APR
30

DISSECTING AORTIC DISSECTION

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Ever heard the phrase “the aorta will F#*k you up”? Well this blog will cover one aortic pathology that can do just that, the Aortic Dissection. 

Sir William Osler said it best: 

“The tragedies of life are largely arterial”

You are dispatched to a community access hospital to transfer a patient who had presented with an acute onset of chest pain back to your tertiary hospital. 

When you arrive you are met by the patient who is just returning from radiology. The patient is a 74-year-old male with a history of hypertension who advised that while walking he developed an acute onset of chest pain, which radiated to his back, specifically between his shoulder blades. He further describes the pain as a tearing sensation. You note his vital signs to be a heart rate of 94, blood pressure of 154/70, respiratory rate of 20 and pulse ox of 97% on ambient air. 

As you are packaging the patient the ER physician advises you that the patients CT scan revealed a type A aortic dissection and you discuss a treatment plan. 

You receive orders for a HR goal of <60 and a systolic blood pressure of <100. 

How will you proceed? What medications will you utilize? 

Blood vessels are composed of three layers, the intima, media and adventitia. The inner most layer being the intima, the outer most being the adventitia with the media residing in the middle. If you were to look at a blood vessel in a cross sectional view you would notice a lumen in which blood flows through. 

An aortic dissection occurs with a tear or let’s say a DISSECTION of the intimal layer Creating a pathway from blood to pass into the medial layer creating a false lumen.  With the development of a the false lumen, blood will flow either antegrade or retrograde from its origin, which can result in aortic regurgitation, pericardial effusion or tamponade or end-organ malperfusion. 

 

Anatomy: 

 

Classification:

There are two main anatomic classifications of aortic dissection; the DeBakey coming from the famous cardiothoracic surgeon Michael DeBakey and the Standford classification system. Both of these systems differentiate aortic dissection by the area of aorta that is involved, either ascending or descending. Of the two classifications systems the Stanford classification is more commonly used due to its ease of use.  

Stanford:

Type A: Ascending 

Type B: Descending 

DeBakey:

I: Beginning in the ascending aorta but continuing till at least the aortic arch 

II: Confined to the ascending aorta 

III: Beginning in the descending aorta but can continue both distally and/or proximally, however not passing the left subclavian. 

Differentiation of Type A and B aortic dissections is important as types A dissections managed surgically whereas type B dissections are traditionally managed medically. Type A aortic dissections are a surgical emergency and surgical management is the gold standard with mortality increasing 1-2% per hour, leading to a 50% mortality rate at 48 hours without surgery. 

So why are Type A dissections going to the operating room and Type B dissections being admitted to the ICU? 

Type A dissections are a surgical emergency and operative repair is the gold standard due to their higher risk of mortality secondary to their complications such as MI, stroke and cardiac tamponade.   Mortality increases by 1-2% each hour, leading to a 50% mortality rate at 48 hours. 

Type B dissection on the other hand are usually managed medically with endovascular repair being taken in patients with malperfusion or dissection of expansion. 

 

Incidence & Risk Factors: 

The incidence of aortic dissection is approximately 3 per every 100,000. Aortic dissection is most common in men between the ages of 60-80. 

Risk Factors: 

  • Hypertension
  • Cocaine orMethamphetamine Use 
  • Connective Tissue Disorders 
    • Marfan Syndrome 
    • Ehlers-Danlos Syndrome 
  • Aortic Instrumentation or surgery 
  • Vasculitis secondary to Inflammatory disease 
    • Giant Cell Arteritis 
    • Rheumatoid Arthritis 
  • Family History 

 

Presentation:

We all know the textbook picture of aortic dissection, a sudden onset chest or back pain that is described as ripping or tearing. 

The hallmark presentation of aortic dissection is an abrupt onset of sharp pain that is described as ripping or tearing located to the chest or back. Chest pain is a more common presentation in patients experiencing type A dissections, whereas back and abdominal pain is more common in type B dissections. 

While hypertension is an associated risk factor of aortic dissection it is important to note that most type B dissections will present hypertensive whereas type A dissections will be hypotensive. 

A number of other clinical signs and symptoms that may present with an aortic dissection are syncope, abdominal pain, neurological deficits, cardiac tamponade, nausea and vomiting. 

Examination:

While physical examination is imperative it is important to note that specific physical exam findings are found in less than 50% of  patients with aortic dissection. 

Physical examination findings associated with aortic dissection: 

  • Diminished or absent pulses 
  • Pulse deficit 
  • New Murmur 
  • Blood pressure differential (>20mmHg)

 

Diagnosis: 

The gold standard for diagnosis of aortic dissection is CT angiography, so unless you are working in a mobile stroke CT ambulance that won’t be an option. So our presumptive diagnosis of aortic dissection will be based on history and physical exam in the prehospital setting. 

 

POCUS: 

Point of care ultrasound can be helpful in the diagnosis of aortic dissection, as well as the diagnosis of other pathologies related to aortic dissection , such as pericardial effusion or aortic regurgitation. 

Examination of the descending aorta using the abdominal short view, can aide in the diagnosis of type B dissection by visualization of a intimal dissection flap. Type A dissection are more difficult to diagnosis, using POCUS, however this can be done utilizing a parasternal long axis or suprasternal notch view. 

 

Initial Management:

Initial management aims at controlling pain, heart rate and blood pressure for both type A and B dissections. 

Controlling a patients pain through the use of narcotic analgesics such as fentanyl can assist in decreasing heart rate and inotropy by decreasing the release of endogenous catecholamines experienced with pain. By decreasing both heart rate and blood pressure it will decrease the shear forces being placed on the intimal wall as well as expansion of the dissection and the risk of aortic rupture. 

Consider the heart rate as a mallett that is pushing blood through the aorta and a wedge has been placed at the site of the dissection. With each beat, the mallett swings, propelling the blood against the wedge, driving it into the dissection. Using this analogy you can see why it is important to reduce both heart rate as well a blood pressure. As the heart rate is decreased, the fewer the amount of times the malett strikes the wedge, further driving it into the dissection. 

Control of heart rate and blood pressure is best accomplished with a beta blocker such as Esmolol, as it will decrease heart rate, inotropy and blood pressure. While Calcium Channel Blockers can be utilized as a second line agent to control blood pressure, they should not be used initially as they can cause a reflex tachycardia resulting in increased aortic wall stress. 

 

HR & BP Goals: 

There has been no specific blood pressure or heart rate goal that has shown a reduction in morbidity or mortality, though most recommend a systolic blood pressure <100-110 mmHg and a heart rate <60. 

 

Conclusion: 

A radial arterial line is placed for continuous blood pressure monitoring and your patient is packaged for transport. You administer Fentanyl and administer a loading dose of Esmolol and initiate an infusion. During your 45 minute flight you titrate up the Esmolol and shortly after, her HR and blood pressure goal are met. You administer a second dose of Fentanyl just prior to your arrival. She is taken directly to the operating room. Upon follow up you learn the patient had a succesfful repair of her aortic dissection. 

 

 

REFRENCES:  

Borloz , M. (n.d.). Thoracic Aortic Dissection. Retrieved from https://www.saem.org/cdem/education/online-education/m4-curriculum/group-m4-cardiovascular/thoracic-aortic-dissection

Brown, D. L. (2019). Cardiac intensive care. Amsterdam: Elsevier.

Carbonatto, G. (2019, October 28). Aortic Dissection - Stanford Type A. Retrieved from https://www.criticalcare-sonography.com/2017/03/28/aortic-dissection-stanford-type-a/

Diaz , G. (n.d.). Type A Dissection on POCUS (PLAX view) 39 yo M w CP drops ... Retrieved from https://www.grepmed.com/images/5253

Kinnaman, K., Rempell, J., Kimberly, H., Pivetta, E., Platz, E., Hiroshima, E., … Stone, M. (2013). Accuracy of Suprasternal Notch View Using Focused Cardiac Ultrasound to Evaluate Aortic Arch Measurements. Annals of Emergency Medicine62(4). doi: 10.1016/j.annemergmed.2013.07.042

Ln, A. A. S. G., C, D. R. L., & Rv, G. B. S. (2015). A Contemporary Review of Acute Aortic Dissection. Emergency Medicine: Open Access05(05). doi: 10.4172/2165-7548.1000274

Ultrasound of Aortic Dissection. (2017, February). Retrieved from https://www.emrap.org/episode/ultrasoundof/ultrasoundof

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APR
25

Attrition in a Bed of Roses

 

 

 

In our field, we are blessed to see life begin and end, whether in normalcy or chaos. Time is short. You do not know what tomorrow will bring. What is your life? It's even a vapor that appears for a little time and then vanishes away. So why, as clinicians, who should be most connected to this, act like we are so far from it in understanding? Why do we not take advantage of this principle? It is time to find our way out of auto-pilot. What I am going to write about is not a new concept, it seems it is just forgotten and we all need reminded, especially in this time. 

 

The results of your organization are a direct reflection of the behavior of the people who operate in it. This includes you. How much time, money and energy do we put into everything around us? How much of that do we invest in personal transformation? We are the most complex, confusing, interesting variable. So everything we do must touch on behavior, even down to the hiring process. We will change what we believe just to belong, right? Going against the grain, the self-motivation, it makes you stick out like a sore thumb. This especially occurs in organizations where certain behaviors are tolerated and not remediated or educated to improve. "To educate a man in mind and not in morals is to educate a menace to society."

 

Don't be average in what you do. Too many good people are average leaders. There is less competition at the top with elite clinicians. If you are in the pile of average, you are in the most competitive arena and there is no chance anyone is going to find you, as an organization or individual. Average feels so safe. Because if I try to become elite I could fail, right? Okay and what, become average again? You go back to the same place you were already in. You are just afraid of being where you are already at. The second you look around and you notice most people look like you and do it like you, that is the first sign you are in the wrong place. If you want your organization to change it starts with the individuals changing, including you. Everybody says, "they need to change." Some people say, "we need to change." Only the elite say, "I need to change." The culture you get is not what you declare for yourself or where you work. It is not a framed quote on the wall. It is discipline and behaviors of each individual. What do we do to change?

 

It is written of "The Four Loves." All these words in Greek translate to love but all a different meaning. First is Storge. This is a need or gift-type love. Second is Philia. This is a friend or "we" oriented love based on common interests. Third is Eros, a romantic but selfish love based on feeling. Lastly, Agape love. This is others oriented. This is a selfless, sacrificial love. Uncommon commitment. This love drives the individual. To be elite, you need this agape love. This is unconditional love. If you can acquire this, you will do the unthinkable and change the organization you work in. This love is not always fun, it is serious conversation and discipline. It is love that bounds anything from the Navy Seals to a elite college football team. If you don't love where you are at in a job or position, that doesnt make you a bad person. Lift up the hood of the car and see what's the problem. You need to examine where you are at and if after attempting to escape auto-pilot with no changes, don't continue to bring hate, a negative attitude and average to your co-workers and the organization. These negative attributes are like birds, you can't keep them from flying over time to time but you don't have to let them nest in your hair. In this line of work, that is something that others around you and patients do not deserve. 

 

As a clinician, there will be pain but you will come out better because of it. When adversity and challenges hit, I rejoice because I know the good that will come from it. Stop asking yourself, "why me." Start asking yourself, "what is this teaching me?" "How can I help others from this?" A bed of roses is a beautiful place, but nothing ever develops there. You can be comfortable all you want but you can equate being comfortable to being lifeless. If you ever want to grow, there will be heavy discomfort and sacrifice. We are all, including myself, going to hit that wall of opposition and adversity. I am sure you, like me, have been there many times already as well. Though it is never about what happens to us, it's about how we respond to it. We can control that. If you are resilient you will get what you're looking for and if you are consistent you will keep it. 

 

In life, we do not burn out because of what we do. We burn out because life makes us forget why we do it. Every single day in whatever you do as a Paramedic, Nurse, Emergency Physician or whatever it may be, ask yourself a question. Dig deep down to your core with conviction and ask yourself why do I really do this? Most importantly, who am I really doing it for? Ego? Pride? Extrinsic reasons? My three whys are on a post-it note on my dash so I am reminded of why I do what I do every day. It reminds me why I sacrifice time to educate myself on subjects that do not involve my schooling. Why I train on topics that are out of my scope of practice. Why I read literature that I may never apply in the field. Why I lose sleep and add stress like most here. Why I sit with books instead of a gaming console. My three whys is what makes me aware that every single day until I take my last breath, I am going to spend training mentally and physically, study and educate to impact others lives in what I do in and out of the job and give them the best possible chance. Even if that just means holding their hand. What is your why?  

 

 

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