The use of extracorporeal carbon dioxide removal to avoid intubation in patients failing non-invasive ventilation--a cost analysis

Extracorporeal carbon dioxide removal for patients with acute respiratory failure: a systematic review and meta-analysis

BACKGROUND

Acute respiratory failure (ARF) is a common clinical critical syndrome with substantial mortality. Extracorporeal carbon dioxide removal (ECCO₂R) has been proposed for the treatment of ARF. However, whether ECCO₂R could provide a survival advantage for patients with ARF is still controversial.

METHODS

Electronic databases (PubMed, Embase, Web of Science, and the Cochrane database) were searched from inception to 30 April 2022. Randomized controlled trials (RCTs) and observational studies that examined the following outcomes were included: mortality, length of hospital and ICU stay, intubation and tracheotomy rate, mechanical ventilation days, ventilator-free days (VFDs), respiratory parameters, and reported adverse events.

RESULTS

Four RCTs and five observational studies including 1173 participants with ARF due to COPD or ARDS were included in this meta-analysis. Pooled analyses of related studies showed no significant difference in overall mortality between ECCO₂R and control group, neither in RCTs targeted ARDS or acute hypoxic respiratory failure patients (RR 1.05, 95% CI 0.83 to 1.32, p = 0.70, I² =0.0%), nor in studies targeted patients with ARF secondary to COPD (RR 0.80, 95% CI 0.58 to 1.11, p = 0.19, I² =0.0%). A shorter duration of ICU stay in the ECCO₂R group was only obtained in observational studies (WMD -4.25, p < 0.01), and ECCO₂R was associated with a longer length of hospital stay (p = 0.02). ECCO₂R was associated with lower intubation rate (p < 0.01) and tracheotomy rate (p = 0.01), and shorter mechanical ventilation days (p < 0.01) in comparison to control group in ARF patients with COPD. In addition, an improvement in pH (p = 0.01), PaO2 (p = 0.01), respiratory rate (p < 0.01), and PaCO2 (p = 0.04) was also observed in patients with COPD exacerbations by ECCO₂R therapy. However, the ECCO₂R-related complication rate was high in six of the included studies.

CONCLUSIONS

Our findings from both RCTs and observational studies did not confirm a significant beneficial effect of ECCO₂R therapy on mortality. A shorter length of ICU stay in the ECCO₂R group was only obtained in observational studies, and ECCO₂R was associated with a longer length of hospital stay. ECCO₂R was associated with lower intubation rate and tracheotomy rate, and shorter mechanical ventilation days in ARF patients with COPD. And an improvement in pH, PaO2, respiratory rate and PaCO2 was observed in the ECCO₂R group. However, outcomes largely relied on data from observational studies targeted patients with ARF secondary to COPD, thus further larger high-quality RCTs are desirable to strengthen the evidence on the efficacy and benefits of ECCO₂R for patients with ARF.Key messagesECCO₂R therapy did not confirm a significant beneficial effect on mortality.ECCO₂R was associated with lower intubation and tracheotomy rate, and shorter mechanical ventilation days in patients with ARF secondary to COPD.An improvement in pH, PaO2, respiratory rate, and PaCO2 was observed in ECCO₂R group in patients with COPD exacerbations.Evidence for the future application of ECCO₂R therapy for patients with ARF. The protocol of this meta-analysis was registered on PROSPERO (CRD42022295174).

Extracorporeal carbon dioxide removal for acute respiratory failure: a review of potential indications, clinical practice and open research questions

Extracorporeal carbon dioxide removal (ECCO₂R) is a form of extracorporeal life support (ECLS) largely aimed at removing carbon dioxide in patients with acute hypoxemic or acute hypercapnic respiratory failure, so as to minimize respiratory acidosis, allowing more lung protective ventilatory settings which should decrease ventilator-induced lung injury. ECCO₂R is increasingly being used despite the lack of high-quality evidence, while complications associated with the technique remain an issue of concern. This review explains the physiological basis underlying the use of ECCO₂R, reviews the evidence regarding indications and contraindications, patient management and complications, and addresses organizational and ethical considerations. The indications and the risk-to-benefit ratio of this technique should now be carefully evaluated using structured national or international registries and large randomized trials.

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.

Hospital Costs of Extracorporeal Membrane Oxygenation in Adults: A Systematic Review

BACKGROUND

Costs associated with extracorporeal membrane oxygenation (ECMO) are an important factor in establishing cost effectiveness. In this systematic review, we aimed to determine the total hospital costs of ECMO for adults.

METHODS

The literature was retrieved from the PubMed/MEDLINE, EMBASE, and Web of Science databases from inception to 4 March 2020 using the search terms 'extracorporeal membrane oxygenation' combined with 'costs'; similar terms or phrases were then added to the search, i.e. 'Extracorporeal Life Support' or 'ECMO' or 'ECLS' combined with 'costs'. We included any type of study (e.g. randomized trial or observational cohort) evaluating hospital costs of ECMO in adults (age ≥18 years).

RESULTS

A total of 1768 unique articles were retrieved during our search. We assessed 74 full-text articles for eligibility, of which 14 articles were selected for inclusion in this review; six papers were from the US, five were from Europe, and one each from Japan, Australia, and Taiwan. The sample sizes ranged from 16 to 18,684 patients. One paper exclusively used prospective cost data collection, while all other papers used retrospective data collection. Five papers reported charges instead of costs. There was large variation in hospital costs, ranging from US$22,305 to US$334,608 (2019 values), largely depending on the indication for ECMO support and location. The highest reported costs were for lung transplant recipients who were receiving ECMO support in the US, and the lowest reported costs were for extracorporeal cardiopulmonary resuscitation patients presenting with non-shockable rhythm in Japan. The additional costs of ECMO patients compared with non-ECMO patients varied between US$2518 and US$200,658. Personnel costs varied between 11 and 52% of the total amount.

CONCLUSIONS

ECMO therapy is an advanced and expensive technology, although reported costs differ considerably depending on ECMO indication and whether charges or costs are measured. Combined with the ongoing gathering of outcome data, cost effectiveness per ECMO indication could be determined in the future.

The use of extracorporeal CO2 removal in acute respiratory failure

Background

Chronic obstructive pulmonary disease (COPD) exacerbation and protective mechanical ventilation of acute respiratory distress syndrome (ARDS) patients induce hypercapnic respiratory acidosis.

Main text

Extracorporeal carbon dioxide removal (ECCO₂R) aims to eliminate blood CO₂ to fight against the adverse effects of hypercapnia and related acidosis. Hypercapnia has deleterious extrapulmonary consequences, particularly for the brain. In addition, in the lung, hypercapnia leads to: lower pH, pulmonary vasoconstriction, increases in right ventricular afterload, acute cor pulmonale. Moreover, hypercapnic acidosis may further damage the lungs by increasing both nitric oxide production and inflammation and altering alveolar epithelial cells. During an exacerbation of COPD, relieving the native lungs of at least a portion of the CO₂ could potentially reduce the patient's respiratory work, Instead of mechanically increasing alveolar ventilation with MV in an already hyperinflated lung to increase CO₂ removal, the use of ECCO₂R may allow a decrease in respiratory volume and respiratory rate, resulting in improvement of lung mechanic. Thus, the use of ECCO₂R may prevent noninvasive ventilation failure and allow intubated patients to be weaned off mechanical ventilation. In ARDS patients, ECCO₂R may be used to promote an ultraprotective ventilation in allowing to lower tidal volume, plateau (Pplat) and driving pressures, parameters that have identified as a major risk factors for mortality. However, although ECCO₂R appears to be effective in improving gas exchange and possibly in reducing the rate of endotracheal intubation and allowing more protective ventilation, its use may have pulmonary and hemodynamic consequences and may be associated with complications.

Conclusion

In selected patients, ECCO₂R may be a promising adjunctive therapeutic strategy for the management of patients with severe COPD exacerbation and for the establishment of protective or ultraprotective ventilation in patients with ARDS without prognosis-threatening hypoxemia.

Very low blood flow carbon dioxide removal system is not effective in a chronic obstructive pulmonary disease exacerbation setting

Extracorporeal carbon dioxide removal (ECCO₂ R) is a low blood flow veno-venous extracorporeal membrane oxygenation technique that provides artificial blood CO₂ removal. Recently, a new ECCO₂ R system (PrismaLung), providing very low blood flow has been commercialized. The aim of this study is to report its use in severe chronic obstructive pulmonary disease (COPD) patients needing an ECCO₂ R therapy. Six severe COPD patients with acute exacerbation leading to refractory hypercapnic respiratory acidosis were treated with ECCO₂ R therapy. Two different systems were used: a PrismaLung system and a conventional ECCO₂ R device. The maximum blood flow provided by PrismaLung was significantly lower than that with the conventional ECCO₂ R system. In three patients initially treated with PrismaLung, there were no improvements in pH, PaCO₂ , or RR. Thus, the therapy was switched to a conventional ECCO₂ R system in these three patients, and three others were treated from the outset by the conventional ECCO₂ R system, providing significant improvement in pH, PaCO₂ , and RR. The present retrospective study describes the first use of PrismaLung in severe COPD patients with acute exacerbation. When compared with a higher blood flow ECCO₂ R system, our results show that this novel, very low-flow device is not able to remove sufficient CO₂ , normalize pH or decrease respiratory rate.

Update on extracorporeal carbon dioxide removal: a comprehensive review on principles, indications, efficiency, and complications

TECHNOLOGY

Extracorporeal carbon dioxide removal means the removal of carbon dioxide from the blood across a gas exchange membrane without substantially improving oxygenation. Carbon dioxide removal is possible with substantially less extracorporeal blood flow than needed for oxygenation. Techniques for extracorporeal carbon dioxide removal include (1) pumpless arterio-venous circuits, (2) low-flow venovenous circuits based on the technology of continuous renal replacement therapy, and (3) venovenous circuits based on extracorporeal membrane oxygenation technology.

INDICATIONS

Extracorporeal carbon dioxide removal has been shown to enable more protective ventilation in acute respiratory distress syndrome patients, even beyond the so-called "protective" level. Although experimental data suggest a benefit on ventilator induced lung injury, no hard clinical evidence with respect to improved outcome exists. In addition, extracorporeal carbon dioxide removal is a tool to avoid intubation and mechanical ventilation in patients with acute exacerbated chronic obstructive pulmonary disease failing non-invasive ventilation. This concept has been shown to be effective in 56-90% of patients. Extracorporeal carbon dioxide removal has also been used in ventilated patients with hypercapnic respiratory failure to correct acidosis, unload respiratory muscle burden, and facilitate weaning. In patients suffering from terminal fibrosis awaiting lung transplantation, extracorporeal carbon dioxide removal is able to correct acidosis and enable spontaneous breathing during bridging. Keeping these patients awake, ambulatory, and breathing spontaneously is associated with favorable outcome.

COMPLICATIONS

Complications of extracorporeal carbon dioxide removal are mostly associated with vascular access and deranged hemostasis leading to bleeding. Although the spectrum of complications may differ, no technology offers advantages with respect to rate and severity of complications. So called "high-extraction systems" working with higher blood flows and larger membranes may be more effective with respect to clinical goals.

Extracorporeal carbon dioxide removal for lowering the risk of mechanical ventilation: research questions and clinical potential for the future

As a result of technical improvements, extracorporeal carbon dioxide removal (ECCO₂R) now has the potential to play an important role in the management of adults with acute respiratory failure. There is growing interest in the use of ECCO₂R for the management of both hypoxaemic and hypercapnic respiratory failure. However, evidence to support its use is scarce and several questions remain about the best way to implement this therapy, which can be associated with serious side-effects. This Review reflects the consensus opinion of an international group of clinician scientists with expertise in managing acute respiratory failure and in using ECCO₂R therapies in this setting. We concisely review clinically relevant aspects of ECCO₂R, and provide a series of recommendations for clinical practice and future research, covering topics that include the practicalities of ECCO₂R delivery, indications for use, and service delivery.

Airway management changes associated with rising radiologic incidence of external laryngotracheal injury

BACKGROUND

Traumatic laryngeal injuries are uncommon life-threatening injuries that require prompt, rational management of a potentially precarious airway. It is unclear whether the current incidence of laryngotracheal injury is due to enhanced injury detection or increased occurrence. The objective of this study was to evaluate the relations between diagnostic imaging with both initial airway management and surgical treatment in patients with external laryngotracheal injuries (ELTIs) in Alberta.

METHODS

In this large-scale population-based analysis, we used regional health databases containing inpatient admissions, emergency department visits and trauma service activations employing International Classification of Diseases diagnostic codes to identify all ELTIs diagnosed from Apr. 1, 1995, to Dec. 31, 2011, in adults (age ≥ 16 yr). We evaluated health records and diagnostic imaging for injury features, airway management, operative interventions and hospital length of stay (LOS).

RESULTS

Eighty-nine patients met the inclusion criteria. The incidence of ELTIs increased over time, paralleling a rise in detection during the period incorporating greater computed tomography (CT) use (p = 0.002). Endotracheal tube intubation was performed in 8/30 cases (27%) in the pre-CT era, compared to 38/59 cases (64%) in the post-CT era (p = 0.001); the use of surgical intervention remained consistent. The largest contributors to increased endotracheal tube placements were the emergency department and emergency medical services. No change in survival was detected, but mean LOS among patients admitted for minor, isolated ELTIs increased by 2.3 (95% confidence interval 0.14-4.8) days (p = 0.06), mostly for patients admitted under critical care for mechanical ventilation.

CONCLUSION

Management of ELTIs shifted from predominantly conservative airway monitoring to endotracheal tube intubation over the study period in spite of no clinically significant change in injury severity or operative intervention frequency. The location of endotracheal tube placement suggests less comfort with ELTI among first-responder and emergency personnel.

Cost-utility of non-invasive mechanical ventilation: Analysis and implications in acute respiratory failure. A brief narrative review

The growing interest in the quality of patient care at the levels of the health care managers, insurance companies, and health professionals is evident. Further, the growing population requires good quality health services. In this review, we analyzed the cost-effectiveness of noninvasive ventilation (NIV) in an acute setting for the treatment of respiratory failure. The strength of this review is that it identified and summarized the most relevant studies regarding various aspects of the cost-utility of NIV in an acute setting. This is the first review that focuses on the importance of the skills and training of the team in the reduction of costs associated with NIV. However, the small number of studies, heterogeneity of quality, and different outcomes of the different studies are the greatest limitations of this review. In conclusion, although there is great variation in the data drawn from the literature, NIV seems to be a cost-effective tool, especially in specific patients (those with chronic obstructive pulmonary disease) for whom the addition of NIV improves outcomes and has a positive impact on this expenditure.

Applying Precision Medicine to Trial Design Using Physiology. Extracorporeal CO2 Removal for Acute Respiratory Distress Syndrome

In clinical trials of therapies for acute respiratory distress syndrome (ARDS), the average treatment effect in the study population may be attenuated because individual patient responses vary widely. This inflates sample size requirements and increases the cost and difficulty of conducting successful clinical trials. One solution is to enrich the study population with patients most likely to benefit, based on predicted patient response to treatment (predictive enrichment). In this perspective, we apply the precision medicine paradigm to the emerging use of extracorporeal CO₂ removal (ECCO₂R) for ultraprotective ventilation in ARDS. ECCO₂R enables reductions in tidal volume and driving pressure, key determinants of ventilator-induced lung injury. Using basic physiological concepts, we demonstrate that dead space and static compliance determine the effect of ECCO₂R on driving pressure and mechanical power. This framework might enable prediction of individual treatment responses to ECCO₂R. Enriching clinical trials by selectively enrolling patients with a significant predicted treatment response can increase treatment effect size and statistical power more efficiently than conventional enrichment strategies that restrict enrollment according to the baseline risk of death. To support this claim, we simulated the predicted effect of ECCO₂R on driving pressure and mortality in a preexisting cohort of patients with ARDS. Our computations suggest that restricting enrollment to patients in whom ECCO₂R allows driving pressure to be decreased by 5 cm H₂O or more can reduce sample size requirement by more than 50% without increasing the total number of patients to be screened. We discuss potential implications for trial design based on this framework.