M2E Too! Mellick's Multimedia EduBlog

The M2E Too! Blog by Larry Mellick, MD, presents important clinical pearls using multimedia.

By its name, M2E Too! acknowledges that it is one of many emergency medicine blogs, but we hope this will serve as a creative commons for emergency physicians.

Friday, December 1, 2017

There is a saying, "Complexity in the face of adversity breeds chaos." I'm not sure where this maxim originated, but it is definitely true in resuscitation settings. That's the crux of this post: Is the abdominal tourniquet simplicity in the face of adversity compared with the resuscitative endovascular balloon occlusion of the aorta (REBOA)?

We all know how futile it feels to do CPR on a traumatic cardiac arrest patient with suspected massive blood loss. Just what are we pumping, and if there is any remaining intravascular blood, where are we pumping it?

I will never forget the pain of trying to resuscitate an 11-year-old boy who was run over by a neighbor turning into her driveway. She never saw him as he rolled down the street lying flat on his skate board. He received everything we had, including an open thoracotomy and aortic cross-clamping. He ultimately died from severe liver lacerations and venous injuries.

This patient and thousands like him demonstrate that we need more tools in the fight against this type of traumatic cardiac arrest. Before someone else points it out, we need to be clear that traumatic arrests are not simply the proverbial internal injuries. The Centers for Disease Control and Prevention estimated that 30 percent of all injury-related deaths are due to brain injuries in the United States. (MMWR Surveill Summ 2017;66[9]:1.) Many of those patients will also have noncompressible torso hemorrhage.

Open thoracotomy can occasionally be life-saving, and cross-clamping the aorta may be helpful in stopping exsanguinating noncompressible torso hemorrhage. This procedure, however, is not very practical in rural and resource-limited settings. It can be performed by a trained operator, but it creates the "now what?" scenario. The rural emergency physician has to manage an unstable patient who has an open chest and cross-clamped aorta and who needs to be transferred emergently for ongoing resuscitation and critical care. Open thoracotomy can be dangerous to the operator. Lacerations from errant scalpels and jagged edges of broken ribs commonly occur. Exposure to body fluids and blood is almost unavoidable despite the best personal protective equipment.

Open thoracotomy, nevertheless, makes sense for treating penetrating wounds of the heart and life-threatening pericardial effusions, as does cross-clamping the aorta for noncompressible torso hemorrhage. But what if we could compress torso hemorrhage at the same time we cross-clamp the aorta? That leads us to a discussion of the abdominal aortic and junctional tourniquet (AAJT) and REBOA.

REBOA is touted by many, and some evidence suggests that it is effective. One meta-analysis of studies comparing REBOA to cross-clamping of the aorta showed that the odds of mortality did not differ between the compared groups. (World J Emerg Surg 2017;12:30.) But REBOA simply stops blood flow in the aorta. It does not actually compress sites of torso hemorrhage. Even if REBOA stops blood flow in the aorta, venous bleeding will continue until the injured veins are empty. It is also not an entirely practical solution because training, experience, and availability of REBOA remain primarily limited to trauma centers. It is even less available in the prehospital arena where it would be most effective.

On the other hand, the AAJT can cross-clamp the aorta and provide compression to torso hemorrhage, and it is available in prehospital and austere environments. For the record, feedback from field use suggests that training in the correct application of the AAJT is important, and the tourniquet will cause a degree of pain and discomfort in the awake patient.​

Several interesting abstracts on the AAJT and REBOA were presented at the Military Health System Research Symposium (MHSRS) 2017. The animal studies were far from conclusive, but they are an excellent start to answering some important questions. One abstract compared the AAJT and REBOA in a model of noncompressible pelvic hemorrhage using 20 Yorkshire swine. Those authors reported that the AAJT and zone 3 REBOA achieved hemostasis and that blood pressure was elevated with AAJT use proximal and distal to aortic occlusion. The AAJT application increased pulmonary pressure and inspiratory pressure but not the PaO2/FiO2 ratio or SpO2, and lactate and hemoglobin levels were elevated in AAJT-compared with the REBOA-treated animals. No differences were observed in inflammatory markers or microscopic examination of tissues between the two modalities. (See table.)​​​


Also helpful was a paper recently published in Military Medicine by Rall, et al. (Mil Med 2017;182[9]:e2001.) The paper admittedly suffered from the limitations inherent in animal models of trauma and hemorrhage, but it demonstrated that the application of the AAJT improved ROSC in a hemorrhagic cardiac arrest swine model. Twelve male Yorkshire swine weighing between 70 and 90 kg were used in the procedures. The animals underwent controlled hemorrhage until cardiac arrest defined as carotid systolic pressure below 10 mm Hg for 10 seconds occurred.

After three minutes, all animals underwent CPR, transfusion of five units of blood, and were randomized to treatment with or without an AAJT. The primary outcomes for the study were survival and time. Survival time was significantly different between the two groups, and five of the six animals in the CPR with AAJT group survived, while only one animal in the CPR alone (control) group survived to the end. We now have some evidence that applying the AAJT while aggressively transfusing blood might save lives.

Locally, I have been asking why we don't apply the AAJT to all traumatic arrests. Recognizing that time is a factor, ultrasound can fairly effectively rule out hemothorax, pneumothorax, and a life-threatening pericardial effusion. The presence of these findings may indicate that an open thoracotomy is needed. Additional questions exist that need to be answered before the AAJT is applied routinely to all traumatic arrests. If there is concern for a thoracic aorta injury, is application of the AAJT a contraindication? Or if there is a head or c-spine injury in a traumatic cardiac arrest patient, is the AAJT appropriate for these patients? In the end, these are probably judgment calls. But in the words of a colleague on this subject: "Most of these patients are going to die whether or not you apply the AAJT, so you have nothing to lose." I tend to share this opinion.​

The AAJT appears to be a simpler and less complex solution to the problem of noncompressible torso hemorrhage, and evidence is finally starting to trickle in that supports the use of the AAJT in traumatic cardiac arrest patients.​

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Watch a video of Dr. Mellick explaining how to use the AAJT to save lives in the ED​.


Watch a demonstration by Richard Schwartz, MD, who along with John Croushorn, MD, invented an abdominal tourniquet.


Wednesday, November 1, 2017

The labor pains leading to the birth of the specialty of emergency medicine began in the mid-1960s. The public demand for emergency care was growing around the country, and physicians were leaving their private practices in greater numbers and working full-time in urban emergency departments. Nevertheless, the quality of care was at times problematic, and the need for training in emergency medicine was widely recognized.

The American College of Emergency Physicians was founded in 1968, and it became a driving force for the creation of the specialty. The first training institution was the University of Cincinnati, and this organization convinced the American Medical Association to allow a residency program to be developed under the family medicine specialty with a certificate of training in emergency medicine in 1970.

That is where the story of Bruce Janiak, MD, the first emergency medicine residency graduate in the world, began his career. He agreed to do his internship year at the University of Cincinnati in family medicine in return for the opportunity to train in emergency medicine. During that internship year (1969), he worked with several faculty members to develop an emergency medicine residency curriculum. After graduating from the residency in 1972, Bruce served two years in the Navy before moving to Toledo, OH, to become the medical director of the emergency department at Toledo Hospital. That is where we met.

As a first- or second-year medical student at the Medical College of Ohio at Toledo, I remember someone encouraging me to meet with a recent graduate of a new specialty, emergency medicine. I met Bruce just as he was getting on a hospital elevator. We talked briefly about his new specialty, and then our paths parted for several decades. Dr. Janiak would go on to spend the next 28 years at Toledo Hospital, and when that role ended, I played a role in recruiting him to the Medical College of Georgia.

I have had the pleasure of working with Dr. Janiak for several decades, and have come to appreciate his ability to think outside the box and his passion for teaching. Dr. Janiak, now 74, continues to work full-time in academic emergency medicine, and still has the excitement of a medical student starting his clinical rotations. When we work together, I can be guaranteed that Bruce will stop by my work station three or four times to discuss an interesting case or to share a teaching point. And knowing my passion for making educational videos, Dr. Janiak will frequently scout out patients with interesting conditions who might be willing to collaborate on a video. But Dr. Janiak recently volunteered to be the subject of my next video.

We were working parallel shifts, and Bruce mentioned in passing that he thought he might be throwing premature atrial contractions or his known atrial fibrillation dysrhythmia might have returned. Sure enough, near the end of our shifts, Bruce indicated that his atrial fibrillation had indeed returned and that he was planning to undergo a cardioversion in our department. "Let's make a video of my cardioversion," he said. What followed was a once-in-a-lifetime video opportunity. A patient undergoing cardioversion in the emergency department doesn't allow a video every day in which he is also the procedure's primary narrator. For me, personally, this video was an opportunity to highlight the emotional toughness, relentless passion for teaching, and self-effacing humor of my friend and colleague, Bruce Janiak, MD, who also happens to be the first emergency medicine resident in the world.


Watch a video of Dr. Janiak undergo cardioversion and describe the procedure.​


Thursday, October 5, 2017

I’ve heard for years in emergency medicine circles that it was impossible to preoxygenate with a bag-valve mask (BVM) unless one is actually compressing the bag and forcing oxygen flow to the patient. I recently did an informal survey of my colleagues at work, and the responses varied from confident affirmation that the BVM was an inadequate tool for preoxygenation to quasi-warnings not to tread on this dogma without first consulting anesthesia or respiratory therapy. What started as a simple quest to clarify whether the dogma about BVMs and preoxygenation was true turned into a fascinating review and new personal insights into preoxygenation.

The statement that the bag-valve mask is a poor tool for preoxygenation of the spontaneously ventilating patient is simply false. If the mask seal is excellent and the oxygen flow rate is sufficient, one can preoxygenate better with it than with the overly touted non-rebreather mask. This may not be true for all BVM brands, but holds true for the vast majority of them. Adding a PEEP valve to the BVM may not improve oxygenation for patients with healthy lungs, but there is an excellent chance that it will help patients with wet lungs by recruiting back drowning alveoli.

The non-rebreather mask and the bag-valve mask will more effectively oxygenate the patient at flush rates of oxygen. In other words, turn up the wall oxygen to its maximum levels of 50 to 60 L/min and the hyperventilating, air-hungry patient will not be able to overcome the capacity of either tool. (See the video.) An article earlier this year demonstrated that the non-rebreather mask attached to flush rates of oxygen is non-inferior to the BVM at 15 L/min. (Ann Emerg Med 2017;69[1]:1.) It naturally follows that flush rates of oxygen for the BVM would also have an additive effect.

Non-invasive ventilation (NIV) and high-flow oxygen therapy (HFOT) with humidified air are also excellent tools for preoxygenation, but NIV has to address the same problem seen with BVM preoxygenation. Both devices must be removed from the face of the apneic patient to intubate the airway. This is not a problem when using high-flow nasal cannulas or HFOT. Nevertheless, this dilemma with NIV and BVM can be resolved during that interlude of apnea just prior to rapid sequence intubation by quickly placing a standard nasal cannula with oxygen flowing at high rates.

It is absolutely fascinating to me that groupthink and myths are so common in the practice of medicine. Invariably, patients suffer to some degree as a result. Thankfully, medical researchers continue to shine their high-lumen lights through the fog and smoke screens of these medical myths and falsehoods.



Watch Dr. Mellick’s video where he shows how the non-rebreather mask and the BVM can be effectively used to oxygenate patients.

Friday, September 1, 2017

Children have this strange predilection for placing small objects in body cavities and orifices. Besides putting foreign bodies in their mouths, an act that often leads to ingestion or aspiration, the ear canals and nares are their favorite locations for depositing plastic beads, toy parts, paper materials, small vegetables, jewelry, screws, and nails, and that frequently brings them to the emergency department. Unsuccessful attempts to remove the foreign bodies in the ED lead to a consultation or referral to an ENT specialist. The timing, technique, and tools used to remove a foreign body will depend on the anatomic location, the shape of the object, the material it is made of, its consistency and texture, whether it is occlusive, and the potential risks to patient.

Magnetism is a potentially valuable tool in the emergency department that really hasn't received the respect it deserves. The cardiac pacer magnet is probably what everyone thinks of when they consider magnetism in the ED, but magnetism also can be helpful in removing metallic foreign bodies from the mouth, ears, and nasal cavities and in locating and removing ferromagnetic fragments buried under the skin and subcutaneous tissues.

Not all metals are strongly attracted by a magnetic force, but this technique will work with iron, nickel, cobalt, gadolinium, dysprosium, and alloys such as steel that contain ferromagnetic metals. Unfortunately, the majority of pediatric foreign bodies placed in the nose and ears are made of plastic, paper, vegetable matter, or other materials not affected by magnetic force, but it pays to be prepared when the foreign body is susceptible to the forces of magnetism.​

The magnets used to remove foreign bodies should ideally be powerful but small enough to access pediatric-sized nares and auditory canals. That is where rare earth magnets play an important role. These are made from the alloys of these 17 elements in the periodic table. The magnets were first developed in the 1970s, and have especially powerful magnetic fields. The neodymium magnets and samarium-cobalt magnets are two most common types of rare earth magnets used by industries and manufacturing.​

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There are at least two ways to attain magnetism that will latch on to errant ferromagnetic foreign bodies in the emergency department. The donut-shaped cardiac pacer magnet found in almost every emergency department is a very strong rare earth magnet. When it's overlaid a screwdriver or a pair of hemostats, the cardiac pacer magnet can create a magnetized, narrow-tipped tool that will fit into smaller body cavities. Commercial pen magnets can be purchased at auto parts stores, and are small, powerful rare earth magnets that can effectively fit into most anatomical orifices. The cardiac pacer and these pen magnets can also be applied directly over metallic foreign bodies buried in the skin to help locate and pull them toward the surface to facilitate removal.​

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A potential criticism of magnet use is tool sterility. Thankfully, most of the orifices holding foreign bodies are far from sterile, and tools cleaned with the appropriate antiseptics or covered with a sterile glove should be antiseptically appropriate. Some degree of preplanning is needed to purchase the pen magnets for the emergency department and store them so that they can be easily located when needed. The strength of the magnets is critical to accomplishing the stated goals and secondarily magnetizing hemostats, forceps, and screw drivers when that technique is used. The speed and ease of removal of metallic foreign bodies will please and surprise everyone involved.

Many characteristics of these magnets make them especially useful in removing foreign bodies. First, often all that is necessary is to get close to the foreign body. Even if the pen magnet doesn't fit entirely into the ear canal, just getting close to the metallic foreign body is generally all that is needed. Similarly, there is no need to get behind the foreign body to bring it forward as is the case with balloon catheter and right angle hook removal techniques. The maneuvering required by other tools in the tight quarters of smaller body cavities can be uncomfortable. There is no need to get a grip on the object to remove it as is the case with alligator forceps or similar tools.

The actual procedure used will depend somewhat on the patient and the specific orifice holding the foreign body. Topical anesthesia will usually not be needed for the ear, but for the nose, a 1:1 mixture oxymetazoline and 4% lidocaine can be used to prevent bleeding and provide topical anesthesia. Procedural sedation may be necessary depending on the patient and the foreign body's location and characteristics. Directional traction on the helix will make the external auditory canal more accessible, and using an ENT dilator or pushing on the tip of the nose with the non-dominant hand will improve accessibility and visibility to the nares. Proximate location of the foreign body to the airway may also determine the technique used.

It is always important to confirm that a second foreign body is not lurking in the shadows. And, be sure to watch our three videos demonstrating the tools and techniques discussed above.​


Watch Dr. Mellick demonstrate how to use a pacer magnet to remove a foreign object from the ear.​


Watch a video of Dr. Mellick as a guinea pig for testing different magnets for removing a foreign body from the ear.


Watch a video of Jedidiah Ballard, DO, using a pacer magnet to remove a foreign object from the ear.​


Tuesday, August 1, 2017

Double sequential defibrillation appears to work in the electrophysiology lab, and anecdotal evidence shows that lives can be saved in the prehospital setting and in the emergency department. With all the unanswered questions swirling around it, should we use this technique? Let’s consider the evidence.

Using two sets of defibrillators fired simultaneously or in a sequential pattern to treat refractory ventricular fibrillation is a relatively new concept. A number of different names for the procedure exist, but double sequential external defibrillation (DSED) or double simultaneous defibrillation (DSD) are commonly used. This technique was first described in 1994 by Hoch, et al., in five patients who were successfully converted from ventricular fibrillation in an electrophysiology laboratory. (J Am Coll Cardiol 1994;23[5]:1141.) The patients in this report failed to convert to normal sinus rhythm with monophasic energies ranging from 200-360 joules. All of them, however, responded to double shock with a total of 720 joules. The current experience with DSD in treating atrial fibrillation is probably more robust, but the evidence for refractory ventricular fibrillation is mostly case reports and case series. Nonetheless, DSD appears to convert fibrillating hearts and save lives.

Multiple questions still surround this off-label use of defibrillators for ventricular fibrillation. There is evidence of safety based on the use of DSD in atrial fibrillation patients, but the potential risk of myocardial injury from doubling the joules administered to the patient is not completely known. Two defibrillators fired simultaneously at maximal output will deliver 400 or 720 joules depending on whether one is using a biphasic or monophasic defibrillator.

It is also unclear whether quick sequential defibrillation or simultaneous defibrillation is more beneficial. It may be a moot point, though. Simultaneously firing two defibrillators probably doesn’t ever happen when done manually, and it is possible that a short millisecond separation may allow the second set of joules to occur at the moment of greatest drop in electrical resistance following the first attempt.

It is also unclear whether the overall increase in energy levels, the addition of a second vector of current flow, or the greater amount of heart muscle lying directly under the pads is responsible for the successes. It is clear that impedance in a patient relates to body mass and that human anatomy and chest sizes vary. It is also highly likely that the fibrillating ventricles may frequently not align perfectly with a single energy vector.

Another question needing clarification is which pad placement format is best: two sets placed side by side using the traditional anatomic locations for defibrillator pads or one set of pads placed at the traditional locations and the second set placed in an anterior-posterior location. At this time, no one knows for sure which option is more effective.

It is also unknown, or at least unclear, exactly when the dual simultaneous defibrillation should be initiated. Is DSD more effective when incorporated earlier in the attempted resuscitation of a VF arrest? It is known that the longer the patient is in ventricular fibrillation, the more resistant the heart is to being defibrillated. Obviously, the sooner we have a return of spontaneous circulation, the better the cognitive outcome for the patient. It would seem obvious that incorporating DSD sooner is better than later.

What do we know for sure? Additional vectors of current flow are added, and a higher total number of joules are delivered to the flailing heart. And almost definitely a greater cardiac topography is covered by the double sets of pads. We also know that the defibrillation process is probably never going to be exactly simultaneous because of the manual process required.

Equipment:
-Two defibrillators and two sets of pads.

Steps:
-Apply a second set of defibrillation pads in the same configuration as the existing pads but adjacent or in the anterior-posterior position. (Make sure the pads are not touching or applied on top of one another.)
-Charge both monitors to their maximum energy level (200 joules for biphasic, 360 joules for monophasic). Warn all providers not to be in contact with the patient at the time of discharge, and then charge and simultaneously push the defibrillation button on each monitor. Some recommend continuing cardiac compression until just before the defibrillation buttons are pushed. Immediately resume chest compressions. Administer appropriate ACLS medications and repeat as necessary.
-Have a video of double sequential defibrillation available.

So, should we use this technique? Let’s turn to The Aphorisms of Hippocrates: “For extreme diseases, extreme methods of cure, as to restriction, are most suitable.” (http://bit.ly/2sUkilA.) In other words, desperate times call for desperate measures, and double simultaneous defibrillation in the face of refractory ventricular fibrillation easily fits that bill.​

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