ARDS and ALI

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]

Dec 262017
 
ICU Physiology in 1000 Words: Visualizing Heart-Lung Interaction

Jon-Emile S. Kenny MD [@heart_lung] “Upward, not northward.” -E. A. Abbott A pressure chamber within a pressure chamber; the heart within the thorax.  These are two pumps beating in-and-out of time, varying in physiology and pathophysiology between patients and within any one patient during the arc of an illness.  As such, when we inspect the [… read more]

Dec 022017
 
A Great Lecture on Applied Respiratory Physiology

Jon-Emile S. Kenny MD [@heart_lung] -What is the world record for longest breath hold? -Why does the diagnosis of brain death require a rise in PaCO2 to at least 60 mmHg? -What minute ventilation can a human achieve? -What’s the difference between an elevated PaCO2 in someone who ‘won’t’ versus ‘can’t’ breathe? I’d like to [… read more]

Sep 292017
 
State-of-the-ART Trial: Do Recruitment Maneuvers & Higher PEEP Raise Mortality?

Jon-Emile S. Kenny MD [@heart_lung] “To believe in medicine would be the height of folly, if not to believe in it were not a greater folly still.” -Proust A 32 year old man with no past medical history save for a BMI of 51 is admitted with severe acute pancreatitis following a large intake of [… read more]

Sep 142017
 
ICU Physiology in 1000 Words: High Flow Oxygen Therapy

Jon-Emile S. Kenny MD [@heart_lung] That high flow oxygen applied via nasal cannula lends itself to treating hypoxemic respiratory failure may be obvious.  With adequate heat and humidification, oxygen can be employed relatively comfortably at very high flow rates – upwards of 60 L/min – to the nares.  At such rates, the effort of the [… read more]

Aug 302017
 
An Illustrated Guide to the Phases of ARDS: Implications for management

Jon-Emile S. Kenny MD [@heart_lung] with illustrations by Carla M. Canepa MD “Our life consists partly in madness, partly in wisdom: whoever writes about it merely respectfully and by rule leaves more than half of it behind.” -Montaigne Marking the 50 year anniversary of the first description of the adult respiratory distress syndrome – later [… read more]

Aug 202017
 
In ARDS, substandard ventilator care is the norm, not the exception

In acute respiratory distress syndrome (ARDS), anyone with the keys to a ventilator knows low tidal volume ventilation (~6 mL/kg ideal body weight) is standard care. Low tidal volume ventilation can prevent or ameliorate ventilator-associated lung injury ; if early clinical trials represent current reality, one in 11 people with ARDS treated by low tidal volume ventilation could have their [… read more]

Mar 202017
 
ICU Physiology in 1000 Words: Heliox & Mechanical Power

Jon-Emile S. Kenny MD [@heart_lung] Of the countless things taught to me by Dr. Chitkara at the Palo Alto VA Health Care System, one that sticks is the difference between density-dependent and viscosity-dependent airflow.  He often used the chronic bronchitic suffering through the viscous, humid New York City summers as a teaching example.  The importance [… read more]

Dec 012016
 
ICU Physiology in 1000 Words: The Folly of Pulmonary Vascular Resistance

By Jon-Emile S. Kenny [@heart_lung] When interpreting hemodynamic studies of drugs which – potentially – alter the resistance of the pulmonary vascular tree, we often turn to the calculated pulmonary vascular resistance [cPVR] as our guide.  For instance, a vasopressor determined to increase the cPVR is wholly avoided in a patient with pulmonary arterial hypertension.  We [… read more]

Jul 072016
 
The Revised Starling Principle: Implications for Rational Fluid Therapy

Jon-Emile S. Kenny [@heart_lung] “Doctrine once sown strikes deep its root, and respect for antiquity influences all men.” -William Harvey [1628] The use of hyperoncotic albumin to draw fluid from the interstitial space permeates dark corners of the critical care community.  The ‘pull and push’ of 25% albumin followed by furosemide remains somewhat of a [… read more]