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]
Jon-Emile S. Kenny MD [@heart_lung] The mechanical power applied to the lung is a risk factor for ventilator or ventilation-induced lung injury [VILI] [1-4]. But can the work done to the lung over time be homogenized into a single value? Could different components of the power equation carry different VILI risk beyond their mathematical inequalities [… read more]
Jon-Emile S. Kenny MD [@heart_lung] A few years ago I was intrigued by a new concept in Ventilator-Induced Lung Injury [VILI] – the mechanical power. I employed this paradigm, introduced by Gattinoni’s group, as an opening for the ‘ARDS Trilogy.’ Since then, I have also discussed this ‘ergotrauma’ in the context of helium-oxygen physiology and [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “The truth is balance, but the opposite of truth, which is unbalance, may not be a lie.” -Susan Sontag Case A 49 year old man presents with two days of hemoptysis, right-sided pleuritic chest pain and a few hours of ‘confusion’ according to his teammate in a pick-up hockey league. One [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “Nolite te bastardes carborundorum” -Margaret Atwood Case An 86 year old woman presents with two days of decreased intake by mouth and 3 days of melena and vomiting. She is followed closely by her internist and cardiologist for hypertension, severe mitral regurgitation, pulmonary venous hypertension and right ventricular dysfunction with co-morbid [… read more]
Jon-Emile S. Kenny MD [@heart_lung] Why is blood pressure measured by units of length [i.e. millimeters of mercury – mmHg]? What decides systolic and diastolic pressure? What are the determinants of tissue perfusion and what are the clinical implications of this physiology? Can we deceive ourselves into thinking a particular mean arterial pressure [MAP] is [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “I’m burnin’ through the sky, yeah Two hundred degrees, That’s why they call me Mister Fahrenheit” -Freddie Mercury Part 1 gave a brief overview of the mechanisms of atrial fibrillation [AF] as well as pertinent features of rate controlling agents and anticoagulation. In this brief second part, nuanced features of ventricular [… read more]
Jon-Emile S. Kenny MD [@heart_lung] with illustrations by Carla M Canepa MD [@_carlemd_] “The habit of writing for my eye is good practice. It loosens the ligaments.” ― Virginia Woolf Case A 28 year old woman with known severe mitral stenosis from rheumatic heart disease presents with acute onset shortness of breath. Her acute dyspnea began while [… read more]
Jon-Emile S. Kenny MD [@heart_lung] Remarkably, non-invasive cardiology did not begin with ultrasound but rather as investigations into systolic time [1]. Indeed, studies on the duration of systole began in 1875 with Garrod who showed that the left ventricular ejection time [LVET] – the time that the aortic valve is open and ejecting blood – varies [… read more]
Jon-Emile S. Kenny MD [@heart_lung] with illustrations by Carla M Canepa MD [@_carlemd_] “I’ve never known any trouble than an hour’s reading didn’t assuage.” -Schopenhauer The last few decades have infamously boasted numerous failed therapies for sepsis and septic shock. Because sepsis represents an explosive and chaotic cacophony of pro and anti-inflammatory mediators – treatments which [… read more]
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