Lung- and diaphragm-protective strategies in acute respiratory failure: an in silico trial

BACKGROUND

Lung- and diaphragm-protective (LDP) ventilation may prevent diaphragm atrophy and patient self-inflicted lung injury in acute respiratory failure, but feasibility is uncertain. The objectives of this study were to estimate the proportion of patients achieving LDP targets in different modes of ventilation, and to identify predictors of need for extracorporeal carbon dioxide removal (ECCO2R) to achieve LDP targets.

METHODS

An in silico clinical trial was conducted using a previously published mathematical model of patient-ventilator interaction in a simulated patient population (n = 5000) with clinically relevant physiological characteristics. Ventilation and sedation were titrated according to a pre-defined algorithm in pressure support ventilation (PSV) and proportional assist ventilation (PAV+) modes, with or without adjunctive ECCO2R, and using ECCO2R alone (without ventilation or sedation). Random forest modelling was employed to identify patient-level factors associated with achieving targets.

RESULTS

After titration, the proportion of patients achieving targets was lower in PAV+ vs. PSV (37% vs. 43%, odds ratio 0.78, 95% CI 0.73-0.85). Adjunctive ECCO2R substantially increased the probability of achieving targets in both PSV and PAV+ (85% vs. 84%). ECCO2R alone without ventilation or sedation achieved LDP targets in 9%. The main determinants of success without ECCO2R were lung compliance, ventilatory ratio, and strong ion difference. In silico trial results corresponded closely with the results obtained in a clinical trial of the LDP titration algorithm (n = 30).

CONCLUSIONS

In this in silico trial, many patients required ECCO2R in combination with mechanical ventilation and sedation to achieve LDP targets. ECCO2R increased the probability of achieving LDP targets in patients with intermediate degrees of derangement in elastance and ventilatory ratio.

A randomised controlled trial of non-invasive ventilation compared with extracorporeal carbon dioxide removal for acute hypercapnic exacerbations of chronic obstructive pulmonary disease

Background

Patients presenting with acute hypercapnic respiratory failure due to exacerbations of chronic obstructive pulmonary disease (AECOPD) are typically managed with non-invasive ventilation (NIV). The impact of low-flow extracorporeal carbon dioxide removal (ECCO₂R) on outcome in these patients has not been explored in randomised trials.

Methods

Open-label randomised trial comparing NIV (NIV arm) with ECCO₂R (ECCO₂R arm) in patients with AECOPD at high risk of NIV failure (pH < 7.30 after ≥ 1 h of NIV). The primary endpoint was time to cessation of NIV. Secondary outcomes included device tolerance and complications, changes in arterial blood gases, hospital survival.

Results

Eighteen patients (median age 67.5, IQR (61.5–71) years; median GOLD stage 3 were enrolled (nine in each arm). Time to NIV discontinuation was shorter with ECCO₂R (7:00 (6:18–8:30) vs 24:30 (18:15–49:45) h, p = 0.004). Arterial pH was higher with ECCO₂R at 4 h post-randomisation (7.35 (7.31–7.37) vs 7.25 (7.21–7.26), p < 0.001). Partial pressure of arterial CO₂ (PaCO₂) was significantly lower with ECCO₂R at 4 h (6.8 (6.2–7.15) vs 8.3 (7.74–9.3) kPa; p = 0.024). Dyspnoea and comfort both rapidly improved with commencement of ECCO₂R. There were no severe or life-threatening complications in the study population. There were no episodes of major bleeding or red blood cell transfusion in either group. ICU and hospital length of stay were longer with ECCO₂R, and there was no difference in 90-day mortality or functional outcomes at follow-up.

Interpretation

There is evidence of benefit associated with ECCO₂R with time to improvement in respiratory acidosis, in respiratory physiology and an immediate improvement in patient comfort and dyspnoea with commencement of ECCO₂R. In addition, there was minimal clinically significant adverse events associated with ECCO₂R use in patients with AECOPD at risk of failing or not tolerating NIV. However, the ICU and hospital lengths of stay were longer in the ECCO₂R for similar outcomes.

Trial registration The trial is prospectively registered on ClinicalTrials.gov: NCT02086084. Registered on 13th March 2014, https://clinicaltrials.gov/ct2/show/NCT02086084?cond=ecco2r&draw=2&rank=8

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01006-8.

Extracorporeal carbon dioxide removal for treatment of exacerbated chronic obstructive pulmonary disease (ORION): study protocol for a randomised controlled trial

Background

Hypercapnic exacerbations are severe complications of chronic obstructive pulmonary disease (COPD), characterized by negative impact on prognosis, quality of life and healthcare costs. The present standard of care for acute exacerbations of COPD is non-invasive ventilation; when it fails, the use of invasive mechanical ventilation is inevitable, but is associated with extremely poor prognosis. Extracorporeal circuits designed to remove CO₂ (ECCO₂R) may enhance the efficacy of NIV to remove CO₂ and avoid the worsening of respiratory acidosis, which inevitably leads to failure of non-invasive ventilation. Although the use of ECCO₂R for acute exacerbations of COPD is steadily increasing, solid evidence on its efficacy and safety is scarce, thus the need for a randomized controlled trial.

Methods

multicenter randomized controlled unblinded clinical trial including 284 (142 per arm) patients with acute hypercapnic respiratory failure caused by exacerbation of COPD, requiring respiratory support with NIV. The primary outcome is event free survival at 28 days, a composite outcome defined by survival in absence of prolonged mechanical ventilation, severe hypoxemia, septic shock and second episode of COPD exacerbation. Secondary outcomes are incidence of endotracheal intubation and tracheostomy, intensive care and hospital length-of-stay and 90-day mortality.

Discussion

Acute exacerbations of COPD represent a significant burden in terms of prognosis, quality of life and healthcare costs. Lack definite evidence despite increasing use of ECCO₂R justifies a randomized trial to evaluate whether patients with acute hypercapnic acidosis not responsive to NIV should undergo invasive mechanical ventilation (with all serious related risks) or be treated with ECCO₂R to avoid invasive ventilation but be exposed to possible adverse events of ECCO₂R. Owing to its pragmatic nature, sample size and composite primary outcome, this trial aims at providing valuable answers to relevant questions for clinical treatment of acute exacerbations of COPD.

Trial registration

ClinicalTrials.gov, NCT04582799. Registered 12 October 2020, .

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05692-w.

Ultraprotective ventilation allowed by extracorporeal CO2 removal improves the right ventricular function in acute respiratory distress syndrome patients: a quasi-experimental pilot study

Background

Right ventricular (RV) failure is a common complication in moderate-to-severe acute respiratory distress syndrome (ARDS). RV failure is exacerbated by hypercapnic acidosis and overdistension induced by mechanical ventilation. Veno-venous extracorporeal CO₂ removal (ECCO₂R) might allow ultraprotective ventilation with lower tidal volume (V_T) and plateau pressure (P_plat). This study investigated whether ECCO₂R therapy could affect RV function.

Methods

This was a quasi-experimental prospective observational pilot study performed in a French medical ICU. Patients with moderate-to-severe ARDS with PaO₂/FiO₂ ratio between 80 and 150 mmHg were enrolled. An ultraprotective ventilation strategy was used with V_T at 4 mL/kg of predicted body weight during the 24 h following the start of a low-flow ECCO₂R device. RV function was assessed by transthoracic echocardiography (TTE) during the study protocol.

Results

The efficacy of ECCO₂R facilitated an ultraprotective strategy in all 18 patients included. We observed a significant improvement in RV systolic function parameters. Tricuspid annular plane systolic excursion (TAPSE) increased significantly under ultraprotective ventilation compared to baseline (from 22.8 to 25.4 mm; p < 0.05). Systolic excursion velocity (S’ wave) also increased after the 1-day protocol (from 13.8 m/s to 15.1 m/s; p < 0.05). A significant improvement in the aortic velocity time integral (VTIAo) under ultraprotective ventilation settings was observed (p = 0.05). There were no significant differences in the values of systolic pulmonary arterial pressure (sPAP) and RV preload.

Conclusion

Low-flow ECCO₂R facilitates an ultraprotective ventilation strategy thatwould improve RV function in moderate-to-severe ARDS patients. Improvement in RV contractility appears to be mainly due to a decrease in intrathoracic pressure allowed by ultraprotective ventilation, rather than a reduction of PaCO₂.

Extracorporeal multiorgan support including CO2-removal with the ADVanced Organ Support (ADVOS) system for COVID-19: A case report

A substantial part of COVID-19-patients suffers from multi-organ failure (MOF). We report on an 80-year old patient with pulmonary, renal, circulatory, and hepatic failure. We decided against the use of extracorporeal membrane oxygenation (ECMO) due to old age and a SOFA-score of 13. However, the patient was continuously treated with the extracorporeal multi-organ- “ADVanced Organ Support” (ADVOS) device (ADVITOS GmbH, Munich, Germany). During eight 24h-treatment-sessions blood flow (100–300 mL/min), dialysate flow (160–320 mL/min) and dialysate pH (7.6–9.0) were adapted to optimize arterial PaCO₂ and pH. Effective CO₂ removal and correction of acidosis could be demonstrated by mean arterial- versus post-dialyzer values of pCO₂ (68.7 ± 13.8 vs. 26.9 ± 11.6 mmHg; p < 0.001). The CO₂-elimination rate was 48 ± 23mL/min. The initial vasopressor requirement could be reduced in parallel to pH-normalization. Interruptions of ADVOS-treatment repeatedly resulted in reversible deteriorations of p_aCO₂ and pH. After 95 h of continuous extracorporeal decarboxylating therapy the patient had markedly improved circulatory parameters compared to baseline. In the context of secondary pulmonary infection and progressive liver failure, the patient had a sudden cardiac arrest. In accordance with the presumed patient will, we decided against mechanical resuscitation. Irrespective of the outcome we conclude that extracorporeal CO₂ removal and multiorgan-support were feasible in this COVID-19-patient. Combined and less invasive approaches such as ADVOS might be considered in old-age-COVID-19 patients with MOF.

In vivo testing of the low-flow CO2 removal application of a compact, platform respiratory device

BACKGROUND

Non-invasive and lung-protective ventilation techniques may improve outcomes for patients with an acute exacerbation of chronic obstructive pulmonary disease or moderate acute respiratory distress syndrome by reducing airway pressures. These less invasive techniques can fail due to hypercapnia and require transitioning patients to invasive mechanical ventilation. Extracorporeal CO2 removal devices remove CO2 independent of the lungs thereby controlling the hypercapnia and permitting non-invasive or lung-protective ventilation techniques. We are developing the Modular Extracorporeal Lung Assist System as a platform technology capable of providing three levels of respiratory assist: adult and pediatric full respiratory support and adult low-flow CO2 removal. The objective of this study was to evaluate the in vivo performance of our device to achieve low-flow CO2 removal.

METHODS

The Modular Extracorporeal Lung Assist System was connected to 6 healthy sheep via a 15.5 Fr dual-lumen catheter placed in the external jugular vein. The animals were recovered and tethered within a pen while supported by the device for 7 days. The pump speed was set to achieve a targeted blood flow of 500 mL/min. The extracorporeal CO2 removal rate was measured daily at a sweep gas independent regime. Hematological parameters were measured pre-operatively and regularly throughout the study. Histopathological samples of the end organs were taken at the end of each study.

RESULTS

All animals survived the surgery and generally tolerated the device well. One animal required early termination due to a pulmonary embolism. Intra-device thrombus formation occurred in a single animal due to improper anticoagulation. The average CO2 removal rate (normalized to an inlet pCO2 of 45 mmHg) was 75.6 ± 4.7 mL/min and did not significantly change over the course of the study (p > 0.05). No signs of consistent hemolysis or end organ damage were observed.

CONCLUSION

These in vivo results indicate positive performance of the Modular Extracorporeal Lung Assist System as a low-flow CO2 removal device.

Options in extracorporeal support of multiple organ failure

Multiorgan failure is among the most frequent reasons of death in critically ill patients. Based on extensive and long-term use of renal replacement therapy, extracorporeal organ support became available for other organ failures. Initially, most of these techniques (e.g. extracorporeal membrane oxygenation, extracorporeal CO₂ removal [ECCO2R] and extracorporeal liver support) were used as stand-alone single organ support systems. Considering multiple interactions between native organs (“crosstalk”), combined or integrated extracorporeal organ support (ECOS) devices are intriguing. The concept of multiple organ support therapy (MOST) providing simultaneous and combined support for different failing organs was described more than 15 years ago by Ronco and Bellomo. This concept also implicates overcoming the “compartmentalized” approach provided by different single organ specialized professionals by a multidisciplinary and multiprofessional strategy. The idea of MOST is supported by the failure of several recent studies on single organ support including liver and lung support. Improvement of outcome by ECOS necessarily depends on optimized patient selection, integrated organ support and limitation of its side effects. This implicates challenges for engineers, industry and healthcare professionals. From a technical viewpoint, modular combination of pre-existing technologies such as renal replacement, albumin-dialysis, ECCO2R and potentially cytokine elimination can be considered as a first step. While this allows for stepwise and individual combination of standard organ support facilities, it carries the disadvantage of large extracorporeal blood volume and surfaces as well as additive costs. The more intriguing next step is an integrated platform providing the capacity of multiple organ support within one device. (This article is freely available.)

A 2-year multicenter, observational, prospective, cohort study on extracorporeal CO2 removal in a large metropolis area

Background

Extracorporeal carbon dioxide removal (ECCO₂R) is a promising technique for the management of acute respiratory failure, but with a limited level of evidence to support its use outside clinical trials and/or data collection initiatives. We report a collaborative initiative in a large metropolis.

Methods

To assess on a structural basis the rate of utilization as well as efficacy and safety parameters of 2 ECCO₂R devices in 10 intensive care units (ICU) during a 2-year period.

Results

Seventy patients were recruited in 10 voluntary and specifically trained centers. The median utilization rate was 0.19 patient/month/center (min 0.04; max 1.20). ECCO₂R was started under invasive mechanical ventilation (IMV) in 59 patients and non-invasive ventilation in 11 patients. The Hemolung Respiratory Assist System (Alung) was used in 53 patients and the iLA Activve iLA kit (Xenios Novalung) in 17 patients. Main indications were ultraprotective ventilation for ARDS patients (n = 24), shortening the duration of IMV in COPD patients (n = 21), preventing intubation in COPD patients (n = 9), and controlling hypercapnia and dynamic hyperinflation in mechanically ventilated patients with severe acute asthma (n = 6). A reduction in median V_T was observed in ARDS patients from 5.9 to 4.1 ml/kg (p <0.001). A reduction in PaCO₂ values was observed in AE-COPD patients from 67.5 to 51 mmHg (p< 0.001). Median duration of ECCO₂R was 5 days (IQR 3–8). Reasons for ECCO₂R discontinuation were improvement (n = 33), ECCO₂R-related complications (n = 18), limitation of life-sustaining therapies or measures decision (n = 10), and death (n = 9). Main adverse events were hemolysis (n = 21), bleeding (n = 17), and lung membrane clotting (n = 11), with different profiles between the devices. Thirty-five deaths occurred during the ICU stay, 3 of which being ECCO₂R-related.

Conclusions

Based on a registry, we report a low rate of ECCO₂R device utilization, mainly in severe COPD and ARDS patients. Physiological efficacy was confirmed in these two populations. We confirmed safety concerns such as hemolysis, bleeding, and thrombosis, with different profiles between the devices. Such results could help to design future studies aiming to enhance safety, to demonstrate a still-lacking strong clinical benefit of ECCO₂R, and to guide the choice between different devices.

Trial registration

ClinicalTrials.gov: Identifier: NCT02965079 retrospectively registered https://clinicaltrials.gov/ct2/show/NCT02965079

Extracorporeal carbon dioxide removal for acute hypercapnic exacerbations of chronic obstructive pulmonary disease: study protocol for a randomised controlled trial

Background

Chronic obstructive pulmonary disease (COPD) is a common cause of chronic respiratory failure and its course is punctuated by a series of acute exacerbations which commonly lead to hospital admission. Exacerbations are managed through the application of non-invasive ventilation and, when this fails, tracheal intubation and mechanical ventilation. The need for mechanical ventilation significantly increases the risk of death. An alternative therapy, extracorporeal carbon dioxide removal (ECCO₂R), has been shown to be efficacious in removing carbon dioxide from the blood; however, its impact on respiratory physiology and patient outcomes has not been explored.

Methods/design

A randomised controlled open label trial of patients (12 in each arm) with acute exacerbations of COPD at risk of failing conventional therapy (NIV) randomised to either remaining on NIV or having ECCO₂R added to NIV with a primary endpoint of time to cessation of NIV. The change in respiratory physiology following the application of ECCO₂R and/or NIV will be measured using electrical impedance tomography, oesophageal pressure and parasternal electromyography. Additional outcomes, including patient tolerance, outcomes, need for readmission, changes in blood gases and biochemistry and procedural complications, will be measured. Physiological changes will be compared within one patient over time and between the two groups. Healthcare costs in the UK system will also be compared between the two groups.

Discussion

COPD is a common disease and exacerbations are a leading cause of hospital admission in the UK and worldwide, with a sizeable mortality. The management of patients with COPD consumes significant hospital and financial resources. This study seeks to understand the feasibility of a novel approach to the management of patients with acute exacerbations of COPD as well as to understand the underlying physiological changes to explain why the approach does or does not assist this patient cohort. Detailed respiratory physiology has not been previously undertaken using this technique and there are no other randomised controlled trials currently in the literature.

Trial registration

ClinicalTrials.gov, NCT02086084.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3548-4) contains supplementary material, which is available to authorized users.

Regional anticoagulation with heparin of an extracorporeal CO2 removal circuit: a case report

Background

Extracorporeal carbon dioxide removal is an increasingly used respiratory support technique. As is true of all extracorporeal techniques, extracorporeal carbon dioxide removal needs proper anticoagulation. We report a case of a patient at risk of bleeding complications who was treated with extracorporeal carbon dioxide removal and anticoagulated with a regional technique.

Case presentation

A 56-year-old Caucasian man with a history of chronic obstructive pulmonary disease exacerbation required extracorporeal carbon dioxide removal for severe hypercapnia and acidosis despite mechanical ventilation. The extracorporeal circuit was anticoagulated using a regional heparin technique to limit the patient’s risk of bleeding due to a low platelet count. The patient underwent 96 h of effective extracorporeal carbon dioxide removal without any adverse events. He was successfully weaned from extracorporeal carbon dioxide removal. During the treatment, no bleeding complications or unexpected circuit clotting was observed.

Conclusions

The use of regional heparin anticoagulation technique seems to be feasible and safe during extracorporeal carbon dioxide removal.

Bench Validation of a Compact Low-Flow CO2 Removal Device

Background

There is increasing evidence demonstrating the value of partial extracorporeal CO₂ removal (ECCO₂R) for the treatment of hypercapnia in patients with acute exacerbations of chronic obstructive pulmonary disease and acute respiratory distress syndrome. Mechanical ventilation has traditionally been used to treat hypercapnia in these patients, however, it has been well-established that aggressive ventilator settings can lead to ventilator-induced lung injury. ECCO₂R removes CO₂ independently of the lungs and has been used to permit lung protective ventilation to prevent ventilator-induced lung injury, prevent intubation, and aid in ventilator weaning. The Low-Flow Pittsburgh Ambulatory Lung (LF-PAL) is a low-flow ECCO₂R device that integrates the fiber bundle (0.65 m²) and centrifugal pump into a compact unit to permit patient ambulation.

Methods

A blood analog was used to evaluate the performance of the pump at various impeller rotation rates. In vitro CO₂ removal tested under normocapnic conditions and 6-h hemolysis testing were completed using bovine blood. Computational fluid dynamics and a mass-transfer model were also used to evaluate the performance of the LF-PAL.

Results

The integrated pump was able to generate flows up to 700 mL/min against the Hemolung 15.5 Fr dual lumen catheter. The maximum vCO₂ of 105 mL/min was achieved at a blood flow rate of 700 mL/min. The therapeutic index of hemolysis was 0.080 g/(100 min). The normalized index of hemolysis was 0.158 g/(100 L).

Conclusions

The LF-PAL met pumping, CO₂ removal, and hemolysis design targets and has the potential to enable ambulation while on ECCO₂R.

A mathematical model of CO2, O2 and N2 exchange during venovenous extracorporeal membrane oxygenation

Background

Venovenous extracorporeal membrane oxygenation (vv-ECMO) is an effective treatment for severe respiratory failure. The interaction between the cardiorespiratory system and the oxygenator can be explored with mathematical models. Understanding the physiology will help the clinician optimise therapy. As others have examined O₂ exchange, the main focus of this study was on CO₂ exchange.

Methods

A model of the cardiorespiratory system during vv-ECMO was developed, incorporating O₂, CO₂ and N₂ exchange in both the lung and the oxygenator. We modelled lungs with shunt fractions varying from 0 to 1, covering the plausible range from normal lung to severe acute respiratory distress syndrome. The effects on P_aCO₂ of varying the input parameters for the cardiorespiratory system and for the oxygenator were examined.

Results

P_aCO₂ increased as the shunt fraction in the lung and metabolic CO₂ production rose. Changes in haemoglobin and F_IO₂ had minimal effect on P_aCO₂. The effect of cardiac output on P_aCO₂ was variable, depending on the shunt fraction in the lung.

P_aCO₂ decreased as extracorporeal circuit blood flow was increased, but the changes were relatively small in the range used clinically for vv-ECMO of > 2 l/min. P_aCO₂ decreased as gas flow to the oxygenator rose and increased with recirculation. The oxygen fraction of gas flow to the oxygenator had minimal effect on P_aCO₂.

Conclusions

This mathematical model of gas exchange during vv-ECMO found that the main determinants of P_aCO₂ during vv-ECMO were pulmonary shunt fraction, metabolic CO₂ production, gas flow to the oxygenator and extracorporeal circuit recirculation.

Electronic supplementary material

The online version of this article (10.1186/s40635-018-0183-4) contains supplementary material, which is available to authorized users.

Daily use of extracorporeal CO2 removal in a critical care unit: indications and results

Background

While outcome improvement with extracorporeal CO₂ removal (ECCO₂R) is not demonstrated, a strong pathophysiological rational supports its use in the setting of acute respiratory distress syndrome (ARDS) and COPD exacerbation. We aimed to describe our single-center experience of ECCO₂R indications and outcome.

Methods

Patients treated with ECCO₂R in our medial ICU, from March 2014 to November 2017, were retrospectively enrolled. Primary end point was evolution of ventilator settings during the two first days following ECCO₂R start.

Results

Thirty-three patients received ECCO₂R. Seventeen were managed with Hemolung®, 10 with Prismalung®, 4 with ILA®, and 2 with Cardiohelp®. Indications for ECCO₂R were mild or moderate ARDS (n = 16), COPD exacerbation (n = 11), or uncontrolled hypercapnia due to other causes (n = 6). Four patients were not intubated at the time of ECCO₂R start. Median duration of ECCO₂R treatment was 7 days [5–10]. In ARDS patients, between baseline and day 2, median tidal volume and driving pressure decreased from 5.3 [4.4–5.9] mL/kg and 10 [8–15] to 3.8 [3.3–4.1] mL/kg and 9 [8–11], respectively. Prone positioning was performed in 10 of the 16 patients, without serious adverse event. In COPD patients, between baseline and day 2, median ventilation minute and PaCO2 decreased significantly from respectively 7.6 [6.6–8.7] L/min and 9.4 [8.4–10.1] kPa to 5.8 [4.9–6.2] L/min and 6 [5.3–6.8] kPa. Four out of 11 COPD patients were extubated while on ECCO₂R. Device thrombosis occurred in 5 patients (15%). Hemolysis was documented in 16 patients (48%). One patient died of intracranial hemorrhage, while on ECCO₂R. Twenty-four patients were discharged from ICU alive. Twenty-eight day mortality was 31% in ARDS, 9% in COPD patients, and 50% in other causes of refractory hypercapnic respiratory failure.

Conclusion

ECCO₂R was useful to apply ultra-protective ventilation among ARDS patients and improved PaCO₂, pH, and minute ventilation in COPD patients.

Electronic supplementary material

The online version of this article (10.1186/s40560-018-0304-x) contains supplementary material, which is available to authorized users.

Do we need randomized clinical trials in extracorporeal respiratory support? Yes

Extracorporeal respiratory support, also known as extracorporeal gas exchange, may be used to rescue the most severe forms of acute hypoxemic respiratory failure with high blood flow venovenous extracorporeal membrane oxygenation. Alternatively, lower flow extracorporeal carbon dioxide removal might be applied to reduce the intensity of mechanical ventilation in patients with less severe forms of the disease. However, critical reading of the results of the randomized trials and case series published to date reveals major methodological biases. Older trials are not relevant anymore since the ECMO circuitry was not heparin-coated leading to severe hemorrhagic complications due to high levels of anticoagulation, and because extracorporeal membrane oxygenation (ECMO) and control group patients did not receive lung-protective ventilation. Alternatively, in the more recent CESAR trial, many patients randomized to the ECMO arm did not receive ECMO and no standardized protocol for lung-protective mechanical ventilation existed in the control group. Since these techniques are costly and associated with potentially serious adverse events, there is an urgent need for high-quality data, for which the cornerstone remains randomized controlled trials.

Extracorporeal carbon dioxide removal (ECCO2R) in patients with acute respiratory failure

PURPOSE

To review the available knowledge related to the use of ECCO₂R as adjuvant strategy to mechanical ventilation (MV) in various clinical settings of acute respiratory failure (ARF).

METHODS

Expert opinion and review of the literature.

RESULTS

ECCO₂R may be a promising adjuvant therapeutic strategy for the management of patients with severe exacerbations of COPD and for the achievement of protective or ultra-protective ventilation in patients with ARDS without life-threatening hypoxemia. Given the observational nature of most of the available clinical data and differences in technical features and performances of current devices, the balance of risks and benefits for or against ECCO₂R in such patient populations remains unclear CONCLUSIONS: ECCO₂R is currently an experimental technique rather than an accepted therapeutic strategy in ARF-its safety and efficacy require confirmation in clinical trials.

[Extracorporeal CO2 removal as an alternative to tracheotomy in a patient with extubation failure]

We report a patient with chest trauma who was admitted to the ICU after surgery. As he fulfilled protocol-based criteria, he was extubated 7 days after admission. However, despite intermittent non-invasive ventilation, the patient had to be re-intubated on day 10 owing to progressive hypercapnia. We decided to support the patient with a mid-flow veno-venous extracorporeal carbon dioxide removal (ECCO₂‑R) system instead of a tracheotomy. Sufficient CO₂ removal was established with a blood flow of 1.5 l/min and the patient was successfully extubated within a few hours. After 5 days of ECCO₂‑R the patient could be weaned and transferred to a general ward in a stable condition.

Successful management of acute respiratory failure in an Idiopathic Pulmonary Fibrosis patient using an extracorporeal carbon dioxide removal system

Patients with Idiopathic Pulmonary Fibrosis (IPF) requiring Invasive Mechanical Ventilation (IMV) following unsuccessful treatment with Non-Invasive Ventilation (NIV) have a high mortality rate. IMV is, moreover, an independent predictor of poor outcome during the post-transplantation period in patients on waiting lists for Lung Transplantation (LT). Here we describe the successful management of an IPF patient with acute respiratory failure (ARF) using a pump-assisted veno-venous system for extracorporeal CO2 removal (ECCO2R) (ProLUNG® system) as an alternative to endotracheal intubation (ETI) following NIV failure. Given this positive experience, further studies are warranted focusing on the ECCO2R system's tolerability, safety, and efficacy in patients with IPF and severe ARF in whom NIV alone is ineffective.

Extracorporeal life support for patients with acute respiratory distress syndrome: report of a Consensus Conference

The influenza H1N1 epidemics in 2009 led a substantial number of people to develop severe acute respiratory distress syndrome and refractory hypoxemia. In these patients, extracorporeal membrane oxygenation was used as rescue oxygenation therapy. Several randomized clinical trials and observational studies suggested that extracorporeal membrane oxygenation associated with protective mechanical ventilation could improve outcome, but its efficacy remains uncertain. Organized by the Société de Réanimation de Langue Française (SRLF) in conjunction with the Société Française d’Anesthésie et de Réanimation (SFAR), the Société de Pneumologie de Langue Française (SPLF), the Groupe Francophone de Réanimation et d’Urgences Pédiatriques (GFRUP), the Société Française de Perfusion (SOFRAPERF), the Société Française de Chirurgie Thoracique et Cardiovasculaire (SFCTV) et the Sociedad Española de Medecina Intensiva Critica y Unidades Coronarias (SEMICYUC), a Consensus Conference was held in December 2013 and a jury of 13 members wrote 65 recommendations to answer the five following questions regarding the place of extracorporeal life support for patients with acute respiratory distress syndrome: 1) What are the available techniques?; 2) Which patients could benefit from extracorporeal life support?; 3) How to perform extracorporeal life support?; 4) How and when to stop extracorporeal life support?; 5) Which organization should be recommended? To write the recommendations, evidence-based medicine (GRADE method), expert panel opinions, and shared decisions taken by all the thirteen members of the jury of the Consensus Conference were taken into account.