Avoidance of intubation during acute exacerbation of chronic obstructive pulmonary disease for a lung transplant candidate using extracorporeal carbon dioxide removal with the Hemolung

Use of Subclavian Extracorporeal Carbon Dioxide Removal for COVID-19 Acute Respiratory Distress Syndrome as a Bridge to Lung Transplantation

Severe acute hypercapnia is independently associated with increased adverse effects and intensive care unit mortality in mechanically ventilated patients. During the severe acute respiratory syndrome coronavirus 2 (COVID-19) pandemic, some patients were placed on extracorporeal carbon dioxide removal support when extracorporeal membrane oxygenation (ECMO) support was at capacity or not offered. We present a patient with severe acute respiratory distress syndrome caused by COVID-19 pneumonia, who was supported with Hemolung Respiratory Assist System (ALung Technologies, Inc., LivaNova, Pittsburgh, PA) via the right subclavian vein as a bridge to lung transplantation after venovenous ECMO support. The patient survived and was discharged home.

Bridge to second double lung transplant with an extracorporeal carbon dioxide removal system in situs inversus patient

BACKGROUND

Extracorporeal life support use in redo-lung transplant is limited due to poor outcomes. Extracorporeal circulation with a single duo-lumen cannula provides the advantage of more comfortable mobilization particularly in patients in which we expect a longer bridge to transplant.

CASE

A 29-year-old female with Kartagener syndrome and complete situs inversus underwent a double lung transplant for end stage lung disease. Within one year after transplant the patient had primarily hypercapnic respiratory failure with radiographic signs of chronic lung allograft dysfunction. To optimize her nutritional status and muscle strength before re-do lung transplantation, we decided to bridge her with an extracorporeal carbon dioxide removal system due to anatomical difficulty. She was listed and underwent an uneventful re-do double lung transplant with cardiopulmonary support.

CONCLUSIONS

We report a first case with the use of extracorporeal carbon dioxide removal system as a bridge to re-do lung transplant in complete situs inversus patient.

Lung Transplant from ECMO: Current Results and Predictors of Post-transplant Mortality

Purpose of Review

We examined data from the last 5 years describing extracorporeal life support (ECLS) as a bridge to lung transplantation. We assessed predictors of survival to transplantation and post-transplant mortality.

Recent Findings

The number of lung transplants performed worldwide is increasing. This is accompanied by an increase in the type of patients being transplanted, including sicker patients with more advanced disease. Consequently, there is an increase in the need for bridging strategies, with varying success. Several predictors of failure have been identified. Major risk factors include retransplantation, other organ dysfunction, and deconditioning.

Summary

ECLS is a risky strategy but necessary for patients who would otherwise die if not bridged to transplantation. The presence of predictors for failure is not a contraindication for bridging. However, major risk factors should be approached cautiously. Other, more minor risk factors may be considered acceptable. More importantly, the strategy should be individualized for each patient to achieve the best possible outcomes.

Effect of Hematocrit on the CO2 Removal Rate of Artificial Lungs

Extracorporeal CO2 removal (ECCO2R) can permit lung protective or noninvasive ventilation strategies in patients with chronic obstructive pulmonary disease (COPD) and acute respiratory distress syndrome (ARDS). With evidence supporting ECCO2R growing, investigating factors which affect CO2 removal is necessary. Multiple factors are known to affect the CO2 removal rate (vCO2) which can complicate the interpretation of changes in vCO2; however, the effect of hematocrit on the vCO2 of artificial lungs has not been investigated. This in vitro study evaluates the relationship between hematocrit level and vCO2 within an ECCO2R device. In vitro gas transfer was measured in bovine blood in accordance with the ISO 7199 standard. Plasma and saline were used to hemodilute the blood to hematocrits between 33% and 8%. The vCO2 significantly decreased as the blood was hemodiluted with saline and plasma by 42% and 32%, respectively, between a hematocrit of 33% and 8%. The hemodilution method did not significantly affect the vCO2. In conclusion, the hematocrit level significantly affects vCO2 and should be taken into account when interpreting changes in the vCO2 of an ECCO2R device.

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.

In vitro characterization of PrismaLung+: a novel ECCO2R device

BACKGROUND

Invasive mechanical ventilation is lifesaving in the setting of severe acute respiratory failure but can cause ventilation-induced lung injury. Advances in extracorporeal CO₂ removal (ECCO₂R) technologies may facilitate more protective lung ventilation in acute respiratory distress syndrome, and enable earlier weaning and/or avoid invasive mechanical ventilation entirely in chronic obstructive pulmonary disease exacerbations. We evaluated the in vitro CO₂ removal capacity of the novel PrismaLung+ ECCO₂R device compared with two existing gas exchangers.

METHODS

The in vitro CO₂ removal capacity of the PrismaLung+ (surface area 0.8 m², Baxter) was compared with the PrismaLung (surface area 0.35 m², Baxter) and A.L.ONE (surface area 1.35 m², Eurosets) devices, using a closed-loop bovine blood-perfused extracorporeal circuit. The efficacy of each device was measured at varying pCO₂ inlet (p_inCO₂) levels (45, 60, and 80 mmHg) and blood flow rates (Q_B) of 200-450 mL/min; the PrismaLung+ and A.L.ONE devices were also tested at a Q_B of 600 mL/min. The amount of CO₂ removed by each device was assessed by measurement of the CO₂ infused to maintain circuit equilibrium (CO₂ infusion method) and compared with measured CO₂ concentrations in the inlet and outlet of the CO₂ removal device (blood gas analysis method).

RESULTS

The PrismaLung+ device performed similarly to the A.L.ONE device, with both devices demonstrating CO₂ removal rates ~ 50% greater than the PrismaLung device. CO₂ removal rates were 73 ± 4.0, 44 ± 2.5, and 72 ± 1.9 mL/min, for PrismaLung+, PrismaLung, and A.L.ONE, respectively, at Q_B 300 mL/min and p_inCO₂ 45 mmHg. A Bland-Altman plot demonstrated that the CO₂ infusion method was comparable to the blood gas analysis method for calculating CO₂ removal. The resistance to blood flow across the test device, as measured by pressure drop, varied as a function of blood flow rate, and was greatest for PrismaLung and lowest for the A.L.ONE device.

CONCLUSIONS

The newly developed PrismaLung+ performed more effectively than PrismaLung, with performance of CO₂ removal comparable to A.L.ONE at the flow rates tested, despite the smaller membrane surface area of PrismaLung+ versus A.L.ONE. Clinical testing of PrismaLung+ is warranted to further characterize its performance.

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.

Extracorporeal carbon dioxide removal in acute exacerbations of chronic obstructive pulmonary disease

Extracorporeal carbon dioxide removal (ECCO2R) has been proposed as an adjunctive intervention to avoid worsening respiratory acidosis, thereby preventing or shortening the duration of invasive mechanical ventilation (IMV) in patients with exacerbation of chronic obstructive pulmonary disease (COPD). This review will present a comprehensive summary of the pathophysiological rationale and clinical evidence of ECCO2R in patients suffering from severe COPD exacerbations.

Extracorporeal Gas Exchange: The Expanding Role of Extracorporeal Support in Respiratory Failure

The use of extracorporeal support is expanding quickly in adult respiratory failure. Extracorporeal gas exchange is an accepted rescue therapy for severe acute respiratory distress syndrome (ARDS) in select patients. Extracorporeal carbon dioxide removal is also being investigated as a preventative, preemptive, and management platform in patients with respiratory failure other than severe ARDS. The non-ARDS patient population is much larger, so the potential for rapid growth is high. This article hopes to inform decisions about the use of extracorporeal support by increasing understanding concerning the past and present practice of extracorporeal gas exchange.

An extracorporeal carbon dioxide removal (ECCO2R) device operating at hemodialysis blood flow rates

Background

Extracorporeal carbon dioxide removal (ECCO₂R) systems have gained clinical appeal as supplemental therapy in the treatment of acute and chronic respiratory injuries with low tidal volume or non-invasive ventilation. We have developed an ultra-low-flow ECCO₂R device (ULFED) capable of operating at blood flows comparable to renal hemodialysis (250 mL/min). Comparable operating conditions allow use of minimally invasive dialysis cannulation strategies with potential for direct integration to existing dialysis circuitry.

Methods

A carbon dioxide (CO₂) removal device was fabricated with rotating impellers inside an annular hollow fiber membrane bundle to disrupt blood flow patterns and enhance gas exchange. In vitro gas exchange and hemolysis testing was conducted at hemodialysis blood flows (250 mL/min).

Results

In vitro carbon dioxide removal rates up to 75 mL/min were achieved in blood at normocapnia (pCO₂ = 45 mmHg). In vitro hemolysis (including cannula and blood pump) was comparable to a Medtronic Minimax oxygenator control loop using a time-of-therapy normalized index of hemolysis (0.19 ± 0.04 g/100 min versus 0.12 ± 0.01 g/100 min, p = 0.169).

Conclusions

In vitro performance suggests a new ultra-low-flow extracorporeal CO₂ removal device could be utilized for safe and effective CO₂ removal at hemodialysis flow rates using simplified and minimally invasive connection strategies.

Extracorporeal CO2 removal by hemodialysis: in vitro model and feasibility

BACKGROUND

Critically ill patients with acute respiratory distress syndrome and acute exacerbations of chronic obstructive pulmonary disease often develop hypercapnia and require mechanical ventilation. Extracorporeal carbon dioxide removal can manage hypercarbia by removing carbon dioxide directly from the bloodstream. Respiratory hemodialysis uses traditional hemodialysis to remove CO₂ from the blood, mainly as bicarbonate. In this study, Stewart's approach to acid-base chemistry was used to create a dialysate that would maintain blood pH while removing CO₂ as well as determine the blood and dialysate flow rates necessary to remove clinically relevant CO₂ volumes.

METHODS

Bench studies were performed using a scaled down respiratory hemodialyzer in bovine or porcine blood. The scaling factor for the bench top experiments was 22.5. In vitro dialysate flow rates ranged from 2.2 to 24 mL/min (49.5-540 mL/min scaled up) and blood flow rates were set at 11 and 18.7 mL/min (248-421 mL/min scaled up). Blood inlet CO₂ concentrations were set at 50 and 100 mmHg.

RESULTS

Results are reported as scaled up values. The CO₂ removal rate was highest at intermittent hemodialysis blood and dialysate flow rates. At an inlet pCO₂ of 50 mmHg, the CO₂ removal rate increased from 62.6 ± 4.8 to 77.7 ± 3 mL/min when the blood flow rate increased from 248 to 421 mL/min. At an inlet pCO₂ of 100 mmHg, the device was able to remove up to 117.8 ± 3.8 mL/min of CO₂. None of the test conditions caused the blood pH to decrease, and increases were ≤0.08.

CONCLUSIONS

When the bench top data is scaled up, the system removes a therapeutic amount of CO₂ standard intermittent hemodialysis flow rates. The zero bicarbonate dialysate did not cause acidosis in the post-dialyzer blood. These results demonstrate that, with further development, respiratory hemodialysis can be a minimally invasive extracorporeal carbon dioxide removal treatment option.

Management of acute hypercapnic respiratory failure

PURPOSE OF REVIEW

The objective of this article is to review the most recent literature regarding the management of acute hypercapnic respiratory failure (AHRF).

RECENT FINDINGS

In the field of AHRF management, noninvasive ventilation (NIV) has become the standard method of providing primary mechanical ventilator support. Recently, extracorporeal carbon dioxide removal (ECCO2R) devices have been proposed as new therapeutic option.

SUMMARY

NIV is an effective strategy in specific settings and in selected population with AHRF. To date, evidence on ECCO2R is based only on case reports and case-control trials. Although the preliminary results using ECCO2R to decrease the rate of NIV failure and to wean hypercapnic patients from invasive ventilation are remarkable; further randomized studies are needed to assess the effects of this technique on both short-term and long-term clinical outcomes.

Extracorporeal Support for Chronic Obstructive Pulmonary Disease: A Bright Future

In the past the only option for the treatment of respiratory failure due to acute exacerbation of chronic obstructive pulmonary disease (aeCOPD) was invasive mechanical ventilation. In recent decades, the potential for extracorporeal carbon dioxide (CO₂) removal has been realized. We review the various types of extracorporeal CO₂ removal, outline the optimal use of these therapies for aeCOPD, and make suggestions for future controlled trials. We also describe the advantages and requirements for an ideal long-term ambulatory CO₂ removal system for palliation of COPD.

Extracorporeal carbon dioxide removal (ECCO2R) in respiratory deficiency and current investigations on its improvement: a review

The implementation of extracorporeal carbon dioxide removal (ECCO₂R) as one of the extracorporeal life support system is getting more attention today. Thus, the objectives of this paper are to study the clinical practice of commercial ECCO₂R system, current trend of its development and also the perspective on future improvement that can be done to the existing ECCO₂R system. The strength of this article lies in its review scope, which focuses on the commercial ECCO₂R therapy in the market based on membrane lung and current investigation to improve the efficiency of the ECCO₂R system, in terms of surface modification by carbonic anhydrase (CA) immobilization technique and respiratory electrodialysis (R-ED). Our methodology approach involves the identification of relevant published literature from PubMed and Web of Sciences search engine using the terms Extracorporeal Carbon Dioxide Removal (ECCO₂R), Extracorporeal life support, by combining terms between ECCO₂R and CA and also ECCO₂R with R-ED. This identification only limits articles in English language. Overall, several commercial ECCO₂R systems are known and proven safe to be used in patients in terms of efficiency, safety and risk of complication. In addition, CA-modified hollow fiber for membrane lung and R-ED are proven to have good potential to be applied in conventional ECCO₂R design. The detailed technique and current progress on CA immobilization and R-ED development were also reviewed in this article.

Prolonged Use of the Hemolung Respiratory Assist System as a Bridge to Redo Lung Transplantation

Although extracorporeal membrane oxygenation (ECMO) has been used frequently as a bridge to primary lung transplantation, active centers are conservative with this approach in patients requiring redo lung transplantation. We report the use of extracorporeal carbon dioxide removal, using the Hemolung respiratory assist system, as a prolonged bridge to lung transplantation, and the first use of the Hemolung as a bridge to redo lung transplantation. Hemolung support improved the patient's clinical status and allowed redo lung transplantation.

Imatinib for bleomycin induced pulmonary toxicity: a case report and evidence-base review

The evidence supporting therapy with imatinib for bleomycin‐induced pneumonitis (BIP) is equivocal. Further experience is needed to establish its role in BIP management. While it may be considered in the management of BIP, it is important to be mindful of the adverse effects including thrombocytopenia and gastrointestinal bleeding.

Extracorporeal carbon dioxide removal in patients with chronic obstructive pulmonary disease: a systematic review

INTRODUCTION

Extracorporeal carbon dioxide removal (ECCO2R) has been proposed for hypercapnic respiratory failure in chronic obstructive pulmonary disease (COPD) exacerbations, to avoid intubation or reduce length of invasive ventilation. Balance of risks, efficacy, and benefits of ECCO2R in patients with COPD is unclear.

METHODS

We systematically searched MEDLINE and EMBASE to identify all publications reporting use of ECCO2R in COPD. We looked at physiological and clinical efficacy. A favorable outcome was defined as prevention of intubation or successful extubation. Major and minor complications were compiled.

RESULTS

We identified 3123 citations. Ten studies (87 patients), primarily case series, met inclusion criteria. ECCO2R prevented intubation in 65/70 (93%) patients and assisted in the successful extubation of 9/17 (53%) mechanically ventilated subjects. One case-control study matching to noninvasively ventilated controls reported lower intubation rates and hospital mortality with ECCO2R that trended toward significance. Physiological data comparing pre- to post-ECCO2R changes suggest improvements for pH (0.07-0.15 higher), PaCO2 (25 mmHg lower), and respiratory rate (7 breaths/min lower), but not PaO2/FiO2. Studies reported 11 major (eight bleeds requiring blood transfusion of 2 units, and three line-related complications, including one death related to retroperitoneal bleeding) and 30 minor complications (13 bleeds, five related to anticoagulation, and nine clotting-related device malfunctions resulting in two emergent intubations).

CONCLUSION

The technique is still experimental and no randomized trial is available. Recognizing selection bias associated with case series, there still appears to be potential for benefit of ECCO2R in patients with COPD exacerbations. However, it is associated with frequent and potentially severe complications. Higher-quality studies are required to better elucidate this risk-benefit balance.

Extracorporeal Co2 removal in hypercapnic patients at risk of noninvasive ventilation failure: a matched cohort study with historical control

OBJECTIVES

To assess efficacy and safety of noninvasive ventilation-plus-extracorporeal Co2 removal in comparison to noninvasive ventilation-only to prevent endotracheal intubation patients with acute hypercapnic respiratory failure at risk of failing noninvasive ventilation.

DESIGN

Matched cohort study with historical control.

SETTING

Two academic Italian ICUs.

PATIENTS

Patients treated with noninvasive ventilation for acute hypercapnic respiratory failure due to exacerbation of chronic obstructive pulmonary disease (May 2011 to November 2013).

INTERVENTIONS

Extracorporeal CO2 removal was added to noninvasive ventilation when noninvasive ventilation was at risk of failure (arterial pH ≤ 7.30 with arterial PCO2 > 20% of baseline, and respiratory rate ≥ 30 breaths/min or use of accessory muscles/paradoxical abdominal movements). The noninvasive ventilation-only group was created applying the genetic matching technique (GenMatch) on a dataset including patients enrolled in two previous studies. Exclusion criteria for both groups were mean arterial pressure less than 60 mm Hg, contraindications to anticoagulation, body weight greater than 120 kg, contraindication to continuation of active treatment, and failure to obtain consent.

MEASUREMENTS AND MAIN RESULTS

Primary endpoint was the cumulative prevalence of endotracheal intubation. Twenty-five patients were included in the noninvasive ventilation-plus-extracorporeal CO2 removal group. The GenMatch identified 21 patients for the noninvasive ventilation-only group. Risk of being intubated was three times higher in patients treated with noninvasive ventilation-only than in patients treated with noninvasive ventilation-plus-extracorporeal CO2 removal (hazard ratio, 0.27; 95% CI, 0.07-0.98; p = 0.047). Intubation rate in noninvasive ventilation-plus-extracorporeal CO2 removal was 12% (95% CI, 2.5-31.2) and in noninvasive ventilation-only was 33% (95% CI, 14.6-57.0), but the difference was not statistically different (p = 0.1495). Thirteen patients (52%) experienced adverse events related to extracorporeal CO2 removal. Bleeding episodes were observed in three patients, and one patient experienced vein perforation. Malfunctioning of the system caused all other adverse events.

CONCLUSIONS

These data provide the rationale for future randomized clinical trials that are required to validate extracorporeal CO2 removal in patients with hypercapnic respiratory failure and respiratory acidosis nonresponsive to noninvasive ventilation.

Extracorporeal Carbon Dioxide Removal as an Alternative to Endotracheal Intubation for Non-Invasive Ventilation Failure in Acute Exacerbation of COPD

Extracorporeal carbon dioxide removal (ECCO2R) is an efficient technique used in the management of hypercapnic respiratory failure. Its application in mechanically ventilated patients has been studied for over 30 years. We describe a case of severe, acute exacerbation of chronic obstructive pulmonary disease (AECOPD) unresponsive to non-invasive ventilation (NIV), where initiation of ECCO2R was used effectively to prevent endotracheal intubation.

Removing extra CO2 in COPD patients

For patients experiencing acute respiratory failure due to a severe exacerbation of chronic obstructive pulmonary disease (COPD), noninvasive positive pressure ventilation has been shown to significantly reduce mortality and hospital length of stay compared to respiratory support with invasive mechanical ventilation. Despite continued improvements in the administration of noninvasive ventilation (NIV), refractory hypercapnia and hypercapnic acidosis continue to prevent its successful use in many patients. Recent advances in extracorporeal gas exchange technology have led to the development of systems designed to be safer and simpler by focusing on the clinical benefits of partial extracorporeal carbon dioxide removal (ECCO2R), as opposed to full cardiopulmonary support. While the use of ECCO2R has been studied in the treatment of acute respiratory distress syndrome (ARDS), its use for acute hypercapnic respiratory during COPD exacerbations has not been evaluated until recently. This review will focus on literature published over the last year on the use of ECCO2R for removing extra CO2 in patients experiencing an acute exacerbation of COPD.