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] “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]
In a new randomized trial, use of dexmedetomidine (Precedex) as the primary sedative in mechanically ventilated patients in the ICU resulted in no reduction in 90 day mortality. Dexmedetomidine resulted in a small improvement in delirium and ventilator days, but was almost never adequate to sedate patients on its own, and brought a small increase [… read more]
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]
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]
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]
A randomized trial confirmed what most intensivists have long believed and practiced: in the moments before endotracheal intubation, we should help patients achieve the highest arterial oxygen saturation possible, using bag-mask ventilation (BMV). This seems self evident — why wouldn’t we? Bag-mask ventilation can distend the stomach with air, potentially increasing the risk for vomiting [… read more]
Proton pump inhibitors (PPIs) are widely prescribed to mechanically ventilated patients to prevent gastrointestinal (GI) bleeding. The evidence for their use is not strong; individual randomized trials have not shown a clear benefit over histamine blockers, but when many trials were pooled into meta-analyses, PPIs do appear to be superior. The Surviving Sepsis Guidelines have [… read more]
Most families have never suffered through a loved one experiencing prolonged critical illness and respiratory failure (defined as ventilator dependence for weeks, usually with a tracheostomy). But each year, more do. An estimated 400,000 people currently live with chronic critical illness in long-term acute care hospitals (LTACHs) and other facilities — a population that has [… read more]
More than 60% of patients receiving mechanical ventilation have continued to receive daily chest x-rays since the publication of guidelines recommending against the practice. The findings came from a database review of hundreds of thousands of patients and were published in JAMA Network Open. The American College of Radiology once recommended daily chest films in [… read more]
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]
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]
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]
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]
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]
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]
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]
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