2020 Year in Review: Mechanical Ventilation During the First Year of the COVID-19 Pandemic

Abstract

Corona virus disease 2019 represents the greatest medical crisis encountered in the young history of critical care and respiratory care. During the early months of the pandemic, when little was known about the virus, the acute hypoxemic respiratory failure it caused did not appear to fit conveniently or consistently into our classification of acute respiratory distress syndrome (ARDS). This not only reignited a half-century's long simmering debate over taxonomy, but also fueled similar debates over how PEEP and lung-protective ventilation should be titrated, as well as the appropriate role of non-invasive ventilation in ARDS. Furthermore, COVID-19 ignited other debates on emerging concepts such as ARDS phenotypes and patient self-inflicted lung injury from vigorous spontaneous breathing. Over a year later these early perplexities have receded into the background without having been reviewed or resolved.With a full year of evidence having been published this narrative review systematically analyzes whether or not COVID-19 associated respiratory failure is essentially ARDS, with perhaps a somewhat different course of presentation. This includes a review of the severity of hypoxemia and derangements in pulmonary mechanics, PEEP requirements, recruitment potential, the ability to achieve lung-protective ventilation goals, duration of mechanical ventilation, associated mortality, and response to non-invasive ventilation. It also reviews the concepts of ARDS phenotypes and patient self-inflicted lung injury as these are crucial to understanding the contentious debate over the nature and management of COVID-19.

Mechanical ventilation for COVID-19: Outcomes following discharge from inpatient treatment

“…However, these findings are novel because COVID-19 illness may not be entirely comparable to previous causes for ARDS. Firstly, there is controversy regarding the phenotypes underlying traditional ARDS and respiratory failure due to COVID-19 illness [19]. Secondly, the clinical presentation for respiratory failure in COVID-19 has been demonstrated to be more variable and non-uniform than what is traditionally seen in ARDS [19,64].…”

“…Firstly, there is controversy regarding the phenotypes underlying traditional ARDS and respiratory failure due to COVID-19 illness [19]. Secondly, the clinical presentation for respiratory failure in COVID-19 has been demonstrated to be more variable and non-uniform than what is traditionally seen in ARDS [19,64]. With these facts in mind, comparing outcomes following MV treatment for COVID-19 illness and non-COVID-19 ARDS is difficult.…”

“…studying the outcomes for this subset of COVID-19 patients is particularly important. Understanding the outcomes following MV treatment is especially important considering that the ventilation treatment guidelines for COVID-19 were slow to develop during the early stages of the pandemic and there were high levels of uncertainty and confusion in how MV should be implemented among patients hospitalized with COVID-19 [19,20].…”

The Impact of Different Ventilatory Strategies on Clinical Outcomes in Patients with COVID-19 Pneumonia

“…According to recent findings, the need for a specific ventilator approach could be guided by the identification of COVID-19 phenotypes (1 or L and 2 or H) [ 29 ], taking into account the risk of aerosol generator procedures, as well as the development of patient self-inflicted lung injury (P-SILI) [ 30 ]. In another perspective, preemptive intubation was proposed to avoid progressive acute respiratory failure [ 31 ]. Recent data confirmed that in patients receiving NIV, late intubation was associated with worse clinical presentation and more severe disease than early, suggesting that the delay in intubation might have an impact on patient’s outcome [ 7 ].…”

Respiratory Drive, Dyspnea, and Silent Hypoxemia: A Physiological Review in the Context of COVID-19

“…The majority of patients with COVID-19-associated acute respiratory failure has or eventually develops ARDS. 61 Elevated respiratory drive in ARDS is multifactorial, and it is impossible to gauge the specific contributions of any one sensory input. Common characteristics associated with ARDS include rapid shallow breathing and vigorous inspiratory effort.…”