Author Archives: Kavish Chandra

RCP – Regional anesthesia of the hand

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Regional anesthesia of the hand: ultrasound-guided vs tumescent anesthesia

Resident Clinical Pearl (RCP) – February 2018

Sean Hurley Emergency Medicine PGY1 (FRCPC), Dalhousie University, Halifax, Nova Scotia

Reviewed by Dr. David Lewis

 

The goal of this resident clinical pearl is to discuss two different methods of achieving complete anesthesia of the hand. Hopefully, by the end of this article, you will have the knowledge to perform both methods in the emergency department. The first method is ultrasound (US)-guided nerve blocks of the ulnar, median, and radial nerves. The second method is the “tumescent anaesthesia” approach used by many hand surgeons around the world for wide-awake hand surgery, including local, local anesthetic guru and plastic surgeon, Dr. Donald Lalonde who provided many of the clinical pearls in this article.

 

Method 1:  Ultrasound-guided nerve block

In a recent article by Amini et al. (2016), 84% of 121 emergency medicine residency programs surveyed in the United States reported that US-guided nerve blocks are performed at their institution. Of the 16 different nerve blocks reported, forearm blocks were the most commonly performed (74%) (Table 1). The main indications for nerve blocks are outlined in Table 2 1.

Table 1 and 2 from Amini et al., 2016 1

 

Three major nerves, median, ulnar, and radial, provide sensory innervation of the hand (Figure 1). Each nerve needs to be blocked in a simple straightforward approach, which was shown to to be quick, safe and effective. After a 1-hour training session, residents, fellows, and staff emergency physicians had 100% success rate with no rescue anesthesia on 11 hand pathology patients presenting to the ED. The blocks were performed in a median time of 9 minutes with no complications 2.

 

Figure 1. Cutaenous innervation of the hand. https://www.nysora.com/wrist-block

 

Figure 2. Indications for different nerve blocks of the hand http://highlandultrasound.com/forearm-blocks/

 

Radial Nerve: Palpate the radial artery in the volar aspect of distal forearm then place the US probe over the artery in a transverse orientation. Move the probe proximally until you clearly identify the radial nerve (Figure 3), which is located at the radial aspect of the radial artery. Insert your needle using an in-line approach (Figure 4). Inject 5-10cc of 1% lidocaine with epinephrine until you can clearly see the nerve bathed in lidocaine.

Pearl: The radial nerve is often difficult to visualize in the forearm. The radial nerve is more easily visualized above the elbow along the spiral groove of the humerus. Place the probe in a transverse orientation along the lateral aspect of the humerus between the brachioradialis and brachialis muscles. This block is more proximal and will require longer time to peak anesthesia.

 

Ulnar nerve: Use the exact same 2-step approach but on the ulnar side of the forearm. The ulnar nerve is located at the ulnar aspect of the ulnar artery (Figure 3).

 

Median nerve: The median nerve lies between the palmaris longus and the flexor carpi radialis. Position the probe in the transverse plane over this location. Insert your needle from either side using an in-plane or out-of-plane approach

 

Pearl: the median nerve and the many tendons of the distal forearm can be difficult to distinguish. You can identify the nerve by tilting the probe, which causes the tendons to disappear, as the US waves are no longer reflected back to probe, while the median nerve fibers still reflect waves back to the probe. Alternatively, you can slide the probe proximally where the tendons transition to muscle fibers, allowing the median nerve to be easily distinguishable.

Pearl: The palmar cutaneous branch of the median nerve that supplies the thenar eminence branches off before the carpal tunnel. Make sure you move the probe proximally before blocking the nerve so you don’t miss this important sensory branch.

Pearl: The more local anesthetic, the better! Some resources recommend 3-5cc of 1% lidocaine per nerve. Why not use 10cc or more for each nerve? You will still be safely under 7mg/kg limit.

 

Figure 3. Ultrasound identification of the ulnar nerve (left), median nerve (middle), and radial nerve (right). (Figure from Liebemann et al, 2006) 2.

 

Figure 4. Ultrasound guided ulnar nerve block using an in-plane technique (Figure from Sohoni et al., 2016) 3.

 

Please see link to excellent descriptions and videos of ulnar, radial, and median US-guided nerve blocks in the ED. www.highlandultrasound.com/forearm-blocks/

 

Method 2: Tumescent anesthesia

Tumescent means “Swollen”. In relation to local anaesthesia, Dr. Lalonde provides the following definition in his textbook Wide-Awake Hand Surgery: “Injecting a large enough volume of local anesthetic that you can see it plump up the skin and feel its slightly firm consistency with your finger through the skin” 4. The tumescent anesthesia approach has been described in depth for a variety of hand surgeries 4-6.

Using a 10cc syringe, aim for the space directly between the median and ulnar nerve (figure 5 and Video 1).  As you puncture the skin, Inject 3-5cc in the subcutaneous space. This is critical to block superficial nerves in this region, including the palmar cutaneous branch of the median nerve. Then, move your needle >3-4mm deeper through the superficial fascia in the forearm compartment where the median and ulnar nerves reside. Inject the remainder of your 10cc syringe into this space. With a single poke, the ulnar and median nerve distributions should be completely anesthetized.

Now, all that remain are the superficial branches of radial nerves and the posterior interosseus nerve. The superficial branches of radial nerve lie over the anatomical snuffbox. Insert your needle within 1cm of your previously anesthetized skin and blow local anesthesia into the subcutaneous space as you slowly move your needle towards the radial aspect of the wrist until you have a tumescent area of local anesthesia over the snuffbox. For the PIN, which is primarily a motor branch of radial nerve but has some sensory contribution, palpate the distal radial ulnar joint  of the dorsal aspect of the wrist. The PIN runs along the interosseous membrane so the needle needs to pass through the deep fascia of the forearm. Inject another 5cc of lidocaine in this location.

 

Figure 5. Tumescent anesthesia of the median and ulnar nerve 5.

 

Video 1. Tumescent anesthesia of the hand (courtesy of S. Hurley).

 

Which approach is better?

No studies have directly compared the two approaches discussed in this article. A recent Cochrane review article reviewed compared US-guided vs. anatomical landmark technique vs. trans-arterial vs. peripheral nerve stimulation for lower and upper limb blocks by trained anaesthetists. They found US-guided had greater success rates, less conversions to general anesthetic, lower rates of parathesias and vascular puncture 7.

A recent small randomized control trial compared US-guided nerve blocks of the forearm to anatomical landmark-based technique and found 14 of 18 ultrasound-guided forearm blocks were successful, as opposed to 10 of 18 for the anatomical technique 3.

Pearl: The tumescent anesthesia technique blocks both smaller and larger nerves of the hand and will likely achieve faster anesthesia compared to nerve blocks of the ulnar, median, and radial nerve.  Expect up to an hour for the large nerve blocks to take full effect.

 

Conclusions

Both methods, US-Guided nerve blocks and tumescent anesthesia are safe, effective, and relatively easy options to achieve complete anesthesia of the hand. For both techniques, remember basic principles for minimizing pain during injection of local anaesthesia to optimize patient comfort and satisfaction 4-6.

 

References

  1. Amini R, Kartchner JZ, Nagdev A, Adhikari S. 2016. Ultrasound‐Guided nerve blocks in emergency medicine practice. Journal of Ultrasound in Medicine 35: 731-736.
  2. Liebmann O, Price D, Mills C, et al. 2006. Feasibility of forearm ultrasonography-guided nerve blocks of the radial, ulnar, and median nerves for hand procedures in the emergency department. Ann Emerg Med 48: 558-562.
  3. Sohoni A, Nagdev A, Takhar S, Stone M. 2016. Forearm ultrasound-guided nerve blocks vs landmark-based wrist blocks for hand anesthesia in healthy volunteers. Am J Emerg Med 34: 730-734.
  4. Lalonde D. 2016. Wide awake hand surgery, CRC Press, Taylor & Francis Group. Boca Raton, FL.
  5. Lalonde DH. 2010. “Hole-in-one” local anesthesia for wide-awake carpal tunnel surgery. Plast Reconstr Surg 126: 1642-1644.
  6. Farhangkhoee H, Lalonde J, Lalonde DH. 2012. Teaching medical students and residents how to inject local anesthesia almost painlessly. Can J Plast Surg 20: 169-172.
  7. Lewis SR, Price A, Walker KJ, McGrattan K, Smith AF. 2015. Ultrasound guidance for upper and lower limb blocks. The Cochrane Library.

 

This post was copyedited by Kavish Chandra @kavishpchandra

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RCP – Pediatric syncope: an investigative dilemma?

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Pediatric syncope: an investigative dilemma??

Resident Clinical Pearl (RCP) – February 2018

Kalen Leech-Porter R3 FMEM, Dalhousie University, Saint John, New Brunswick

Reviewed by Dr. David Lewis

 

The case

A 16 year old girl comes in by ambulance, after fainting while singing at church on a Sunday morning.  Her vitals are: HR 90, RR 16, Temp 36.5, BP 92/64. O2 Sat 99% on RA.  On arrival she is alert and looks well.  She explains that she stood up to sing, felt lightheaded and then, soon after, lost consciousness.  The paramedic lets you know witnesses say she turned ashen grey and sweaty, and was out for about 2 minutes.  She had some ‘seizure like activity for 10 seconds’ with a few twitches in different parts of her body.  The patient states she was fully recovered within a few minutes.  Family history is unremarkable, with no sudden early deaths.  Physical examination is also unremarkable.  The nurse rolls in an ECG machine to check her rhythm.

What investigations does she require?

 

Why It Matters?

Pediatric syncope is very common in the emergency setting, accounting for ~1 % of pediatric emergency visits.   Between 15 and 50% of children will have at least one syncopal event in their childhood (peaking in adolescence).  – It’s a common problem!

 

The problem?

Historically, working up pediatric syncope has varied widely.  ECG use has been routine and some centers have regularly ordered bloodwork, CTs and even EEGs.  This onslaught of testing has led to increased hospital costs, stressful false positives for patients and has not improved patient outcomes.  Plus, reading pediatric ECGs can be challenging – see the end of this pearl.

 

A potential solution

In 2017, the Canadian Cardiovascular Society and Canadian Pediatric Cardiology Association published a position statement on an approach to pediatric syncope¹  Full Article – click here

A thorough history and physical can be sufficient in low risk patients – no investigations are required for many pediatric syncope presentations. 

Red flags

  • Lack of Prodrome: warm/clammy sensation, lightheaded ness, visual changes. Having a prodrome is the most important factor in benign syncope
  • Midexertional syncope; however post exertional syncope (having an opportunity to stop) is typically benign
  • Chest Pain preceding the event
  • Prolonged loss of consciousness
  • Family history of cardiovascular disease/sudden death
  • Syncope triggered by loud noise
  • New medications (QT prolonging drugs)
  • Abnormal physical exam – pathologic murmur, sternotomy scar, neurologic deficits

 Red herrings

  • Pallor is common in vasovagal events
  • Palpitations are common in vasovagal events (although evidence around this not robust)
  • Involuntary movement is also common in vasovagal syncope. Benign movements can be a muscle twitch to violent jerks of the whole body

 

Investigative Algorithm

Figure 1. Pediatric syncope investigative algorithm, adapted from Sanatani et al. (2017)

 

The Evidence

To create this position statement, the Canadian Cardiovascular Society (CCS) performed a literature review of 4307 references, ultimately including 231 articles for full-text review.

Most of the studies referred to in the article are retrospective reviews. Therefore, recommendations in the position statement were mostly graded as ‘Strong recommendation, low level of evidence’. I found the most compelling evidence against routine ECG was the statement: “The ECG was the only indicator of cardiac disease in 5 of 480 patients (1%) and causality could not be determined”.¹  However, they did not list a reference for this statement and I’m not sure what study they drew this conclusion from.  I do feel they make a compelling case against over investigation, but as in many areas of medicine, the evidence could be more robust.

 

Pediatric ECGs – how to interpret?

The nurse hands you the ECG, what features are worrisome on a pediatric ECG?

See following chart from the CCS¹

Figure 2. Pediatric ECG findings in syncope, adapted from Sanatani et al. (2017)

In summary, red light features should prompt an emergent cardiology referral. Yellow light features should prompt a non-urgent cardiology referral while green light features are normal variants and require no further work up.

 

Case Resolution

There were no red flags, arguably she requires no investigations, not even an ECG.   Of course, clinical acumen trumps guidelines, but at least you will be CCS endorsed if you chose to not do any further investigations.

 

References

  1. Sanatani, V. Chau, A. Fournier, A. Dixon, R. Blondin, R. Sheldon. Canadian Cardiovascular Society and Canadian Pediatric Cardiology Association Position Statement on the Approach to Syncope in the Pediatric Patient. Canadian Journal of Cardiology. 2017; 33: 189-198.

 

 

This post was copyedited by Kavish Chandra @kavishpchandra

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RCP – Wired shut: cutting jaw wires in an emergency

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Wired shut: cutting jaw wires in an emergency

Resident Clinical Pearl (RCP) – January 2018

Kavish Chandra R3 FMEM, Dalhousie University, Saint John, New Brunswick

Reviewed by Dr. Awdesh Chandra

 

It’s 0300 and you are on a solo night shift when a couple are rushed into the resuscitation bay by the triage nurse. The woman says that the man had his jaw “wired shut” three weeks ago and began retching an hour ago. Your suspicions are confirmed when you look at his mouth and see the image below:

Figure 1. Arch bars (green arrows) are used for mandibular fixation, adapted from Jones and Read (2006).

 

As your patient is being placed on cardiac and oxygen monitoring, you can see they are agitated and hypoxic. You ask yourself, how can I get access to their oropharynx and begin my resuscitation?

 

Background

Arch bars and intermaxillary fixation are placed after mandibular fractures. In Figure 1, the arch bars, horizontal bars indicated by the green arrow, are fixated by circumferential wires around the teeth.1 In order to fixate the mandible and maxilla, fixation wires (vertical wires indicated by the red arrow seen in Figure 2) bring together and upper and lower arch bars, effectively eliminating mouth opening.1

Figure 2. Intermaxillary fixation wires, vertical wires indicated by the red arrows. Adapted from Jones and Read (2006).

 

While it is standard procedure for dentists and oral surgeons to provide patients with wire cutters and instructions following intermaxillary fixation for emergencies, this may not be readily available in the emergency department when needed the most.

 

The materials required:

  1. A deep breath
  2. Wire cutters (or if not, heavy metal scissors)
  3. Hemostat or needle driver

 

The steps:

  1. Identify and cut the vertical fixation wire on one side of the twist as seen in Figure 2. This is similar to cutting a single interrupted suture.
  2. Pull on the twist with a hemostat or needle driver and pull the wire out. There are generally 2-4 fixation wires per each side that require cutting in order to open the mouth.
  3. In some instances, there may be heavy elastics vertically as well, pull and cut those as well.
  4. Proceed with the resuscitation as deemed necessary (airway access or allowing the patient to vomit)
  5. The dentist or oral surgeon can re-fixate the wires non-urgently after the emergency has passed

 

See the following links on how arch bars and intermaxillary fixating wires are placed (to get an understanding of where to cut to release the mandible)

  1. https://www.youtube.com/watch?v=RGp46yHoVag&feature=youtu.be (minute 14 and on for application of intermaxillary fixation wires)
  2. https://emcrit.org/racc/airway-decisions/

 

Pearl: consider having wire cutters as part of your difficult airway cart or kit

 

Bottom Line: intermaxillary fixation can pose a serious threat to a patient needing to vomit or one that requires emergency airway access. Be prepared to cut the right wires in order allow mouth opening.

 

References

(1) Jones TR, Read L. Emergent separation of arch bars. J Emerg Med 2006; 35(2):205-206.

 

This post was copyedited by Kavish Chandra @kavishpchandra

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RCP – Elb-‘ow’! Does my patient with an elbow injury require an x-ray?

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Elb-‘ow’! Does my patient with an elbow injury require an x-ray?

Resident Clinical Pearl (RCP) – December 2017

Allyson Cornelis R1 FMEM, Dalhousie University, Saint John, New Brunswick

Reviewed by Dr. David Lewis

 

Why should you care?

Trauma to the upper extremity can result in injury to the various components of the elbow joint and associated anatomical structures. Important neurovascular structures associated with the elbow joint are the brachial artery, radial artery, ulnar artery, median, radial, and ulnar nerve¹. Elbow injuries causing fracture increase the likelihood of neurovascular damage. If fractures are missed, this may result in further damage and complications including prolonged functional limitations to the joint, nerve damage causing distal functional decline, and potential vascular compromise to the limb more distal to the injury.

Tintinalli’s Comprehensive Guide to Emergency Medicine.2

Functionally, the elbow has two primary movements: flexion/extension, and supination/pronation¹.

Fractures at the elbow may occur at the distal humerus (supracondylar, epicondylar, condylar, trochlea, and capitellum fractures), the proximal ulna (coronoid process, olecranon fractures), and the proximal radius (radial head fractures)¹. Of these, radial head fractures are the most common. Common mechanisms for these injuries include falling on an outstretched hand and direct blows to the elbow.

 

How do I know if my patient requires an X-ray for their elbow pain?

There is a rule for that! The elbow extension rule!

Simply stated: If a patient with an elbow injury is able to fully extend their elbow, they are unlikely to have a fracture and do not require imaging³.

The “how to”:

  1. Provide analgesia to patients
  2. Have patient seated with supinated arms
  3. Have patient flex shoulder to 90 degrees
  4. Ask patient to fully extend elbow to either the point of locking or the same level of extension as contralateral side

Of course, no rule is perfect, and the patient should be reassessed later if the following occur

  • Can no longer fully straighten elbow
  • Pain is getting worse
  • Cannot use their arm as previous

The patient should have imaging at the current visit if:

  • Patient is unreliable for follow up
  • If olecranon fracture is possible

 

The evidence³

Of 1740 patients presenting within 72 hours of traumatic elbow injury, 31% had a fracture³. In adults with the ability to fully extend their elbow following trauma, there was a 2% chance they had a fracture. In adults unable to fully extend their elbow following trauma, there was a 48% chance they had a fracture.

In children able to fully extend their elbow following trauma, there was a 4% chance they have a fracture, and in children unable to fully extend their elbow following trauma, there was a 43% chance they had a fracture³.

 

Bottom Line: Patients presenting with elbow trauma and an inability to extend their elbow fully require radiography. Those able to fully extend their elbow do not require imaging unless follow up is unreliable, an olecranon fracture is suspected. Caution should be exercised with assessment in children.

 

Addendum: 

Consider adding PoCUS to your clinical assessment of elbow injuries. Elbow joint effusions are very easily visualized. The presence of a joint effusion in a patient with elbow pain following trauma is a significant finding and warrants further investigation with radiography. Some studies have shown PoCUS to be more sensitive than x-ray in diagnosing occult elbow fractures.

 

Download (PDF, 2.87MB)

 

References

(1) Appleboam, A., Reuben, AD., Benger, JR., Beech, F., Dutson, J., Haig, S., Lloyd, G. (2008). Elbow extension test to rule out elbow fracture: Multicentre, prospective validation and observational study of diagnostic accuracy in adults and children. British Medical Journal, 337:a2428.

(2) Tintinalli, JE. (2016). Cardiogenic Shock (8th ed.) Tintinalli’s Emergency Medicine: A Comprehensive Study Guide (pages 1816-1817). New York: McGraw-Hill.

(3) Sheehan, SE., Dyer, GS., Sodickson, AD., Ketankumar, IP., Khurana, B. (2013). Traumatic elbow injuries: What the orthopedic surgeon wants to know. Radiographics, 33(3), 869-884.

 

This post was copyedited by Kavish Chandra @kavishpchandra

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RCP – Animal Bites

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Animal Bites

Resident Clinical Pearl (RCP) – November 2017

Renée Amiro, R1 FMEM, Dalhousie University, Saint John, New Brunswick

Reviewed by Dr. David Lewis

 

Mr. Stark brings in his 8-year-old adopted son, Jon Snow, to the emergency room on Christmas day. Jon had just received a puppy, Ghost, as a Christmas present that morning. Jon, who knows nothing (about raising puppies), was playing too rough with the pup and got a bite on his right hand.

How do we appropriately manage this animal bite in the emergency room?

Management

When a patient presents to the ED with an animal bite, the factors in management that need to be addressed are:

  1. How to properly care for the wound
  2. Is antibiotic prophylaxis needed?
  3. Does the wound require closure with sutures?
  4. When does a bite require surgical consultation?
  5. When should you worry about tetanus and rabies?

 

Caring for the wound

Managing an animal bite has much of the same principles of usual good wound care

  1. Control hemorrhage
  2. Preform a neurovascular assessment
  3. Clean the wound meticulously. This is very important in animal and human bites. To reduce the number of bacteria, the wound should be flushed with copious amounts of saline or water

Local anesthetic should be used to reduce pain and facilitate cleaning. The wound should also be inspected for foreign bodies. Bites overlying joints should be put through their entire range of motion (bone, tendon or joint capsule involvement). If you suspect a foreign body but can’t see it, get an x-ray.

Pearl: for puncture wounds (cats are the biggest perpetrators), the same principles of wound care apply except superficially irrigate wounds and do not use high pressure

 

Is antibiotic prophylaxis needed?

Most bites to not require prophylactic antibiotics. There are some high-risk wounds that do. Those include:

  1. Deep puncture wounds (think cats)
  2. Associated crush injury
  3. Injury in areas overlying venous or lymphatic compromise
  4. Primary closure of the wound
  5. Wounds on hands, genitals or overlying joints
  6. Host factors: immunocompromised, diabetes

Table of prophylactic antibiotic choices. Duration of therapy depends on the antibiotic choice.

Ellis and Ellis. Am Fam Physician. 2014 Aug 15;90(4):239-243.

 

Does the wound requires closure with sutures

Generally, no, especially if cats are the perpetrators. But if cosmetic concerns arise, wounds should meet all the following criteria before primary closure:

  1. Clinically uninfected
  2. < 12 hrs old (<24 hrs on the face)
  3. NOT located on the hand or the foot

The wound should NOT be closed primarily if the following criteria are met:

  1. Crush injuries
  2. Hand and foot wounds
  3. Deep puncture wounds
  4. Cat or human wounds
  5. Immunocompromised host
  6. >12 hrs old

 

When does a bite require surgical consultation?

If the injury results in complex facial wounds, neurovascular compromise, osteomyelitis or joint infection or deep wounds that penetrate underlying structures (joint, bone, tendon), get a surgical consultation.

That being said, consider consultation with any deep wound on the hand.

 

When do I worry about tetanus and rabies prophylaxis?

When considering tetanus prophylaxis, the decision to intervene is the same in non-bite wounds.

   Ellis and Ellis. Am Fam Physician. 2014 Aug 15;90(4):239-243.

 

For rabies, post-exposure prophylaxis is generally not needed in patients with a dog or cat bite as long as the animal is not showing signs of rabies: dysphagia, abnormal behaviour, paralysis, seizures and ataxia.

Ellis and Ellis. Am Fam Physician. 2014 Aug 15;90(4):239-243.

 

Bottom Line: Animal bites, like other wounds, require regular wound care with a focus on meticulous cleaning. Cat bites usually need prophylactic antibiotics, dogs usually do not. All immunocompromised hosts get prophylactic antibiotics

 

References

  1. Baddour, L. and Sexton, D. Soft tissue infections due to dog and cat bites. Retrieved from https://www.uptodate.com/contents/soft-tissue-infections-due-to-dog-and-cat-bites. Accessed August 1, 2017.
  2. Callaham, M. Controversies in antibiotic choices for bite wounds. Ann Emerg Med 1988; 17:1321.
  3. Ellis, R. and Ellis, C. Am Fam Physician. 2014 Aug 15;90(4):239-243.

 

This post was copyedited by Kavish Chandra @kavishpchandra

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What we missed in FOAM October 2017

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Welcome to SJRHEM’s newest feature, “Best of FOAM”. This is a quick curated list of the best free open access medical education the internet has to offer!

Subscribe to our twitter feed for regular updates and enjoy!

 

EM procedures

 

Clinical summaries

 

Kavish Chandra, R3 FMEM, Dalhousie University, Saint John, New Brunswick

 

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RCP – Aortic Dissection

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Aortic Dissection

Resident Clinical Pearl (RCP) – October 2017

Luke Taylor, R2 FMEM, Dalhousie University, Saint John, New Brunswick

Edited by Dr Kavish Chandra – @kavishpchandra

Reviewed by Dr. David Lewis

 

Why should we care?

  • Aortic dissection remains difficult to diagnosis despite improvements in our understanding of the process and its characteristic features
  • Many cases are still missed at the initial ED presentation
  • Dissections occur after some violation of the intimal layer allows blood to enter the media and dissect between the intimal and adventitia. The blood flow entering the tear can extend the dissection proximally, distally, or both
  • With each hour that passes there is a 1-2% increase in mortality as the dissection extends

 

History

The presentation is similar across all acute aortic syndromes (AAS)

  • Acute intense chest or back pain (“SAH” of the torso)
  • Ask about:
    • Location
    • Intensity at onset
    • Radiation of pain
  • Aortic dissection can be painless ~5% of the time

IRAD 12 features most associated with acute aortic dissection

  • The characteristic tearing/ripping was not found to be a common descriptor in International Registry of Aortic Dissection (IRAD)

Pearl : When assessing a patient with chest pain (CP), think CP+ 1 (see EMCases episode 92)

  • CP+ CVA
  • CP+ paralysis
  • CP+ hoarseness
  • CP+ limb ischemia

These features should drastically increase your suspicion for dissection

 

Physical examination

  • Keep in mind a large portion of general population have a BP differential >10mmHg
  • Vital signs can be normal but patients may have variation in their pulse or BP in the form a pulse deficit, SBP differential, hypertension or hypotension
    • Pulse Deficit: feel for difference between heart rate and the pulse rate
  • Murmur of aortic insufficiency:
    https://www.youtube.com/watch?v=aGLTJduxwvw
  • Neurological findings: objective focal neurological deficit

 

Investigations

  • CXR: Look for a wide mediastinum, loss of aortic knob, calcium sign
    • A normal CXR does not rule out aortic dissection as 1/3 of CXRs in aortic dissection are normal
    • Pearl : Measure the distance from the white line to the outer edge of the aortic knob. A distance >0.5cm is considered a 

positive calcium sign

https://radiopaedia.org/articles/tangential-calcium-sign

 

  • POCUS: If attempting, look for a dissection flap in the parasternal long axis view above the aortic valve. The flap may also be visible in abdominal aorta
    • Low sensitivity, but high specificity

  • Look for pericardial effusion from a retrograde dissection into the pericardium

http://rubble.heppell.net/chestnet/t/ecgtut.htm

 

 

 

FOAMED Links and Resources

http://edeblog.com/2014/02/pocus-for-aortic-dissection-a-case-2/

https://emergencymedicinecases.com/aortic-dissection-em-cases-course/

http://circ.ahajournals.org/content/112/24/3802

https://lifeinthefastlane.com/collections/ebm-lecture-notes/aortic-dissection/

https://first10em.com/2017/02/07/d-dimer-aortic-dissection/

 

This post was copyedited by Kavish Chandra @kavishpchandra

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What we missed in FOAM Sept 2017

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Welcome to SJRHEM’s newest feature, “Best of FOAM”. This is a quick curated list of the best free open access medical education the internet has to offer!

Subscribe to our twitter feed for regular updates and enjoy!

 

EM procedures

Clinical tools

 

Clinical summaries

 

Kavish Chandra, R3 FMEM, Dalhousie University, Saint John, New Brunswick

 

 

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RCP – the “Easy IJ”

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The “easy IJ”, a quick solution for difficult intravenous access?

Resident Clinical Pearl (RCP) – September 2017

Kavish Chandra, R3 FMEM, Dalhousie University, Saint John, New Brunswick

Reviewed by Dr. David Lewis

The importance of intravenous (IV) access is something seared in the mind of every practicing emergency department physician. Over the years, central intravenous access for difficult IV access has been obviated by the intraosseous drill and line. Furthermore, we just see and do less central IV lines. The likely reasons for this are that running vasopressors in peripheral intravenous (IV) lines is becoming more accepted as well as the increased time associated with placing a fully sterile central line (draping, etc.) as well as the risks of the over-the-wire procedure (infection, deep vein thrombosis, cardiac arrhythmias).

Enter the internal jugular vein catheterization using a peripheral IV catheter1, which is placed under a limited sterile environment. Is the 5 minutes to establish access that “easy” when peripheral access and external jugular catheterization has failed?

The materials required:

  1. US machine with high-frequency linear transducer probe
  2. Chlorhexidine swab
  3. 4.8-cm, 18-gauge single lumen catheter
  4. Two bio-occlusive adherent dressings
  5. Sterile ultrasound jelly
  6. A loop catheter extension
  7. A saline flush

Figure 1. Visual diagram of required materials for the “easy IJ”, adapted from Moayedi et al. (2016).

 

The steps:

  • Place your patient in the Trendelenburg position or instruct them to perform a Valsalva maneuver
  • The needle is inserted into the skin at approximately 45 degrees
  • Ultrasound is used to confirm real-time placement out of plane, followed by in-plane visualization to see the catheter in the vessel lumen
  • See this video for a demonstration: https://www.youtube.com/watch?v=FjSmbUWXznY

 

 

 

What does the evidence say2?

  • When studied in stable emergency department patients when peripheral or external jugular venous access was unsuccessful, the success rate of this procedure was 88% (95% CI 79-94)
  • The mean time to procedure completion was 4.4 minutes (3.8-4.9)
  • In 83 access attempts, there were no cases of pneumothorax, infection or arterial puncture
  • There was a 14% loss of IV patency immediately after insertion
  • Painful? Don’t forget, these lines were placed without local anesthesia; however, the mean pain score was 3.9 out of 10 (3.4-4.5)

Practical considerations:

So will this technique change your practice? A few things to be aware of:

  • In obese patients, the target vessel will be inherently more difficult to visualize, as well as the catheter length in this study may not be long enough to ensure patency. The median BMI in the Moayedi et al. (2016) study was 27
  • Operator skill: the vast majority of lines were placed by clinicians experienced in ultrasound guided line placement. Success and time to placement may be increased as experience decreases
  • Will more definitive access be required? The catheters placed in this study were largely only used for 24 hours. This would certainly be more than sufficient during the treatment of an ED patient, but usage time increases, infection rates will likely increase
  • Will this line achieve the infusion rate you need? See this article on infusion rates of various IV catheters

 

The bottom line: the “easy IJ” is a rapid, effective and safe alternative to establish IV access in stable patients in whom peripheral and external jugular venous attempts have failed.

 

References

(1) Teismann NA, Knight RS, Rehrer M, Shah S, Nagdev A, Stone M. The ultrasound-guided “peripheral IJ”: internal jugular vein catheterization using a standard intravenous catheter. J Emerg Med 2013 Jan;44(1):150-154.

(2) Moayedi S, Witting M, Pirotte M. Safety and Efficacy of the “Easy Internal Jugular (IJ)”: An Approach to Difficult Intravenous Access. J Emerg Med 2016 Dec;51(6):636-642.

 

 

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RCP – Nar’ pump, mo’ problems

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Nar’ pump, mo’ problems, a case on cardiogenic shock

Resident Clinical Pearl (RCP) – June 2017

Mandy Peach, R2 FMEM, Dalhousie University, Saint John, New Brunswick

Reviewed/Edited by Dr. David Lewis and Dr. Kavish Chandra

It’s 11 pm, you’re doing the overnight shift and EMS calls in to report a patient with an ETA of 3 minutes: “80 yo female, found on floor in apartment by husband after reportedly feeling unwell for 2 days. Decreased LOC but arousable and responding appropriately. BP 82/36, HR 120, RR 22, Afebrile, oxygen sat 86% on 6L nasal cannula.”

You hear the vitals, and many differentials run through your mind – PE, sepsis, hemorrhage, tamponade. Your main concerns are: this person needs more airway support and they are in shock, and when you think shock you think ‘fluids’.

EMS rolls in with your patient and she looks awful – pale, mottled extremities and drowsy. She is being re-assessed, RT is present to switch to a face mask, IV access is being established and you’re about to pound her with fluids when you are handed her ECG:

1https://lifeinthefastlane.com/ecg-library/basics/inferior-stemi/

This lady clearly is having an inferior STEMI – there is marked ST elevation in II, III and aVF with early Q wave formation.

 

Take home point #1: In any Inferior STEMI, you must suspect RV involvement

Look for ST elevation in V1 and depression in V2, or ST elevation in lead III > lead II. If these are present – get a 15 lead ECG.1

On closer look at our patient’s ECG there is ST elevation in V1-V2 and the elevation in lead III is indeed larger than lead II. You order the 15 lead.

2 https://lifeinthefastlane.com/ecg-library/right-ventricular-infarction/

Look for ST elevation in right sided leads V3-V6, but the money is on V4R – ST elevation in this lead has a sensitivity of 88%, specificity of 78% and diagnostic accuracy of 83% for RV infarction2. Our patient does have RV infarction seen by ST elevation in V4R.

 

Take home point #2: RV involvement is associated with increased risk of cardiogenic shock and death with a mortality of 50% within the first 48 hours3. If there is RV involvement, giving nitroglycerin for chest pain is CONTRAINDICATED

Due to a poorly functioning RV, patients are pre-load sensitive2. If you decrease the pre-load then they have even less to pump, further worsening the hypotension.

So we have diagnosed this lady with cardiogenic shock secondary to AMI (the most common cause of cardiac related shock) and we determined she has RV involvement. We know we can’t give her nitroglycerin. Let’s reassess her status – the basic ABC’s.

Airway & Breathing – the RT has since advanced her to a non-rebreather with a sat level in the high 80’s. You suggest trying Optiflow or BiPAP as a temporizing measure – this lady is going to need to be intubated.

 

Take home point #3: Positive pressure ventilation requires a stable, cooperative patient – which is often not the case in cardiogenic shock

Positive pressure can decrease pre-load and potentially worsen hypotension3. It is a temporizing measure only. The majority will require endotracheal intubation to maintain their saturation as their work of breathing is a large expenditure of energy.

You successfully complete a RSI and the saturation improves to 94-98%.

Circulation – Repeat BP is 82/36. You complete a cardiac point-of-care-ultrasound (PoCUS) and see poor contractility, but no pericardial effusion or large clots suggesting chordae or papillary rupture. IVC is > 50% collapsible.

 

Take home point #4: On PoCUS, heart failure caused by acute ischemia will show a large RV and small LV secondary to low filling pressures, which is best seen on the apical 4 chamber view3

Your patient continues to be hypotensive – you give a small 500 cc bolus; you don’t want to overload a poorly pumping heart with fluid it can’t handle. However you anticipate that this will not be enough to improve her BP, and as she continues to be hypotensive her myocardial ischemia worsens, which subsequently worsens her pump dysfunction in a vicious cycle. She needs pressure support.

 

Take home point #5: Cardiogenic shock requires vasopressor support

If systolic BP > 90: Start with dobutamine for inotropy. Double up on agents – likely will need to add a vasoconstrictor. Dopamine is usually the next to add.

If systolic BP < 90: Can still use dobutamine, but need to add norepinephrine for vasoconstriction. Dopamine alone will worsen BP as it is a vasodilator.

3Tintinalli’s Comprehensive Guide to Emergency Medicine.

You start dobutamine and dopamine peripherally with the intention of obtaining central venous assess once stabilized.

In the meantime, cardiac labs and portable CXR are pending, you treat this patient as any other STEMI in terms of dual anti-platelet and anti-coagulation loading.

 

Take home point #6: Do not give beta blockers

Do not give beta blockers in RV infarcts as high risk of bradycardia and AV block due to ischemia of the AV nodal artery3.

You consult cardiology to activate the cath lab.

 

Take home point #7: Early revascularization in ischemic related cardiogenic shock is key

Early revascularization has a long term mortality benefit, preferably if done within 6 hours4.  Catheterization or CABG is the preferred method over thrombolytic therapy.

You consult cardiology to activate the cath lab.

Back to our patient –

This lady did go on to the cath lab and had stenting of her RCA, however her infarct likely occurred > 48 hours before presentation. Unfortunately, despite aggressive vasopressor therapy and revascularization, she coded immediately after the procedure and resuscitation attempts were unsuccessful, emphasizing the poor prognosis associated with ischemia related cardiogenic shock.

 

Bottom line for cardiogenic shock: fluid bolus 500 cc 0.9% NaCl, vasopressor support and RSI. Early revascularization is key – catheterization is preferred. Despite these interventions, the diagnosis portends a poor prognosis.

 

References

  1. Inferior STEMI – Life in the Fast Lane https://lifeinthefastlane.com/ecg-library/basics/inferior-stemi/
  2. Right Ventricular Infarction – Life in the Fast Lane https://lifeinthefastlane.com/ecg-library/right-ventricular-infarction/
  3. Tintinalli, JE. (2016). Cardiogenic Shock (8th ed.) Tintinalli’s Emergency Medicine: A Comprehensive Study Guide (pages 349-352). New York: McGraw-Hill.
  4. Cardiogenic Shock – Literature Summary – Life in the Fast Lane https://lifeinthefastlane.com/ccc/cardiogenic-shock-literature-summaries/

 

This post was copyedited by Kavish Chandra @kavishpchandra

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