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.

The Interplay of Inflammation and Coagulation in COVID-19 Patients Receiving Extracorporeal Membrane Oxygenation Support

Objective Bleeding and thrombosis are common complications during Extracorporeal Membrane Oxygenation (ECMO) support for COVID-19 patients. We sought to examine the relationship between inflammatory status, coagulation effects, and observed bleeding and thrombosis in patients receiving venovenous (VV) ECMO for COVID-19 respiratory failure. Study Design Cross-sectional cohort study Settings Quaternary care institution. Patients The study period from April 1, 2020, to January 1, 2021, we included all patients with confirmed COVID-19 who received VV ECMO support. Intervention None. Measurements and Main Results Thirty-two patients were supported with VV ECMO during the study period, and 17 patients (53%) survived to hospital discharge. The ECMO nonsurvivors mean lactate dehydrogenase (LDH) levels were markedly elevated in comparison to survivors (1046 u/L [IQR = 509, 1305] vs 489 u/L [385 658], p = 0.003). Platelet/fibrinogen dysfunction, as reflected by the low Maximum Amplitude (MA) on viscoelastic testing, was worse in nonsurvivors (65.25 mm [60.68, 67.67] vs 74.80 mm [73.10, 78.40], p = 0.01). Time-group interaction for the first seven days of ECMO support, showed significantly lower platelet count in the nonsurvivors (140 k/ul [103, 170] vs 189.5 k/ul [ 146, 315], p < 0.001) and higher D-dimer in (21 μg/mL [13, 21] vs 14 μg/mL [3, 21], p < 0.001) in comparison to the survivors. Finally, we found profound statistically significant correlations between the clinical markers of inflammation and markers of coagulation in the nonsurvivors group. The ECMO nonsurvivors experienced higher rate of bleeding (73.3% vs 35.3%, p = 0.03), digital ischemia (46.7% vs 11.8%, p = 0.02), acute renal failure (60% vs 11.8%, p = 0.01) and bloodstream infection (60% vs 23.5%, p = 0.03). Conclusion The correlation between inflammation and coagulation in the nonsurvivors supported with VV ECMO could indicate dysregulated inflammatory response and worse clinical outcomes.

Hybrid extracorporeal membrane oxygenation (ECMO) cannulation following traumatic pneumonectomy: A case report

A 28-year-old man presented in extremis after a motorcycle crash. Following traumatic pneumonectomy, he developed right heart failure and was placed on veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) only to transition to veno-arteriovenous (VAV) ECMO due to persistent hypoxemia. Resulting flow limitation caused distal ischemia of his left leg, requiring thrombectomy and fasciotomy. Potential loss of limb necessitated transitioning to veno-venous (VV) ECMO from which he was successfully decannulated thereafter. ECMO can bridge recovery following the most dire injuries, and hybrid strategies can ameliorate post-operative complications; however, ECMO itself carries significant risks that must be weighed against intended benefit.

The physiology of extracorporeal membrane oxygenation: The Fick principle

Extracorporeal membrane oxygenation (ECMO) can be delivered in veno-arterial (VA) and veno-venous (VV) configurations based on the cannulation strategy. VA and VV ECMO are delivered primarily for haemodynamic and respiratory support in patients with severe heart and lung failure, respectively. The Fick principle describes the relationship between blood flow and oxygen consumption – key parameters in the physiological management of extracorporeal support. This review will discuss the application of the Fick principle in: (i) recirculation in VV ECMO; (ii) the quantification of oxygen delivery (DO2) in VV ECMO and (iii) the quantification of transpulmonary blood flow and systemic arterial oxygen saturation in VA ECMO.

Multiple Secondary Healthcare-Associated Infections Due to Carbapenem-Resistant Organisms in a Critically Ill COVID-19 Patient on Extensively Prolonged Venovenous Extracorporeal Membrane Oxygenation Support—A Case Report

Patients with severe Coronavirus disease 2019 (COVID-19) are at high risk for secondary infection with multidrug-resistant organisms (MDROs). Secondary infections contribute to a more severe clinical course and longer intensive care unit (ICU) stays in patients with COVID-19. A man in his 60s was admitted to the ICU at a university hospital for severe COVID-19 pneumonia requiring mechanical ventilation. His respiratory condition worsened further due to persistent bacteremia caused by imipenem-non-susceptible Klebsiella aerogenes and he required VV-ECMO. Subsequently, he developed a catheter-related bloodstream infection (CRBSI) due to Candida albicans, ventilator-associated pneumonia (VAP) due to multidrug-resistant Pseudomonas aeruginosa (MDRP), and a perianal abscess due to carbapenem-resistant K. aerogenes despite infection control procedures that maximized contact precautions and the absence of MDRO contamination in the patient’s room environment. He was decannulated from VV-ECMO after a total of 72 days of ECMO support, and was eventually weaned off ventilator support and discharged from the ICU on day 138. This case highlights the challenges of preventing, diagnosing, and treating multidrug-resistant organisms and healthcare-associated infections (HAIs) in the critical care management of severe COVID-19. In addition to the stringent implementation of infection prevention measures, a high index of suspicion and a careful evaluation of HAIs are required in such patients.

Association of COVID-19 with Intracranial Hemorrhage during Extracorporeal Membrane Oxygenation for Acute Respiratory Distress Syndrome: A 10-Year Retrospective Observational Study

Extracorporeal membrane oxygenation (ECMO) is potentially lifesaving for patients with acute respiratory distress syndrome (ARDS) but may be accompanied by serious adverse events, including intracranial hemorrhage (ICRH). We hypothesized that ICRH occurs more frequently in patients with COVID-19 than in patients with ARDS of other etiologies. We performed a single-center retrospective analysis of adult patients treated with venovenous (vv-) ECMO for ARDS between January 2011 and April 2021. Patients were included if they had received a cranial computed tomography (cCT) scan during vv-ECMO support or within 72 h after ECMO removal. Cox regression analysis was used to identify factors associated with ICRH. During the study period, we identified 204 patients with vv-ECMO for ARDS, for whom a cCT scan was available. We observed ICRH in 35.4% (n = 17/48) of patients with COVID-19 and in 16.7% (n = 26/156) of patients with ARDS attributable to factors other than COVID-19. COVID-19 (HR: 2.945; 95%; CI: 1.079–8.038; p = 0.035) and carboxyhemoglobin (HR: 0.330; 95%; CI: 0.135–0.806; p = 0.015) were associated with ICRH during vv-ECMO. In patients receiving vv-ECMO, the incidence of ICRH is doubled in patients with COVID-19 compared to patients suffering from ARDS attributable to other causes. More studies on the association between COVID-19 and ICRH during vv-ECMO are urgently needed to identify risk patterns and targets for potential therapeutic interventions.

Characteristics of Venous-Venous Extracorporeal Membrane Oxygenation Related Bloodstream Infections

Infectious complications have been shown to increase the morbidity of venous-venous extracorporeal membrane oxygenation (VV-ECMO) population, including the use of right ventricular assist devices. We aimed to evaluate our VV-ECMO population for ECMO related bloodstream infections (E-BSI) and characteristics that affect risk and overall outcomes. We report a low infection rate of 2.7%. We postulate our low BSI rate may be due to our use of perioperative antimicrobials as well as a majority of our cannulations occurring in the operating room. Further investigation into trends, risks, and outcomes related to E-BSI is needed.