ARDS and ALI

Aug 232019
 
APRV and Esophageal Manometry: a new way to titrate T-Low?

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]

May 302019
 
Neuromuscular blockade for ARDS was no help, in supine patients

Continuous neuromuscular blockade for severe ARDS became common practice after the ACURASYS trial (2010) showed it reduced mortality by an absolute 9%. A larger trial, ROSE, now finds no benefit of the therapy over usual care — but leaves lingering questions due to major design differences. The ROSE trial was a multicenter randomized trial in [… read more]

Apr 292019
 
ICU Physiology in 1000 Words: The Respiratory System Pressure-Volume Curve

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]

Apr 282019
 
Open the Lung with Esophageal Manometry to Avoid VV-ECMO?

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]

Apr 142019
 
Titrating PEEP using esophageal pressures did not improve ARDS outcomes (EPVent-2)

In acute respiratory distress syndrome (ARDS), using pleural pressure to adjust positive end-expiratory pressure (PEEP) has long been considered a cumbersome but theoretically ideal technique to optimize ventilator management. Using esophageal pressure as a surrogate for pleural pressure can allow one to calculate and minimize the transpulmonary pressure gradient, elevations in which are the putative [… read more]

Mar 292019
 
ICU Physiology in 1000 Words: The Driving Power & Ventilator-Induced Lung Injury

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]

Mar 262019
 
ICU Physiology in 1000 Words: The Mechanical Power & Ventilator-Induced Lung Injury

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]

Nov 112018
 
ICU Physiology in 1000 Words: Volutrauma or Barotrauma?

Jon-Emile S. Kenny MD [@heart_lung] In a recent and excellent open-access review, Gattinoni, Quintel and Marini ask which is worse, volutrauma or atelectrauma [1]?  This concise review is an absolute must-read and forms the fabric from which this short article assembles.  Last spring – in Montreal – I was asked a few questions about volutrauma [… read more]

Oct 162018
 
Near Apneic Ventilation & Extracorporeal Membrane Oxygenation: close the lungs & keep them closed?

Jon-Emile S. Kenny MD [@heart_lung] “Once had a love and it was a gas …” -Blondie Case A 56 year old professor returns from a hiking trip in the ‘Four Corners’ area of New Mexico.  She was previously well and decided to rent a secluded desert cabin whilst writing a novel on the ethical obligations [… read more]

Sep 132018
 
ECMO fails as first-line treatment for ARDS. Or did it?

Extracorporeal membrane oxygenation (ECMO) is an accepted salvage therapy for severe acute respiratory distress syndrome (ARDS) after conventional mechanical ventilation with low tidal volumes, neuromuscular blockade and prone positioning have failed. ECMO has been proposed as the ultimate lung protection strategy for ARDS, because it bypasses the lungs entirely. So why shouldn’t it be first-line [… read more]

Sep 082018
 
High Flow Oxygen in Chronic Obstructive Pulmonary Disease: improved work of breathing or respiratory effort?

Jon-Emile S. Kenny MD [@heart_lung] “WANTED: Somebody to go back in time with me.  This is not a joke …” -John Silveira Case A 78 year old man with known moderate-to-severe emphysema is extubated in the ICU; he was initially admitted with hypercapneic respiratory failure secondary to influenza pneumonia and pulmonary edema from the medical [… read more]

Aug 282018
 
Simvastatin & Hyper-inflammatory ARDS: re-analysis of the HARP-2 trial

Jon-Emile S. Kenny MD [@heart_lung] with illustrations by Carla M. Canepa MD “For others, in spite of myself, from myself.” -Emmanuel Levinas Case A 52 year old man is admitted to the intensive care unit with bilateral pulmonary opacities, worsening gas-exchange and hypotension requiring peripherally-administered norepinephrine.  His PaO2-to-FiO2 ratio is less than 100; he is [… read more]

Jun 182018
 
Driving Pressure in Airway Pressure Release Ventilation: a fool’s errand?

Jon-Emile S. Kenny MD [@heart_lung] “One of the symptoms of an approaching nervous breakdown is the belief that one’s work is terribly important.” -Bertrand Russel I read with great interest a recent letter penned by Taylor and Camporota in response to an investigation on airway pressure release ventilation [APRV] by Zhou and colleagues.  Their brief [… read more]

May 162018
 
ICU Physiology in 1000 Words: Airway Pressure Release Ventilation – Part 3

Jon-Emile S. Kenny MD [@heart_lung] Lung Stress in Pulmonary & Extrapulmonary ARDS Initially described in the late 1990s, the distinction between direct pulmonary insults [i.e. pulmonary ARDS] and indirect pulmonary insults [i.e. extra-pulmonary ARDS] is important [1].  Additionally, direct pulmonary injury such as gastric acid aspiration may have a different molecular phenotype from indirect, extra-pulmonary [… read more]

May 152018
 
ICU Physiology in 1000 Words: Airway Pressure Release Ventilation – Part 2

Jon-Emile S. Kenny MD [@heart_lung] In the previous segment, time constants [t] – and their limitations – were described as a lesson in applied respiratory physiology for setting T-Low and prediction of auto-PEEP in airway pressure release ventilation [APRV].  In this brief missive an alternative approach to titrating T-low is described and critiqued.  As well, [… read more]

May 142018
 
ICU Physiology in 1000 Words: Airway Pressure Release Ventilation – Part 1

Jon-Emile S. Kenny MD [@heart_lung] While the lung in the throes of acute respiratory distress syndrome [ARDS] is shrunken, edematous and inflamed, a basic management maneuver is to ‘recruit’ lost pulmonary surface area.  In other words, unfold alveolar-capillary units with the ventilator like a respirothoracic party horn.  One ‘unconventional’ method of maximizing and maintaining lung [… read more]

Apr 232018
 
Lectures from the Inaugural 'Hospitalist and the Resuscitationist' Conference in Montreal, Canada

Jon-Emile S. Kenny MD [@heart_lung] “The real process of education should be the process of learning to think through the application of real problems.” -John Dewey On April 18 & 19, 2018, I had the pleasure of participating in the inaugural conference “The Hospitalist and the Resuscitationist” in Montreal.  The entirety of this meeting was [… read more]

Mar 242018
 
High-Flow Nasal Cannula, Work of Breathing & Mechanical Power: is there benefit?

Jon-Emile S. Kenny MD [@heart_lung] “I grow old … I grow old … I shall wear the bottoms of my trousers rolled.” -T. S. Eliot Background While it is tempting to isolate nasal high flow [NHF] into one’s cognitive schema for hypoxemia, NHF rightly deserves an esteemed position within one’s cerebral scaffolds for both hypercapnia [… read more]

Mar 122018
 
Is There Synergy between PEEP & Prone Position in ARDS?

Jon-Emile S. Kenny MD [@heart_lung] “… when you walk around a kitchen, you will say to yourself, this is interesting, this is grand, this is beautiful like Chardin.” -Marcel Proust Background Titration of positive end-expiratory pressure [PEEP] in the acute respiratory distress syndrome [ARDS] is achieved by a diverse assortment of practices undergirded by equally [… read more]

Jan 202018
 
Prone positioning for severe ARDS advised by major societies

In case you missed it, major professional societies in critical care now strongly recommend prone positioning for patients with severe acute respiratory distress syndrome (ARDS), with a PaO2-to-FiO2 (P/F) ratio of ≤ 100. The recommendation marks a major shift in advised care for ARDS. Prone positioning improves ventilation-perfusion matching (transferring delivered oxygen into the bloodstream more [… read more]