medicine - tech - life
The venous-to-arterial carbon dioxide difference (PCO₂ gap), defined as PcvCO₂ (taken from a central line blood gas) – PaCO₂ (taken from an arterial blood gas), answers a question that neither lactate nor ScvO₂ can typically answer directly. Whereas ScvO₂ focuses on the balance between oxygen delivery and consumption, the pCO₂ gap asks whether blood flow […]
Vitamin K (phytonadione) is an essential, fat-soluble cofactor for γ-carboxylation of clotting factors II, VII, IX, and X, as well as proteins C and S. This post-translational modification allows these proteins to bind calcium and participate in coagulation. In vitamin K deficiency or during warfarin therapy, the liver continues to synthesize these factors, but they […]
This post was last updated on 5/27/2026. Between the operating room, ICU responsibilities, education, research, content creation, app development, administrative work, and everything else life throws at me, I realized fairly early on that there are not enough hours in the day to simply “work harder” forever. During medical training, I stopped asking, “How can […]
Mitral paravalvular leaks (PVL) occur when there is dehiscence between the prosthetic sewing ring and the native annulus, allowing blood to regurgitate around the valve rather than through it. The prosthesis itself may function normally, while a high velocity eccentric jet produces significant physiologic consequences. These leaks are often associated with annular calcification, endocarditis,…
My homelab has gradually evolved into infrastructure I rely on every day. VPN access, dashboards, containers, AI workloads, monitoring, and remote services all quietly sit behind the scenes, powering my life. Unfortunately, when the Internet drops, the entire ecosystem feels broken. To add some redundancy, I just installed the UniFi 5G Backup alongside my UniFi […]
One of the first things I look for when performing transesophageal echocardiography (TEE) for a mitral valve replacement is how the new valve is functioning as we prepare to separate from cardiopulmonary bypass. A mechanical mitral valve is engineered for crisp, nearly effortless leaflet excursion; however, the following 3D TEE view of a mechanical On-X […]
Procalcitonin is a peptide precursor of calcitonin that becomes detectable in the setting of systemic bacterial infection, driven by cytokines and endotoxin released throughout the body rather than from the thyroid alone. Levels rise over 12-24 hours with bacterial sepsis and fall as the inflammatory signal resolves. This time course, combined with the sparing in […]
Total pneumonectomy (removal of the entire lung) is most commonly performed for centrally located lung cancer when sleeve resection or lung-sparing surgery is not feasible. Less common indications include severe bronchiectasis, invasive infection, massive hemoptysis, or traumatic destruction of the lung. Unlike lobectomy, pneumonectomy abruptly removes half of the pulmonary vascular bed, leaving…
Today, I was notified by my department leadership of my promotion to Associate Professor of Anesthesiology, effective September 1, 2026. As an attending physician in academic medicine, progress is often measured in milestones, publications, promotions, and titles, but there’s a tremendous amount of work that goes into achieving those. For me as a cardiac anesthesiologist […]
As a physician, one of the most frustrating public takes is the claim that doctors don’t receive enough training in medical school about nutrition, as though that is the central reason chronic disease continues to overwhelm healthcare. It’s an easy accusation because it sounds thoughtful on the surface… especially when it comes from people who […]
I never thought I would be the person cross-shopping a Tesla Model S Plaid and a Porsche Taycan Turbo S, let alone owning both. Porsche people tend to scoff at the idea of driving a Tesla, while Tesla owners usually couldn’t care less. That dynamic alone says a lot about the two cars. One comes […]
Sometimes I’m asked by medical students and anesthesiology residents what a typical work schedule looks like for me as a dual-trained adult cardiac anesthesiologist and CVICU intensivist working in academic medicine. Although my schedule has changed with growing administrative and leadership responsibilities, I feel like it’s a great balance between fixed clinical time, opportunities to […]
Katie and I took a two-week vacation to Japan for the Japanese Grand Prix (my favorite track of the year) and to visit other popular tourist attractions. I catalog our adventures in this post. Day 1: Flight from Houston to Narita-Tokyo The day of our nonstop flight to Narita started absurdly early. We got to […]
Fibryga (human fibrinogen) is a concentrate designed to restore factor I (fibrinogen), the final substrate of clot formation. Fibrinogen is converted by thrombin into fibrin, which polymerizes and stabilizes the platelet plug. When fibrinogen levels fall, the resulting clot is weak, easily disrupted, and unable to achieve durable hemostasis. In critical illness and major bleeding […]
In patients with extensive disease involving the aortic arch and proximal descending thoracic aorta, a frozen elephant trunk (FET) extends the repair distally by combining an open surgical ascending/transverse aortic arch replacement with deployment of a stented graft into the descending thoracic aorta. This gives my surgical colleagues a way to treat complex aneurysmal or […]
After endotracheal intubation for a general anesthetic, it is not uncommon for patients to report a sore throat in the recovery area. Although it’s usually self-limited, small details in airway management can often shape a patient’s overall satisfaction with their perioperative care. In appropriate patients, I will downsize the endotracheal tube and lubricate it with […]
This video walks through how I approach extubation for many of my postoperative patients in the CVICU, drawing directly from the same physiologic framework I use as a cardiac anesthesiologist in the operating room. View this post on Instagram A post shared by Rishi Kumar, MD | RK.MD (@rishimd)
I’ve been renting apartments since my days as an anesthesiology resident; however, I didn’t discover the original Bilt card until very late in the game, and to be honest, it seemed a little too good to be true. A card that lets me put a fixed monthly expense (not to mention my largest expense by far) on […]
In August 2025, I transitioned my Eero-based networking hardware to Ubiquiti and have been extremely satisfied with the granular control I have over advanced networking features, metrics, and network performance. As part of this, I created VLANs to separate devices, firewall rules to define which devices can communicate with which others, DNS filtering, and more. […]
I don’t normally deviate from medical/tech-related topics, but today was an important milestone in my life. I got engaged! View this post on Instagram A post shared by Rishi Kumar, MD | RK.MD (@rishimd)
Chronic hypertension, medial degeneration, elastic fiber fragmentation, smooth muscle cell loss, and progressive aortic dilation are all mechanisms implicated in acute aortic dissection (AAD). Although cold weather does not create medial degeneration, it can precipitate issues in an already compromised aorta. Population-level data consistently show winter peaks in acute aortic dissection and…
Maintenance of certification in anesthesiology (MOCA) evolved from an exam taken every decade to now having to complete 30 online questions every quarter, maintain an unrestricted license to practice medicine, obtain 250 category 1 continuing medical education (CME) credits (20 of which are approved as “patient safety” CMEs), and quality improvement activities. The nice part […]
“Thiamine before glucose” is a bedside teaching that started with a sound physiologic concept and slowly hardened into dogma when dealing with patients with alcohol use disorder. Thiamine deficiency underlies Wernicke encephalopathy, a preventable but often missed neurologic emergency most commonly seen in alcohol use disorder, malnutrition, prolonged vomiting, and after bariatric surgery. The…
Premature atrial complexes (PACs) are something I’ve explained to trainees and patients for years, but about a week ago, I started having them following a really rough stretch in the CVICU. As a cardiac anesthesiologist and intensivist, I know how common PACs are and how often they are benign, but when the rhythm is yours, […]
Left ventricular (LV) thrombus is typically a result of stasis from myocardial hypokinesis/akinesis. A segment of myocardium stops moving, blood lingers in the cul-de-sac of an akinetic apex, and the endocardial surface becomes a scaffold for clot. Large anterior infarctions, end-stage heart failure, and dilated ventricles can set the stage for stasis, injury, and time […]
2025 was an interesting year for me as an academician. I’m still balancing clinical time as an attending cardiac anesthesiologist and cardiovascular ICU intensivist; however, I’ve also been humbled to receive leadership opportunities as the medical director of our organ donor care center (DCC) and will be serving on the medical board of our organ […]
High altitude pulmonary edema (HAPE) typically shows up in otherwise healthy patients after rapid ascent (e.g., mountain-climbing) with subsequent coughing, tachycardia, hypoxemia, and fatigue. These symptoms are often attributed to overexertion or dehydration, but it’s important to recognize the underlying physiology. At its core, altitude exposes the lung to hypoxia and triggers hypoxic…
Olanzapine (Zyprexa) and quetiapine (Seroquel) are often discussed as if they are interchangeable sedating antipsychotics used to help with addressing facets of delirium (insomnia, emotional lability, etc.). It often feels like dealer’s choice when deciding which one to use. Here are some of my considerations as an intensivist. Olanzapine is available as an orally disintegrating […]
Andexanet alfa (Andexxa) will leave the US market on December 22, 2025, after AstraZeneca withdrew its biologics license application for commercial reasons. For a drug that costs as much as a car (~$25-50K per dose) and carries meaningful safety concerns… good riddance! Andexanet entered practice as the only FDA-approved reversal agent specifically targeting factor Xa […]
Middle aortic (“mid-aortic”) syndrome (MAS) refers to a segmental narrowing of the distal thoracic or abdominal aorta, often with associated stenosis of the renal and visceral branches. The result is severe renovascular hypertension in children and young adults who otherwise have “healthy” hearts and no atherosclerotic risk profile. Etiologies range from isolated congenital aortic hypoplasia […]
Every few years, I tweak RK.MD’s design to refresh my content and to leverage the latest technologies at that time. My goals for 2026 are to address a few lingering headaches built up over the years: The goal was simple: make this as lean, consistent, and content-centered as possible by leveraging native WordPress functions, eliminating […]
Over the last month, I’ve been slowly refining a workflow that lets me run a private large language model (LLM) on my NVIDIA DGX Spark. I wanted an inference model that lives entirely on my own hardware, never leaves my network, and feels responsive enough for writing, coding, and day-to-day experimentation. GPT-OSS:120B has become the […]
Creating a new arteriovenous fistula (AVF) generates a major hemodynamic shift. Connecting a high-resistance artery to a low-resistance vein increases venous return, lowers systemic vascular resistance, and forces the heart to sustain a chronic high-flow load. Many patients adapt, but those with limited reserve can decompensate quickly with dyspnea, edema, tachycardia, and a warm, high-output […]
Candida auris (C. auris) has become a significant challenge in critical care across the country. It spreads across surfaces, equipment, and even skin, allowing outbreaks to take hold long before they are detected. These infections tend to appear in patients with comorbidities like advanced age, diabetes, kidney disease, malignancy, dialysis dependence, immunocompromised states, invasive devices,…
Tramadol (Ultram) is often prescribed for analgesia because it’s easy to write for (especially at hospital discharge); however, its pharmacology makes it unreliable for pain control. The parent compound has only weak affinity for the mu opioid receptor, so most of the meaningful opioid effect comes from its active metabolite O-desmethyltramadol. That metabolite is produced […]
As with any procedure, cardiac surgery carries risks that are explained to patients by their surgical team. The Society of Thoracic Surgeons Short-Term Operative Risk Calculator provides clinicians with a way to anchor these discussions. It uses data from hundreds of thousands of cardiac operations to estimate the chance of outcomes like mortality, stroke, renal […]
Gerbode defects create an abnormal communication between the high-pressure left ventricle (LV) and the right atrium (RA), thereby completely bypassing the right ventricle. That pathway sets up a distinctive left-to-right shunt with hemodynamics that can be subtle or profoundly destabilizing, depending on the size of the communication and the clinical context. I think about Gerbode […]
The NxStage System One continuous renal replacement therapy (CRRT) system provides convective and diffusive clearance through a simplified cartridge system. It has an interface centered on three large, color-coded numeric fields that offer the most essential information for therapy. When I’m rounding in the CVICU, I often look at these numbers to determine whether they […]
Rather than using a separate plugin or paid service, I used macOS’s Automator application to create a folder action that converts popular image and video file types to AVIF and WebM, respectively. This way, regardless of the media format, I can drop it into a predetermined folder on my Mac Studio and MacBook Pro, and […]
Acetaminophen (Tylenol) is routinely administered in IV and PO (pill) forms in perioperative and critical care medicine, but the debate of which route of administration is superior comes up all the time, despite the evidence being consistent for years. TLDR – once both formulations are absorbed, the analgesic effect is the same. The distinction is […]
Isopropyl alcohol (IPA) aromatherapy by means of inhaling the vapors from an IPA pad has been a simple bedside practice used to relieve nausea. Several studies suggest that IPA inhalation can provide a quick, modest reduction in nausea severity in an inexpensive, safe, and easy-to-administer intervention. However, other trials and meta-analyses have shown no significant […]
As a cardiac anesthesiologist and intensivist, vasoplegia following cardiopulmonary bypass is an issue I often face in the OR and ICU. This distributive shock phenotype is characterized by low systemic vascular resistance, despite preserved or elevated cardiac output, primarily driven by dysregulated nitric oxide (NO) and guanylate cyclase signaling, which promotes pathologic vasodilation and…
Mentors shape us in ways we often don’t appreciate until much later. They see potential when we doubt ourselves, offer perspective when we feel lost, and guide us through the moments that define our careers. Dr. George Williams wasn’t just my leader… he was the heart of our team, the kind of physician and human […]
Aldosterone escape is the phenomenon where, despite persistently elevated aldosterone levels (endogenous or exogenous), the body prevents unchecked sodium retention and volume overload. After an initial period of sodium retention, renal compensatory mechanisms “escape” from aldosterone’s effects. This is clinically relevant in conditions like primary hyperaldosteronism (Conn’s syndrome), patients…
With the assistance of my department, I recently submitted my application for promotion to the rank of Associate Professor. I wanted to outline some considerations for promotion in academic medicine, including the benefits and the process. First, one of the single worst mistakes I made was starting in October (instead of September). Traditional promotion from […]
It’s been a few years since I last did a “What’s in my work bag?” post, so here’s an update! Check out my prior posts from 2021, 2020, 2019, 2017, and 2016. Depending on what I’m doing on any given day (reading journal articles, programming at a coffee shop, creating a PowerPoint lecture, etc.), I’ll […]
A eutectic mixture refers to a combination of two or more substances that, when mixed in a specific ratio, form a mixture with a lower melting point than any of the individual components alone. As a cardiac anesthesiologist and intensivist, I occasionally use a eutectic mixture of local anesthetics (EMLA) cream, which contains 2.5% lidocaine […]
Pump controlled retrograde trial off (PCRTO) is a weaning technique for venoarterial ECMO (VA-ECMO) in which pump speed is gradually decreased until net retrograde flow develops from the arterial to the venous limb of the circuit. This maneuver suspends mechanical circulatory support without decannulation, offering a real-time, physiologic test of native cardiac function while preserving circuit…
McConnell’s sign is an echocardiographic finding classically described as akinesis of the right ventricle’s (RV) mid-free wall with preserved apical contractility on echocardiography. It’s often associated with acute pulmonary embolism (PE) and is thought to reflect regional wall motion abnormalities from acute RV pressure overload and tethering of the apex to a hyperdynamic LV. While […]
Dexmedetomidine (Precedex) is a selective alpha-2 agonist I frequently use as a cardiac anesthesiologist and intensivist to provide analgosedation before extubation. Beyond its sedative and sympatholytic effects, dexmedetomidine has been increasingly implicated in drug-induced fever. Although listed in the FDA label, recent literature provides a clearer picture. A post hoc analysis of 703…