Sep 232021
 
ICU Physiology in 1000 Words: The Geometry of Ejection Fraction

Jon-Emile S. Kenny MD [@heart_lung] The left ventricular ejection fraction [LVEF] is a commonly-sought cardiac measure.  With the explosion of bedside ultrasound and automated methods to capture LVEF, the ejection fraction will grow in clinical prominence and affect decisions for the acutely-ill.  Asked the meaning of the LVEF, many clinicians might describe it as a ‘measure [… read more]

Sep 132021
 
ICU Physiology in 1000 Words: The Pulse

Jon-Emile S. Kenny MD [@heart_lung] The relative simplicity of extending one’s finger onto the tissue overlaying a major artery belies the complicated forces generating an arterial pulse.  Descriptions and physiological elucidations have been put forth across the decades, yet even today the machinations relating cardiac contraction to a waxing and waning arterial wall are a bit [… read more]

Sep 092021
 
Back to the BaSICS: does the infusion rate of a fluid bolus affect mortality?

Jon-Emile S. Kenny MD [@heart_lung] “He walked away across the room, his cowboy boots echoing like pistol shots.” -Sylvia Plath Background Implicit in resuscitation is speed.  Throughout training we are zealously instructed that ‘time is tissue’ for all manners of compromised perfusion. We envision spendthrift mitochondria chewing through oxygen without regard to withering supply; as such, [… read more]

Sep 012021
 
Another 0.9% Saline versus Balanced Solution Trial: BaSICS released

Jon-Emile S. Kenny MD [@heart_lung] “May I be the tiniest nail in the house of the universe, tiny but useful.” -Mary Oliver Background The use of ‘balanced’ intravenous fluids as compared to 0.9% saline – so-called ‘normal’ saline – has garnered much scientific interest in the last half-decade.  Propelling some of this curiosity is a newfound [… read more]

Jul 212021
 
Heat Exhaustion & Heatstroke – part 2

Jon-Emile S. Kenny MD [@heart_lung] “There are hills, rounded, blunt, burned, squeezed up out of chaos, chrome and vermilion painted, aspiring to the snow-line.” -Mary Austin With very basic introductions to heat transfer, the cardiovascular response to heat stress and the distinction between heat exhaustion and heatstroke, this final section addresses fundamental aspects of treating heat-related [… read more]

Jul 202021
 
Heat Exhaustion & Heatstroke – part 1

Jon-Emile S. Kenny MD [@heart_lung] “Tell me, what is it you plan to do, with your one wild and precious life?” -Mary Oliver When carbon dioxide retention tickles intensivists’ neurons, clusters of adjacent synapses spark in deep sulci – discharging neural silos of respiratory physiology, alveolar ventilation, pH interpretation and the like. But like flash-bulbs against [… read more]

Jul 202021
 
Heat-Related Illness & Hemodynamics

Jon-Emile S. Kenny MD [@heart_lung] “I believe that the very process of looking can make a thing beautiful.” -David Hockney With the basics of temperature, heat and heat transfer described previously, this section turns to some select physiological aspects of heat-related illness. While this is clearly a very broad topic with multiple, intersecting avenues of discussion, [… read more]

Jul 192021
 
Heat-Related Illness & First Principles

Jon-Emile S. Kenny MD [@heart_lung] “Study hard what interests you the most in the most undisciplined, irreverent and original manner possible.” -Richard Feynman Heat-related illness is a very common form of environmental injury. Like many insults, it may be modelled by ‘diathesis-stress.’ In other words, heat-related illness materializes at the cross-roads of inherent patient characteristics [e.g., [… read more]

Mar 312021
 
On Cytokines, Fluvoxamine and COVID-19 – Part 2

Jon-Emile S. Kenny MD [@heart_lung] “Apocalypse is played out now on a personal scale; it is not in the sky above us, but in our bed.” -Mark Doty Introduction With a proposed pathway coupling pathogen-associated molecular patterns to the elaboration of pro-inflammatory cytokines, sketched lightly in part 1, this segment ties murine biomolecular theory to human [… read more]

Mar 282021
 
On Cytokines, Fluvoxamine and COVID-19 – Part 1

Jon-Emile S. Kenny MD [@heart_lung] “You see, we have a kind of allergy to the past; it’s our national disease, and the very assurance with which you insist that the past is within the present is likely to seem quite repellent, even offensive, to these new readers.” -Richard Howard Introduction Early in the COVID-19 pandemic, the [… read more]

Feb 172021
 
Open Critical Care: a great new hub for critical care resources

I’m excited to share the link to Open Critical Care, a new hub providing open access critical care learning tools, COVID-19 treatment guidelines, and loads of other high-quality resources. Funded by USAID and directed by physicians at UCSF, it’s an endeavor worth following. Although their offerings are directed especially toward health care workers in resource-variable [… read more]

Jan 292021
 
A Cursory Review of Casirivimab and Imdevimab for COVID-19

Jon-Emile S. Kenny MD [@heart_lung] “Booksellers are the most valuable destination for the lonely, given the numbers of books that were written because authors couldn’t find anyone to talk to.” – Alain de Botton Introduction An important reason for treating both tuberculosis and HIV with multiple pharmacological agents is the ability of these infectious scourges to [… read more]

Jan 082021
 
Kambô Intoxication for the Intensivist – Part 2

Jon-Emile S. Kenny MD [@heart_lung] “There are poisons that blind you, and poisons that open your eyes.“ – August Strindberg. In the introduction to kambô, or what Esparmer and colleagues called a “fantastic chemical cocktail with potential medical applications, unequaled by any other amphibian,” a superficial overview was offered. This first part included a very basic [… read more]

Jan 072021
 
Kambô Intoxication for the Intensivist – Part 1

Jon-Emile S. Kenny MD [@heart_lung] “All things are poisons, for there is nothing without poisonous qualities. It is only the dose which makes a thing poison.” -Paracelsus Background Per one account, many living in the village Kaxinauá were seriously-ill and the shaman could not help them with known herbal medicines. During a ritual involving ayahuasca, the [… read more]

Dec 312020
 
Epinephrine and Cerebral Blood Flow in Cardiac Arrest

Jon-Emile S. Kenny MD [@heart_lung] “I am a necessary part of an important search to which there is no end.” -Keith Haring Background With PARAMEDIC-2, the role of epinephrine in cardiac arrest, and especially its effects on cerebral perfusion and neurological outcome, have been appropriately questioned. Recall that Perkins and colleagues studied epinephrine in out-of-hospital cardiac arrest in a [… read more]

Nov 112020
 
ICU Physiology in 1000 Words: Pulmonary Vascular Resistance & Linear Assumptions

Jon-Emile S. Kenny MD [@heart_lung] A recent review of Paul Wood’s consummate approach to pulmonary hypertension is well-worth a read [1].  In it, the basic physiology of the calculated pulmonary vascular resistance [cPVR] is presented, as it often is, as a linear function.  Recall, maybe traumatically, the grade-school equation y = mx + b.  With this [… read more]

Oct 302020
 
ICU Physiology in 1000 Words: On Venous Capacitance and the U.S. Election

Jon-Emile S. Kenny MD [@heart_lung] Administering norepinephrine during sepsis resuscitation has a myriad of hemodynamic effects [1]. Importantly, the predominant mechanism probably varies around multiple patient, intervention and time-dependent elements.  Most commonly, perhaps, norepinephrine is provided to raise ‘mean arterial pressure’ – an effect driven by its alpha-agonist stimulation of pre-capillary arterioles.  While this plays a [… read more]

Oct 102020
 
ICU Physiology in 1000 Words: The Diastolic Shock Index & Subendocardial Perfusion

Jon-Emile S. Kenny MD [@heart_lung] When we model the circulation at the bedside, we resort to generalizations.  While these mechanistic heuristics don’t completely capture the complexity of hemodynamics, they do help us think quickly when confronted by clinical urgency.  For example, distilling ‘venous return’ into an upstream pressure and downstream pressure separated by a single resistance, [… read more]

Sep 122020
 
More on Corticosteroids in COVID-19 – Part 2: REACT meta-analysis

Jon-Emile S. Kenny MD [@heart_lung] “As human beings, don’t we need questions without answers as well as questions with answers?” -Alan Lightman With the publication of REMAP-CAP, CAPE-COVID and CoDEX, the World Health Organization [WHO] Rapid Evidence Appraisal for COVID-19 Therapies [REACT] Working Group combined these results with 4 other randomized trials of corticosteroids in COVID-19.  [… read more]