"Thanks to Covid-19, DVT and PE More Common" 

Case: a 67-year-old obese female with a history of COPD calls 911 when she is experiencing shortness of breath and chest tightness. She suffered from COVID two months ago but had a prolonged hospitalization complicated by a blood clot (DVT) in her right leg. She was started on an oral blood thinner medication but stopped taking it two weeks earlier when she ran out. On arrival, she is in significant distress. She is lying in bed but does not have her oxygen on. Her vital signs are BP 140/82, HR 130, respirations 25, and oxygen saturation 82% on room air. Your physical exam reveals clear lungs and a markedly swollen right leg. You place her on oxygen and transport her to the emergency department where she undergoes a CT angiogram and is found to have a large blood clot in her lungs.

Pulmonary embolism (PE) occurs when a blood clot occludes the pulmonary arteries. They range from very small (in the peripheral arteries) to large central clots known as "saddle" emboli. Saddle emboli can be deadly and patients often present in cardiac arrest with PEA rhythm (but sinus tachycardia is the most common rhythm). The risk factors for pulmonary embolism are the same for DVT. Recent immobilization, including travel, surgery, and prolonged hospitalization, are risk factors. Obesity, cancer, anti-estrogen medications, and inherited clotting disorders are also significant risk factors. Patients typically present with chest pain or shortness of breath and the conclusive diagnosis is made using a specialized CT scan with IV contrast dye. This type of CT scan is known as an "angiogram" or CTA chest.

For reasons not completely understood, COVID-19 affects the human body's clotting system and, making patients more prone to venous thromboembolism (VTE), including DVT and PE. It is therefore important to keep VTE high on your differential when evaluating this patient population. The definitive treatment is usually a blood thinner medication, but mechanical clot retrieval is becoming more common, especially with large saddle emboli.

The mechanical clot retrieval is typically performed by an interventional cardiologist in a heart cath lab. A device is passed through the blood vessel system, and the clot is mechanically removed. Many hospitals have implemented what is known as a PE response team to help PERT facilitate this procedure. It is performed with a sense of urgency similar to STEMI or stroke patients (the sooner, the better). The PERT is composed of many different medical specialties to coordinate the spectrum of care. Patients undergoing this procedure have been proven to have better survival rates and speedier recoveries. 

The burden of a clot that is physically removed is quite impressive as you can see in the below pictures (thanks to Dr. Jun Li, Interventional Cardiologist at University Hospitals).

In the initial phase of COVID, we did not know that the clotting system would be affected. This phenomenon was discovered only when there was an increase of DVTs, PEs, and other vascular issues such as "covid toes." As time passed, we learned more about the disease, and certain high-risk patients are now started on blood thinners prophylactically when discharged from the hospital.

Please consider massive pulmonary embolism as a cause for your patient's acute onset chest pain, especially when tachycardic, hypoxic, or recently suffered from COVID. If you have a high suspicion, please share this with the receiving hospital when you call the report. A high index of suspicion can expedite the diagnosis and definitive treatment, which can save your patient's life. Thank you again for all you do and take care. 

Christopher Dussel, MD

Aortic Dissection - October 11, 2021

Consider Aortic Dissection when evaluating chest pain patients.

Your crew is dispatched to the home of a 68-year-old male with chest pain. Upon arrival, you find a distressed gentleman sitting at the kitchen table, clutching his chest. He is diaphoretic and complaining of ripping/tearing chest pain radiating into his back. His blood pressure is 220/110, and his left radial pulse is weaker than the left. In addition to the usual cardiac causes, what else should be in your differential diagnosis? 

Aortic dissection is estimated to affect anywhere between five and thirty per 1 million people in the population. Advanced age, hypertension, and connective tissue disorders (such as Marfan's syndrome) are major risk factors. While still relatively uncommon, it is often deadly. Often presenting very similarly to acute MI, it is essential to consider when evaluating chest pain patients.

Like fire hoses, arteries are made up of multiple layers. An arterial dissection starts when there is a small tear in the blood vessels inside layer (called the intima). A false passageway is created between the inner and outer layers of the vessel. This dissection most commonly occurs in the ascending aorta, which is intuitive because the ascending aorta undergoes the most force of any vessel in the body. After all, it is curved and sustains repeated high pressure as blood is pumped from the left ventricle. The descending aorta can also be affected but is less common since the pressure force is lower and the vessel is straighter and therefore less prone to tearing on the internal layer. Considering how many times blood is pumped through this vessel, it is surprising that aortic dissection isn't more common!

Aortic dissection typically presents just like an acute MI. STEMI EKG findings are common because the coronary arteries branch off of the ascending aorta and their blood flow. It is not uncommon to diagnose aortic dissection in the heart cath lab during a STEMI activation. It can be discovered when the first injection of dye is made into the ascending aorta. 

The textbook description of aortic dissection pain is the sudden and severe onset of "ripping or tearing," often radiating to the back. Classic is not typical, as we all have learned, and the diagnosis of aortic dissection is often tricky, with unusual and atypical presentations being far more common. For example, if the left subclavian artery is affected, the patient can have left upper extremity symptoms and a week pulse. Acute stroke presentations can also occur if the common carotid arteries are affected. Patients with connective tissue diseases such as Marfan syndrome or inflammatory blood vessel diseases are also at higher risk.

It is vital to consider aortic dissection in any patient complaining of chest pain. While it can be a deadly disease, early recognition and surgical intervention cannot save your patient's life. 

If you have any questions regarding aortic dissection diagnosis or treatment, please don't hesitate to contact me or ask your instructor during the November continuing education series. Thank you for all you do and please stay safe. 

Christopher J. Dussel, MD

Associate Chief Medical Officer and Emergency Department Medical Director

University Hospitals Parma Medical Center

EMS Medical Director, Cities of Parma, and Brooklyn Heights

Medical Director, UH Parma Paramedic Training Program

Dialysis Access - October 18, 2021

Understanding the Different Types of Dialysis Access

Case: Your crew is dispatched to the freestanding dialysis center for a 72-year-old female bleeding from her dialysis site. She was done with her treatment, but the staff could not control her bleeding after 60 minutes of their usual techniques. On arrival, you find an elderly female in no apparent distress. She appears somewhat weak, but she's awake and alert. Her vitals are within normal limits. When the staff removed her dressing, there was significant bleeding from her left upper extremity access site. What is your next step to control the bleeding? 

1. Place two gloved fingers gently over the site to control bleeding and transport to the hospital 

2. Apply a tourniquet directly over the bleeding

3. Apply a blood pressure cuff proximal to the site

Answer: #1

End-stage renal disease is relatively common in the United States, typically a complication of poorly controlled diabetes or hypertension. More than 350,000 people annually require hemodialysis, and vascular access complications cost over $1 billion annually--rising each year. Therefore it is paramount that prehospital providers are familiar with managing these complications. 

Considered a lifeline for patients with end-stage renal disease, the basic concept of dialysis is simple. A semipermeable membrane is placed between blood and a special fluid, allowing pressure and diffusion to balance electrolytes between the two fluids. This process draws waste products and excess water out of the blood into the dialysate. The semipermeable membrane only allows small particles and water to cross, just like the capillaries inside of the kidney. There are two different types of dialysis: hemodialysis and peritoneal dialysis. Peritoneal dialysis requires a peritoneal dialysis catheter placed into the peritoneal cavity on the lower abdomen.  

This type of dialysis is much less common and is typically used in younger, more active patients. The treatments involve a particular type of sterile solution that essentially cleans the blood in the body rather than transporting it out for cleaning. The treatments occur nightly and require much more reliable patients. Complications are less common and typically involve infections in the peritoneal cavity or peritoneal dialysis catheter site. 

Hemodialysis is the process in which blood is transported out of the body for cleaning. These treatments take several hours and typically occur three days a week (Monday/Wednesday/Friday, or Tuesday/Thursday/Saturday. EMS providers are more likely to encounter hemodialysis patients since they are generally elderly (although not always), have comorbidities, and may reside in long-term care facilities. Complications at the dialysis site itself are not uncommon, and it is essential to understand the types of hemodialysis access and the complications that can occur.  

Before a patient can undergo hemodialysis, they must first obtain dialysis access. There are three options for access: arteriovenous (AV) fistulas, arteriovenous (AV) grafts, and central venous catheters (CVC). All three provide access to your blood for regularly scheduled hemodialysis sessions but have unique complications.  

Arteriovenous (AV) refers to the connection between an artery and a vein. As an anatomy review, recall that veins transport the deoxygenated blood back to the heart. The veins are much more pliable with thinner walls and easier to access regularly with a dialysis needle. They are generally not large enough to accommodate the needles required for accessing the blood and do not usually have a strong enough blood flow for the process to work. A connection between a vein and artery is therefore required in the form of an AV fistula or an AV graft; both are placed surgically to directly connect between an artery and a vein, bypassing the capillaries (smaller blood vessels). 

AV fistulas are created from the patient's own blood vessels. A connection between the artery and vein is surgically made. Over time, this results in enlargement of the vein, allowing for the successful placement of the dialysis needle during treatments. Since arteries are larger, deeper vessels with very high blood flow, they have stiffer, more rigid walls making them difficult to access with needles. When the surgical connection is created between the artery and vein, the vein naturally enlarges over time through a process known as quote maturing". The vein walls grow stronger in response to the increased pressure and volume of blood. After it has matured, it can then be used for regular hemodialysis sessions. Arteriovenous fistulas are considered to be the preferred type of dialysis access. They last longer, perform better, and are less likely to become clotted or infected than the other options. 

Next week we will discuss additional complications including dialysis fistula and infection.

Thank you for all you do. Please stay safe, and do not hesitate to contact me directly should you have any questions or feedback.

Christopher J. Dussel, MD

Associate Chief Medical Officer and Emergency Department Medical Director

University Hospitals Parma Medical Center

EMS Medical Director, Cities of Parma, and Brooklyn Heights

Medical Director, UH Parma Paramedic Training Program

Dialysis Complications - October 25, 2021

Last week we discussed two different types of dialysis, treatments, and the possible complications that may occur. This week we will expand upon the various complications and options involved.

"Steal syndrome" is a potential complication of arteriovenous fistulas encountered by prehospital providers.  Steal syndrome occurs when the artery diverts too much blood into the vein, and it is therefore not enough to feed the hands and fingers distal to the fistula. This phenomenon can cause the patient's hands and feet to feel cold and typically resolves over time. Sometimes surgical intervention by a vascular specialist is required to limit some of the blood flow into the fistula. 

Another complication occurs with repeated use of the dialysis fistula. Scar tissue may develop inside the fistula and block the blood flow path, essentially clogging the fistula. Clogged fistulas or grafts require surgical intervention by a vascular specialist (angioplasty) to remove the scar tissue using a balloon-tipped catheter to maintain adequate blood flow through the fistula. It is best not to draw blood, place an IV, or take blood pressure on an upper extremity with an AV fistula to prevent this. 

What is a "thrill?"

Because of the high-pressure blood flow through the AV fistula (from the artery), you can palpate a rapid vibration when placing your fingers over an AV fistula.  

An arterial-venous (AV) graft is an option for patients with weak veins unlikely to "mature" into a working fistula. A graft involves a vascular surgeon connecting a soft, flexible tube between the artery and vein beneath your skin, rather than using the patient's vessels as with an arteriovenous fistula. AV grafts still involve blood flowing from the artery, through the graft, and into the vein, creating a suitable site for regular hemodialysis access. The AV graft material is strong and can be used repeatedly. It also takes less time than an AV fistula to be ready for use. Most can be used after only a few weeks from placement. Rates of infection and complications are somewhat higher when compared to AV fistulas, though. It is considered the second-best option and still has less infection rates and lasts longer than central venous catheters, which we will discuss next. 

Since the arteriovenous grafts are made of artificial material, they have a higher risk of infection. With repeated access, germs can enter the body and bind the material, resulting in conditions that require long-term antibiotics and surgical intervention. Scar tissue can also build up inside the graft, just like it can inside a fistula. With every access, scar tissue develops naturally to seal the hole in the skin. Eventually, this can lead to clotting and slowing of blood flow, requiring angioplasty just like with an AV fistula. 

Since arteriovenous fistulas and grafts both require time to "mature" before they are used, they are not an option for patients requiring immediate dialysis access, such as certain overdoses or acute kidney failure. A temporary, although a less desirable option, is a central venous catheter (CVC). These are often placed concurrently with an AV graft or AV fistula until the graft or fistula matures. It is then removed. A central venous catheter is a flexible plastic tube placed through the skin either in your neck, chest wall, or groin. It allows immediate access to remove the blood for hemodialysis and stays in place for repeated use instead of being inserted/removed with each dialysis session.  

Central venous catheters (CVC) have a much higher risk of complications and require much more daily care. It must stay clean and dry to limit the risk of infection. Patients with central venous catheters cannot shower or swim and must also be very careful not to displace the catheter. Other complications include direct damage to the central veins with bleeding, hematomas, or stenosis limiting future access sites. Central venous catheters can also become clogged when clots buildup around the tip of the catheter. Clogging can often be treated in the emergency department with small doses of clot-busting medication (TPA: the same that we use to treat acute strokes), which is injected into the catheter and allowed to sit and break up the clots.  

Infection is another potentially serious complication. It can lead to septic shock or even death. The risk of infection with chronic indwelling central catheters underlines the importance of doing a complete physical examination on your patients with chronic illness, especially those at skilled nursing facilities with known histories of renal failure. The infections are often indolent and difficult to diagnose, often only discovered after blood cultures are obtained in the hospital. 

Remember that hemodialysis involves physically removing blood from the body through a shunt (fistula, graft, or central venous catheter) in place through a machine to perform the dialysis and then placed back into the body through the same shunt. Patients are administered heparin (an anticoagulant) during this process to prevent the blood from clotting in the dialysis machine and tubing. Because of the heparin use, patients are at an increased risk of bleeding at the dialysis access site and other body areas. Bleeding at the dialysis site should be treated as an arterial bleed, managed with direct pressure and elevation of the affected extremity. 

Far and away, the most common call will be regarding bleeding dialysis access sites. These can be controlled using direct digital pressure, and tourniquets should not be placed. Extreme pressure using a tourniquet or blood pressure cuff can damage the fistula or graft, requiring surgery to repair. Recall that the access sites are small, and the bleeding can typically be controlled using one or two gloved fingers and minimal pressure. Many dialysis treatment centers employ a plastic clamp with foam on and to control bleeding. 

These can be left in place during transport to the receiving hospital. Turncoat application proximal to the dialysis access site should only be used in a worst-case scenario, life-threatening bleeding situations. Invariably, this results in thrombosis formation within the graft or fistula, making it nonfunctional. This extreme measure is rarely necessary but can still be lifesaving in certain circumstances, so it should not be ruled out entirely. 

If you are called for a painful/cold hand in the setting of a recent dialysis graft or fistula placement, consider "steal syndrome," as we discussed earlier. You will likely feel diminished pulses, and it can easily be confused with an acute clot/thromboembolic event. You will likely still feel a "thrill" with steal syndrome because the arterial blood flows more heavily into the venous system and bypasses the distal limb. It is important to consider pain control in these situations. Intravenous opioid pain medication will likely be needed, as these can be severely painful experiences for the patient. 

When encountering patients with fevers or symptoms of sepsis, consider infections of the dialysis fistula/graft, and more commonly in the central venous catheters. Follow your standard treatment algorithms for septic patients but be sure to alert the receiving hospital that the patient has dialysis access in place, as this could be a source of the infection.  

When called to a dialysis access emergency, it is essential to ask the staff at the dialysis center what type of access the patient has. This information is critical for the receiving care team at the hospital and is often difficult to determine, especially if placed at an outside institution. Most of these emergencies occur at the dialysis treatment centers, and the staff is generally quite familiar with the type of access. Prehospital providers need to be familiar with the two types of dialysis and the three types of hemodialysis access to handle emergencies appropriately. 

Thank you for all you. Please stay safe, and do not hesitate to contact me directly should you have any questions or feedback.  

Christopher J. Dussel, MD

Associate Chief Medical Officer and Emergency Department Medical Director

University Hospitals Parma Medical Center

EMS Medical Director, Cities of Parma, and Brooklyn Heights

Medical Director, UH Parma Paramedic Training Program