Cardiovascular medicine and surgery
Evolution of ECMO as a result of COVID
A year and a half ago, the enormity of this pandemic was only beginning to be realized. Likewise, we have never before been so well-equipped to communicate, investigate, and collaborate through modern innovations. Despite our monumental progress with diagnostics and expedited vaccine production, there remain significant challenges with management of infected individuals suffering from severe sequelae after infection such as respiratory failure. Pharmacologic therapies with steroids, antivirals, and targeted immune modulators have demonstrated modest results at best thus far.
Early intubation unsurprisingly resulted in poor outcomes and a return to other established methods using high-flow nasal cannula and noninvasive positive-pressure ventilation (NIPPV) with a goal of avoiding mechanical ventilation are again the standard of care (Rola P, et al. Clin Exp Emerg Med. 2020 Jun 10. doi: 10.15441/ceem.20.043). Furthermore, limited resources encouraged utilization of established and probably previously underutilized techniques, such as proning with expected improvements in outcomes.
When conventional lung protective mechanical ventilation strategies have been unsuccessful, we have seen improved survival with the incorporation of extracorporeal membrane oxygenation (ECMO), especially when cannulated earlier (Giraud R, et al. 2021. Phys Rep). Many centers now offer ECMO support with considerable expertise and trends toward earlier ECMO cannulation, which permit ultraprotective lung ventilation (Schmidt M, et al. Am J Respir Crit Care Med. 2019 Oct 15;200[8]:1002-12). With benefits that parallel early tracheostomy, early ECMO may permit decreased sedation and earlier mobilization, which contribute to improved outcomes (Levin NM, et al. J Clin Med. 2021 Jan 12;10[2]:25). We may be approaching a paradigm shift where ECMO is performed in lieu of mechanical ventilation (Kurihara C, et al. 2018. Crit Care Med. 2018 Nov;46[11]:e1070-e1073). Future randomized clinical trials will need to be designed to answer this question.
Robert Baeten, II, DSc, PA-C, FCCP
NetWork Steering Committee Member
Chest infections
COVID-19-associated pulmonary aspergillosis: A cause for concern?
Since the global spread of SARS-CoV-2 more than a year ago, reports of secondary infections with Aspergillus spp. have emerged. Like influenza, there has been speculation that severe COVID-19 pneumonia is a unique risk factor for invasive pulmonary aspergillosis (IPA). This entity has been dubbed CAPA, or COVID-associated pulmonary aspergillosis. While the reported incidence of CAPA has ranged from around 5% to 35% in critically ill patients, it has been difficult to distinguish reports of colonization from true infection as histopathologic evidence of disease has been limited. Using stringent diagnostic criteria, a retrospective review of 145 mechanically ventilated patients with COVID-19 found the incidence of CAPA to be 4.8% (Fekkar A, et al. Am J Respir Crit Care Med. 2021 Feb 1;203[3]:307-17) which is similar to other non-COVID ARDS series. The authors found solid organ transplant and prolonged steroid treatment to be risk factors. Like other studies, no comparator group was utilized, limiting the conclusions regarding COVID-19 as an independent risk factor for IPA. Diagnostic criteria have been adapted to assist clinicians and allow for future research: Proven infection requires temporal relation with COVID-19 ICU admission and histopathologic evidence of Aspergillus spp. invasion or positive culture from sterile sites (Koehler P, et al. Lancet Infect Dis. 2020 Dec 14;S1473-3099[20]30847-1).