ECMO for severe ARDS: systematic review and individual patient data meta-analysis

Advances in acute respiratory distress syndrome: focusing on heterogeneity, pathophysiology, and therapeutic strategies

In recent years, the incidence of acute respiratory distress syndrome (ARDS) has been gradually increasing. Despite advances in supportive care, ARDS remains a significant cause of morbidity and mortality in critically ill patients. ARDS is characterized by acute hypoxaemic respiratory failure with diffuse pulmonary inflammation and bilateral edema due to excessive alveolocapillary permeability in patients with non-cardiogenic pulmonary diseases. Over the past seven decades, our understanding of the pathology and clinical characteristics of ARDS has evolved significantly, yet it remains an area of active research and discovery. ARDS is highly heterogeneous, including diverse pathological causes, clinical presentations, and treatment responses, presenting a significant challenge for clinicians and researchers. In this review, we comprehensively discuss the latest advancements in ARDS research, focusing on its heterogeneity, pathophysiological mechanisms, and emerging therapeutic approaches, such as cellular therapy, immunotherapy, and targeted therapy. Moreover, we also examine the pathological characteristics of COVID-19-related ARDS and discuss the corresponding therapeutic approaches. In the face of challenges posed by ARDS heterogeneity, recent advancements offer hope for improved patient outcomes. Further research is essential to translate these findings into effective clinical interventions and personalized treatment approaches for ARDS, ultimately leading to better outcomes for patients suffering from ARDS.

Impact of extracorporeal blood pump gap sizes on the performance and hemocompatibility under off-design operation

BACKGROUND

Hemocompatibility remains the dominant challenge in rotary blood pumps, and more information on the relationship between individual pump design features, hemodynamics, and blood trauma in various operation conditions is necessary. The study evaluated the variation of gap sizes in extracorporeal blood pumps concerning their influence on blood compatibility, particularly during off-design conditions.

METHODS

We developed a parametric generic blood pump framework for in-silico and in-vitro design feature analysis. Thirty-six designs with varying axial and radial gap sizes between 0.5 mm and 3 mm were generated. CFD was applied to calculate and compare device hemodynamics and evaluate the performance and hemocompatibility during off-design and target operation conditions. The following quantities were analyzed: pressure difference, hemolysis potential, residence times, hydraulic efficiency, and recirculation ratio.

RESULTS

The in-vitro prototype showed excellent agreement with in-silico predictions regarding hydraulic performance (R2 = 0.996 with a RMSE = 2.07). Our results show a modest impact of gap size variations ±10% on key metrics. Domain-resolved analyses revealed a significant contribution of the gap regions to the device's overall hemolytic performance, with an increasing contribution for off-design flow rates. Overall elevated hemolysis levels were identified if at least one gap size was held minimal.

CONCLUSIONS

We introduced and showed the feasibility of a parametric rotary blood pump framework to systematically investigate design feature impact. Results suggest, larger and uniformly sized gaps being overall beneficial regarding hemocompatibility.

Double the Trouble: Successful Cannulation and Air Transportation of Two Obese Trauma Patients Requiring Extracorporeal Membrane Oxygenation

Acute Respiratory Distress Syndrome (ARDS) is a known and severe complication of thoracic trauma. Many patients, despite appropriate ventilator and medical support, continue to worsen requiring additional cardiopulmonary support with extracorporeal membrane oxygenation (ECMO). Additionally, obesity adds a layer of complexity in the management of trauma ARDS on ECMO. We describe the first U.S. Military air transportation mission via Critical Care Air Transport (CCAT) involving the cannulation and transportation of 2 obese trauma patients requiring ECMO support. We reviewed a cohort of 2 obese patients with ARDS secondary to trauma cannulated for venovenous ECMO and simultaneously transferred via Critical Care Air Transport to a DoD ECMO Center. We describe the logistics involved in the transport and management of obese trauma patients on ECMO. Both patients were safely cannulated and transported without complications, and survived their ECMO run and hospital stay. This is the first air transport of 2 obese ECMO patients simultaneously in U.S. Military history. This transport highlights the safety of cannulation and transportation of obese trauma patients, in addition to the flexibility and logistics needed to successfully complete an ECMO military transport.

Teicoplanin pharmacokinetics in critically ill patients on extracorporeal organ support: a retrospective analysis

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) can alter the pharmacokinetics of diverse antimicrobials, posing challenges in achieving therapeutic drug levels. Some literature suggests that teicoplanin may require higher dosing in ECMO patients, however the respective evidence is scarce. The aim of this study was to assess teicoplanin trough levels in critically patients on ECMO support and to compare patients with and without additional continuous renal replacement therapy (CRRT). We conducted a retrospective study at the Intensive Care Unit (ICU) of the University Hospital Zurich, Switzerland. Teicoplanin trough levels and doses were analyzed in critically ill patients during ECMO support by means of a non-parametric local estimated polynomial regression. Outcomes included the proportion of patients with insufficient or toxic teicoplanin trough levels, dosage adjustments, and differences in teicoplanin trough levels between patients with and without additional CRRT during ECMO support.

RESULTS

After screening 172 patients receiving teicoplanin therapy during their ICU stay from 1.1.2020 to 19.07.2023, a total of 23 adult patients were included. The proportion of patients with insufficient teicoplanin levels was notably higher during ECMO support compared to patients with toxic levels (78.3% vs. 13% of patients, respectively). Teicoplanin dosages mostly were increased during the first few days of ECMO treatment. Concomitant CRRT led to a further increase in the proportion of patients with insufficient levels.

CONCLUSIONS

Teicoplanin trough levels using standard dosing tend to be low in patients on ECMO support, especially in the early days of therapy. Higher doses than the standard regimen are often necessary to achieve therapeutic levels, particularly in patients receiving additional CRRT.

Extracorporeal Membrane Oxygenation Use in Fat Embolism Syndrome: Current Perspectives and Clinical Insights (A 20-Year Review)

Background/Objectives: Fat embolism syndrome (FES) is a rare but serious complication that may arise after long bone fractures, characterized by fat globules entering the bloodstream and causing multi-organ dysfunction, particularly respiratory failure. While initial treatment focuses on supportive care including oxygen therapy, fluid management, and hemodynamic stabilization, severe cases may require advanced life support, such as extracorporeal membrane oxygenation (ECMO). The aim of this study is to evaluate the role of ECMO in managing severe cases of FES with refractory hypoxemia and hemodynamic instability by analyzing patient outcomes. Methods: This mini-review explores the role of ECMO in managing FES by analyzing published case reports from the first documented case in 2004 and reviewing the broader literature. By examining the physiological principles, clinical applications, and reported outcomes of ECMO in FES, we aim to provide insights into its potential benefits and limitations. Results: A total of 12 case reports were identified and evaluated for eligibility. All 12 cases met the inclusion criteria and were included in the analysis. These cases involved patients who had FES-related refractory hypoxemia and required ECMO support. Conclusions: Our analysis of case reports presents supportive evidence that incorporating ECMO into the management of FES serves as a crucial bridge to recovery for patients who do not respond to conventional therapies.

The Protective Effects of Sivelestat Sodium on the Basis of Corticosteroid Therapy in Patients With Moderate-to-Severe Acute Respiratory Distress Syndrome

Objective: We aimed to evaluate the protective effects of sivelestat sodium on the basis of corticosteroid therapy in patients with moderate-to-severe acute respiratory distress syndrome (ARDS). Methods: We retrospectively investigated 127 patients with confirmed moderate-to-severe ARDS treated in the intensive care unit (ICU) at Dazhou Central Hospital. Patients were divided into the control group (corticosteroids alone) and the combination therapy of steroids and sivelestat sodium (CTSSS) group according to the therapeutic interventions. The primary outcome was in-hospital mortality. And the baseline characteristics and laboratory findings of patients were collected for analysis. Results: The overall mortality rate in 127 patients was 48.8%. There was no statistically significant difference in in-hospital mortality between the CTSSS group and the control group (45.3% vs. 56.1%). In the subgroup of patients aged < 80 years or with an Acute Physiology and Chronic Health Evaluation (APACHE) II score < 30, CTSSS could reduce the risk of mortality (odds ratio [OR] = 0.41, 95% confidence interval [CI], 0.17-0.96, p=0.041; OR = 0.31, 95% CI, 0.13-0.77, p=0.012; respectively). Among patients aged 80 years or older, those with CTSSS exhibited a significantly elevated risk of mortality (OR = 13; 95% CI, 1.20-140.73; p=0.035). Conclusion: Compared with corticosteroids alone, CTSSS could improve oxygenation index, increase lymphocyte count, protect extrapulmonary organs and reduce in-hospital mortality rate in patients with moderate-to-severe ARDS in specific subgroups (age < 80 years or APACHE II score < 30). It might be advisable to avoid CTSSS in moderate-to-severe ARDS patients aged 80 years or older. Prospective studies involving larger sample sizes are needed to verify these findings.

[Acute respiratory distress syndrome : Pathophysiology, definition and treatment strategies]

Acute respiratory distress syndrome (ARDS) is defined as an acute inflammatory syndrome leading to increased pulmonary capillary leakage and subsequent interstitial and alveolar pulmonary edema. Hypoxia is the predominant symptom. The definition of ARDS comprises acute onset, bilateral patchy infiltration on chest X‑ray and a reduction of the ratio of arterial partial pressure of oxygen (PaO2) to the fraction of inspired oxygen (FiO2), which also determines the classification into mild (≤ 300), moderate (≤ 200) and severe (≤ 100) ARDS. Treating the underlying cause is the only causal treatment measure. The aim of adjunctive therapy is the maintenance of life or organ functions by ensuring an adequate gas exchange without further damaging the lungs. Adjunctive therapy consists mainly of individually adapted "protective" ventilation treatment and the prone position. In severest ARDS, the use of venovenous extracorporeal membrane oxygenation (VV-ECMO) can improve survival if strict criteria for indications and contraindications are followed.

Clinical impact of hypermagnesemia in acute kidney injury patients undergoing continuous kidney replacement therapy: A propensity score analysis utilizing real-world data

PURPOSE

While hypomagnesemia is known to be a risk factor for acute kidney injury (AKI), the impact of hypermagnesemia on prognosis in AKI patients undergoing continuous kidney replacement therapy (CKRT) remains unclear. This study investigates the relationship between hypermagnesemia and clinical outcomes in this patient population.

METHODS

A retrospective analysis was conducted using data from a multicenter medical repository spanning from 2001 to 2019, involving patients who underwent CKRT. Patients were categorized into normomagnesemia (<2 mEq/L) and hypermagnesemia groups based (≥2 mEq/L) on their levels at CKRT initiation.

RESULTS

Among the 2625 patients, 1194 (45.5 %) had elevated serum magnesium levels. The hypermagnesemia group exhibited a similar rate of non-recovery of renal function at 90-days compared to the normomagnesemia group (63.1 % vs. 62.8 %, odds ratio [OR] = 1.01, 95 % confidence interval [CI] 0.90-1.14). Furthermore, the high magnesium group demonstrated higher one-year all-cause mortality (hazard ratio [HR] 1.14, 95 % CI 1.07-1.21) and an elevated risk of one-year arrhythmia (HR 4.77, 95 % CI 1.59-14.29). There was no difference of incidence of seizure between hypermagnesemia and normomagnesemia group.

CONCLUSIONS

Our study suggests that hypermagnesemia in AKI patients undergoing CKRT is not associated with improved renal recovery but is linked to worse clinical outcomes, including all-cause mortality and arrhythmia. Close monitoring of serum magnesium levels is recommended in this population for optimizing clinical outcomes.

Microbiological findings in a cohort of patients with coronavirus disease 2019 and venovenous extracorporeal membrane oxygenation

BACKGROUND

Venovenous extracorporeal membrane oxygenation (VV ECMO) is an established support option for patients with very severe respiratory failure and played an important role during the coronavirus disease 2019 (COVID-19) pandemic. Bacteria and fungi can lead to severe infectious complications in critically ill patients. The aim of this study was to describe the microbiological spectrum of bacteria and fungi detected in patients with COVID-19-associated respiratory failure supported with VV ECMO in our center.

METHODS

This retrospective single-center analysis included all patients with COVID-19-associated respiratory failure supported with VV ECMO in our center between March 2020 and May 2022. All findings from microbiological samples, taken as part of clinical routine assessment from initiation of VV ECMO until day 30 were included. Samples were described by site and time of detection and microbiological characteristics.

RESULTS

From March 2020 through May 2022, 88 patients with COVID-19-associated respiratory failure received VV ECMO support at our center. In 83/88 patients (94.3%), one or more pathogens were found in microbiological samples. Most pathogens were isolated from samples from the respiratory tract (88.6%). Earliest detection occurred in samples from the respiratory tract with a median time of 5 days to first detection. The most frequently detected pathogens were Staphylococcus spp., Candida spp., Klebsiella spp., Escherichia coli and Enterococcus spp.

CONCLUSION

In this cohort of severely ill COVID-19 patients receiving VV ECMO support, pathogens were frequently detected.

Veno-venous extracorporeal membrane oxygenation (VV-ECMO) for acute poisonings in United States: a retrospective analysis of the Extracorporeal Life Support Organization Registry

INTRODUCTION

Veno-arterial extracorporeal membrane oxygenation is frequently considered and implemented to help manage patients with cardiogenic shock from acute poisoning. However, utilization of veno-venous extracorporeal membrane oxygenation in acutely poisoned patients is largely unknown.

METHOD

We conducted a retrospective study analyzing the epidemiologic, clinical characteristics and survival of acutely poisoned patients placed on veno-venous extracorporeal membrane oxygenation using the Extracorporeal Life Support Organization registry. Adult cases in the United States were included after a systematic search of the registry between January 1, 2003, and November 30, 2019. Study outcomes included survival to discharge, time to cannulation, and changes in metabolic, hemodynamic, and ventilatory parameters stratified by survival.

RESULTS

One hundred and seventeen cases were included in the analysis after excluding 216 non-poisoning-related cases. Their median age was 34 years and 69.2% were male. Opioids (45.3%) were most commonly implicated, followed by neurologic drugs (e.g., antidepressants, antiepileptics) (14.5%) and smoke inhalation (13.7%); 23 patients (19.7%) had a pre-extracorporeal membrane oxygenation cardiac arrest. The median time from admission to extracorporeal membrane oxygenation was 47 h with a median duration of extracorporeal membrane oxygenation support of 146.5 h. Survivors were cannulated significantly earlier than non-survivors (25 h versus 123 h; P = 0.02). Eighty-four patients (71.2%) survived to hospital discharge. Clinical parameters (hemodynamic, metabolic, and ventilatory) improved with veno-venous extracorporeal membrane oxygenation support, but no statistically significant difference was noted between survivors and non-survivors.

DISCUSSION

Our study showed that veno-venous extracorporeal membrane oxygenation was infrequently utilized for poisoning-associated acute respiratory distress syndrome. Opioids were the most frequently reported exposure among the cases in which indirect lung injury may have occurred from aspiration. Although no specific clinical parameters were associated with survival, early initiation of extracorporeal membrane oxygenation may improve clinical outcomes.

CONCLUSIONS

The use of veno-venous extracorporeal membrane oxygenation for refractory respiratory failure due to poisoning was associated with a clinically significant survival benefit compared to other respiratory diagnoses requiring veno-venous extracorporeal membrane oxygenation.

Gene expression profiles in respiratory settings in rats under extracorporeal membrane oxygenation

Background

Venovenous extracorporeal membrane oxygenation (VV-ECMO) is an effective lung protection strategy that avoids ventilator-induced lung injury. However, appropriate respiratory settings for VV-ECMO are yet to be established. This study aimed to elucidate the effects of ventilation under VV-ECMO using a newly developed rat VV-ECMO model and analyzed gene expression profiles.

Methods

Rats were assigned to three groups of five rats each: spontaneous breathing, conventional-protective ventilation, and ultra-protective ventilation. The conventional protective and ultraprotective ventilation groups received volume-controlled ventilation at a frequency of 60 and 20 beats/min, with tidal volumes of 6 and 3 mL/kg, respectively. VV-ECMO was performed at a pump flow rate of 20-30 mL/kg/min. At 120 min post initiation of VV-ECMO, rats were euthanized, and their lungs were harvested. Changes in gene expression were assessed using microarray analysis.

Results

Gene expression profile analyses revealed lowest expression of inflammation/immune promotion, cytotoxicity, and cell proliferation related genes (Defa5, Prg2, Siglec8, Atf3, Rnd1, Ctsg, and Gc), and the highest expression of inflammation/immune suppression related genes (Pp2d1) in the spontaneous breathing group as compared to that in the other two mechanical ventilation groups.

Conclusions

The findings of this study demonstrated that spontaneous breathing was the least invasive respiratory setting under VV-ECMO. Further, mechanical ventilation may be associated with lung injury even at low ventilation frequency and tidal volume.

Factors Associated with the Initiation of Renal Replacement Therapy in Patients on VV-ECMO: A Case-Control Study

Acute Kidney Injury (AKI) is a common complication in patients with Acute Respiratory Distress Syndrome (ARDS) receiving VV-ECMO support, carrying a high risk of progression to Renal Replacement Therapy (RRT). Both AKI and RRT are linked to an increased risk of mortality. This study aims to evaluate the risk factors associated with the need for RRT in patients undergoing VV-ECMO. Methods: This is a retrospective case-control study involving patients on VV-ECMO therapy admitted to the intensive care unit (ICU) between 2019 and 2023. Patients on VV ECMO support, with or without RRT, were included and their severity scores and associated mortality were calculated. A multivariate logistic regression analysis was performed to assess the variable RRT using odds ratios (OR) with their corresponding confidence intervals (CI) for the outcome variables. Results: A total of 192 subjects were included, with a mortality rate of 39.6%. Of these, 68.7% were male, with an average ICU stay of 25.1 days and a need for RRT in 19.7% of cases. The multivariate analysis independently associated the use of vasopressors with RRT norepinephrine OR 5.61 (95% CI, 1.64-19.1) and vasopressin OR 4.64 (95% CI, 2.15-10.0)). An increase in creatinine levels before ECMO support is associated with an increased risk OR 2.21 (95% CI 1.54-3.18), and 24 h after ECMO support, the risk rises further adjusted odds ratio (AOR) 3.32 (95% IC 1.55-7.09). The accuracy of severity scores presented weak discrimination and similar behavior, except for DEOx for the primary outcome, with an AUC of 0.79 (95% CI, 0.72-0.87), and APACHE II with an AUC of 0.68 (95% CI, 0.59-0.78). Conclusions: The prediction of RRT in patients on VV-ECMO support was superior for DEOx, which is influenced by the use of vasopressors, creatinine levels, and platelet transfusion prior to cannulation. This could be useful for predicting early interventions in this patient population.

Awake Venovenous Extracorporeal Membrane Oxygenation in the Intensive Care Unit: Challenges and Emerging Concepts

Extracorporeal membrane oxygenation (ECMO) is an advanced treatment for severe respiratory failure. Implantation of ECMO before invasive ventilation or extubation during ECMO has been reported and is becoming increasingly popular. Avoidance of sedation and invasive ventilation during ECMO (commonly referred to as "awake ECMO") may have potential advantages, including a lower rate of delirium, shorter mechanical ventilation time, and the possibility of undergoing early rehabilitation and/or physiotherapy. However, awake ECMO is also associated with several risks, such as self-inflicted lung injury and cannula displacement or self-removal. Accordingly, invasive ventilation before ECMO, as well as weaning from ECMO before weaning from mechanical ventilation, remain the most common approaches. In this review, the authors describe indications, contraindications, advantages, disadvantages, and current evidence on the use of ECMO without invasive ventilation in patients with respiratory failure.

Extracorporeal membrane oxygenation in trauma patient in France: A retrospective nationwide registry

BACKGROUND

Indications for Veno-venous (VV) or veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) after trauma rely on poor evidence. The main aims were to describe the population of trauma patients requiring either VV or VA ECMO and report their clinical management and outcomes.

METHODS

An observational multicentre retrospective study was conducted in 17 Level 1 trauma centres in France between January 2010 and December 2021. All patients admitted for major trauma were screened for inclusion, and those receiving either VV ECMO or VA ECMO were included. The primary outcome was in-hospital mortality.

RESULTS

Among the 52,851 patients screened, 179 were included, with 143 supported by VV ECMO (median [Q1-Q3] age 32 years [24-48]; men 83.5%; injury severity score [ISS] 33 [25-43] and 76 (53.6%) with a traumatic brain injury [TBI]) and 36 supported by VA ECMO (median age 39 years [25-55]; men 88.9%; ISS 36 [25-56] and 23 (63.9%) with a TBI). In the VV ECMO group, three indications for ECMO implementation were chest injuries (n = 68, 47.6%), ventilator-associated pneumonia (VAP; n = 57, 39.9%), and extra-respiratory acute respiratory distress syndrome (ARDS; n = 57, 39.9%). In the VV ECMO group, 45.8% (n = 65) died in the hospital, with 33 (48.5%) deaths following cannulation for chest injuries, 22 (39.3%) following cannulation for VAP, and 10 (55.6%) following cannulation for extrapulmonary ARDS. In the VA ECMO group, 75.0% (n = 27) died during their hospital stay.

CONCLUSIONS

In-hospital mortality of trauma patients requiring ECMO for refractory ARDS varied according to indications. The best prognosis was observed in the subgroup of pneumonia-induced ARDS patients.

Anticoagulation Can Be Held in Traumatically Injured Patients on Veno-Venous Extracorporeal Membrane Oxygenation Support

Traumatic injury is associated with several pulmonary complications, including pulmonary contusion, transfusion-related acute lung injury (TRALI), and the development of acute respiratory distress syndrome (ARDS). There is a lack of literature on these patients supported with veno-venous extracorporeal oxygenation (VV ECMO). Understanding the safety of using VV ECMO to support trauma patients and the ability to hold anticoagulation is important to broaden utilization. This is a single-center retrospective cohort study of adult trauma patients cannulated for VV ECMO during their initial admission over an 8 year period (2014-2021). We hypothesize that anticoagulation can be held in trauma patients on VV ECMO without increasing mortality or prothrombotic complications. We also describe the coagulopathy of traumatically injured patients on VV ECMO. Withholding anticoagulation was not associated with mortality in our study population, and there were no significant differences in bleeding or clotting complications between patients who did and did not receive systemic anticoagulation. Patients in the nonsurvivor group had increased coagulopathy both pre- and post-cannulation. Our study suggests anticoagulation can be safely withheld in traumatically injured VV ECMO patients without increasing mortality, complication rates, or transfusion requirements. Future, multicenter prospective studies with larger sample sizes are required to confirm our results.

The use of protective mechanical ventilation during extracorporeal membrane oxygenation for the treatment of acute respiratory failure

Acute respiratory failure (ARF) strikes an estimated two million people in the United States each year, with care exceeding US$50 billion. The hallmark of ARF is a heterogeneous injury, with normal tissue intermingled with a large volume of low compliance and collapsed tissue. Mechanical ventilation is necessary to oxygenate and ventilate patients with ARF, but if set inappropriately, it can cause an unintended ventilator-induced lung injury (VILI). The mechanism of VILI is believed to be overdistension of the remaining normal tissue known as the 'baby' lung, causing volutrauma, repetitive collapse and reopening of lung tissue with each breath, causing atelectrauma, and inflammation secondary to this mechanical damage, causing biotrauma. To avoid VILI, extracorporeal membrane oxygenation (ECMO) can temporally replace the pulmonary function of gas exchange without requiring high tidal volumes (VT) or airway pressures. In theory, the lower VT and airway pressure will minimize all three VILI mechanisms, allowing the lung to 'rest' and heal in the collapsed state. The optimal method of mechanical ventilation for the patient on ECMO is unknown. The ARDSNetwork Acute Respiratory Management Approach (ARMA) is a Rest Lung Approach (RLA) that attempts to reduce the excessive stress and strain on the remaining normal lung tissue and buys time for the lung to heal in the collapsed state. Theoretically, excessive tissue stress and strain can also be avoided if the lung is fully open, as long as the alveolar re-collapse is prevented during expiration, an approach known as the Open Lung Approach (OLA). A third lung-protective strategy is the Stabilize Lung Approach (SLA), in which the lung is initially stabilized and gradually reopened over time. This review will analyze the physiologic efficacy and pathophysiologic potential of the above lung-protective approaches.

Pregnancy and COVID-19: Comparing ICU Outcomes for Pregnant and Nonpregnant Women

BACKGROUND

This study compares organ dysfunction, treatment strategies, and unfavorable outcome rates between pregnant and nonpregnant women admitted to the ICU with severe COVID-19, highlighting the increased susceptibility of pregnant women to respiratory infections due to physiological changes.

METHODS

A retrospective, age-matched study was conducted at a referral center specializing in critical care for pregnant women. Data from 14 pregnant/postpartum and 11 nonpregnant women were analyzed at ICU admission and on days 3, 5, and 7.

RESULTS

Acute respiratory distress syndrome was diagnosed in 100% of the pregnant/postpartum group and 64% of the nonpregnant group (p = 0.026). Inflammatory parameters were similar between groups, except for lower ferritin levels in the pregnant/postpartum group compared to the nonpregnant (120 vs. 568 µg/L at admission and 90 vs. 616 µg/L on day 3). Creatinine, lactate, and lactate dehydrogenase levels were significantly lower in the pregnant/postpartum group. A reduction in the SOFA score was observed over time in the pregnant/postpartum group (from 7.0 to 4.0 points, p = 0.009), while no change was noticed in the nonpregnant group (from 3.0 to 2.5 points, p = 0.181). Unfavorable outcome rates were similar, with two patients from each group succumbing to the disease (p = 0.604).

CONCLUSIONS

The findings suggest that pregnancy does not increase the risk of unfavorable outcomes among women with severe COVID-19 receiving ICU treatment. However, additional studies with larger sample sizes are needed to validate these observations.

ECMO for Adult Respiratory Failure: A Rapid Review of Clinical and Service Delivery Evidence to Guide Policy in Wales

BACKGROUND

While several studies have summarised the clinical effectiveness evidence for extracorporeal membrane oxygenation (ECMO), there are no evidence syntheses of the impact of centres' ECMO patient volume on patient outcomes or the impact of bedside ECMO care being delivered by either a perfusionist or a nurse. There is also limited information on the cost-effectiveness of ECMO.

PURPOSE

This review was carried out to evaluate the clinical effectiveness and cost of different service delivery models of pulmonary ECMO to inform NHS Wales commissioning policy.

RESEARCH DESIGN

The study utilised rapid review methodology, consisting of a systematic literature search and the inclusion of the highest quality of evidence available.

DATA COLLECTION

Out of 1997 records identified via literature searches, 12 studies fell within the scope. The 2 meta-analyses comparing ECMO with lung-protective ventilation favoured ECMO.

RESULTS

Five studies looking at the clinical impact of centre patient volume had large heterogeneity. Three studies estimated that with sufficient patient volume, nurse-delivered ECMO was cost-saving, with thresholds varying between 92 and 155 patient days per year. Three studies looked at the cost impact of ECMO delivery, with ECMO being cost incurring, but potentially cost-effective, with costs per patient being lower at higher volume centres.

CONCLUSIONS

The available evidence supports the use of ECMO in adult respiratory failure patients, despite it being cost-incurring. ECMO can be nurse-delivered without a significant negative impact on patient care. Yet decision-makers need to consider their local circumstances when making commissioning decisions.

Risk factors for mortality in patients receiving extracorporeal membrane oxygenation

OBJECTIVE

Patients on extracorporeal membrane oxygenation (ECMO) are often complex and have a high mortality rate. Currently, risk assessment and treatment decisions for patients receiving ECMO are controversial. Therefore, we sought to identify risk factors for mortality in patients receiving ECMO and provide a reference for patient management.

METHODS

We retrospectively analyzed the clinical data of 199 patients who received ECMO support from December 2013 to April 2023. Univariate and multivariable logistic regression analyses were used to identify risk factors. The cutoff value was determined by receiver operating characteristic (ROC) curve analysis.

RESULTS

A total of 199 patients were selected for this study, and the mortality rate was 76.38%. More than half of the patients underwent surgery during hospitalization. Multivariable logistic regression analysis revealed that continuous renal replacement therapy (CRRT) implantation (OR = 2.994; 95% CI, 1.405-6.167; p = 0.004) and age (OR = 1.021; 95% CI, 1.002-1.040; p = 0.032) were the independent risk factors for mortality. In the ROC curve analysis, age had the best predictive effect (AUC 0.646, 95% CI 0.559-0.732, p = 0.003) for death when the cutoff value was 48.5 years. Furthermore, in patients receiving combined CRRT and ECMO, lack of congenital heart disease and previous surgical history were the independent risk factors for mortality.

CONCLUSIONS

CRRT implantation and age were independent risk factors for patients with ECMO implantation in a predominantly surgical cohort. In patients receiving a combination of CRRT and ECMO, lack of congenital heart disease and previous surgical history were independent risk factors for mortality.

Extracorporeal Support for Acute Respiratory Distress Syndrome

Extracorporeal life support (ECLS) has a long history in the management of the acute respiratory distress syndrome (ARDS). The objectives of this review are to summarize the rationale and evidence for ECLS in ARDS including its role in reducing ventilator-induced lung injury (VILI), suggest best practice management strategies during ECLS, and identify areas that require additional research to better inform patient care.

The development of a C5.0 machine learning model in a limited data set to predict early mortality in patients with ARDS undergoing an initial session of prone positioning

BACKGROUND

Acute Respiratory Distress Syndrome (ARDS) has a high morbidity and mortality. One therapy that can decrease mortality is ventilation in the prone position (PP). Patients undergoing PP are amongst the sickest, and there is a need for early identification of patients at particularly high risk of death. These patients may benefit from an in-depth review of treatment or consideration of rescue therapies. We report the development of a machine learning model trained to predict early mortality in patients undergoing prone positioning as part of the management of their ARDS.

METHODS

Prospectively collected clinical data were analysed retrospectively from a single tertiary ICU. The records of patients who underwent an initial session of prone positioning whilst receiving invasive mechanical ventilation were identified (n = 131). The decision to perform prone positioning was based on the criteria in the PROSEVA study. A C5.0 classifier algorithm with adaptive boosting was trained on data gathered before, during, and after initial proning. Data was split between training (85% of data) and testing (15% of data). Hyperparameter tuning was achieved through a grid-search using a maximal entropy configuration. Predictions for 7-day mortality after initial proning session were made on the training and testing data.

RESULTS

The model demonstrated good performance in predicting 7-day mortality (AUROC: 0.89 training, 0.78 testing). Seven variables were used for prediction. Sensitivity was 0.80 and specificity was 0.67 on the testing data set. Patients predicted to survive had 13.3% mortality, while those predicted to die had 66.67% mortality. Among patients in whom the model predicted patient would survive to day 7 based on their response, mortality at day 7 was 13.3%. Conversely, if the model predicted the patient would not survive to day 7, mortality was 66.67%.

CONCLUSIONS

This proof-of-concept study shows that with a limited data set, a C5.0 classifier can predict 7-day mortality from a number of variables, including the response to initial proning, and identify a cohort at significantly higher risk of death. This can help identify patients failing conventional therapies who may benefit from a thorough review of their management, including consideration of rescue treatments, such as extracorporeal membrane oxygenation. This study shows the potential of a machine learning model to identify ARDS patients at high risk of early mortality following PP. This information can guide clinicians in tailoring treatment strategies and considering rescue therapies. Further validation in larger cohorts is needed.

Diffuse Alveolar Hemorrhage in Hematopoietic Cell Transplantation

Diffuse alveolar hemorrhage (DAH) is a morbid syndrome that occurs after autologous and allogeneic hematopoietic cell transplantation in children and adults. DAH manifests most often in the first few weeks following transplantation. It presents with pneumonia-like symptoms and acute respiratory failure, often requiring high levels of oxygen supplementation or mechanical ventilatory support. Hemoptysis is variably present. Chest radiographs typically feature widespread alveolar filling, sometimes with peripheral sparing and pleural effusions. The diagnosis is suspected when serial bronchoalveolar lavages return increasingly bloody fluid. DAH is differentiated from infectious causes of alveolar hemorrhage when extensive microbiological testing reveals no pulmonary pathogens. The cause is poorly understood, though preclinical and clinical studies implicate pretransplant conditioning regimens, particularly those using high doses of total-body-irradiation, acute graft-versus-host disease (GVHD), medications used to prevent GVHD, and other factors. Treatment consists of supportive care, systemic corticosteroids, platelet transfusions, and sometimes includes antifibrinolytic drugs and topical procoagulant factors. Therapeutic blockade of tumor necrosis factor-α showed promise in observational studies, but its benefit for DAH remains uncertain after small clinical trials. Even with these treatments, mortality from progression and relapse is high. Future investigational therapies could target the vascular endothelial cell biology theorized to contribute to alveolar bleeding and pathways that contribute to susceptibility, inflammation, cellular resilience, and tissue repair. This review will help clinicians navigate through the limited evidence to diagnose and treat DAH, counsel patients and families, and plan for future research.

Lessons Learned From Extracorporeal Life Support Practice and Outcomes During the COVID-19 Pandemic

Extracorporeal membrane oxygenation is increasingly being used to support patients with hypoxemic respiratory failure and cardiogenic shock. During the COVID-19 pandemic, consensus guidance recommended extracorporeal life support for patients with COVID-19-related cardiopulmonary disease refractory to optimal conventional therapy, prompting a substantial expansion in the use of this support modality. Extracorporeal membrane oxygenation was particularly integral to the bridging of COVID-19 patients to heart or lung transplantation. Limited human and physical resources precluded widespread utilization of mechanical support during the COVID-19 pandemic, necessitating careful patient selection and optimal management by expert healthcare teams for judicious extracorporeal membrane oxygenation use. This review outlines the evidence supporting the use of extracorporeal life support in COVID-19, describes the practice and outcomes of extracorporeal membrane oxygenation for COVID-19-related respiratory failure and cardiogenic shock, and proposes lessons learned for the implementation of extracorporeal membrane oxygenation as a bridge to transplantation in future public health emergencies.

Acute respiratory distress syndrome

The understanding of acute respiratory distress syndrome (ARDS) has evolved greatly since it was first described in a 1967 case series, with several subsequent updates to the definition of the syndrome. Basic science advances and clinical trials have provided insight into the mechanisms of lung injury in ARDS and led to reduced mortality through comprehensive critical care interventions. This review summarizes the current understanding of the epidemiology, pathophysiology, and management of ARDS. Key highlights include a recommended new global definition of ARDS and updated guidelines for managing ARDS on a backbone of established interventions such as low tidal volume ventilation, prone positioning, and a conservative fluid strategy. Future priorities for investigation of ARDS are also highlighted.

Association Between Tidal Volume in Invasive Mechanical Ventilation and Mortality in Children With Extracorporeal Membrane Oxygenation

Mechanical ventilation (MV) strategies in children on extracorporeal membrane oxygenation (ECMO) have not been studied much and the ventilatory parameters to avoid greater lung damage are still unclear. Our objective was to determine the relationship between conventional tidal volume (4-8 ml/kg, CTV) versus low tidal volume (<4 ml/kg, LTV) and mortality in children with MV at the beginning of ECMO. This was a retrospective cohort study that included 101 (10.9 months interquartile range [IQR]: 6.0-24.0) children. Children with LTV had greater odds of hospital mortality (adjusted odds ratio [aOR]: 2.45; 95% confidence interval [CI]: 1.05-5.71; p = 0.03) regardless of age, reason for ECMO, and disease severity, as well as a longer duration of MV after ECMO. We found no differences between the groups in other MV settings. The CTV group required fewer fibrobronchoscopies than patients with LTV (aOR: 0.38; 95% CI: 0.15-0.99; p = 0.04). We found that a tidal volume (VT) lower than 4 ml/kg at the onset of ECMO support in children with MV was associated with higher odds of mortality, longer post-decannulation ventilation, and a greater need for fibrobronchoscopies. Lung-protective bundles in patients with ECMO and MV should consider the VT to maintain plateau and driving pressure that avoid major lung injury caused by MV.

Long-term lung function recovery after ECMO versus non-ECMO management in acute respiratory failure: a systematic review and meta-analysis

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is increasingly employed to support lung function in patients with acute respiratory failure (ARF). However, the long-term outcomes of the approach have not been encouraging when compared to those of conventional mechanical ventilation. Further, the long-term effects of ECMO on lung function and recovery are unclear. For this review, we examined the long-term lung function outcomes of patients with ARF treated with and without ECMO.

METHODS

We searched the Embase, CENTRAL, Web of Science, and PubMed sites for studies comparing long-term (≥ 6 months) pulmonary function test results in patients with ARF treated with and without ECMO published until January 2024. We conducted a meta-analysis for percentage predicted values.

RESULTS

We included five studies. Our meta-analysis showed similar values of forced vital capacity (FVC%) (MD, 0.47; 95% CI, -3.56-4.50) and forced expiratory flow in the first second % (MD, 1.79; 95% CI, -2.17-5.75) in patients with ARF treated with or without ECMO. The FEV1/FVC % values were slightly higher in patients treated with ECMO than in those without ECMO (MD, 2.03; 95% CI, 0.01-4.04; p-value = 0.05). According to the meta-analysis, the values for total lung capacity % (MD, -3.20; 95% CI, -8.83-2.44) and carbon monoxide diffusion capacity % (MD, -0.72; 95% CI, -3.83-2.39) were also similar between patients undergoing ECMO and those without it.

CONCLUSION

The meta-analysis of a small number of studies with significant selection bias indicates that patients with ARF treated with ECMO may have comparable long-term pulmonary function recovery to those treated with conventional strategies. Further investigations including a larger number of patients and focusing on the long-term impact of ECMO are needed to supplement the current evidence.

Blood trauma in veno-venous extracorporeal membrane oxygenation: low pump pressures and low circuit resistance matter

BACKGROUND

Veno-venous extracorporeal membrane oxygenation (VV ECMO) has become standard of care in patients with the most severe forms of acute respiratory distress syndrome. However, hemolysis and bleeding are one of the most frequent side effects, affecting mortality. Despite the widespread use of VV ECMO, current protocols lack detailed, in-vivo data-based recommendations for safe ECMO pump operating conditions. This study aims to comprehensively analyze the impact of VV ECMO pump operating conditions on hemolysis by combining in-silico modeling and clinical data analysis.

METHODS

We combined data from 580 patients treated with VV ECMO in conjunction with numerical predictions of hemolysis using computational fluid dynamics and reduced order modeling of the Rotaflow (Getinge) and DP3 (Xenios) pumps. Blood trauma parameters across 94,779 pump operating points were associated with numerical predictions of shear induced hemolysis.

RESULTS

Minimal hemolysis was observed at low pump pressures and low circuit resistance across all flow rates, whereas high pump pressures and circuit resistance consistently precipitated substantial hemolysis, irrespective of flow rate. However, the lower the flow rate, the more pronounced the influence of circuit resistance on hemolysis became. Numerical models validated against clinical data demonstrated a strong association (Spearman's r = 0.8) between simulated and observed hemolysis, irrespective of the pump type.

CONCLUSIONS

Integrating in-silico predictions with clinical data provided a novel approach in understanding and potentially reducing blood trauma in VV ECMO. This study further demonstrated that a key factor in lowering side effects of ECMO support is the maintenance of low circuit resistance, including oxygenators with the lowest possible resistance, the shortest feasible circuit tubing, and cannulae with an optimal diameter.

[Peripheral extracorporeal membrane oxygenation in perioperative medicine : Principles, indications and challenges]

In recent years the number of patients treated in intensive care units by extracorporeal membrane oxygenation (ECMO) due to severe respiratory failure or cardiogenic shock has steadily increased [1]. Consequently, the number of invasive procedures and operations in these patients has also increased. A fundamental understanding of these systems and the clinical indications is therefore helpful for the practicing (non-cardiac) surgeon. This review article focuses on peripheral ECMO procedures: venovenous (V-V) ECMO for patients with respiratory failure and venoarterial (V-A) ECMO for circulatory support in cardiogenic shock.

Mechanical ventilation settings during weaning from venovenous extracorporeal membrane oxygenation

BACKGROUND

The optimal timing of weaning from venovenous extracorporeal membrane oxygenation (VV ECMO) and its modalities have been rarely studied.

METHODS

Retrospective, multicenter cohort study over 7 years in two tertiary ICUs, high-volume ECMO centers in France and Italy. Patients with ARDS on ECMO and successfully weaned from VV ECMO were classified based on their mechanical ventilation modality during the sweep gas-off trial (SGOT) with either controlled mechanical ventilation or spontaneous breathing (i.e. pressure support ventilation). The primary endpoint was the time to successful weaning from mechanical ventilation within 90 days post-ECMO weaning.

RESULTS

292 adult patients with severe ARDS were weaned from controlled ventilation, and 101 were on spontaneous breathing during SGOT. The 90-day probability of successful weaning from mechanical ventilation was not significantly different between the two groups (sHR [95% CI], 1.23 [0.84-1.82]). ECMO-related complications were not statistically different between patients receiving these two mechanical ventilation strategies. After adjusting for covariates, older age, higher pre-ECMO sequential organ failure assessment score, pneumothorax, ventilator-associated pneumonia, and renal replacement therapy, but not mechanical ventilation modalities during SGOT, were independently associated with a lower probability of successful weaning from mechanical ventilation after ECMO weaning.

CONCLUSIONS

Time to successful weaning from mechanical ventilation within 90 days post-ECMO was not associated with the mechanical ventilation strategy used during SGOT. Further research is needed to assess the optimal ventilation strategy during weaning off VV ECMO and its impact on short- and long-term outcomes.

Successful management of intracranial hemorrhage with brain herniation in a postpartum patient on extracorporeal membranous oxygenation: A case report

Managing intracranial hemorrhage in patients supported by extracorporeal oxygenation (ECMO) presents significant clinical challenges. We report a case of a postpartum patient with severe acute respiratory distress syndrome (ARDS) necessitating venovenous ECMO support, complicated by multicompartmental intracranial hemorrhage resulting in brain herniation and necessitating emergent medical and surgical management of refractory intracranial hypertension. Care was guided by multimodal neuromonitoring, including intracranial pressure monitoring and electroencephalography. Despite these challenges, the patient achieved excellent neurological recovery. This case underscores the intricacies of managing neurological complications during ECMO and highlights the potential benefits of comprehensive neuromonitoring strategies.

Use of Extracorporeal Membrane Oxygenation for Patients with Coronavirus Disease 2019 Infection

The coronavirus disease 2019 (COVID-19) pandemic was a cataclysmic event that infected over 772 million and killed over 6.9 million people worldwide. The pandemic pushed hospitals and society to their limits and resulted in incredibly severe respiratory disease in millions of people. This severe respiratory disease often necessitated maximum medical therapy, including the use of extracorporeal membrane oxygenation. While our understanding of COVID-19 and its treatment continue to evolve, we review the current evidence to guide the care of patients with severe COVID-19 infection.

Definition and management of right ventricular injury in adult patients receiving extracorporeal membrane oxygenation for respiratory support using the Delphi method: a PRORVnet study. Expert position statements

PURPOSE

Veno-venous extracorporeal membrane oxygenation (VV-ECMO) is an integral part of the management algorithm of patients with severe respiratory failure refractory to evidence-based conventional treatments. Right ventricular injury (RVI) pertaining to abnormalities in the dimensions and/or function of the right ventricle (RV) in the context of VV-ECMO significantly influences mortality. However, in the absence of a universally accepted RVI definition and evidence-based guidance for the management of RVI in this very high-risk patient cohort, variations in clinical practice continue to exist.

METHODS

Following a systematic search of the literature, an international Steering Committee consisting of eight healthcare professionals involved in the management of patients receiving ECMO identified domains and knowledge gaps pertaining to RVI definition and management where the evidence is limited or ambiguous. Using a Delphi process, an international panel of 52 Experts developed Expert position statements in those areas. The process also conferred RV-centric overarching open questions for future research. Consensus was defined as achieved when 70% or more of the Experts agreed or disagreed on a Likert-scale statement or when 80% or more of the Experts agreed on a particular option in multiple-choice questions.

RESULTS

The Delphi process was conducted through four rounds and consensus was achieved on 31 (89%) of 35 statements from which 24 Expert position statements were derived. Expert position statements provided recommendations for RVI nomenclature in the setting of VV-ECMO, a multi-modal diagnostic approach to RVI, the timing and parameters of diagnostic echocardiography, and VV-ECMO settings during RVI assessment and management. Consensus was not reached on RV-protective driving pressure thresholds or the effect of prone positioning on patient-centric outcomes.

CONCLUSION

The proposed definition of RVI in the context of VV-ECMO needs to be validated through a systematic aggregation of data across studies. Until further evidence emerges, the Expert position statements can guide informed decision-making in the management of these patients.

In-Hospital Outcomes of Patients With Acute Respiratory Distress Syndrome Treated With Extracorporeal Membrane Oxygenation

BACKGROUND

Treatment of acute respiratory distress syndrome (ARDS) with extracorporeal membrane oxygenation (ECMO) remains controversial.

OBJECTIVE

This study aims to examine outcomes in ARDS patients treated with or without ECMO.

METHODS

Using the National Inpatient Sample (NIS) database, all ARDS patients including those who were treated with ECMO were included in the analysis. Univariable and multivariable logistic regressions were used to estimate the odds of in-hospital outcomes between groups.

RESULTS

A total of 2,540,350 patients were identified (2,538,849 with ARDS; 1,501 with ARDS on ECMO). The patients who underwent ECMO included younger patients and more men. Using ECMO in ARDS patients was associated with higher in-hospital mortality, cardiopulmonary arrest, major bleeding, sepsis, acute kidney injury, and longer hospital stays (31.7 vs. 8.3 days; p < 0.001 for all). A subgroup analysis based on age and sex had similar outcomes.

CONCLUSION

Using ECMO in patients with ARDS was associated with worse in-hospital outcomes, including mortality and length of stay.

Obesity associated with improved mortality of extracorporeal membrane oxygenation for severe COVID-19 pneumonia

INTRODUCTION

Determining a patient's candidacy for extracorporeal membrane oxygenation (ECMO) in severe COVID-19 pneumonia is a critical aspect of efficient healthcare delivery. A body mass index (BMI) ≥40 is considered a relative contraindication for ECMO by the Extracorporeal Life Support Organization (ELSO). We sought to determine the impact of obesity on the survival of patients with COVID-19 on ECMO.

METHODS

This project was a retrospective review of a multicenter US database from January 2020 to December 2021. The primary outcome was in-hospital mortality after ECMO initiation, with a comparison between patients classified into body mass index categories (<30, 30-39.9, and ≥40). Secondary outcomes included ventilator days, intensive care days, and complications.

RESULTS

We completed records review on 359 patients, with 90 patients excluded because of missing data. The overall mortality for the 269 patients was 37.5%. Patients with a BMI <30 had higher odds of mortality compared to all patients with BMI >30 (OR 1.98; p = 0.013), those with BMI 30-39.9 (OR 1.84; p = 0.036), and BMI ≥40 (OR 2.33; p = 0.024). There were no differences between BMI groups for ECMO duration; length of stay (LOS); or rate of bloodstream infection, stroke, or blood transfusion. Age, ECMO duration, and modified-Elixhauser index were not independent risk factors for mortality.

CONCLUSIONS

In patients receiving ECMO for severe COVID-19, neither obesity (BMI >30) nor morbid obesity (BMI >40) were associated with in-hospital mortality. These results are consistent with previous reports and held true after adjusting for age and comorbidities. Our data suggest further examination of the recommendations to withhold ECMO in patients who are obese.

Positive end-expiratory pressure management in patients with severe ARDS: implications of prone positioning and extracorporeal membrane oxygenation

The optimal strategy for positive end-expiratory pressure (PEEP) titration in the management of severe acute respiratory distress syndrome (ARDS) patients remains unclear. Current guidelines emphasize the importance of a careful risk-benefit assessment for PEEP titration in terms of cardiopulmonary function in these patients. Over the last few decades, the primary goal of PEEP usage has shifted from merely improving oxygenation to emphasizing lung protection, with a growing focus on the individual pattern of lung injury, lung and chest wall mechanics, and the hemodynamic consequences of PEEP. In moderate-to-severe ARDS patients, prone positioning (PP) is recommended as part of a lung protective ventilation strategy to reduce mortality. However, the physiologic changes in respiratory mechanics and hemodynamics during PP may require careful re-assessment of the ventilation strategy, including PEEP. For the most severe ARDS patients with refractory gas exchange impairment, where lung protective ventilation is not possible, veno-venous extracorporeal membrane oxygenation (V-V ECMO) facilitates gas exchange and allows for a "lung rest" strategy using "ultraprotective" ventilation. Consequently, the importance of lung recruitment to improve oxygenation and homogenize ventilation with adequate PEEP may differ in severe ARDS patients treated with V-V ECMO compared to those managed conservatively. This review discusses PEEP management in severe ARDS patients and the implications of management with PP or V-V ECMO with respect to respiratory mechanics and hemodynamic function.

Early reapplication of prone position during venovenous ECMO for acute respiratory distress syndrome: a prospective observational study and propensity-matched analysis

BACKGROUND

A combination of prone positioning (PP) and venovenous extracorporeal membrane oxygenation (VV-ECMO) is safe, feasible, and associated with potentially improved survival for severe acute respiratory distress syndrome (ARDS). However, whether ARDS patients, especially non-COVID-19 patients, placed in PP before VV-ECMO should continue PP after a VV-ECMO connection is unknown. This study aimed to test the hypothesis that early use of PP during VV-ECMO could increase the proportion of patients successfully weaned from ECMO support in severe ARDS patients who received PP before ECMO.

METHODS

In this prospective observational study, patients with severe ARDS who were treated with VV-ECMO were divided into two groups: the prone group and the supine group, based on whether early PP was combined with VV-ECMO. The proportion of patients successfully weaned from VV-ECMO and 60-day mortality were analyzed before and after propensity score matching.

RESULTS

A total of 165 patients were enrolled, 50 in the prone and 115 in the supine group. Thirty-two (64%) and 61 (53%) patients were successfully weaned from ECMO in the prone and the supine groups, respectively. The proportion of patients successfully weaned from VV-ECMO in the prone group tended to be higher, albeit not statistically significant. During PP, there was a significant increase in partial pressure of arterial oxygen (PaO2) without a change in ventilator or ECMO settings. Tidal impedance shifted significantly to the dorsal region, and lung ultrasound scores significantly decreased in the anterior and posterior regions. Forty-five propensity score-matched patients were included in each group. In this matched sample, the prone group had a higher proportion of patients successfully weaned from VV-ECMO (64.4% vs. 42.2%; P = 0.035) and lower 60-day mortality (37.8% vs. 60.0%; P = 0.035).

CONCLUSIONS

Patients with severe ARDS placed in PP before VV-ECMO should continue PP after VV-ECMO support. This approach could increase the probability of successful weaning from VV-ECMO.

TRIAL REGISTRATION

ClinicalTrials.Gov: NCT04139733. Registered 23 October 2019.

Characterizing the Relationship Between Arterial Carbon Dioxide Trajectory and Serial Brain Biomarkers with Central Nervous System Injury During Veno-Venous Extracorporeal Membrane Oxygenation: A Prospective Cohort Study

BACKGROUND

Central nervous system (CNS) injury following initiation of veno-venous extracorporeal membrane oxygenation (VV-ECMO) is common. An acute decrease in partial pressure of arterial carbon dioxide (PaCO2) following VV-ECMO initiation has been suggested as an etiological factor, but the challenges of diagnosing CNS injuries has made discerning a relationship between PaCO2 and CNS injury difficult.

METHODS

We conducted a prospective cohort study of adult patients undergoing VV-ECMO for acute respiratory failure. Arterial blood gas measurements were obtained prior to initiation of VV-ECMO, and at every 2-4 h for the first 24 h. Neuroimaging was conducted within the first 7-14 days in patients who were suspected of having neurological injury or unable to be examined because of sedation. We collected blood biospecimens to measure brain biomarkers [neurofilament light (NF-L); glial fibrillary acidic protein (GFAP); and phosphorylated-tau 181] in the first 7 days following initiation of VV-ECMO. We assessed the relationship between both PaCO2 over the first 24 h and brain biomarkers with CNS injury using mixed methods linear regression. Finally, we explored the effects of absolute change of PaCO2 on serum levels of neurological biomarkers by separate mixed methods linear regression for each biomarker using three PaCO2 exposures hypothesized to result in CNS injury.

RESULTS

In our cohort, 12 of 59 (20%) patients had overt CNS injury identified on head computed tomography. The PaCO2 decrease with VV-ECMO initiation was steeper in patients who developed a CNS injury (- 0.32%, 95% confidence interval - 0.25 to - 0.39) compared with those without (- 0.18%, 95% confidence interval - 0.14 to - 0.21, P interaction < 0.001). The mean concentration of NF-L increased over time and was higher in those with a CNS injury (464 [739]) compared with those without (127 [257]; P = 0.001). GFAP was higher in those with a CNS injury (4278 [11,653] pg/ml) compared with those without (116 [108] pg/ml; P < 0.001). The mean NF-L, GFAP, and tau over time in patients stratified by the three thresholds of absolute change of PaCO2 showed no differences and had no significant interaction for time.

CONCLUSIONS

Although rapid decreases in PaCO2 following initiation of VV-ECMO were slightly greater in patients who had CNS injuries versus those without, data overlap and absence of relationships between PaCO2 and brain biomarkers suggests other pathophysiologic variables are likely at play.

Imaging the Lung in ARDS: A Primer

Despite periodic changes in the clinical definition of ARDS, imaging of the lung remains a central component of its diagnostic identification. Several imaging modalities are available to the clinician to establish a diagnosis of the syndrome, monitor its clinical course, or assess the impact of treatment and management strategies. Each imaging modality provides unique insight into ARDS from structural and/or functional perspectives. This review will highlight several methods for lung imaging in ARDS, emphasizing basic operational and physical principles for the respiratory therapist. Advantages and disadvantages of each modality will be discussed in the context of their utility for clinical management and decision-making.

Worldwide application and valuation of extracorporeal membrane oxygenation support during the COVID-19 pandemic (WAVES)

OBJECTIVE

The outcomes of COVID-19 patients on venovenous extracorporeal membrane oxygenation (VV-ECMO) varied. We aim to investigate the variability concerning location and timeframe. We conducted a retrospective analysis of data from 351 institutions in 53 countries. The primary outcome was survival to hospital discharge or death up to 90 days from ECMO start. The associations between calendar time (month and year) of ECMO initiation and the primary outcome were examined by Cox regression modeling. Multivariable survival analyses were adjusted for the time of ECMO start, age, body mass index, APACHE II, SOFA, and the duration of mechanical ventilation before ECMO.

RESULTS

1060 adult COVID-19 patients enrolled in the COVID-19 Critical Care Consortium (COVID Critical) international registry and required VV-ECMO support. The study period is from January 2020 to December 2021. The median age was 51 years old, and 70% were male patients. Most patients were from Europe (39.3%) and North America (37.4%). The in-hospital mortality of the entire cohort was 47.12%. In North America and Europe, there was an increased probability of death from May 2020 through February 2021. Latin America showed a steady rate of survival until late in the study. South Asia, the Middle East, and Africa showed an increased chance of mortality around May 2020. In the Asian-Pacific region, after February 2021, there was an increased probability of death. The time of ECMO initiation and advanced patient age were associated with increased mortality.

CONCLUSION

Variability in the outcomes of COVID-19 patients on VV-ECMO existed within different regions. This variability reflects the differences in resources, policies, patient selection, management, and possibly COVID-19 virus subtypes. Our findings might help guide global response in the future by early adoption of patient selection protocols, worldwide policies, and delivery of resources.

Comparison of venovenous extracorporeal membrane oxygenation, prone position and supine mechanical ventilation for severely hypoxemic acute respiratory distress syndrome: a network meta-analysis

PURPOSE

Severe acute respiratory distress syndrome (ARDS) with PaO2/FiO2 < 80 mmHg is a life-threatening condition. The optimal management strategy is unclear. The aim of this meta-analysis was to compare the effects of low tidal volumes (Vt), moderate Vt, prone ventilation, and venovenous extracorporeal membrane oxygenation (VV-ECMO) on mortality in severe ARDS.

METHODS

We performed a frequentist network meta-analysis of randomised controlled trials (RCTs) with participants who had severe ARDS and met eligibility criteria for VV-ECMO or had PaO2/FiO2 < 80 mmHg. We applied the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) methodology to discern the relative effect of interventions on mortality and the certainty of the evidence.

RESULTS

Ten RCTs including 812 participants with severe ARDS were eligible. VV-ECMO reduces mortality compared to low Vt (risk ratio [RR] 0.77, 95% confidence interval [CI] 0.59-0.99, moderate certainty) and compared to moderate Vt (RR 0.75, 95% CI 0.57-0.98, low certainty). Prone ventilation reduces mortality compared to moderate Vt (RR 0.78, 95% CI 0.66-0.93, high certainty) and compared to low Vt (RR 0.81, 95% CI 0.63-1.02, moderate certainty). We found no difference in the network comparison of VV-ECMO compared to prone ventilation (RR 0.95, 95% CI 0.72-1.26), but inferences were based solely on indirect comparisons with very low certainty due to very wide confidence intervals.

CONCLUSIONS

In adults with ARDS and severe hypoxia, both VV-ECMO (low to moderate certainty evidence) and prone ventilation (moderate to high certainty evidence) improve mortality relative to low and moderate Vt strategies. The impact of VV-ECMO versus prone ventilation remains uncertain.

Is there still a place for ECCO2R?

The therapeutic target of extracorporeal carbon dioxide removal (ECCO2R) is the elimination of carbon dioxide (CO2) from the blood across a gas exchange membrane without influencing oxygenation to a clinically relevant extent. In acute respiratory distress syndrome (ARDS), ECCO2R has been used to reduce tidal volume, plateau pressure, and driving pressure ("ultraprotective ventilation"). Despite achieving these goals, no benefits in outcome could be shown. Thus, in ARDS, the use of ECCO2R to achieve ultraprotective ventilation can no longer be recommended. Furthermore, ECCO2R has also been used to avoid intubation or facilitate weaning in obstructive lung failure as well as to avoid mechanical ventilation in patients during bridging to lung transplantation. Although these goals can be achieved in many patients, the effects on outcome still remain unclear due to lack of evidence. Despite involving less blood flow, smaller cannulas, and smaller gas exchange membranes compared with extracorporeal membrane oxygenation, ECCO2R bears a comparable risk of complications, especially bleeding. Trials to define indications and analyze the risk-benefit balance are needed prior to implementation of ECCO2R as a standard therapy. Consequently, until then, ECCO2R should be used in clinical studies and experienced centers only. This article is freely available.

Respiratory extracorporeal membrane oxygenation : From rescue therapy to standard tool for treatment of acute respiratory distress syndrome?

BACKGROUND

The use of extracorporeal membrane oxygenation (ECMO) for patients with acute respiratory distress syndrome (ARDS) has increased substantially. With modern trials supporting its efficacy, ECMO has become an important tool in the management of severe ARDS.

OBJECTIVES

The objectives of this paper are to discuss ECMO physiology and configurations used for patients with ARDS, review evidence supporting the use of ECMO for ARDS, and discuss aspects of management during ECMO.

CONCLUSION

Current evidence supports the use of ECMO, combined with an ultra-lung-protective approach to mechanical ventilation, in patients with ARDS who have refractory hypoxemia or hypercapnia with severe respiratory acidosis. Furthermore, data suggest that center volume and experience are important factors in the care of patients receiving ECMO. The use of extracorporeal technologies in expanded patient populations and the optimal management of patients during ECMO remain areas of investigation. This article is freely available.

Long term outcome in patients treated with veno-venous extracorporeal membrane oxygenation: A prospective observational study

INTRODUCTION

Over the last few decades, the use of veno-venous extracorporeal membrane oxygenation (VV-ECMO) support for severe respiratory failure has increased.

AIM

This study aimed to assess the long-term outcomes of patients treated with VV-ECMO for respiratory failure.

METHODS

We performed a single-centre prospective evaluation of patients on VV-ECMO who were successfully discharged from the intensive care unit of an Italian University Hospital between January 2018 and May 2021. The enrolled patients underwent follow-up evaluations at 6 and 12 months after ICU discharge. The follow-up team performed psychological and functional assessments using the following instruments: Hospital Anxiety and Depression Scale (HADS), Post-traumatic Stress Disorder Symptom Severity Scale (PTSS-10), Euro Quality Five Domains Five Levels (EQ-5L-5D), and 6-minute walk test.

RESULTS

We enrolled 33 patients who were evaluated at a follow-up clinic. The median patient age was 51 years (range: 45-58 years). The median duration of VV-ECMO support was 12 (9-19) days and the length of ICU stay was 23 (18-42) days. A HADS score higher than 14 was reported in 8 (24 %) and 7 (21 %) patients at the six- and twelve-month visit, respectively. PTSS-10 total score ≥ 35 points was present in three (9 %) and two (6 %) patients at the six- and twelve-month examination. The median EQ-5L-5D-VAS was respectively 80 (80-90) and 87.5 (70-95). The PTSS-10 score significantly decreased from six to 12 months in COVID-19 survivors (p = 0.024).

CONCLUSIONS

In this cohort of patients treated with VV-ECMO, cognitive and psychological outcomes were good and comparable to those of patients with Adult Respiratory Distress Syndrome (ARDS) managed without ECMO.

IMPLICATIONS FOR CLINICAL PRACTICE

The findings of this study confirm the need for long-term follow-up and rehabilitation programs for every ICU survivor after discharge. COVID-19 survivors treated with VV-ECMO had outcomes comparable to those reported in non-COVID patients.

Physical Rehabilitation and Mobilization in Patients Receiving Extracorporeal Life Support: A Systematic Review

OBJECTIVES

We planned to synthesize evidence examining the potential efficacy and safety of performing physical rehabilitation and/or mobilization (PR&M) in adult patients receiving extracorporeal life support (ECLS).

DATA SOURCES

We included any study that compared PR&M to no PR&M or among different PR&M strategies in adult patients receiving any ECLS for any indication and any cannulation. We searched seven electronic databases with no language limitations.

STUDY SELECTION AND DATA EXTRACTION

Two reviewers, independently and in duplicate, screened all citations for eligibility. We used the Cochrane Risk of Bias 2 and Cochrane Risk Of Bias In Non-randomized Studies of Interventions tools to assess individual study risk of bias. Although we had planned for meta-analysis, this was not possible due to insufficient data, so we used narrative and tabular data summaries for presenting results. We assessed the overall certainty of the evidence for each outcome using the Grading of Recommendations Assessment, Development, and Evaluation framework.

DATA SYNTHESIS

We included 17 studies that enrolled 996 patients. Most studies examined venovenous extracorporeal membrane oxygenation (ECMO) and/or venoarterial ECMO as a bridge to recovery in the ICU. We found an uncertain effect of high-intensity/active PR&M on mortality, duration of mechanical ventilation, ICU length of stay, hospital length of stay, or quality of life compared with low-intensity/passive PR&M in patients receiving ECLS (very low certainty due to very serious imprecision). There was similarly an uncertain effect on safety events including clinically important bleeding, spontaneous intracerebral hemorrhage, limb ischemia, accidental decannulation, or ECLS circuit dysfunction (very low certainty due to very serious risk of bias and imprecision).

CONCLUSIONS

Based on the currently available summary of evidence, there is an uncertain effect of high-intensity/active PR&M on patient important outcomes or safety in patients receiving ECLS. Despite indirect data from other populations suggesting potential benefit of high-intensity PR&M in the ICU; further high-quality randomized trials evaluating the benefits and risks of physical therapy and/or mobilization in this population are needed.

Assessment of Nutritional Risk Scores (the Nutritional Risk Screening 2002 and Modified Nutrition Risk in Critically Ill Scores) as Predictors of Mortality in Critically Ill Patients on Extracorporeal Membrane Oxygenation

Nutritional risk is associated with intensive care unit (ICU) stay and mortality, the Nutritional Risk Screening 2002 (NRS 2002) and the modified Nutritional Risk in the Critically Ill (mNUTRIC) score are assessment instruments and useful in predicting the risk regarding mortality in ICU patients. Our aim was to assess the effects of mNUTRIC and NRS 2002 on mortality in patients on extracorporeal membrane oxygenation (ECMO). A retrospective cohort study was performed and 78 patients were included for final analysis. In the current study, the NRS 2002 and the mNUTRIC score within 24 hours before starting ECMO were applied to assess patients' nutritional status on ECMO and explore the relationship between nutritional status and patient outcomes. This study suggests that both mNUTRIC and NRS 2002 scores were found to be significant independent risk and prognostic factors for in-hospital and 90 day morality among ECMO patients based on multivariable logistic regression analysis ( p < 0.05), with those in the high-risk group having higher in-hospital and 90 day mortality rates than those identified as being at low risk ( p < 0.001). In comparison to the NRS 2002 score, the mNUTRIC score demonstrated a superior prognostic ability in ECMO patients.

The occurrence of pressure injuries and related risk factors in patients undergoing extracorporeal membrane oxygenation for respiratory failure: A retrospective single centre study

INTRODUCTION

Limited data is available regarding the incidence of pressure injuries in patients who have undergone Extracorporeal Membrane Oxygenation (ECMO), a life-saving technique that provides respiratory support for hypoxemia that does not respond to conventional treatment.

AIM

To assess the incidence of pressure injuries and identify the risk factors in Acute Respiratory Distress Syndrome patients receiving ECMO.

METHODS

A retrospective observational study utilizing prospectively collected data was performed in an Italian intensive care unit, between 1 January 2012 and 30 April 2022 enrolling all consecutive patients with Acute Respiratory Distress Syndrome who underwent ECMO.

RESULTS

One hundred patients were included in this study. 67 patients (67%) developed pressure injuries during their intensive care unit stay, with a median of 2 (1-3) sites affected. The subgroup of patients with pressure injuries was more hypoxic before ECMO implementation, received more frequent continuous renal replacement therapy and prone positioning, and showed prolonged ECMO duration, intensive care unit and hospital length of stay compared to patients without pressure injuries. The logistic model demonstrated an independent association between the pO2/FiO2 ratio prior to ECMO initiation, the utilization of the prone positioning during ECMO, and the occurrence of pressure injuries.

CONCLUSIONS

The incidence of pressure injuries was elevated in patients with Adult Respiratory Distress Syndrome who received ECMO. The development of pressure injuries was found to be independently associated with hypoxemia before ECMO initiation and the utilization of prone positioning during ECMO.

IMPLICATIONS FOR CLINICAL PRACTICE

Patients who require ECMO for respiratory failure are at a high risk of developing pressure injuries. To ensure optimal outcomes during ECMO implementation and treatment, it is vital to implement preventive measures and to closely monitor skin health in at-risk areas.

Study on risk factors and treatment strategies of hypoxemia after acute type a aortic dissection surgery

Acute type A aortic dissection is a life-threatening cardiovascular disease characterized by rapid onset and high mortality. Emergency surgery is the preferred and reliable treatment option. However, postoperative complications significantly impact patient prognosis. Hypoxemia, a common complication, poses challenges in clinical treatment, negatively affecting patient outcomes and increasing the risk of mortality. Therefore, it is crucial to study and comprehend the risk factors and treatment strategies for hypoxemia following acute type A aortic dissection to facilitate early intervention.

[COVID-19 in the intensive care unit]

The acute respiratory failure as well as ARDS (acute respiratory distress syndrome) have challenged clinicians since the initial description over 50 years ago. Various causes can lead to ARDS and therapeutic approaches for ARDS/ARF are limited to the support or replacement of organ functions and the prevention of therapy-induced consequences. In recent years, triggered by the SARS-CoV-2 pathogen, numerous cases of acute lung failure (C-ARDS) have emerged. The pathophysiological processes of classical ARDS and C-ARDS are essentially similar. In their final stages of inflammation, both lead to a disruption of the blood-air barrier. Treatment strategies for C-ARDS, like classical ARDS, focus on supporting or replacing organ functions and preventing consequential damage. This article summarizes the treatment strategies in the intensive care unit.

PCO 2 Gradient Between Inlet and Outlet Blood of Extracorporeal Respiratory Support Is a Reliable Marker of CO 2 Elimination

Our objective was to assess the relationship between the pre-/post-oxygenator gradient of the partial pressure of carbon dioxide (∆ EC PCO 2 ; dissolved form) and CO 2 elimination under extracorporeal respiratory support. All patients who were treated with veno-venous extracorporeal membrane oxygenation and high-flow extracorporeal CO 2 removal in our intensive care unit over 18 months were included. Pre-/post-oxygenator blood gases were collected every 12 h and CO 2 elimination was calculated for each pair of samples (pre-/post-oxygenator total carbon dioxide content in blood [ ct CO 2 ] × pump flow [extracorporeal pump flow {Q EC }]). The relationship between ∆ EC PCO 2 and CO 2 elimination, as well as the origin of CO 2 removed. Eighteen patients were analyzed (24 oxygenators and 293 datasets). Each additional unit of ∆ EC PCO 2 × Q EC was associated with an increase in CO 2 elimination of 5.2 ml (95% confidence interval [CI], 4.7-5.6 ml; p < 0.001). Each reduction of 1 ml STPD/dl of CO 2 across the oxygenator was associated with a reduction of 0.63 ml STPD/dl (95% CI, 0.60-0.66) of CO 2 combined with water, 0.08 ml STPD/dl (95% CI, 0.07-0.09) of dissolved CO 2 , and 0.29 ml STPD/dl (95% CI, 0.27-0.31) of CO 2 in erythrocytes. The pre-/post-oxygenator PCO 2 gradient under extracorporeal respiratory support is thus linearly associated with CO 2 elimination; however, most of the CO 2 removed comes from combined CO 2 in plasma, generating bicarbonate.