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.

Is the prognosis of non-hypertensive, COVID-19 patients treated with renin-angiotensin-aldosterone system inhibitors more uncertain?

Previous studies suggested that ongoing treatment with renin-angiotensin-aldosterone system (RAAS) inhibitor drugs may alter the course of SARS-CoV-2 infection and promote the development of more severe forms of the disease. The authors conducted a comparative, observational study to retrospectively analyze data collected from 394 patients admitted to ICU due to SARS-CoV-2 pneumonia. The primary aim of the study was to establish an association between the use of RAAS inhibitor drugs and mortality in the ICU. The secondary aims of the study were to establish an association between the use of RAAS inhibitor drugs and clinical severity at ICU admission, the need for tracheal intubation, total days of mechanical ventilation, and the ICU length of stay. The authors found no statistically significant difference in ICU mortality between patients on RAAS inhibitor drugs at admission and those who were not (31.3% versus 26.2% mortality, p-value 0.3). However, the group of patients taking RAAS inhibitor drugs appeared to be more critical at ICU admission, and this difference became statistically significant in the subgroup of non-hypertensive patients. ICU mortality in the subgroup of non-hypertensive patients treated with RAAS inhibitor drugs also tended to be higher. Overexpression of the angiotensin-converting enzyme 2 (ACE2) in human cells, induced by RAAS inhibitor drugs, promotes viral entry-replication of SARS-CoV-2 and alters the basal balance of the RAAS, which may explain the findings observed in the present study. These phenomena may be amplified in non-hypertensive patients treated with RAAS inhibitor therapy.

Reply to Böning et al. Comment on "Ceruti et al. Temporal Changes in the Oxyhemoglobin Dissociation Curve of Critically Ill COVID-19 Patients. J. Clin. Med. 2022, 11, 788".

We would like to thank Böning et al. for all the important issues raised in the present commentary [...].

[Cardiac surgery in the time of COVID19 - A narrative of three very unusual cases and lessons learned]. / Chirurgie cardiaque au temps du Covid-19 - Récit de trois cas très inhabituels et leçons retenues.

COVID19 altered and impacted medical and surgical practice around the world. Standard of care and routine procedures are disrupted. Majors shift in personnel, and ad hoc new team as well as delocalization and working with new infrastructures are further challenges to be dealt with. This review of three very unusual scenarios illustrates pitfalls and dangers harbored in the re-shaped landscape of COVID19 exemplifying the narrow path bridging from the medical and surgical comfort zone to uncharted territory and eventually leading to collateral damage.

Le Covid-19 a profondément modifié et sévèrement impacté les pratiques médicales et chirurgicales à long terme. Les standards de prise en charge et les procédures de routine sont altérés, voire perturbés. Des mutations majeures au niveau du personnel et des équipes de même que la délocalisation ou le travail avec de nouvelles infrastructures sont autant de défis à relever, encore aujourd'hui. Trois scénarios inhabituels illustrent les pièges et les dangers qui se cachent dans le paysage marqué par le Covid-19. Ces exemples démontrent la marge étroite entre la zone de confort médicale et chirurgicale classique et l'appréhension d'une situation inhabituelle qui risque d'entraîner des dommages collatéraux pour les patients.

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.

Delayed intubation is associated with mortality in patients with severe COVID-19: A single-centre observational study in Switzerland.

INTRODUCTION: Switzerland experienced two waves of COVID-19 in 2020, but with a different ICU admission and treatment management strategy. The timing of ICU admission and intubation remains a matter of debate in severe patients. The aim of our study was to describe the characteristics of ICU patients between two subsequent waves of COVID-19 who underwent a different management strategy and to assess whether the timing of intubation was associated with differences in mortality. PATIENTS AND METHODS: We conducted a prospective observational study of all adult patients with acute respiratory failure due to COVID-19 who required intubation between the 9th of March 2020 and the 9th of January 2021 in the intensive care unit (ICU) at Geneva University Hospitals, Switzerland. RESULTS: Two hundred twenty-three patients were intubated during the study period; 124 during the first wave, and 99 during the second wave. Patients admitted to the ICU during the second wave had a higher SAPS II severity score (52.5 vs. 60; p = 0.01). The time from hospital admission to intubation was significantly longer during the second compared to the first wave (4 days [IQR, 1-7] vs. 2 days [IQR, 0-4]; p < 0.01). All-cause ICU mortality was significantly higher during the second wave (42% vs. 23%; p < 0.01). In a multivariate analysis, the delay between hospital admission and intubation was significantly associated with ICU mortality (OR 3.25 [95% CI, 1.38-7.67]; p < 0.05). CONCLUSIONS: In this observational study, delayed intubation was associated with increased mortality in patients with severe COVID-19. Further randomised controlled trials are needed.

Coronavirus disease 2019-associated coronary endotheliitis and thrombotic microangiopathy causing cardiogenic shock: a case report.

Background: Coronavirus disease 2019 (COVID-19) primarily affects the respiratory tract but serious cardiovascular complications have been reported. Up to one-third of patients admitted to the intensive care unit may develop an acute myocardial injury, characterized by cardiac troponin elevation. However, the pathology underlying COVID-19-associated myocardial injury has rarely been reported. Case summary: Three days after being diagnosed for a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, a 52-year-old woman without a notable past medical history developed cardiogenic shock with severely reduced left ventricular ejection fraction (LVEF) at 25%. Coronary angiography was normal. Endomyocardial biopsy demonstrated coronary endotheliitis with multiple microvascular thromboses but no lymphocytic infiltrate and a negative polymerase chain reaction for SARS-CoV-2. The patient was implanted with a short-term LV assist device (Impella CP®, Abiomed, Aachen, Germany) and treated with therapeutic anticoagulation. She suffered from concomitant respiratory failure that required 14 days of orotracheal intubation, 10 days of dexamethasone, and broad-spectrum antibiotics. Clinical outcome was favourable with weaning of the Impella device after 6 days and full recovery of LVEF (65%) at 30 days. Cardiac magnetic resonance performed at Day 30 showed no evidence of myocarditis or scars and confirmed the normalization of LVEF. Discussion: This case highlights how COVID-19-associated coronary endotheliitis and thrombotic microangiopathy, in the absence of myocarditis, may induce transient severe LV dysfunction and cardiogenic shock.

Temporal Changes in the Oxyhemoglobin Dissociation Curve of Critically Ill COVID-19 Patients.

Critical COVID-19 is a life-threatening disease characterized by severe hypoxemia with complex pathophysiological mechanisms that are not yet completely understood. A pathological shift in the oxyhemoglobin curve (ODC) was previously described through the analysis of p50, intended as the oxygen tension at which hemoglobin is saturated by oxygen at 50%. The aim of this study was to analyze Hb-O2 affinity features over time in a cohort of critically ill COVID-19 patients, through the analysis of ODC p50 behavior. A retrospective analysis was performed; through multiple arterial blood gas (ABG) analyses, each p50 was calculated and normalized according to PaCO2, pH and temperature; patients' p50 evolution over time was reported, comparing the first 3 days (early p50s) with the last 3 days (late p50s) of ICU stay. A total of 3514 ABG analyses of 32 consecutive patients were analyzed. The majority of patients presented a left shift over time (p = 0.03). A difference between early p50s and late p50s was found (20.63 ± 2.1 vs. 18.68 ± 3.3 mmHg, p = 0.03); median p50 of deceased patients showed more right shifts than those of alive patients (24.1 vs. 18.45 mmHg, p = 0.01). One-way ANOVA revealed a p50 variance greater in the early p50s (σ2 = 8.6) than in the late p50s (σ2 = 3.84), associated with a reduction over time (p < 0.001). Comparing the Hb-O2 affinity in critically ill COVID-19 patients between ICU admission and ICU discharge, a temporal shift in the ODC was observed.

Pathophysiology of COVID-19: Everywhere You Look You Will See ACE2!

Angiotensin converting enzyme 2 (ACE2) seems to be a central actor in the pathophysiology of SARS-Cov-2 infection. First, it acts as the receptor for the virus and permits its attachment to cells expressing ACE2. Second, the relative deficiency of ACE2 during infection could be linked to several clinical features encountered during the disease, like ARDS and coagulation abnormalities. This study explores the strong link between ACE2 and the majority of risk factors for the severe evolution of COVID-19. It seems that all these risks factors are linked to an increased level of ACE2 and/or imbalance in ACE/ACE2.

Oesophageal balloon positioning by echocardiography to guide positive pressure ventilation.

Understanding the respiratory mechanics of ARDS patients is crucial to avoid ventilator-induced lung injury (VILI), and this is much more challenging if not only lung compliance is altered but the whole compliance of the respiratory system is abnormal, as in obese patients. We face this problem daily in the ICU, and to optimize ventilation, we estimate respiratory mechanics using an oesophageal balloon. The balloon position is crucial to assess reliable values. In the present technical note, we describe the use of echocardiography to confirm the correct position of this instrument.

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.

Multi-organ point-of-care ultrasound for COVID-19 (PoCUS4COVID): international expert consensus.

COVID-19 has caused great devastation in the past year. Multi-organ point-of-care ultrasound (PoCUS) including lung ultrasound (LUS) and focused cardiac ultrasound (FoCUS) as a clinical adjunct has played a significant role in triaging, diagnosis and medical management of COVID-19 patients. The expert panel from 27 countries and 6 continents with considerable experience of direct application of PoCUS on COVID-19 patients presents evidence-based consensus using GRADE methodology for the quality of evidence and an expedited, modified-Delphi process for the strength of expert consensus. The use of ultrasound is suggested in many clinical situations related to respiratory, cardiovascular and thromboembolic aspects of COVID-19, comparing well with other imaging modalities. The limitations due to insufficient data are highlighted as opportunities for future research.

Preparedness and Reorganization of Care for Coronavirus Disease 2019 Patients in a Swiss ICU: Characteristics and Outcomes of 129 Patients.

OBJECTIVES: In many countries, large numbers of critically ill patients with coronavirus disease 2019 are admitted to the ICUs within a short period of time, overwhelming usual care capacities. Preparedness and reorganization ahead of the wave to increase ICU surge capacity may be associated with favorable outcome. The purpose of this study was to report our experience in terms of ICU organization and anticipation, as well as reporting patient characteristics, treatment, and outcomes. DESIGN: A prospective observational study. SETTING: The division of intensive care at the Geneva University Hospitals (Geneva, Switzerland). PATIENTS: All consecutive adult patients with acute respiratory failure due to coronavirus disease 2019 admitted in the ICU between March 9, 2020, and May 19, 2020, were enrolled. Patients' demographic data, comorbidities, laboratory values, treatments, and clinical outcomes were collected. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The ICU was reorganized into cells of six to eight patients under the care of three physicians and five nurses. Its capacity increased from 30 to 110 beds, fully equipped and staffed, transforming the surgical intermediate care unit, the postoperative care facility, and operating theaters into ICUs. Surge capacity has always exceeded the number of patients hospitalized. Among 129 critically ill patients with severe acute hypoxemic respiratory failure, 96% required invasive mechanical ventilation. A total of 105 patients (81%) were discharged alive and 24 died, corresponding to a mortality of 19%. Patients who died were significantly older, with higher severity scores at admission, had higher levels of d-dimers, plasma creatinine, high-sensitive troponin T, C-reactive protein, and procalcitonin, and required more frequent prone sessions. CONCLUSIONS: A rapid increase in ICU bed capacity, including adequate equipment and staffing, allowed for a large number of critically ill coronavirus disease 2019 patients to be taken care of within a short period of time. Anticipation and preparedness ahead of the wave may account for the low mortality observed in our center. These results highlight the importance of resources management strategy in the context of the ongoing coronavirus disease 2019 pandemic.