Physiological effects of adding ECCO2R to invasive mechanical ventilation for COPD exacerbations

Recent Advances and Future Directions in Extracorporeal Carbon Dioxide Removal

Extracorporeal carbon dioxide removal (ECCO2R) is an emerging technique designed to reduce carbon dioxide (CO2) levels in venous blood while enabling lung-protective ventilation or alleviating the work of breathing. Unlike high-flow extracorporeal membrane oxygenation (ECMO), ECCO2R operates at lower blood flows (0.4-1.5 L/min), making it less invasive, with smaller cannulas and simpler devices. Despite encouraging results in controlling respiratory acidosis, its broader adoption is hindered by complications, including haemolysis, thrombosis, and bleeding. Technological advances, including enhanced membrane design, gas exchange efficiency, and anticoagulation strategies, are essential to improving safety and efficacy. Innovations such as wearable prototypes that adapt CO2 removal to patient activity and catheter-based systems for lower blood flow are expanding the potential applications of ECCO2R, including as a bridge-to-lung transplantation and in outpatient settings. Promising experimental approaches include respiratory dialysis, carbonic anhydrase-coated membranes, and electrodialysis to maximise CO2 removal. Further research is needed to optimise device performance, develop cost-effective systems, and establish standardised protocols for safe clinical implementation. As the technology matures, integration with artificial intelligence (AI) and machine learning may personalise therapy, improving outcomes. Ongoing clinical trials will be pivotal in addressing these challenges, ultimately enhancing the role of ECCO2R in critical care and its accessibility across healthcare settings.

Physiological Assessment of ECCO2R on the Work of Breathing in Exacerbations of COPD

RATIONALE

The impact of extracorporeal carbon dioxide removal (ECCO2R) on work of breathing and aeration in exacerbations of chronic obstructive pulmonary disease (AECOPD) is poorly understood.

OBJECTIVES

The study explores the impact of non-invasive ventilation (NIV) and ECCO2R on respiratory drive, effort and distribution of ventilation in AECOPD.

METHODS

Patients enrolled in a randomised controlled study of the addition of ECCO2R to NIV compared with NIV underwent oesophageal pressure measurement, electrical impedance tomography and parasternal electromyography.

MEASUREMENTS AND MAIN RESULTS

18 patients were enrolled, nine in each arm. Of these, eight in the NIV arm and seven in the ECCO2R arm underwent physiological assessment. Patients randomised to ECCO2R, had a period of NIV combined with ECCO2R and, after removal of NIV, a period of ECCO2R alone. The removal of NIV whilst remaining on ECCO2R resulted in a respiratory acidosis (pH 7.34 (7.31-7.34) vs. 7.31 (7.31-7.34), p < 0.0001), increased work of breathing (7.43 (6.08-10.19) vs. 11.1 (8.11-15.15) J/min, p < 0.0001) and increased neural drive (884.4 (684.7-967.3) vs. 1321.1 (903.3-1575.3) AU, p = 0.0005). On day 1, the work of breathing was lower in the NIV than the ECCO2R group (4.38 (2.76-7.27) vs. 8.03 (4.8-15.94) J/min, p < 0.0001), minute ventilation was higher (15.54 (13.14-18.48) vs. 12.24 (8.51-13.9) L/min, p < 0.0001) and neural drive was the same (1,163.8 (1,085.5-1,325.5) vs. 1,093.8 (885.7-1,258.7) AU, p = 0.5556).

CONCLUSIONS

The combination of NIV and ECCO2R results in lower work of breathing and improved neuro-ventilatory coupling. NIV fully supports ventilation early whilst ECCO2R improves neuro-ventilatory coupling and work of breathing over time.

TRIAL REGISTRATION

Clinicaltrials.gov; NCT02086084; registered 1 December 2015; https://clinicaltrials.gov/study/NCT02086084?cond=copd&term=ecco2r&rank=4.

Effects of extracorporeal CO2 removal on gas exchange and ventilator settings: a systematic review and meta-analysis

PURPOSE

A systematic review and meta-analysis to evaluate the impact of extracorporeal carbon dioxide removal (ECCO2R) on gas exchange and respiratory settings in critically ill adults with respiratory failure.

METHODS

We conducted a comprehensive database search, including observational studies and randomized controlled trials (RCTs) from January 2000 to March 2022, targeting adult ICU patients undergoing ECCO2R. Primary outcomes were changes in gas exchange and ventilator settings 24 h after ECCO2R initiation, estimated as mean of differences, or proportions for adverse events (AEs); with subgroup analyses for disease indication and technology. Across RCTs, we assessed mortality, length of stay, ventilation days, and AEs as mean differences or odds ratios.

RESULTS

A total of 49 studies encompassing 1672 patients were included. ECCO2R was associated with a significant decrease in PaCO2, plateau pressure, and tidal volume and an increase in pH across all patient groups, at an overall 19% adverse event rate. In ARDS and lung transplant patients, the PaO2/FiO2 ratio increased significantly while ventilator settings were variable. "Higher extraction" systems reduced PaCO2 and respiratory rate more efficiently. The three available RCTs did not demonstrate an effect on mortality, but a significantly longer ICU and hospital stay associated with ECCO2R.

CONCLUSIONS

ECCO2R effectively reduces PaCO2 and acidosis allowing for less invasive ventilation. "Higher extraction" systems may be more efficient to achieve this goal. However, as RCTs have not shown a mortality benefit but increase AEs, ECCO2R's effects on clinical outcome remain unclear. Future studies should target patient groups that may benefit from ECCO2R. PROSPERO Registration No: CRD 42020154110 (on January 24, 2021).

Extracorporeal Carbon Dioxide Removal to Avoid Invasive Ventilation During Exacerbations of Chronic Obstructive Pulmonary Disease: VENT-AVOID Trial - A Randomized Clinical Trial

Rationale: It is unclear whether extracorporeal CO2 removal (ECCO2R) can reduce the rate of intubation or the total time on invasive mechanical ventilation (IMV) in adults experiencing an exacerbation of chronic obstructive pulmonary disease (COPD). Objectives: To determine whether ECCO2R increases the number of ventilator-free days within the first 5 days postrandomization (VFD-5) in exacerbation of COPD in patients who are either failing noninvasive ventilation (NIV) or who are failing to wean from IMV. Methods: This randomized clinical trial was conducted in 41 U.S. institutions (2018-2022) (ClinicalTrials.gov ID: NCT03255057). Subjects were randomized to receive either standard care with venovenous ECCO2R (NIV stratum: n = 26; IMV stratum: n = 32) or standard care alone (NIV stratum: n = 22; IMV stratum: n = 33). Measurements and Main Results: The trial was stopped early because of slow enrollment and enrolled 113 subjects of the planned sample size of 180. There was no significant difference in the median VFD-5 between the arms controlled by strata (P = 0.36). In the NIV stratum, the median VFD-5 for both arms was 5 days (median shift = 0.0; 95% confidence interval [CI]: 0.0-0.0). In the IMV stratum, the median VFD-5 in the standard care and ECCO2R arms were 0.25 and 2 days, respectively; median shift = 0.00 (95% confidence interval: 0.00-1.25). In the NIV stratum, all-cause in-hospital mortality was significantly higher in the ECCO2R arm (22% vs. 0%, P = 0.02) with no difference in the IMV stratum (17% vs. 15%, P = 0.73). Conclusions: In subjects with exacerbation of COPD, the use of ECCO2R compared with standard care did not improve VFD-5. Clinical trial registered with www.clinicaltrials.gov (NCT03255057).

Debate: Intermittent Hemodialysis versus Continuous Kidney Replacement Therapy in the Critically Ill Patient: The Argument for CKRT

Continuous kidney replacement therapy (CKRT) is well entrenched as one of the dominant KRT modalities in modern critical care practice. Since its introduction four decades ago, there have been considerable innovations in CKRT machines that have improved precision, safety, and simplicity. CKRT is the preferred KRT modality for critically ill patients with hemodynamic instability. Early physical therapy and rehabilitation can be feasibly and safely provided to patients connected to CKRT, thus obviating concerns about immobility. Although randomized clinical trials have not shown a mortality difference when comparing CKRT and intermittent hemodialysis, CKRT allows precision delivery of solute and fluid removal that can be readily adjusted in the face of dynamic circumstances. Accumulated evidence from observational studies, although susceptible to bias, has shown that CKRT, when compared with intermittent hemodialysis, is associated with better short- and long-term kidney recovery and KRT independence. Critical care medicine encompasses a wide range of sick patients, and no single KRT modality is likely to ideally suit every patient in every context and for every condition. The provision of KRT represents a spectrum of modalities to which patients can flexibly transition in response to their evolving condition. As a vital tool for organ support in the intensive care unit, CKRT enables the personalization of KRT to meet the clinical demands of patients during the most severe phases of their illness.

ERS International Congress, Virtual 2021: Highlights from the Respiratory Intensive Care Assembly Early Career Members

Early Career Members of Assembly 2 (Respiratory Intensive Care) attended the European Respiratory Society International Congress through a virtual platform in 2021. Sessions of interest to our assembly members included symposia on the implications of acute respiratory distress syndrome phenotyping on diagnosis and treatment, safe applications of noninvasive ventilation in hypoxaemic respiratory failure, and new developments in mechanical ventilation and weaning, and a guidelines session on applying high-flow therapy in acute respiratory failure. These sessions are summarised in this article.

Early Career Members of @ERSAssembly2 attended the #ERSCongress 2021, and reported on symposia on ARDS phenotyping, noninvasive ventilation in hypoxic respiratory failure, ventilator weaning and high-flow therapy in acute respiratory failurehttps://bit.ly/3D68r50

Extracorporeal CO2 removal in acute exacerbation of COPD unresponsive to non-invasive ventilation

Background

The gold-standard treatment for acute exacerbation of chronic obstructive pulmonary disease (ae-COPD) is non-invasive ventilation (NIV). However, NIV failures may be observed, and invasive mechanical ventilation (IMV) is required. Extracorporeal CO₂ removal (ECCO₂R) devices can be an alternative to intubation. The aim of the study was to assess ECCO₂R effectiveness and safety.

Methods

Patients with consecutive ae-COPD who experienced NIV failure were retrospectively assessed over two periods of time: before and after ECCO₂R device implementation in our ICU in 2015 (Xenios AG).

Results

Both groups (ECCO₂R: n=26, control group: n=25) were comparable at baseline, except for BMI, which was significantly higher in the ECCO₂R group (30 kg/m² vs 25 kg/m²). pH and PaCO₂ significantly improved in both groups. The mean time on ECCO₂R was 5.4 days versus 27 days for IMV in the control group. Four patients required IMV in the ECCO₂R group, of whom three received IMV after ECCO₂R weaning. Seven major bleeding events were observed with ECCO₂R, but only three led to premature discontinuation of ECCO₂R. Eight cases of ventilator-associated pneumonia were observed in the control group. Mean time spent in the ICU and mean hospital stay in the ECCO₂R and control groups were, respectively, 18 vs 30 days, 29 vs 49 days, and the 90-day mortality rates were 15% vs 28%.

Conclusions

ECCO₂R was associated with significant improvement of pH and PaCO₂ in patients with ae-COPD failing NIV therapy. It also led to avoiding intubation in 85% of cases, with low complication rates.

Trial registration number

ClinicalTrials.gov, NCT04882410. Date of registration 12 May 2021, retrospectively registered.

https://www.clinicaltrials.gov/ct2/show/NCT04882410.