Today I was so fortunate to be joined in The Doctor’s Lounge by my great friend Dr. Lauren Westafer to discuss pulmonary embolisms, the medical condition that caused the death of the legendary actor Catherine O’Hara.
Dr. Westafer is an NIH-funded researcher who studies both this condition and how clinicians integrate new data into their clinical practice. It was our goal to glean something of public value out of the sad passing of Catherine O’Hara—an opportunity to educate both patients and our colleagues on the numerous complexities around pulmonary embolisms (which are dangerous blood clots that form inside the body).
This conversation also provides a window into how emergency physicians like Dr. Westafer and I think about complicated questions, emerging data, and nuance.
We covered common (and uncommon) symptoms, the incredibly wide spectrum of disease, risk factors, how the condition is diagnosed, and the wide variety of treatment algorithms that exist. We also covered what both patients and clinicians need to know, whether to save a life or—on the opposite end of the spectrum—to avoid the problems associated with overtesting, overdiagnosis, and uneccesary treatment. As I always expect when I speak to Dr. Westafer, the conversation was equally data-driven and interesting. I hope you find it useful!
About that…
Closed captions (㏄) for the above video and a transcript option (📄) can be found beneath the video playback control bar above.
Summary & Highlights.
Aided by ChatGPT.
Welcome + why we’re here (00:00:31)
We open The Doctor’s Lounge with a clear intention: recognizing a celebrity death—Catherine O’Hara’s, attributed to pulmonary embolism (PE)—as a teachable moment without exploiting the tragedy. We frame the conversation around public education, sensitivity to family, and the real-world value of medical “news pegs.” (00:00:31–00:02:02)
Meet the guest + why she’s the right guide (00:02:06)
We introduce Dr. Lauren Westerfer (Baystate Medical Center), an emergency physician and NIH-funded PE researcher. We set up her core lane: implementation—why clinicians adopt (or fail to adopt) evidence, and how that shapes PE testing, treatment, and communication. (00:02:06–00:03:11)
What a pulmonary embolism is (00:03:11)
We define PE simply: a blood clot blocking a vessel in the lungs, often originating as a clot in the leg that breaks off and travels to the pulmonary arteries. (00:03:11–00:04:02)
Why clots happen (00:04:02)
We explain PE risk as a mix of:
Bad luck/genetics (a smaller proportion)
Stasis: blood isn’t moving—often from illness or reduced movement (bedrest, being “laid up”)
Predisposing conditions that increase clotting tendency
We emphasize the “Goldilocks” nature of clotting: blood can’t be too thin (bleeding) or too thick (clotting). That framing matters because treatment is powerful and risky. (00:04:02–00:06:20)
Symptoms: DVT in the limb vs PE in the lung (00:06:28)
We separate symptoms into two buckets:
Clot in the limb (DVT):
Swelling, pain, redness—blood can’t return normally. (00:06:52–00:07:14)
PE symptoms:
We stress the brutal truth: PE can look like almost anything.
Classic textbook: pleuritic chest pain, shortness of breath, tachycardia
Real life: sometimes no symptoms; sometimes collapse/death; often vague chest/back pain, upper abdominal pain, exertional dyspnea, syncope, palpitations (sometimes irregular rhythm too). (00:07:14–00:09:15)
“Bloody cough” and why people misread it (00:09:15)
We tackle hemoptysis head-on:
It’s real but uncommon as a PE symptom.
Its absence should not reassure you too much; its presence should not automatically terrify you.
We highlight common benign explanations for small streaks of blood: irritation/tears from coughing and bronchitis-type inflammation. (00:09:15–00:11:49)
The spectrum problem + the PTSD problem (00:11:49)
We underline the central challenge: PE ranges from incidental and clinically trivial to immediately fatal. That spectrum drives patient anxiety—especially after Googling—and contributes to high distress and reduced quality of life after diagnosis. We discuss how clinicians should “place” the patient on that spectrum and communicate risk without either minimizing or catastrophizing. (00:11:49–00:14:05)
Why PE is seen as a “killer.” (Spoiler: it can be.) (00:15:43)
We widen the lens: PE often travels with other serious illness (especially cancer). Outcomes may be driven partly by the underlying condition, complicating how people interpret whether diagnosing/treating the PE “saved a life.” (00:15:43–00:16:35)
Who’s at risk: provoked vs unprovoked (00:16:37)
We lay out risk in a practical way:
Provoked: surgery, fractures/casts/boots, immobilization, hospitalization, being knocked out by illness for days
Unprovoked: no obvious trigger; sometimes genetics discovered only after evaluation
We stress the difference between “my mom got a clot after surgery” (not the same signal) and true unprovoked/family-pattern clotting. (00:16:37–00:17:47)
COVID/flu and clot risk: immobility + inflammation (00:17:47)
We frame post-viral clot risk as two converging mechanisms:
people are weak/immobile
illness is inflammatory, creating a more thrombotic physiology
We explicitly resist “COVID exceptionalism” while acknowledging that COVID’s scale made these patterns impossible to miss. (00:17:47–00:20:39)
How little immobility can matter + travel tips (00:20:41)
We emphasize that “immobilization” doesn’t require weeks in a cast:
Even 5–8 hours in a plane/car can raise risk in the right person, partly because calves aren’t pumping blood uphill.
Practical prevention: get up and walk on long flights; if stuck seated, flex calves/ankles periodically. (00:20:41–00:23:47)
The “weird presentations” humility lesson (00:25:24)
We make a broader clinical point: textbook presentations are a minority; real life is messy. We share the Quincy Jones documentary anecdote as a reminder that serious PE can present in unexpected ways—and that this is why emergency medicine relies on probabilities, pathways, and imperfect tools. (00:25:24–00:27:35)
Why we can’t just scan everyone (00:27:35)
We puncture the “CT as truth machine” idea:
CT interpretation has meaningful disagreement—another expert may say “no PE.”
Over-testing creates false positives → unnecessary anticoagulation → bleeding risk.
We explicitly name the trap: the more you look, the more uncertain findings you generate, and treatment is not benign. (00:27:35–00:28:33)
What Lauren studies: obsession, over-testing, better treatment, uncertainty (00:30:03)
We outline her research agenda:
Why clinicians get a dopamine hit from diagnosing PE (and how that can lead to over-testing)
How to implement evidence-based testing pathways
How to treat appropriately—including sending more low-risk patients home
How to communicate uncertainty when imaging is equivocal (00:30:03–00:31:44)
What happens in the ER: checklist → D-dimer → CT (00:31:44)
We walk through the modern PE diagnostic pathway:
Checklist/risk stratification: some patients require no further testing.
D-dimer: a sensitive but non-specific blood test used for many who don’t clear the first step.
CT pulmonary angiography (contrast CT) if D-dimer is positive / pathway indicates. (00:31:44–00:35:48)
The ethical point of checklists (00:34:00)
We make the key clarification: “low risk” doesn’t mean zero risk. It means the harm of chasing it (false positives → anticoagulation → bleeding, downstream fear/PTSD) can outweigh the benefit. The pathway is designed to protect patients—not dismiss them. (00:34:00–00:34:39)
What a high D-dimer means (and doesn’t) + the smoke alarm analogy (00:35:50)
We answer the classic patient question: “Why was my D-dimer positive but my CT normal?”
D-dimer rises with age, pregnancy, inflammation, infection, cancer, and many other states.
We compare it to a smoke alarm: it detects “something,” but not all “something” is dangerous. Sometimes it’s steak smoke, not a house fire. It’s often physiologically “true” but clinically not relevant. (00:35:50–00:38:14)
Treatment spectrum: pills → thrombolytics → thrombectomy → sometimes no treatment (00:38:15)
We map treatment intensity to severity and certainty:
Most: anticoagulation, often oral pills; sometimes injections; IV heparin in select scenarios.
Crashing patients: thrombolytics may be given emergently, sometimes even before CT.
Increasing use: catheter-based procedures to remove/suction clots, with ongoing uncertainty about who truly benefits vs what “looks better.”
Frontier controversy: subsegmental PE—tiny, distal findings where some cases may be artifact or clinically unimportant; decision-making depends on context (cancer, age, other clots). (00:38:15–00:40:18)
How long anticoagulation lasts (00:40:18)
We give the practical framework:
Provoked (cast, surgery, transient risk): often ~3 months
Unprovoked: may require indefinite/lifelong treatment—one reason diagnostic certainty matters so much.
Cancer-associated: often longer and individualized. (00:40:18–00:41:31)
Rough epidemiology: how often is cancer the driver? (00:41:42)
Lauren notes a common estimate: ~1 in 5 clots may be cancer-associated, while “most” are provoked overall—though true counts are hard because fatal out-of-hospital events don’t always get labeled as PE. (00:41:42–00:42:50)
What we want patients to keep in context: awareness, not paranoia (00:42:51)
We strike the balance: be aware of PE, but don’t assume it’s likely without risk factors. We also highlight a better family-history question: not only “blood clots,” but early unexplained cardiovascular death (which may have been clotting). (00:42:51–00:44:19)
Hidden clue: recurrent pregnancy loss (00:44:19)
Lauren flags recurrent unexplained miscarriages as a possible sign of an underlying thrombophilia in some patients. (00:44:19–00:44:52)
Final “magic wand” takeaways (00:45:31)
What clinicians should know (00:45:56)
Lauren’s plea: don’t treat an equivocal CT like a certainty. If imaging is uncertain, pursue diagnostic clarity (even repeat imaging when appropriate) before starting anticoagulation—because the diagnosis and its consequences can follow a patient for life. (00:45:56–00:47:26)
What patients should know (00:47:26)
Patients should seek care when symptoms persist—especially shortness of breath, which can be under-recognized unless specifically asked about. And they should understand that “no CT” is sometimes the safest, most evidence-based outcome—not neglect. (00:47:26–00:48:19)
Close + where to follow Lauren (00:48:23)
We close with plugs for following Lauren (Twitter/Bluesky) and a nostalgic nod to Foamcast as “public learning” in emergency medicine—then thank viewers and wrap. (00:48:23–00:49:36)
If you have more questions, we can definitely get Dr. Westafer to answer them. So feel free to add your questions in the Comments section below.
