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]
Jon-Emile S. Kenny MD [@heart_lung] with illustration by Carla M. Canepa MD [@_carlemd_] “Inside the word ‘emergency’ is ‘emerge’; from an emergency, new things come forth.” -Rebecca Solnit Case A 32-year-old man is admitted with three days of fevers, chills, malaise, dyspnea and productive cough. He works in a stressful job in the heart of Manhattan [… read more]
Jon-Emile S. Kenny MD [@heart_lung] with illustrations by Carla M. Canepa MD [@_carlemd_] “Better never means better for everyone… It always means worse, for some.” -Margaret Atwood Case A 73-year-old woman with a history of severe chronic bronchitis, ESRD receiving thrice-weekly hemodialysis and heart failure with a preserved ejection fraction is admitted from home with fevers, [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “I know that character exists from the outside alone. I know that inside the body there’s just temperature.” -Sheila Heti Background: DPG versus PVR In 1971, the use of the pulmonary artery diastolic pressure gradient [DPG] was introduced to better refine the hemodynamic definition of pulmonary vascular disease. What is the [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “I had some dreams, they were clouds in my coffee, clouds in my coffee …” -Carly Simon Background A recent letter to the editor in Critical Care posed a rather provocative question – ‘Are we really preventing lung collapse with APRV?’ The authors cited a case report of esophageal manometry used in [… read more]
Jon-Emile S. Kenny MD [@heart_lung] In part 1, the basics of ventriculo-arterial coupling [VAC] were described and related to the Guyton Diagram. In this second part, the notion of cardiac performance [Eh] is explored in relation to venous Doppler velocimetry. Subsequently, I hypothesize that ‘veno-cardiac uncoupling’ – a concept analogous to VAC – is a [… read more]
Jon-Emile S. Kenny MD [@heart_lung] Background Concepts have been clanging around my head since I participated in Philippe Rola’s [@thinkingCC] sedulous Hospitalist & Resuscitationist Conference in Montreal. Initially, the abstractions of ventriculo-arterial coupling, Guytonian physiology and venous Doppler seemed insuperably sundered; but the cognitive haranguing recently gave way to harmony. What is ventriculo-arterial coupling and [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “I’ve looked at clouds from both sides now …” -Joni Mitchell Background In a recent physiological study – brought to my attention by the erudite and kinetic [@iceman_ex] – the detailed physiological effects of intravenous fluids, norepinephrine and dobutamine were sequentially evaluated in patients with sepsis. Sepsis was defined as [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “Our deeds determine us, as much as we determine our deeds.” -George Eliot Considering the independent and dependent variables of ventilation marked my final contribution to the “Hospitalist and the Resuscitationist” conference in Montreal, Canada; I gave a workshop on graphical analyses of ventilation. This began with the basics of [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “I am fearful, or suspicious of generalizations … they cannot guide me reliably in making decisions about particular individuals.” -Ruth Bader Ginsburg Between the 22nd and 24th of May, I participated in the “Hospitalist and the Resuscitationist” conference in Montreal, Canada. I spoke on the stanchions of physiology and evidence [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “There is no power for change greater than a community discovering what it cares about.” -Margaret J. Wheatley Between the 22nd and 24th of May, I participated in the galvanic, second-annual “Hospitalist and the Resuscitationist” conference in Montreal, Canada. The entirety of this meeting was organized by Dr. Philippe Rola [… read more]
Jon-Emile S. Kenny MD [@heart_lung] More than 20 years ago Amato and colleagues reported a significant mortality reduction in ARDS patients who had their ventilator settings guided by the pressure-volume [PV] curve [1]. The 28-day mortality reduction was profound – 71% versus 38% – in favour of the patients who had their positive end-expiratory pressure [… read more]
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