Prone Positioning of Patients during Venovenous Extracorporeal Membrane Oxygenation

Invasive mechanical ventilation in patients with acute respiratory distress syndrome receiving extracorporeal support: a narrative review of strategies to mitigate lung injury

Veno-venous extracorporeal membrane oxygenation is indicated in patients with acute respiratory distress syndrome and severely impaired gas exchange despite evidence-based lung protective ventilation, prone positioning and other parts of the standard algorithm for treating such patients. Extracorporeal support can facilitate ultra-lung-protective ventilation, meaning even lower volumes and pressures than standard lung-protective ventilation, by directly removing carbon dioxide in patients needing injurious ventilator settings to maintain sufficient gas exchange. Injurious ventilation results in ventilator-induced lung injury, which is one of the main determinants of mortality in acute respiratory distress syndrome. Marked reductions in the intensity of ventilation to the lowest tolerable levels under extracorporeal support may be achieved and could thereby potentially mitigate ventilator-induced lung injury and theoretically patient self-inflicted lung injury in spontaneously breathing patients with high respiratory drive. However, the benefits of this strategy may be counterbalanced by the use of continuous deep sedation and even neuromuscular blocking drugs, which may impair physical rehabilitation and impact long-term outcomes. There are currently a lack of large-scale prospective data to inform optimal invasive ventilation practices and how to best apply a holistic approach to patients receiving veno-venous extracorporeal membrane oxygenation, while minimising ventilator-induced and patient self-inflicted lung injury. We aimed to review the literature relating to invasive ventilation strategies in patients with acute respiratory distress syndrome receiving extracorporeal support and discuss personalised ventilation approaches and the potential role of adjunctive therapies in facilitating lung protection.

Effects of Prone Positioning on Respiratory Mechanics and Oxygenation in Critically Ill Patients With COVID-19 Requiring Venovenous Extracorporeal Membrane Oxygenation

Background:

The effect of prone positioning (PP) on respiratory mechanics remains uncertain in patients with severe acute respiratory distress syndrome (ARDS) requiring venovenous extracorporeal membrane oxygenation (VV-ECMO).

Methods:

We prospectively analyzed the effects of PP on respiratory mechanics from continuous data with over a thousand time points during 16-h PP sessions in patients with COVID-19 and ARDS under VV-ECMO conditions. The evolution of respiratory mechanical and oxygenation parameters during the PP sessions was evaluated by dividing each PP session into four time quartiles: first quartile: 0–4 h, second quartile: 4–8 h, third quartile: 8–12 h, and fourth quartile: 12–16 h.

Results:

Overall, 38 PP sessions were performed in 10 patients, with 3 [2–5] PP sessions per patient. Seven (70%) patients were responders to at least one PP session. PP significantly increased the PaO₂/FiO₂ ratio by 14 ± 21% and compliance by 8 ± 15%, and significantly decreased the oxygenation index by 13 ± 18% and driving pressure by 8 ± 12%. The effects of PP on respiratory mechanics but not on oxygenation persisted after supine repositioning. PP-induced changes in different respiratory mechanical parameters and oxygenation started as early as the first-time quartile, without any difference in PP-induced changes among the different time quartiles. PP-induced changes in driving pressure (−14 ± 14 vs. −6 ± 10%, p = 0.04) and mechanical power (−11 ± 13 vs. −0.1 ± 12%, p = 0.02) were significantly higher in responders (increase in PaO₂/FiO₂ ratio > 20%) than in non-responder patients.

Conclusions:

In patients with COVID-19 and severe ARDS, PP under VV-ECMO conditions improved the respiratory mechanical and oxygenation parameters, and the effects of PP on respiratory mechanics persisted after supine repositioning.

Extracorporeal membrane oxygenation and rehabilitation in patients with COVID-19: A scoping review

Background and purpose

The coronavirus diseases 2019 (COVID‐19) pandemic posed severe difficulties in managing critically ill patients in hospital care settings. Extracorporeal membrane oxygenation (ECMO) support has been proven to be lifesaving support during the SARS‐CoV‐2 outbreak. The purpose of this review was to describe the rehabilitative treatments provided to patients undergoing ECMO support during the COVID‐19 pandemic.

Methods

We searched PubMed and Scopus for English‐language studies published from the databases’ inception until June 30, 2021. We excluded editorials, letters to the editor, and studies that did not describe rehabilitative procedures during ECMO support. We also excluded those articles not written in English.

Results

A total of 50 articles were identified. We ultimately included nine studies, seven of which were case reports. Only two studies had more than one patient; an observational design analyzing the clinical course of 19 patients and a case series of three patients. Extracorporeal support duration varied from 9 to 49 days, and the primary indication was acute respiratory distress syndrome COVID‐19‐related. Rehabilitative treatment mainly consisted of in‐bed mobilization, postural transfers (including sitting), and respiratory exercises. After hospital discharge, patients were referred to rehabilitation facilities. Physiotherapeutic interventions provided during ECMO support and after its discontinuation were feasible and safe.

Conclusion

The physiotherapeutic treatment of patients undergoing ECMO support includes several components and must be provided in a multidisciplinary context. The optimal approach depends on the patient’s status, including sedation, level of consciousness, ECMO configuration, types of cannulas, and cannulation site.

Narrative Review of Neurologic Complications in Adults on ECMO: Prevalence, Risks, Outcomes, and Prevention Strategies

Extracorporeal membrane oxygenation (ECMO), a life-saving technique for patients with severe respiratory and cardiac diseases, is being increasingly utilized worldwide, particularly during the coronavirus disease 2019(COVID-19) pandemic, and there has been a sharp increase in the implementation of ECMO. However, due to the presence of various complications, the survival rate of patients undergoing ECMO remains low. Among the complications, the neurologic morbidity significantly associated with venoarterial and venovenous ECMO has received increasing attention. Generally, failure to recognize neurologic injury in time is reportedly associated with poor outcomes in patients on ECMO. Currently, multimodal monitoring is increasingly utilized in patients with devastating neurologic injuries and has been advocated as an important approach for early diagnosis. Here, we highlight the prevalence and outcomes, risk factors, current monitoring technologies, prevention, and treatment of neurologic complications in adult patients on ECMO. We believe that an improved understanding of neurologic complications presumably offers promising therapeutic solutions to prevent and treat neurologic morbidity.

Prone positioning during venovenous extracorporeal membrane oxygenation for acute respiratory distress syndrome: a systematic review and meta-analysis

BACKGROUND

Prone positioning (PP) improves oxygenation and respiratory mechanics and is associated with lower mortality in patients with moderate to severe acute respiratory distress syndrome (ARDS). Despite this, some patients develop refractory hypoxemia and hypercapnia requiring venovenous extracorporeal membrane oxygenation (VV ECMO) support and are usually cared for in supine position. The physiologic and outcome benefits of routine PP of patients during VV ECMO remains unclear. Hence, we conducted the systematic review and meta-analysis to evaluate the outcome benefits of PP for patients with ARDS being treated with VV ECMO.

METHODS

After registration with PROSPERO (CRD42020199723), MEDLINE, EMBASE, Scopus and Cochrane databases were searched for relevant studies that reported PP in more than 10 adult patients supported with VV ECMO from origin to 1 March 2021. Studies were reviewed for quality using appropriate Joanna Briggs Institute (JBI) checklists, and certainty of evidence was assessed using the GRADE approach. The random-effects model (DerSimonian and Laird) was used. The primary outcome of interest was cumulative survival. Secondary outcomes were intensive care unit length of stay (ICU LOS) and ECMO duration. Changes in arterial blood gas (ABG) values, ventilator mechanics and complication rates were also studied.

RESULTS

Of 812 potentially relevant publications, 12 studies (640 patients) met our inclusion criteria. Due to overlapping study populations, 11 studies were included in the final meta-analysis. Cumulative survival in patients that underwent PP was 57% (95% CI 41.9-71.4, high certainty). Patients that underwent PP had longer ICU LOS (+ 14.5 days, 95% CI 3.4-25.7, p = 0.01) and ECMO duration (+ 9.6 days, 95% CI 5.5-13.7, p < 0.0001). After PP, patients had significantly higher PaO2/FiO2 ratio, lower PaCO2 and reduced ventilator driving pressure, and no major complications were reported.

CONCLUSIONS

PP during VV ECMO appears safe with a cumulative survival of 57% and may result in longer ECMO runs and ICU LOS. However, evidence from appropriately designed randomized trials is needed prior to widespread adoption of PP on VV ECMO.