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]
Jon-Emile S. Kenny MD [@heart_lung] “I am suffocated and lost when I have not the bright feeling of progression” -Margaret Fuller A recent letter and review in Critical Care have called for adoption of the ‘Open Lung Approach’ to patients with severe ARDS. More specifically, in refractory ARDS whilst prone, it is argued that esophageal [… read more]
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