Jon-Emile S. Kenny MD [@heart_lung] In part 1, evidence for and against spontaneous breathing effort in acute respiratory distress syndrome [ARDS] was briefly outlined. The mechanisms of patient self-inflicted lung injury [P-SILI] are touched upon herein with reconciliation of the clinical and experimental data. Mechanisms: basics A handful great reviews on spontaneous breathing in ARDS and [… read more]
Jon-Emile S. Kenny MD [@heart_lung] Background In an excellent review from early 2016, Gattinoni and Quintel note that ventilator induced lung injury [VILI] is better considered ventilation induced lung injury because VILI can develop during spontaneous breathing [1]. To support this claim, they reference a classic experimental study from the late 1980s by Mascheroni and colleagues [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “ This is the way the world ends Not with a bang but with a whimper.” -T.S. Eliot As lightly discussed a few months ago, deploying corticosteroids in COVID-19 began, expectedly, with controversy. Russell and colleagues submitted a letter arguing against wholesale administration of corticosteroids in patients infected with SARS-CoV-2. They [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “We’re on a road to nowhere …” -David Byrne Background In early March of this year, Fang and colleagues published a letter noting that patients with diabetes and/or hypertension treated with ACE inhibitors or angiotensin II type-1 receptor blockers [i.e. ARBs] increase their expression of the ACE2 enzyme. Parenthetically, they also stated [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “Knavery and flattery are blood relations.” -Abraham Lincoln Background SARS-CoV-2 is a positive-sense, single-stranded RNA virus with spiked surface glycoproteins emanating from its viral envelope. It is a member of the Coronaviridae family, similar to the first SARS [SARS-CoV] and the Middle East Respiratory Syndrome [MERS]. SARS-CoV-2 preferentially targets respiratory epithelium, [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “This whole thing is not about heroism. It’s about decency. It may seem a ridiculous idea, but the only way to fight the plague is with decency.” -Albert Camus Background In 2013, Dünser and colleagues communicated a rogue viewpoint in shock resuscitation – let us do away with strict macro-hemodynamic goals [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “No facts are to me sacred; none are profane; I simply experiment, an endless seeker with no Past at my back.” -Ralph Waldo Emerson Background When Drs. Marini and Gattinoni author a letter describing a new phenotype of the acute respiratory distress syndrome [ARDS] encountered in patients infected with SARS-CoV-2, we [… read more]
Jon-Emile S. Kenny MD [@heart_lung] with illustrations by Carla M. Canepa MD [@_carlemd_] “…fires had been put out by volunteers using brickmason’s ladders and buckets of water carried in from wherever it could be found, and methods so disorderly that they sometimes caused more damage than the fires.” – Gabriel García Márquez In this second primer [… read more]
Jon-Emile S. Kenny MD [@heart_lung] with illustrations by Carla M. Canepa MD [@_carlemd_] “…but they all had an evasive tremor in their voices and an uncertainty in their eyes that belied their words.” – Gabriel García Márquez Background With early data illustrating upwards of 1 in 5 COVID-19 patients developing acute respiratory distress syndrome [ARDS], there is [… read more]
Jon-Emile S. Kenny MD [@heart_lung] with illustrations by Carla M. Canepa MD [@_carlemd_] “He found a glimmer of hope in the ruins of disaster …” – Gabriel García Márquez Background The coronavirus moniker originates from the appearance of the virus under the electron microscope – protein peplomers radiating from the viral envelope like a crown. Prior [… read more]
Jon-Emile S. Kenny MD [@heart_lung] About a year ago, I explored blood pressure – underscoring mean arterial pressure [MAP] as a determinant, but not necessarily an indicator, of perfusion. The inspiration for that post were these excellent reviews [1, 2] by the legendary Dr. Magder. With the recent 65 Trial [3], a deeper exploration of tissue [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “Sich regen bringt Segen” -German proverb Background It is an overcast day in Bern, Switzerland. I have recently left Zermatt, having had the honour and pleasure of speaking at ‘The Big Sick’ conference. I spent the day roaming the narrowed passages of this old, beautiful city. In the midst of my [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “It is a narrow mind which cannot look at a subject from various points of view.” -George Eliot Background On background reading for the recent entry on ‘Asthmatic Mechanics,’ I happened across a delightful case report submitted as a letter to the editor of the New England Journal of Medicine in [… read more]
Jon-Emile S. Kenny MD [@heart_lung] Background This synopsis will address the basic geometric calculation of respiratory system work for a single breath [in joules] and power [i.e. joules/seconds or watts] which is work multiplied by the respiratory rate. This geometric approach will then be used to explain two shorthand equations – the second of which was [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “Dying is a wild night and a new road.” -Emily Dickinson Background In 2006, a recruitment maneuver to achieve an ‘open lung’ was circulated; it has since been dubbed ‘stairway recruitment’ given its stepwise upthrusts in airway pressure [see figure 1]: Plodding up this ladder of airway pressure was meant to [… read more]
Jon-Emile S. Kenny MD [@heart_lung] Recently, Josh Farkas and Scott Weingart gave a series of engrossing posts and podcasts on asthma. I especially liked their deliberations on mechanical ventilation which inspired me – no pun intended – to create a vodcast of my own and, like a novice troubleshooting a ventilator alarm, poke and prod at [… read more]
Jon-Emile S. Kenny MD [@heart_lung] Commonly, we are sold that acute pulmonary thromboembolism [PE] burns the right ventricular [RV] candle at both ends. This is because perfusion of the right coronary artery [RCA] is mediated by both its upstream mean arterial pressure [MAP] and downstream right ventricular end-diastolic pressure [RVEDP]. Given that a PE may decrease [… read more]
Jon-Emile S. Kenny MD [@heart_lung] What if I told you that in acute pulmonary thromboembolism [PE] that the initiation of intravenous norepinephrine [NE] decreases the calculated pulmonary vascular resistance [cPVR]? Would you believe me? Certainly, you would trust that an infusion of a thrombolytic does so. Of great interest, both NE and thrombolytics decrease the cPVR [… read more]
Jon-Emile S. Kenny MD [@heart_lung] The transient and reversible loss of consciousness that may accompany pulmonary embolism [PE] is well-documented [1-7]. This brief post will not address the controversy regarding the prevalence of PE in ‘unexplained’ syncope; rather, it will focus on pathomechanisms and serve as the foundation for a few forthcoming entries on pulmonary thromboembolism [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “There are sadistic scientists who hurry to hunt down errors instead of establishing the truth.” -Marie Curie In part 1 of Vaping-Associated Lung Injury, the very basics of electronic nicotine delivery systems [ENDS] were covered as well as highlights on clinical presentation, radiology and pathology. In this second part, flurries of [… read more]
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