Crit Bit Corner

Quick critical care insights designed to help you understand the physiology behind what you see at the bedside. Because confident clinicians don’t memorize medicine. They understand it.

Take a Deep Dive Into

  • Disease Physiology
  • Medication Mechanism 
  • Real Life Case Studies
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Pathophysiology
Medications
Case Studies

Pulmonary Hypertension

Explore Pulmonary Hypertension (PH)—why the right ventricle struggles, how to spot trouble early, and what bedside moves actually help. We’ll start with the basics (pre- vs post-capillary PH, why PVR climbs) and build to advanced pearls on RV–LV interaction, echo clues that matter (D-shaped septum, TR, plethoric IVC), and the physiology behind oxygenation, fluids, and PEEP when the RV is on the ropes.
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V/Q Mismatch

Dive into V/Q mismatch—specifically dead space and shunt. We’ll explore our interventions that optimize the V/Q match and dive into the “why” behind these interventions. You’ll see how to recognize each pattern at the bedside (e.g., refractory hypoxemia vs. widening PaCO₂–ETCO₂ gap) and how that guides care—when increasing FiO₂ helps, when you need PEEP/proning to recruit alveoli, and why overdistension can worsen dead space.
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Inhaled Pulmonary Vasodilators

Explore inhaled pulmonary vasodilators—nitric oxide and Veletri. We’ll break down how they selectively dilate blood vessels inside ventilated lung units, why that matters in ARDS or RV failure, and how smart bedside execution (timing, delivery setup, and weaning) can make or break their effectiveness. You’ll see clear physiology, practical troubleshooting, and the reasoning behind when these agents help—and when they can actually make things worse.
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Complete Heart Block

Dive into the complexity of Complete Heart Block and unpack what is truly happening beneath the rhythm strip. This episode explores the underlying pathophysiology that disrupts conduction between the atria and ventricles, helping you move beyond memorization to a deeper understanding of why this arrhythmia behaves the way it does. You will learn how to recognize patients with third-degree AV block through both ECG interpretation and clinical presentation, linking electrical findings to hemodynamic consequences at the bedside.
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Pulmonary Embolism

Explore  the pathophysiology of Pulmonary Embolism (PE)—from the bedside clues (like that sudden drop in EtCO₂ or unexplained tachypnea) to the physiology of dead space, RV strain, and obstructive shock. We’ll walk through how anticoagulation and reperfusion therapies actually work, and why small choices—like cautious fluids, norepinephrine first, or low PEEP—make all the difference in protecting the right ventricle.
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End Tidal CO2

Explore end-tidal CO₂ (EtCO₂)—one of the most underutilized tools in critical care. We’ll walk through the physiology behind the waveform, decode classic patterns like the “shark fin” and “flatline,” and show how EtCO₂ can detect airway dislodgement, guide CPR quality, and flag shock before the pressure drops. Whether you're adjusting a vent, managing sedation, or leading a code, this issue will help you interpret EtCO₂ like a pro.
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Pulseless Electrical Activity

Explore Pulseless Electrical Activity (PEA)—one of the most challenging rhythms you’ll encounter in the ICU. We’ll explore why PEA is a symptom, not a diagnosis, walk through the pathophysiology that underlies electromechanical dissociation, and break down the infamous Hs and Ts with detailed explanations of why each leads to PEA. 
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Giapreza

Explore the role of Giapreza in the management of refractory shock and understand where it fits within the broader hemodynamic strategy. This session dives into how angiotensin II directly targets the renin–angiotensin–aldosterone system to restore vascular tone in patients who remain hypotensive despite conventional vasopressors. Rather than viewing it as just another agent, you will learn to recognize the specific physiologic profile of patients who are most likely to benefit from its use.
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Tham

This edition takes a deeper look at Tromethamine (THAM) and its role as a targeted therapy in the management of metabolic acidosis. Rather than simply correcting numbers on a lab report, THAM works at the level of acid buffering and carbon dioxide handling, offering a unique approach that differs fundamentally from more familiar treatments like sodium bicarbonate. This session will help you understand not just when to use THAM, but why it may be the preferred option in select critically ill patients.
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Histoplasmosis

We’ll unpack how histoplasma moves from an isolated pulmonary infection to systemic dissemination, why transplant patients are uniquely vulnerable, and how macrophages can become the vehicle for spread when cellular immunity is suppressed. We’ll also explore why hyponatremia, cytopenias, and hepatosplenomegaly should widen the differential beyond bacterial pneumonia.
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Insulin Autoimmune Syndrome

Insulin Autoimmune Syndrome (IAS)—a rare and fascinating cause of unpredictable blood sugars. The treatment, including plasmapheresis, offers a great opportunity to better understand the disease process and the rationale behind our evolving management strategy.
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Tumor Lysis Syndrome

We’ll break down what tumor lysis syndrome actually is at a physiologic level—how rapid cancer cell destruction overwhelms the body with potassium, phosphate, and uric acid, and why the kidneys often can’t keep up. We’ll also walk through how the medications used to treat leukemia contribute to this process by driving rapid cell death.
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Herpes Simplex Virus

We’ll walk through how disseminated HSV-1 can masquerade as overdose, sepsis, or HLH—and how immune dysfunction, particularly NK cell failure, allowed a “common” virus to cause catastrophic multi-organ failure. We’ll also break down the physiology behind refractory vasoplegic shock and why hydroxocobalamin was used—not as an antidote, but as a targeted rescue therapy when pressors weren’t enough.
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TCA Overdose

Explore Tricyclic Antidepressant (TCA) Overdose, a high-acuity toxicologic emergency that can escalate rapidly. We’ll unpack the classic anticholinergic toxidrome, ECG findings that can help predict seizures and arrhythmias, and high-yield interventions like sodium bicarbonate. Whether you’re new to TCA overdose or want a deeper understanding of the “why” behind our interventions, this edition is packed with actionable insights and a short knowledge check to reinforce key points.
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#Explore | #Learn | #Stay Curious

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Our goal is simple—help you think deeper, act confidently, and feel truly ready at the bedside.
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Disclaimer: these crit bits are intended to spark curiosity and sharpen critical thinking. They are not a substitute for UpToDate, institutional guidelines, or provider orders. 
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