Use of Carboxyhemoglobin as an Early Sign of Oxygenator Dysfunction in Patients Supported by Extracorporeal Membrane Oxygenation.

Introduction: Plasma free hemoglobin is the gold standard for monitoring hemolysis in extracorporeal membrane oxygenation (ECMO) but its routine use has some limitations. Carboxyhemoglobin (HbCO) is also a marker of intravascular hemolysis. We aimed to investigate HbCO as a marker of both hemolysis and oxygenator dysfunction in patients supported by ECMO. Methods: Retrospective analysis of patients on ECMO in an adult ICU in a tertiary hospital. HbCO was recorded every 6 h in the 48 h before and after oxygenator change in adult patients on ECMO support with an oxygenator dysfunction and replacement. Results: The investigation of 27 oxygenators replacements in 19 patients demonstrated that HbCO values progressively increased over time and then significantly decreased after oxygenator change. Median oxygenator lifespan was 14 days [interquartile range (IQR) 8-21] and there was no correlation between HbCO and oxygenator lifespan [Spearman coefficient 0.23 (p = 0.23)]. HbCO values at oxygenator change [HbCO median 2.7 (IQR 2.5-3.5)] were significantly higher than the HbCO values 1 week before [HbCO median 2.07 (IQR 1.86-2.8)] (p value < 0.001). Conclusion: Our data highlight the potential role of HbCO as a novel marker for ECMO oxygenator dysfunction.

A Dedicated Expert ECMO-Team and Strict Patient Selection Improve Survival of Patients with Severe SARS-CoV-2 ARDS Supported by VV-ECMO.

The SARS-CoV-2 pandemic has overwhelmed health care systems worldwide since its first wave. Intensive care units have been under a significant amount of pressure as patients with the most severe form of the disease presented with acute respiratory distress syndrome (ARDS). A proportion of them experienced refractory acute respiratory failure and had to be supported with veno-venous extracorporeal membrane oxygenation (VV-ECMO). The present retrospective study reports the experiences of our ECMO center in the management of COVID-19 patients with refractory ARDS. Patient characteristics and outcomes are presented through the different waves of the pandemic. A cohort study was conducted on patients with refractory ARDS due to COVID-19 infection who were admitted to the intensive care unit (ICU) at the Geneva University Hospital and supported with VV-ECMO between 14 March 2020 and January 2022. The VV-ECMO implementation criteria were defined according to an institutional algorithm validated by the local crisis unit of the hospital and the Swiss Society of Intensive Care Medicine. Among the 500 ARDS patients admitted to our ICU, 41 patients with a median age of 57 (52−63) years, a body mass index (BMI) of 28 (26−32) kg/m2, and a SAPS II score of 57 (47−67), and 27 (66%) of whom were men required VV-ECMO. None of the patients were vaccinated. The time of ventilation, including noninvasive ventilation (NIV) and mechanical ventilation (MV), and the time of MV before ECMO were 7 (4−11) days and 4 (1−7) days, respectively. The time under ECMO was 20 (10−27) days. The ICU and hospital lengths of stay were 36 (21−45) days and 45 (33−69) days, respectively. The survival rate for patients on ECMO was 59%. Comparative analysis between survivors and non-survivors highlighted that survivors had a significantly shorter ventilation duration before ECMO (NIV + MV: 5.5 (1.3−9) vs. 9 (6.5−13.5) days, p = 0.0026 and MV alone: 1.6 (0.4−5.5) vs. 5.8 (5−8) days, p < 0.0001). The management of patients on ECMO by an experienced ECMO team dedicated to this activity was associated with improved survival (78% vs. 28%, p = 0.0012). Between the first wave and the following waves, patients presented with a higher incidence of ventilator-associated pneumonia (100% vs. 82%, p = 0.0325) but had better survival rates (74% vs. 35%, p = 0.024). The present study suggests that both the prompt insertion of VV-ECMO to control refractory hypoxemia and the involvement of an ECMO team improve the survival of COVID-19 patients.

Extracorporeal membrane oxygenation in COVID-19 associated acute respiratory distress syndrome: A narrative review.

Venovenous extracorporeal membrane oxygenation (VV-ECMO) is an established rescue therapy in the management of refractory acute respiratory distress syndrome (ARDS). Although ECMO played an important role in previous respiratory viral epidemics, concerns about the benefits and usefulness of this technique were raised during the coronavirus disease 2019 (COVID-19) pandemic. Indeed, the mortality rate initially reported in small case series from China was concerning and exceeded 90%. A few months later, the critical care community published the findings from several observational cohorts on the use of extracorporeal membrane oxygenation (ECMO) in COVID-19-related ARDS. Contrary to the preliminary results, data from the first surge supported the use of ECMO in experienced centers because the mortality rate was comparable to those from the ECMO to Rescue Lung Injury in Severe ARDS (EOLIA) trial or other large prospective studies. However, the mortality rate of the population with severe disease evolved during the pandemic, in conjunction with changes in the management of the disease and the occurrence of new variants. The results from subsequent studies confirmed that the outcomes mainly depend on strict patient selection and center expertise. In comparison with non-COVID-related ARDS, the duration of ECMO for COVID-related ARDS was longer and increased over time. Clinicians and decision-makers must integrate this finding in the ECMO decision-making process to plan their ICU capacity and resource allocation. This narrative review summarizes the current evidence and specific considerations for ECMO use in COVID-19-associated ARDS.

Unsupervised clustering reveals phenotypes of AKI in ICU COVID-19 patients.

Background: Acute Kidney Injury (AKI) is a very frequent condition, occurring in about one in three patients admitted to an intensive care unit (ICU). AKI is a syndrome defined as a sudden decrease in glomerular filtration rate. However, this unified definition does not reflect the various mechanisms involved in AKI pathophysiology, each with its own characteristics and sensitivity to therapy. In this study, we aimed at developing an innovative machine learning based method able to subphenotype AKI according to its pattern of risk factors. Methods: We adopted a three-step pipeline of analyses. First, we looked for factors associated with AKI using a generalized additive model. Second, we calculated the importance of each identified AKI related factor in the estimated AKI risk to find the main risk factor for AKI, at the single patient level. Lastly, we clusterized AKI patients according to their profile of risk factors and compared the clinical characteristics and outcome of every cluster. We applied this method to a cohort of severe COVID-19 patients hospitalized in the ICU of the Geneva University Hospitals. Results: Among the 248 patients analyzed, we found 7 factors associated with AKI development. Using the individual expression of these factors, we identified three groups of AKI patients, based on the use of Lopinavir/Ritonavir, baseline eGFR, use of dexamethasone and AKI severity. The three clusters expressed distinct characteristics in terms of AKI severity and recovery, metabolic patterns and hospital mortality. Conclusion: We propose here a new method to phenotype AKI patients according to their most important individual risk factors for AKI development. When applied to an ICU cohort of COVID-19 patients, we were able to differentiate three groups of patients. Each expressed specific AKI characteristics and outcomes, which probably reflect a distinct pathophysiology.

Unsupervised clustering reveals phenotypes of AKI in ICU COVID-19 patients

Background Acute Kidney Injury (AKI) is a very frequent condition, occurring in about one in three patients admitted to an intensive care unit (ICU). AKI is a syndrome defined as a sudden decrease in glomerular filtration rate. However, this unified definition does not reflect the various mechanisms involved in AKI pathophysiology, each with its own characteristics and sensitivity to therapy. In this study, we aimed at developing an innovative machine learning based method able to subphenotype AKI according to its pattern of risk factors. Methods We adopted a three-step pipeline of analyses. First, we looked for factors associated with AKI using a generalized additive model. Second, we calculated the importance of each identified AKI related factor in the estimated AKI risk to find the main risk factor for AKI, at the single patient level. Lastly, we clusterized AKI patients according to their profile of risk factors and compared the clinical characteristics and outcome of every cluster. We applied this method to a cohort of severe COVID-19 patients hospitalized in the ICU of the Geneva University Hospitals. Results Among the 248 patients analyzed, we found 7 factors associated with AKI development. Using the individual expression of these factors, we identified three groups of AKI patients, based on the use of Lopinavir/Ritonavir, baseline eGFR, use of dexamethasone and AKI severity. The three clusters expressed distinct characteristics in terms of AKI severity and recovery, metabolic patterns and hospital mortality. Conclusion We propose here a new method to phenotype AKI patients according to their most important individual risk factors for AKI development. When applied to an ICU cohort of COVID-19 patients, we were able to differentiate three groups of patients. Each expressed specific AKI characteristics and outcomes, which probably reflect a distinct pathophysiology.

Updates in the management of respiratory virus infections in ICU patients: revisiting the non-SARS-CoV-2 pathogens.

INTRODUCTION: Although viruses are an underestimated cause of community-acquired pneumonias (CAP) and hospital-acquired pneumonias (HAP)/ventilator-associated pneumonias (VAP) in intensive care unit (ICU) patients, they have an impact on morbidity and mortality. AREAS COVERED: In this perspective article, we discuss the available data regarding the management of severe influenza CAP and herpesviridae HAP/VAP. We review diagnostic and therapeutic strategies in order to give clear messages and address unsolved questions. EXPERT OPINION: Influenza CAP affects yearly thousands of people; however, robust data regarding antiviral treatment in the most critical forms are scarce. While efficacy of oseltamivir has been investigated in randomized controlled trials (RCT) in uncomplicated influenza, only observational data are available in ICU patients. Herpesviridae are an underestimated cause of HAP/VAP in ICU patients. Whilst incidence of herpesviridae identification in samples from lower respiratory tract of ICU patients is relatively high (from 20% to 50%), efforts should be made to differentiate local reactivation from true lung infection. Only few randomized controlled trials evaluated the efficacy of antiviral treatment in herpesviridae reactivation/infection in ICU patients and all were exploratory or negative. Further studies are needed to evaluate the impact of such treatment in specific populations.

Extracorporeal membrane oxygenation in COVID-19 associated acute respiratory distress syndrome: A narrative review

Venovenous extracorporeal membrane oxygenation (VV-ECMO) is an established rescue therapy in the management of refractory acute respiratory distress syndrome (ARDS). Although ECMO played an important role in previous respiratory viral epidemics, concerns about the benefits and usefulness of this technique were raised during the coronavirus disease 2019 (COVID-19) pandemic. Indeed, the mortality rate initially reported in small case series from China was concerning and exceeded 90%. A few months later, the critical care community published the findings from several observational cohorts on the use of extracorporeal membrane oxygenation (ECMO) in COVID-19-related ARDS. Contrary to the preliminary results, data from the first surge supported the use of ECMO in experienced centers because the mortality rate was comparable to those from the ECMO to Rescue Lung Injury in Severe ARDS (EOLIA) trial or other large prospective studies. However, the mortality rate of the population with severe disease evolved during the pandemic, in conjunction with changes in the management of the disease and the occurrence of new variants. The results from subsequent studies confirmed that the outcomes mainly depend on strict patient selection and center expertise. In comparison with non-COVID-related ARDS, the duration of ECMO for COVID-related ARDS was longer and increased over time. Clinicians and decision-makers must integrate this finding in the ECMO decision-making process to plan their ICU capacity and resource allocation. This narrative review summarizes the current evidence and specific considerations for ECMO use in COVID-19-associated ARDS.

Use of Carboxyhemoglobin as an Early Sign of Oxygenator Dysfunction in Patients Supported by Extracorporeal Membrane Oxygenation

Introduction Plasma free hemoglobin is the gold standard for monitoring hemolysis in extracorporeal membrane oxygenation (ECMO) but its routine use has some limitations. Carboxyhemoglobin (HbCO) is also a marker of intravascular hemolysis. We aimed to investigate HbCO as a marker of both hemolysis and oxygenator dysfunction in patients supported by ECMO. Methods Retrospective analysis of patients on ECMO in an adult ICU in a tertiary hospital. HbCO was recorded every 6 h in the 48 h before and after oxygenator change in adult patients on ECMO support with an oxygenator dysfunction and replacement. Results The investigation of 27 oxygenators replacements in 19 patients demonstrated that HbCO values progressively increased over time and then significantly decreased after oxygenator change. Median oxygenator lifespan was 14 days [interquartile range (IQR) 8–21] and there was no correlation between HbCO and oxygenator lifespan [Spearman coefficient 0.23 (p = 0.23)]. HbCO values at oxygenator change [HbCO median 2.7 (IQR 2.5–3.5)] were significantly higher than the HbCO values 1 week before [HbCO median 2.07 (IQR 1.86–2.8)] (p value < 0.001). Conclusion Our data highlight the potential role of HbCO as a novel marker for ECMO oxygenator dysfunction.

Decreased CRRT Filter Lifespan in COVID-19 ICU Patients.

(1) Background: Increased thromboembolic events and an increased need for continuous renal replacement therapy (CRRT) have been frequently reported in COVID-19 patients. Our aim was to investigate CRRT filter lifespan in intensive care unit (ICU) COVID-19 patients. (2) Methods: We compared CRRT adjusted circuit lifespan in COVID-19 patients admitted for SARS-CoV-2 infection to a control group of patients admitted for septic shock of pulmonary origin other than COVID-19. Both groups underwent at least one session of CRRT for AKI. (3) Results: Twenty-six patients (13 in each group) were included. We analysed 117 CRRT circuits (80 in the COVID-19 group and 37 in the control group). The adjusted filter lifespan was shorter in the COVID-19 group (17 vs. 39 h, p < 0.001). This trend persisted after adjustment for confounding factors (-14 h, p = 0.037). Before CRRT circuit clotting, the COVID-19 group had a more procoagulant profile despite higher heparin infusion rates. Furthermore, we reported a decreased relation between activated partial thromboplastin time (aPTT) and cumulative heparin dose in COVID-19 patients when compared to historical data of 23,058 patients, suggesting a heparin resistance. (4) Conclusion: COVID-19 patients displayed a shorter CRRT filter lifespan that could be related to a procoagulant profile and heparin resistance.

Mortality and high risk of major adverse events in patients with COVID-19 and history of cardiovascular disease.

OBJECTIVE: History of cardiovascular diseases (CVDs) may influence the prognosis of patients hospitalised for COVID-19. We investigated whether patients with previous CVD have increased risk of death and major adverse cardiovascular event (MACE) when hospitalised for COVID-19. METHODS: We included 839 patients with COVID-19 hospitalised at the University Hospitals of Geneva. Demographic characteristics, medical history, laboratory values, ECG at admission and medications at admission were collected based on electronic medical records. The primary outcome was a composite of in-hospital mortality or MACE. RESULTS: Median age was 67 years, 453 (54%) were males and 277 (33%) had history of CVD. In total, 152 (18%) died and 687 (82%) were discharged, including 72 (9%) who survived a MACE. Patients with previous CVD were more at risk of composite outcomes 141/277 (51%) compared with those without CVD 83/562 (15%) (OR=6.0 (95% CI 4.3 to 8.4), p<0.001). Multivariate analyses showed that history of CVD remained an independent risk factor of in-hospital death or MACE (OR=2.4; (95% CI 1.6 to 3.5)), as did age (OR for a 10-year increase=2.2 (95% CI 1.9 to 2.6)), male gender (OR=1.6 (95% CI 1.1 to 2.3)), chronic obstructive pulmonary disease (OR=2.1 (95% CI 1.0 to 4.2)) and lung infiltration associated with COVID-19 at CT scan (OR=1.9 (95% CI 1.2 to 3.0)). History of CVD (OR=2.9 (95% CI 1.7 to 5)), age (OR=2.5 (95% CI 2.0 to 3.2)), male gender (OR=1.6 (95% CI 0.98 to 2.6)) and elevated C reactive protein (CRP) levels on admission (OR for a 10 mg/L increase=1.1 (95% CI 1.1 to 1.2)) were independent risk factors for mortality. CONCLUSION: History of CVD is associated with higher in-hospital mortality and MACE in hospitalised patients with COVID-19. Other factors associated with higher in-hospital mortality are older age, male sex and elevated CRP on admission.

Timing of VV-ECMO therapy implementation influences prognosis of COVID-19 patients.

INTRODUCTION: Current knowledge on the use of extracorporeal membrane oxygenation (ECMO) in COVID-19 remains limited to small series and registry data. In the present retrospective monocentric study, we report on our experience, our basic principles, and our results in establishing and managing ECMO in critically ill COVID-19 patients. METHODS: A cohort study was conducted in patients with severe acute respiratory distress syndrome (ARDS) related to COVID-19 pneumonia admitted to the ICU of the Geneva University Hospitals and supported by VV-ECMO from March 14 to May 31. The VV-ECMO implementation criteria were defined according to an institutional algorithm validated by the local crisis unit and the Swiss Society of Intensive Care Medicine. RESULTS: Out of 137 ARDS patients admitted to our ICU, 10 patients (age 57 ± 4 years, BMI 31.5 ± 5 kg/m2 , and SAPS II score 56 ± 3) were put on VV-ECMO. The mean duration of mechanical ventilation before ECMO and mean time under ECMO were 7 ± 3 days and 19 ± 11 days, respectively. The ICU and hospital length of stay were 26 ± 11 and 35 ± 10 days, respectively. The survival rate for patients on ECMO was 40%. The comparative analysis between survivors and non-survivors highlighted that survivors had a significantly shorter mechanical ventilation duration before ECMO (4 ± 2 days vs. 9 ± 2 days, p = 0.01). All the patients who had more than 150 h of mechanical ventilation before the application of ECMO ultimately died. CONCLUSION: The present results suggest that VV-ECMO can be safely utilized in appropriately selected COVID-19 patients with refractory hypoxemia. The main information for clinicians is that late VV-ECMO therapy (i.e., beyond the seventh day of mechanical ventilation) seems futile.

Extremely high-dose insulin requirement in a diabetic patient with COVID-19: a case report.

BACKGROUND: Detailed description of hyperglycemia management in diabetic patients infected with SARS-CoV-2 remain limited, although patients with diabetes show higher complication and mortality rate than patients without diabetes. Transient non-severe increased insulin requirement in patients hospitalized for medical conditions such as sepsis or myocardial infarction is a well-known phenomenon. However, extremely high-dose insulin requirement remains a very rarely reported entity. Here, we report the case of an extreme and transitory insulin requirement episode in a type 2 diabetic patient presenting an acute respiratory distress syndrome caused by SARS-CoV-2. CASE PRESENTATION: A 57-year-old man resident in Geneva, Switzerland, previously known for type 2 diabetes for 3 years was admitted for an aggravation of his dyspnea. His type 2 diabetes was treated only with metformin and his latest Hb1Ac was 6.1%. Chest CT SCAN showed a bilateral multilobar ground-glass opacification. Twenty-four hours after his admission he presented a worsening of dyspnea and severe hypoxemia requiring a transfer to the intensive care unit rapidly followed by oro-tracheal intubation for mechanical ventilation support. A bronchoalveolar lavage was performed and test of SARS-CoV-2 by RT-qPCR assay was positive. At day 3, he presented a rapidly progressive insulin requirement at a rate of up to 50 units/hour intravenous insulin aspart. Despite the high insulin doses, he maintained an elevated plasma glucose level at 270 mg/dL on average. His extremely high-dose insulin requirement "resolved" at day 9, and the insulin infusion rate was rapidly reduced. CONCLUSIONS: This case may reflect a specific and profound impact of SARS-CoV-2 on metabolic homeostasis, in particular in diabetic patients that appear more prone to complications of COVID-19 infection. Yet, the mechanisms behind this remain to be elucidated. The optimal management of hyperglycemia of diabetic patients infected with SARS-CoV-2 has yet not be defined, however insulin remain the mainstay of treatment approach. Report of extreme dysregulation of chronic conditions such as diabetes in patients with COVID-19 may help clinicians to better take care of patients during the pandemic of SARS-CoV-2. To the best of our knowledge this is the first description of extremely high-dose insulin requirement in patient with COVID-19.

COVID-19 infection and treatment with hydroxychloroquine cause severe haemolysis crisis in a patient with glucose-6-phosphate dehydrogenase deficiency.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an inherited genetic disorder caused by red cell enzymatic defects and is associated with haemolytic crisis when patients are exposed to oxidative agents (fava beans, drugs, infections). Hydroxychloroquine is suspected to trigger haemolytic crisis in G6PD-deficient patients, and off-label administration of this drug to patients infected with the novel coronavirus (SARS-CoV-2) could cause concern. We report here the first case of severe haemolytic crisis in a patient with G6PD deficiency, initiated by severe COVID-19 infection and hydroxychloroquine use. With worldwide spread of COVID-19, especially in regions with a high prevalence of G6PD deficiency, our case should alert physicians to this possible correlation.