Mechanical Ventilation

Oct 042018
 
Targeting normal oxygen saturation associated with death: meta-analysis

A new meta-analysis adds to the evidence that liberal use of supplemental oxygen may be harmful in acutely ill, hospitalized patients. Authors performed a meta-analysis of 25 randomized trials of acutely ill patients (total n ~ 16,000) treated with strategies of either “low” or “high” supplemental oxygenation. Although the cutoffs varied between studies, patients receiving [… 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]

Aug 032018
 
Scheduled nebulization with acetylcysteine didn't help ventilated patients

by Salynn Boyles, Contributing Writer, MedPage Today Regular nebulization proved to be no more effective than nebulization on demand in a randomized trial involving critically ill patients receiving invasive ventilation, researchers reported. Among ICU patients expected to need invasive ventilation for at least 24 hours, scheduled nebulization four times a day involving acetylcysteine with salbutamol did not [… read more]

Jul 202018
 
Prophylactic Precedex prevented delirium in ICU patients

Quick Take: This small (n=100), two-center, industry-funded (Hospira) study showed a remarkable 80% prevention rate of ICU delirium (compared to 20% with placebo) with patients given dexmedetomidine prophylactically during their ICU stay. Although associated with poor outcomes in critically ill patients, delirium is not known to be an independent predictor of those outcomes. This small [… read more]

Jun 132018
 
Bougies for all intubations led to high success rates, even on difficult airways

Bougies are long, stiff plastic wands inserted into the trachea through the glottis during direct laryngoscopy (DL), providing a “guidewire” over which an endotracheal (ET) tube can then be more easily advanced into the trachea. Bougies have traditionally been used after one or more failed intubation attempts with direct laryngoscopy, at which point the airway [… 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]

Mar 022018
 
Corticosteroids do help in sepsis: ADRENAL trial

Stress-dose corticosteroids appear safe and generally beneficial in patients with septic shock undergoing mechanical ventilation, without improving survival. That’s the takeaway from the ADRENAL trial recently published in the New England Journal of Medicine. Investigators (led by the famed ANZICS collaborative) randomized 3,800 patients with septic shock requiring mechanical ventilation in 69 medical-surgical ICUs around the [… 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 142017
 
Sedation interruptions were even more helpful in surgical patients

Most good medical intensive care units have incorporated interruptions in sedation (so-called ‘sedation vacations’) into standard care for patients receiving mechanical ventilation. Avoiding excessive sedation in general is believed to reduce prolonged mechanical ventilation in ICUs. However, there is surprisingly little data about effects of sedation (or over-sedation) on critically ill postoperative patients in 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]

Oct 202017
 
Pain Control and Sedation in Mechanically Ventilated Patients: Review

Treating Pain in Mechanically Ventilated Patients Adult patients in the intensive care unit (ICU) frequently experience pain, resulting from acute and chronic illness as well the positioning and interventions standard to ICU care.1,2 Besides being ethical and humane, adequately treating pain prevents agitation and delirium in mechanically ventilated patients. There are also many physiologic responses to [… read more]

Oct 192017
 
ICU Physiology in 1000 Words: Fighter Pilots!

Jon-Emile S. Kenny MD [@heart_lung] with illustrations by Carla M. Canepa MD Pilots of high-performance, tactical fighter jets each have continuous positive airway pressure [i.e. CPAP] masks as a part of their flight suit.  Strikingly, beyond the clinically-commonplace airway pressure of 5-15 cm of H2O, a fighter pilot may endure a mask-applied pressure of 90 [… 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]