You get called out to a complaint of difficulty breathing for a 20yof. The patient is writhing on the couch, clutching her chest, complaining of shortness of breath. She is hyperventilating, looks supremely anxious, and says she cannot catch her breath. You’re thumbing through her medications, she has a history of anxiety. She’s on birth control. No other gross co-morbidities or noticeable medications. The family states that she hasn’t taken her Xanax today… You attempt to coach her through her breathing, but it just isn’t working. This should just be a simple run… Isn’t she just having a panic attack? You give her 1mg of lorazepam… Why isn’t her breathing improving? Her blood pressure starts to drop… Her heart rate increases… Her mentation deteriorates… Did we ever stop to think about other causes of her hyperventilation? Her anxiety? In my humble opinion, pulmonary embolisms are one of the most looked over differential diagnoses in the prehospital field. So what can we do to better recognize this phenomenon? Let’s start with who is at risk for PEs.
WHAT IS A PULMONARY EMBOLISM
- Could either manifest as a blood clot, air embolism, or fluid/fat embolism (i.e. from extravasated amniotic fluid during delivery), that enters in circulating volume and lodges in the pulmonary artery.
- So… Moment of sobriety. We are all very cavalier about the risks we take with any type of invasive procedure… especially IV access. Careless technique or incomplete flushing of tubing can subject our patients to emboli…
- You have the stereotypical smoking, obesity, and inactivity… Some of the other major factors, though, are pregnancy, using birth control, and recent surgical intervention. Patients that have had previous blood clots should always have a high index of suspicion.
ASSESSMENT OF THE SUSPECTED PE PATIENT
There are some typical landmarks that we usually assess for, but bear in mind that not every patient is a textbook example… So here’s what we can look for.
- Despite the significant shortness of breath, you will often find clear/= lung sounds
- Starts off as acrocyanosis and can progess to cyanosis of the chest and face
- Cyanosis that does not improve despite high flow oxygen therapy (or high quality CPR in the arrested patient) is a classic PE sign.
- The absence of cyanosis should not exclude a PE from your list of suspected illnesses.
- Chest Pain
- Typically reported to be “sharp” in nature and exacerbated by deep inspiration
- Syncope/Near Syncope
- Nausea & Vomiting
INITIAL TREATMENT FOR THE PE PATIENT
It’s important to remember that the pulmonary embolism patient is experiencing a form of obstructive shock; so keep your initial treatment simple. We are attempting to protect the patient from the lethal triad. High flow oxygen, making sure that your patient stays warm, and rapid transport are essential. As the severity of the PE increases, you are going to notice the progression of obstructive shock. Anxiety. Tachypnea. Tachycardia. Narrowing pulse pressures. Hypotension. Bradycardia. Arrest. It’s important to remember that PE patients progress down this road very quickly, and it’s not uncommon to encounter the “talking arrest”.
How long has it been drilled into our heads that extremely hypotensive patients should receive large boluses of fluid? I know I’m guilty of this, and I know that I am not the only one. Let’s break down the set up of a PE… The clot lodged in the pulmonary artery creates significant back pressure in the right ventricle. Hypovolemia is not the problem, the obstruction is the problem. As the obstruction gets worse, the right ventricle becomes larger, compressing the left ventricle, inhibiting left ventricular output.
So where do we start? I genuinely believe a 250ml NS bolus won’t harm the situation, but fluid bolus is not the end solution. If you work in a system with extended transport times (or even services that don’t), this might be a situation that warrants a call to medical control for orders for heparin or a fibrinolytic if no standing order exists.
If fluids aren’t necessarily indicated, what can we do to enhance blood pressure? The common fallacy in prehospital care is that we need to treat hypotension. Like all types of shock, permissive hypotension is completely acceptable in this instance. What we need to be titrating to is mean arterial pressure. Typically in a normal adult patient, that will be about 65mmHg. A wonderful article from EMCrit/PulmCrit suggests this might be the time to consider early pressor initiation.
DIAGNOSTIC TESTS FOR THE PE PATIENT
- Decreased EtCO2 values from hyperventilation as well as poor cardiac output
- Point of Care Testing for Prehospital Lab Values
So that’s it for now. This a topic that could go on for hours, days, months, years, decades, centuries… Okay. Fine. I’ll stop.