Modern Resident - The newsletter of AAEM/RSA
February/March
Volume 1: Issue 5


Critical Care Pearl: Transfusion Reactions

Robert Katzer, MD
Georgetown-Washington Hospital Center

I Was Just Filling up the Tank, Right? When Erythrocyte Transfusion Goes Awry.

Despite a large amount of research on the issue, there is no universally followed set of indications. However, the transfusion of blood and blood products is a hazardous activity, and we all agree that there are several dangers associated with it. This article deals specifically with the noninfectious reactions encountered during and after transfusion.

We should first consider the fact that the subgroup of patients in need of blood products is one that already carries the burden of a high one year and ten year mortality rate on the order of 24% and 52%, respectively.1 The vast majority of this reflects patients' comorbities. In this already critical situation, it is important to remember that transfusion reactions themselves carry their own morbidity and mortality risk. In fact, 2-4% of transfusions will result in one of the several potential reactions.2

One of the major presentations of transfusion reaction is fever. Febrile reaction is very common and may or may not indicate a serious reaction. This reaction is due either to hemolysis (ABO incompatibility) or a non-hemolytic fever. Upon presentation of fever, first stop the transfusion. Perform a urinalysis for blood. Send blood specimen for direct Coombs' test. If either of these is positive, the patient probably has hemolytic fever.

Hemolytic fever affects roughly 1 in 35,000 RBC recipients and kills 1 in every million.2 The catalyst can be as little as 5mL of blood product, and the fatality rate goes up with the volume transfused. What happens? Just think SIRS: fever, hypotension, shock, dyspnea, chest pain, low back pain. What should you do about it? If the patient becomes hypotensive, give fluid boluses. If pressors are needed, chose an agent that improves systemic vascular resistance, like Dopamine or Norepinephrine. Like sepsis, the feared endpoint of hemolytic reaction is multi-organ dysfunction syndrome (MODS).3

Nonhemolytic fever occurs in 1 in 200 RBC recipients, but can occur in up to 20-30% of platelet transfusions. This is a response of recipient antibodies towards antigens on donor leukocytes. The onset is usually more delayed than hemolytic fever, occurring 1 to 6 hours after the transfusion begins. Although reactions typically involve only fever, they may develop into severe presentations including tachycardia and hypotension, but typically do not progress to the SIRS appearance of their hemolytic counterpart. The vast majority of these reactions will not repeat themselves during future transfusions. As a result, this reaction should not become a contraindication to future transfusions.2

Allergic reactions to blood transfusion run the spectrum from isolated urticaria (1/100 transfusions) to full blown anaphylaxis (1/1000 transfusions).2 Unsurprisingly, these are an IgE mediated reaction to allergens in the donor blood and should be evaluated and treated in the same manner as other IgE hypersensitivity reactions. Remember, both anaphylaxis and hemolytic fever can and will result in hypotension, despite two very different underlying processes.

Finally, acute lung injury (TRALI) is found in 1 in 5,000 transfusions. Although not immediate, this reaction will manifest itself within four hours of transfusion.3 This is driven by an inflammatory response whose downstream effect is capillary dysfunction of the pulmonary tissue and resulting pulmonary edema. Patients unsurprisingly develop dyspnea, which may also be accompanied by fever and hypotension. Although the temporal relationship makes a hemolytic reaction less likely, it should not be initially struck from the differential. Management for TRALI follows the same approach as with ARDS, and many of these patients will require ventilatory support. No consensus of the safety of transfusions after TRALI exists at this time.4

In summary, if your patient develops dyspnea, chest pain, fever or hypotension while receiving a transfusion, you must stop the transfusion immediately, resuscitate the patient, obtain a chest X-ray, and send direct Coombs' test and urinalysis to evaluate for a hemolytic process. If the tests are negative, remember the other etiologies that can underlie adverse transfusion reactions.

References:

  1. Vamvakas EC, Taswell HF: Long-term survival after blood transfusion. Transfusion 1994; 4:471- 477.
  2. The ICU Book, 3rd edition Paul Marino.
  3. Goodnough, LT: Risks of Blood Transfusion. Crit Care Med 2003 vol. 31, No. 12 s678-s686.
  4. Consensus Conference on Perioperative Red Blood Cell Transfusion. JAMA 1988;260:2700-2702.
AAEM/RSA would like to thank Western University and the University of California, Irvine for their generous sponsorship of the EMIG Leadership Lunch during the Student Track at the 16th Annual AAEM Scientific Assembly in Las Vegas, NV.

Your Leadership

We welcome your comments and suggestions. Feel free to get in touch with your elected leaders:

President
Michael Ybarra, MD

Vice President
Alicia Pilarski, DO

Immediate Past-President
Megan Boysen, MD

Secretary/Treasurer
Cyrus Shahpar, MD MPH MBA

At-large Board Members
Heather Jimenez, MD
Jennifer Kanapicki, MD
Jeff Pinnow, MD
Ryan Shanahan, MD
Sandra Thomasian, MD

Medical Student Council President
Jamie "Akiva" Kahn

Modern Resident Contributors

Copy Editor: Teresa M. Ross, MD

Special thanks to this month's contributors: Rikin Shah, Steven McGuire, Alex Fisher, Dr. Teresa M. Ross and Dr. Robert Katzer.

Interested in writing?

E-mail submissions to: info@aaemrsa.org

Please submit articles by March 15th for the April/May edition.

In the subject line please indicate: "Tox Talk", "Critical Care Pearl", "Board Review", "Journal Club", "Image of the Month", or submit any new articles you would like us to consider!

EM Today: Updates from the Interview Trail

Alex Fisher, OMS-IV
University of Medicine and Dentistry of New Jersey School of Osteopathic Medicine

The interview season for EM is over! I'm not going to miss it. Most students would agree that by now, they have had their fair share of traveling, disruption and trying to balance a meager student loan budget with the costs of it all. The good news is there is light at the end of the tunnel, and you are moving one step closer to becoming a brilliant and dashing EM doc!

At this point, rank lists are completed and Match Day awaits! I hope that you have sent thank you notes to your interviewers, and in one case, actually showed up in the right state for your interview (some hospitals with the same name can be found in different states).

You may also wonder if there is any data showing a correlation between the number of programs ranked and the chance of a successful match. There is. For example, according to data from NRMP from the 2009 match, ten ranked programs equal about a 97% chance match for U.S. seniors.

Graph EM-1

Charting Outcomes in the Match: Characteristics of Applicants Who Matched to Their Preferred Specialty in the 2009 Main Residency Match. [Internet Resource]. National Resident Matching Program (U.S.); Association of American Medical Colleges. 3rd ed. 2009. Available from: http://www.nrmp.org/data/chartingoutcomes2009v3.pdf.

If you take anything away from this article, understand how the match algorithm works. Your rank list is combined with program's lists in the NRMP computer, which creates the optimal match of resident to program. Remember, by submitting a rank list, you are agreeing to become a resident at the program you match. Similarly, the programs are required to actually hire you as a resident if you match with them! If you are not already familiar with the algorithm NRMP uses to create the perfect match, I would like to inspire you to do some independent research and find out more about the process. An excellent reference is Iserson's Guide to a Residency. The book goes into intricate detail concerning interviewing, choosing a residency, the match, etc. You may also want to sign up for EM Select, a web-based program that makes the residency application process easier to manage (see below for more information).

I wish you success on Match Day. Emergency medicine beckons.


EM Select

Clinical Work-Up: Dyspnea and Dilated Cardiomyopathy

Rikin Shah, MSIII
University of South Florida

History: A 35 year old female presents with 24 hours of shortness of breath. She notes moderate to severe non-productive cough and pain on inspiration. She also complains of nausea and vomiting.

On arrival to the ED, the patient is A&Ox3 but showing severe discomfort on inspiration. Preliminary vital signs are T 97.0, BP 142/107, HR 125, RR 20, O2 sat: 96%. The physical exam shows an intoxicated, diaphoretic patient with diminished bilateral breath sounds, tachycardia and tachypnea. The patient is started on 2L nasal cannula, serial monitoring and IV access is established.1

An EKG shows sinus tachycardia at 125 bpm, a new left bundle branch block and left-axis deviation. Chest X-ray shows an enlarged cardiac silhouette and an increased cardiothoracic ratio. Cephalization of the pulmonary vasculature suggests dilated cardiomegaly secondary to pulmonary venous hypertension. The final read is "cardiomegaly with very early signs of congestive heart failure." Her Troponin-I is elevated to 11 in the setting of a left bundle branch block.

She is sent for cardiac catheterization, which reveals an anterior MI and severe dilated cardiomyopathy. She is treated, stabilized and ultimately discharged home.

Focused History and Physical Examination

Potential etiologies for shortness of breath can be grouped into broad categories including cardiac, pulmonary, mixed and others.

Evaluation of the patient should be ongoing, looking for changes and clues to the underlying cause. Specific signs include tachypnea, tachycardia, stridor and the use of accessory muscles of respiration (i.e., the SCM, sternoclavicular and intercostal muscles). One should evaluate facility of speech, agitation or lethargy. Categorical scales (e.g., the Fletcher or Borg scales) and visual analogue scales can qualify changes in the exam in response to therapeutic intervention.

A significant smoking history can raise suspicion for COPD or lung cancer. A patient without a history of tobacco use is unlikely to have COPD. An intoxicated patient with dyspnea, cough and fever may have aspiration-type pneumonia. Patients using illegal inhalants may contract a pneumonitis from the adulterants used to "cut" the drugs. IV drug abusers can acquire an HIV infection from a dirty needle and can present with Pneumocystis carinii pneumonia (PCP) as a consequence of AIDS.2

It is also important to review the patient's work history or any acute or chronic toxin exposures. An acute hypersensitivity reaction is possible in workers who are exposed to and inhale particulates on the job. A patient with dyspnea who was exposed to a fire could have smoke inhalation or a hypersensitivity reaction from burning chemicals or toxins. Conversely, in a patient with gradual onset of symptoms due to long-term exposure (e.g., over years), asbestosis, silicosis, berylliosis or "coal worker's" pneumoconiosis are more likely possibilities.

Diagnostic Studies

Monitor key respiratory vital signs such as respiratory rate and oxygen saturation. Rule out an infectious cause with blood cultures. Rule out cardiac ischemia with an EKG and cardiac markers such as Troponin T and CK-MB. In diabetics, dyspnea can be the presenting complaint for angina. Rule out thoracic abnormalities with a chest X-ray.

In dilated cardiomyopathy, the ECG is virtually always abnormal. The most common findings include left ventricular hypertrophy and left atrial enlargement. Common arrhythmias include atrial fibrillation and ventricular ectopy. A pseudoinfarction pattern can be produced by Q or QS waves and poor R-wave progression across the anterior precordium.1

Patients with elevated enzymes suggestive of infarction should be sent for cardiac catheterization. Patients without clear infarction should be admitted for evaluation. Echocardiography is indicated to rule out potentially correctable causes of heart failure (such as valvular disease or pericardial effusion), to assess ejection fraction, and to exclude other potential complications (such as mural thrombi).1

References:

  1. Tintinalli, et. al. Emergency Medicine: A Comprehensive Study Guide. The McGraw-Hill Companies, Inc. New York (2004) 437-486.
  2. Mahadevan S, Garmel G. An Introduction to Clinical Emergency Medicine Guide for Practitioners in the Emergency Department. 2005; 6: 485-502.
  3. Morgan WC, Hodge HL. Diagnostic evaluation of dyspnea. Am Fam Physician. 1998 Feb 15;57(4):711-6.
  4. Healey PM, Jacobson EJ. Common Medical Diagnoses: An Algorithmic Approach. 3d ed. Philadelphia: Saunders, 2000:15.

AAEM/RSA is going green! Beginning July 2010, the Journal of Emergency Medicine, the official journal of the American Academy of Emergency Medicine, will be provided in electronic format only. If you prefer to receive JEM in both paper and electronic format, you will be provided the option to pay an additional $20 to continue receiving the paper version of the journal.

Technology Update: Electronic Medical Bracelets

Steven McGuire, MSII
Touro College of Osteopathic Medicine

As a former EMS professional and future EM doc, I know that when assessing an unresponsive patient, I quickly look for bracelets and necklaces that might give a clue as to what is going on with the patient in front of me. Most people know what a "Medic Alert Bracelet" is. But is that just "so last century?"

The idea that people with medical conditions like diabetes, epilepsy or cardiac problems can provide that information via a wearable necklace or bracelet has been around since the 1950s. Today, a Tulsa-based company started by physicians has created the "Invisible Bracelet" or iB. They believe it is the 21st century way to give emergency medical professionals the answers to two key questions:

  1. What do emergency responders [need to] know about you, your allergies and medical needs?
  2. How will your loved ones be notified?

Docvia, the company behind iB, the web-based registry at www.invisibleBracelet.org, started in Oklahoma. When the state government made the program an option for its own employees, things started to take off. There are roughly 100,000 participants in Oklahoma now. The American Ambulance Association (AAA) is participating in the attempt to take the concept national next month. The AAA represents EMS agencies across the U.S. and will begin training its medics, who in turn will urge people in their communities to sign up.

For $5 a year, basic health information and up to 10 emergency contacts are stored under a computer-assigned PIN number that's kept on a wallet card, a key fob or a sticker on an insurance card. Jim Finger, president of the AAA stated, "For millions of Americans, iB will, and should, become an essential. This voluntary method of information sharing between EMS providers and patients could be just the thing that saves more lives and relieves anxiety for family members." In addition to providing EMS and ED staff with the patient history, the service will automatically notify the emergency contacts of the destination hospital via text message and/or email.

This all comes as leaders in organized medicine are trying to determine just what information is the most critical for medics and EM doctors to find when patients are too ill or injured to answer questions, in order to ensure that iB and other similar concepts don't miss any essential pieces of information. Bracelet information is only useful if it is kept current.

This service is nowhere near the ideal, complete Electronic Medical Record that some physicians would like to see carried by every potential emergency patient, but for many with common chronic conditions, allergies to medications, or even those who would like the extra sense of safety the "invisible Bracelet" will provide, this may be the way to go. Anything that gets members of the public thinking about participating in their own health care is okay by me.

References:

  1. Neergaard, L. 'Invisible bracelet' for emergency health alerts? Boston Globe [Internet]. 2009 Dec. Invisible Bracelet Contributor (2010-1-2). "How iB Works." Invisible Bracelet Website. <http://invisiblebracelet.org/site/sections/2>.
  2. ACEP (Nov 18 2009). "Nation's Emergency Physicians and MedicAlert Foundation Offer Holiday Decorating Safety Tips." Press release.
  3. AAA (Dec 22 2009). "American Ambulance Association Introduces First National Emergency Health Registry Through invisibleBracelet.org." Press release.

Board Review: Retained Foreign Bodies

Teresa M. Ross, MD
Georgetown-Washington Hospital Center

A case study: A 59 year old diabetic female was sent to the ED from her podiatrist's office over concern for a retained foreign body (FB) in her toe. Four days prior, she had impaled her right great toe on a blue wooden toothpick. She self-extracted a broken portion of the toothpick, but the toe had become progressively red and swollen, now with inclusion of the distal, dorsal portion of her foot. She complained of a painful FB sensation migrating towards the plantar aspect of the MTP joint of the great toe, worse with walking. She had no fever. At her podiatrist's office, a plain film of the foot was reportedly negative.

In the ED, the toe was obviously cellulitic. No FB was palpable on exam, but a punctuate hemorrhage on the toe seemed to indicate where the initial entry point had been. Bedside ultrasound localized a 1cm long FB penetrating the skin towards the MTP joint, 0.5cm below the skin at its closest point. However, after a successful nerve block, a 20 minute exploration failed to visualize the toothpick. The patient noted that she felt the toothpick had "moved even deeper" after all the probing on exam. The risk of deeper exploration towards the joint was deemed to outweigh the benefits of extraction, and the procedure was terminated.

The patient received a first course of IV Vancomycin. The toe was wrapped for delayed primary closure, and the patient was sent home on clindamycin, levofloxacin and oxycodone for pain. She was instructed to return for wound check and surgical referral in two days. The patient did not return to the ED for wound check, but did follow up in podiatry clinic, where they continued conservative management. Should we have tried harder to remove the foreign body?

Pearl: When to Try, When to Stop

What to Remove: Organic material such as wood, thorns and cactus spines trigger the most severe inflammatory reactions with the greatest risk of infection. Ideally, these items should be removed promptly from soft tissue injuries. Suspect a retained FB in puncture wounds that develop infection or show poor response to antibiotics.

How to Image: This is difficult. Unlike metal, glass and gravel (which are often inert) organic materials are rarely visible on plain film and loose visibility on CT as well, as they absorb water with time and become increasingly isodense. Ultrasound by emergency physicians is highly operator dependent. In one study, EPs asked to detect a wooden FB in a cadaver showed sensitivity of 40-70% and specificity of 30-66% depending on the operator. Positive predictive value was 79.9% (95% CI 76.3%-83.5%), and negative predictive value was 20.0% (95% CI 16.2%-23.7%).

ED Extraction Techniques: Wound margins should be extended with a scalpel for better visibility. Blind probing by inserting and spreading a hemostat is acceptable for deep puncture wounds, but is especially dangerous in the hands, feet and face and is not recommended in the ED. Wooden fragments, in particular, can be impossible to locate precisely. The incision should be lengthwise with extraction via splinter forceps, or the incision can be made to remove a wedge of tissue where a superficial FB is expected to be. Subungual splinters must be removed, and partial or complete fingernail removal can facilitate this procedure.

Disposition: Importantly, the EM physician should recognize his or her limitations in foreign body removal, especially when the object is deep. He or she should devote 15-30 minutes to the procedure and then refer patients to surgery if more time is required. Patients should be informed prior to the procedure that exploration will be limited by time and equipment. Antibiotics are justified for wound infection or retained FB. If a FB is near a highly mobile joint, the area should be splinted for comfort and to prevent further injury. Delayed primary closure is appropriate for all infected wounds or those with poor blood supply. Patients should return for a wound check in two days if they have not yet seen their surgical consult.

References:

  1. Tintinalli, Emergency Medicine. 6th edition, 2004.
  2. Crystal CS, et al. "Bedside Ultrasound for the Detection of Soft Tissue Foreign Bodies: A Cadaveric Study." J Emerg Med. 2009 May:36(4). 377-80.

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