.  They're just going to get a CT anyways.

• Surprisingly, I occasionally let my "inner nerd" shine.  My discovery of EM US has highlighted this personality attribute, typically when discussing a patient's workup and my suggestion for an ultrasound is met with a scoff or a blank look.  I launch into a giddy medical student frenzy citing recent papers on the risks of radiation and efficiency of bedside US.  This is exciting stuff!  
• Both the medical and lay communities are exploring the burgeoning use of CT scans and the costs and risks associated therein, particularly in younger patients.  Thus, as a no-radiation study, US is gaining ground as a first-line imaging modality.  As a public health student, it's easy to get excited about the ways in which bedside US can help achieve better patient outcomes.
• Immediate gratification.  Medical students seemingly live for the pursuit of test results.  With US, one gets immediate feedback, readily allowing appropriate treatment and disposition.
• Bedside US can be quick.  Many challenge this point, but data are accumulating to suggest that ED length of stay (LOS) can actually decrease with bedside ultrasound by EM physicians. 
• Over a decade ago, a retrospective chart review demonstrated that patients with RUQ pain receiving a gallbladder US by EM residents had a significantly reduced LOS compared with those who had scans in radiology (1).
• Recently, a twitter update alerted me to a study at Sinai where ED US in appendicitis was associated with a decreased LOS  (2). 
• US for deep vein thrombosis by EM physicians also apparently decreases LOS (3)
• The CT scanner is often clogged, probably because between 1/8 and 1/14 patients presenting to the ED in the United States receives a CT scan (4).

But, US is so "operator dependent" and too "technical" for mere students.

• These excuses began this blog in the inaugural post, "Ultrasound for Dummies," a tidbit one might never know due to the tortuous and tangential nature of this blog.  In reality, increased emphasis on excellent US training in the EM curriculum is proving the opposite of these common refrains - EM physicians can perform adequate and timely US.  EBMedicine has an excellent summary of the evidence behind ED US.
• The key lies in hands-on practice...even more reason to get hooked early.
• US training and simulation is growing.  Many medical schools such as UC-Irvine are incorporating US throughout the four year medical school curriculum.  Check this out to see what the EDUS2 project is doing to promote cheap, effective US simulation.
• If the US is equivocal, you may still send the patient to the CT scanner (or perform other imaging/tests).  

Perhaps I'm now slightly intrigued by US...where do I start?

• The absolute first place to start is with the brainchild of Dr. Mike Mallin and Dr. Matt Dawson, Ultrasound Podcast where they "Make Horrible Doctors Decent and Good Doctors Great." (I wonder what they do to medical students?)
• This podcast is entertaining, thorough, and emphasizes the practical application of US in the ED.  Warning: (1) A few portions of the cardiac US lectures are dense and technical - bear through this and keep the podcasts on your phone for future reference (2) Don't listen to this podcast whilst running or driving (the video is key and this could be dangerous) (3) Listening to these podcasts on the elliptical in a public space may be detrimental to your image, as they are prone to make one burst into a fit of laughter.
• Although openly biased, the podcasts provide literature sources for the techniques presented and highlight aspects for future research.
• The free 1 Minute Ultrasound application for iPhone and Droid makes US accessible and quick in the ED.
• UC-Irvine has good, instructive video lectures downloadable via iTunes
• Many EM programs offer US electives for visiting medical students.  I can't comment on the quality of these yet, but I will in the next few months.
• Society of Academic Emergency Medicine (SAEM) has narrated lectures on a few techniques

Looking for a manual-style breakdown of various ultrasound procedures?

• SAEM  has Ultrasound Guides for common procedures in .pdf format and a links to other online resources.
• Ultrasound Guide for Emergency Physicians from ACEP is a little dry but one of the "go-to" resources in EM US training.

But, nobody around here ultrasounds...anything!

• Ultrasound each other.  The EM interest group at my medical school set up some time in the Vascular Sonography program's lab.  Students and instructors from that program were available to introduce us to the world of US.  
• Apparently, extra-firm tofu also works well for a delicious and inexpensive ultrasound simulation (reference #SAEM12).
• Ultrasound is an intellectual epidemic in EM.  However, if you just can't wait until your time in the ED, one can manage to find utility for ultrasound in nearly any medical field.
• For example, on a nephrology rotation, I somehow managed to introduce people to bedside IVC ultrasound and they got excited about doing it.  
• EDs have variable access to bedside US.  Tactfully advocate for improved patient care and outcomes by demonstrating the amazingness of US through the "1 Minute Ultrasound" application or by pandering to an outcome they're passionate about (ex: ED LOS).

Your charm and subtle enthusiasm for ultrasound piqued my interest in US...I want more! (Alternatively:  Supplement to an EM US elective)

• Add the SinaiEM.us blog to GoogleReader
• Case-based learner? Check out a plethora of neat case based videos.
• Ultrasoundvillage.com has an amazing image library, sort-able by organ system
• Search the web for EM US fellowship programs.  Many of these programs have extensive links and resources available, similar to the University of Arizona's list that provide excellent education.
• There are also excellent blog posts at takeokun.com
• The Stanford 25 take on bedside ultrasound, with various monotonic modules from USC. 
• Initiate dialogue with other specialists, students, and attendings on the utility and meaning of EM US.  An easy way to do this is to gift someone the "1 Minute Ultrasound" app...it's the right price for medical students.

Ultrasound for Dummies?

On a road trip in the deep south, I stopped at a gas station to fill up my tank.  I was greeted by a man in a camouflage cap embroidered with a confederate flag across the pump.  He struck up conversation with me, commenting on the t-shirt I sported, emblazoned with the name of my medical school.

"So, I just bought a broken sonogram machine for $20 and fixed it up," stated the sketchy man.  "Now, I rented a booth at the flea market and I'm going to charge people $25 for an exam.  See, one of my girlfriends came over and I showed her everything was a'ight with the baby."

I responded with some polite, awkward statement and a "congratulations" before continuing northbound.  A certain confusion permeated my "congratulations" to this man, which, upon reflection, was more of a result of pondering whether the baby was his or how many of his girlfriends were pregnant.  Regardless, as I continued my drive I considered how fitting this man's comments were in the context of the discourse regarding the growing utilization of ultrasound in the Emergency Department.

Over the past few months, the Ultrasound Podcast has transformed into one of my favorite podcasts.  These guys, Dr. Mike Mallin and Dr. Matt Dawson, demonstrate that EM physicians can use ultrasound well and for more than we often credit the imaging modality.

Oftentimes when I tell my attendings that I'm fascinated with ultrasound and would like to see the use expanded at bedside, I often encounter the question, "For what? Why?"  Many of these docs think solely about the FAST (Focused Assessment with Sonography of Trauma) exam.  I've learned, however, that there is so much out there for ultrasound to offer and very little risk associated with this imaging.

Also, if gas station man could use ultrasound at the flea market, I (and other students and physicians) can probably learn to do the same in an emergency department.