In vitro characterization of PrismaLung+: a novel ECCO2R device

Evaluation of the safety and efficacy of extracorporeal carbon dioxide removal in the critically ill using the PrismaLung+ device

BACKGROUND

Several extracorporeal carbon dioxide removal (ECCO2R) devices are currently in use with variable efficacy and safety profiles. PrismaLung+ is an ECCO2R device that was recently introduced into clinical practice. It is a minimally invasive, low flow device that provides partial respiratory support with or without renal replacement therapy. Our aim was to describe the clinical characteristics, efficacy, and safety of PrismaLung+ in patients with acute hypercapnic respiratory failure.

METHODS

All adult patients who required ECCO2R with PrismaLung+ for hypercapnic respiratory failure in our intensive care unit (ICU) during a 6-month period between March and September 2022 were included.

RESULTS

Ten patients were included. The median age was 55.5 (IQR 41-68) years, with 8 (80%) male patients. Six patients had acute respiratory distress syndrome (ARDS), and two patients each had exacerbations of asthma and chronic obstructive pulmonary disease (COPD). All patients were receiving invasive mechanical ventilation at the time of initiation of ECCO2R. The median duration of ECCO2R was 71 h (IQR 57-219). A significant improvement in pH and PaCO2 was noted within 30 min of initiation of ECCO2R. Nine patients (90%) survived to weaning of ECCO2R, eight (80%) survived to ICU discharge and seven (70%) survived to hospital discharge. The median duration of ICU and hospital stays were 14.5 (IQR 8-30) and 17 (IQR 11-38) days, respectively. There were no patient-related complications with the use of ECCO2R. A total of 18 circuits were used in ten patients (median 2 per patient; IQR 1-2). Circuit thrombosis was noted in five circuits (28%) prior to reaching the expected circuit life with no adverse clinical consequences.

CONCLUSION(S)

PrismaLung+ rapidly improved PaCO2 and pH with a good clinical safety profile. Circuit thrombosis was the only complication. This data provides insight into the safety and efficacy of PrismaLung+ that could be useful for centres aspiring to introduce ECCO2R into their clinical practice.

Safety and Effectiveness of Carbon Dioxide Removal CO2RESET Device in Critically Ill Patients

BACKGROUND

In this retrospective study, we report the effectiveness and safety of a dedicated extracorporeal carbon dioxide removal (ECCO₂R) device in critically ill patients.

METHODS

Adult patients on mechanical ventilation due to acute respiratory distress syndrome (ARDS) or decompensated chronic obstructive pulmonary disease (dCOPD), who were treated with a dedicated ECCO₂R device (CO2RESET, Eurosets, Medolla, Italy) in case of hypercapnic acidemia, were included. Repeated measurements of CO₂ removal (VCO₂) at baseline and 1, 12, and 24 h after the initiation of therapy were recorded.

RESULTS

Over a three-year period, 11 patients received ECCO₂R (median age 60 [43-72] years) 3 (2-39) days after ICU admission; nine patients had ARDS and two had dCOPD. Median baseline pH and PaCO₂ levels were 7.27 (7.12-7.33) and 65 (50-84) mmHg, respectively. With a median ECCO₂R blood flow of 800 (500-800) mL/min and maximum gas flow of 6 (2-14) L/min, the VCO₂ at 12 h after ECCO₂R initiation was 157 (58-183) mL/min. Tidal volume, respiratory rate, and driving pressure were significantly reduced over time. Few side effects were reported.

CONCLUSIONS

In this study, a dedicated ECCO₂R device provided a high VCO₂ with a favorable risk profile.

Extracorporeal Carbon Dioxide Removal With the Hemolung in Patients With Acute Respiratory Failure: A Multicenter Retrospective Cohort Study

OBJECTIVES

Extracorporeal carbon dioxide removal (ECCO 2 R) devices are effective in reducing hypercapnia and mechanical ventilation support but have not been shown to reduce mortality. This may be due to case selection, device performance, familiarity, or the management. The objective of this study is to investigate the effectiveness and safety of a single ECCO 2 R device (Hemolung) in patients with acute respiratory failure and identify variables associated with survival that could help case selection in clinical practice as well as future research.

DESIGN

Multicenter, multinational, retrospective review.

SETTING

Data from the Hemolung Registry between April 2013 and June 2021, where 57 ICUs contributed deidentified data.

PATIENTS

Patients with acute respiratory failure treated with the Hemolung. The characteristics of patients who survived to ICU discharge were compared with those who died. Multivariable logistical regression analysis was used to identify variables associated with ICU survival.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of the 159 patients included, 65 (41%) survived to ICU discharge. The survival was highest in status asthmaticus (86%), followed by acute respiratory distress syndrome (ARDS) (52%) and COVID-19 ARDS (31%). All patients had a significant reduction in Pa co2 and improvement in pH with reduction in mechanical ventilation support. Patients who died were older, had a lower Pa o2 :F io2 (P/F) and higher use of adjunctive therapies. There was no difference in the complications between patients who survived to those who died. Multivariable regression analysis showed non-COVID-19 ARDS, age less than 65 years, and P/F at initiation of ECCO 2 R to be independently associated with survival to ICU discharge (P/F 100-200 vs <100: odds ratio, 6.57; 95% CI, 2.03-21.33).

CONCLUSIONS

Significant improvement in hypercapnic acidosis along with reduction in ventilation supports was noted within 4 hours of initiating ECCO 2 R. Non-COVID-19 ARDS, age, and P/F at commencement of ECCO 2 R were independently associated with survival.

Ultraprotective Ventilation via ECCO2R in Three Patients Presenting an Air Leak: Is ECCO2R Effective?

Extracorporeal CO₂ removal (ECCO2R) is a therapeutic approach that allows protective ventilation in acute respiratory failure by preventing hypercapnia and subsequent acidosis. The main indications for ECCO2R in acute respiratory failure are COPD (chronic obstructive pulmonary disease) exacerbation, acute respiratory distress syndrome (ARDS) and other situations of asthmatics status. However, CO₂ removal procedure is not extended to those ARDS patients presenting an air leak. Here, we report three cases of air leaks in patients with an ARDS that were successfully treated using a new ECCO2R device. Case 1 is a polytrauma patient that developed pneumothorax during the hospital stay, case 2 is a patient with a post-surgical bronchial fistula after an Ivor-Lewis esophagectomy, and case 3 is a COVID-19 patient who developed a spontaneous pneumothorax after being hospitalized for a prolonged time. ECCO2R allowed for protective ventilation mitigating VILI (ventilation-induced lung injury) and significantly improved hypercapnia and respiratory acidemia, allowing time for the native lung to heal. Although further investigation is needed, our observations seem to suggest that CO₂ removal can be a safe and effective procedure in patients connected to mechanical ventilation with ARDS-associated air leaks.

Targeting arterial partial pressure of carbon dioxide in acute respiratory distress syndrome patients using extracorporeal carbon dioxide removal

BACKGROUND

A retrospective analysis of SUPERNOVA trial data showed that reductions in tidal volume to ultraprotective levels without significant increases in arterial partial pressure of carbon dioxide (PaCO₂ ) for critically ill, mechanically ventilated patients with acute respiratory distress syndrome (ARDS) depends on the rate of extracorporeal carbon dioxide removal (ECCO₂ R).

METHODS

We used a whole-body mathematical model of acid-base balance to quantify the effect of altering carbon dioxide (CO₂ ) removal rates using different ECCO₂ R devices to achieve target PaCO₂ levels in ARDS patients. Specifically, we predicted the effect of using a new, larger surface area PrismaLung+ device instead of the original PrismaLung device on the results from two multicenter clinical studies in critically ill, mechanically ventilated ARDS patients.

RESULTS

After calibrating model parameters to the clinical study data using the PrismaLung device, model predictions determined optimal extracorporeal blood flow rates for the PrismaLung+ and mechanical ventilation frequencies to obtain target PaCO₂ levels of 45 and 50 mm Hg in mild and moderate ARDS patients treated at a tidal volume of 3.98 ml/kg predicted body weight (PW). Comparable model predictions showed that reductions in tidal volumes below 6 ml/kg PBW may be difficult for acidotic highly severe ARDS patients with acute kidney injury and high CO₂ production rates using a PrismaLung+ device in-series with a continuous venovenous hemofiltration device.

CONCLUSIONS

The described model provides guidance on achieving target PaCO₂ levels in mechanically ventilated ARDS patients using protective and ultraprotective tidal volumes when increasing CO₂ removal rates from ECCO₂ R devices.

Alkaline Liquid Ventilation of the Membrane Lung for Extracorporeal Carbon Dioxide Removal (ECCO2R): In Vitro Study

Extracorporeal carbon dioxide removal (ECCO₂R) is a promising strategy to manage acute respiratory failure. We hypothesized that ECCO₂R could be enhanced by ventilating the membrane lung with a sodium hydroxide (NaOH) solution with high CO₂ absorbing capacity. A computed mathematical model was implemented to assess NaOH–CO₂ interactions. Subsequently, we compared NaOH infusion, named “alkaline liquid ventilation”, to conventional oxygen sweeping flows. We built an extracorporeal circuit with two polypropylene membrane lungs, one to remove CO₂ and the other to maintain a constant PCO₂ (60 ± 2 mmHg). The circuit was primed with swine blood. Blood flow was 500 mL × min⁻¹. After testing the safety and feasibility of increasing concentrations of aqueous NaOH (up to 100 mmol × L⁻¹), the CO₂ removal capacity of sweeping oxygen was compared to that of 100 mmol × L⁻¹ NaOH. We performed six experiments to randomly test four sweep flows (100, 250, 500, 1000 mL × min⁻¹) for each fluid plus 10 L × min⁻¹ oxygen. Alkaline liquid ventilation proved to be feasible and safe. No damages or hemolysis were detected. NaOH showed higher CO₂ removal capacity compared to oxygen for flows up to 1 L × min⁻¹. However, the highest CO₂ extraction power exerted by NaOH was comparable to that of 10 L × min⁻¹ oxygen. Further studies with dedicated devices are required to exploit potential clinical applications of alkaline liquid ventilation.

Comparison of Circular and Parallel-Plated Membrane Lungs for Extracorporeal Carbon Dioxide Elimination

Extracorporeal carbon dioxide removal (ECCO₂R) is an important technique to treat critical lung diseases such as exacerbated chronic obstructive pulmonary disease (COPD) and mild or moderate acute respiratory distress syndrome (ARDS). This study applies our previously presented ECCO₂R mock circuit to compare the CO₂ removal capacity of circular versus parallel-plated membrane lungs at different sweep gas flow rates (0.5, 2, 4, 6 L/min) and blood flow rates (0.3 L/min, 0.9 L/min). For both designs, two low-flow polypropylene membrane lungs (Medos Hilte 1000, Quadrox-i Neonatal) and two mid-flow polymethylpentene membrane lungs (Novalung Minilung, Quadrox-iD Pediatric) were compared. While the parallel-plated Quadrox-iD Pediatric achieved the overall highest CO₂ removal rates under medium and high sweep gas flow rates, the two circular membrane lungs performed relatively better at the lowest gas flow rate of 0.5 L/min. The low-flow Hilite 1000, although overall better than the Quadrox i-Neonatal, had the most significant advantage at a gas flow of 0.5 L/min. Moreover, the circular Minilung, despite being significantly less efficient than the Quadrox-iD Pediatric at medium and high sweep gas flow rates, did not show a significantly worse CO₂ removal rate at a gas flow of 0.5 L/min but rather a slight advantage. We suggest that circular membrane lungs have an advantage at low sweep gas flow rates due to reduced shunting as a result of their fiber orientation. Efficiency for such low gas flow scenarios might be relevant for possible future portable ECCO₂R devices.

Modeling acid-base balance for in-series extracorporeal carbon dioxide removal and continuous venovenous hemofiltration devices

Patients with acute respiratory distress syndrome and acute kidney injury (AKI) treated by kidney replacement therapy may also require treatment with extracorporeal carbon dioxide removal (ECCO₂ R) devices to permit protective or ultraprotective mechanical ventilation. We developed a mathematical model of acid-base balance during extracorporeal therapy using ECCO₂ R and continuous venovenous hemofiltration (CVVH) devices applied in series for the treatment of mechanically ventilated AKI patients. Published data from clinical studies of mechanically ventilated AKI patients treated by CVVH at known infusion rates of substitution fluid without ECCO₂ R were used to adjust the model parameters to fit plasma levels of arterial partial pressure of carbon dioxide (PaCO₂ ), arterial plasma bicarbonate concentration ([HCO₃ ]), and plasma pH (as well as certain other unmeasured physiological variables). The effects of applying ECCO₂ R at an unchanged and a reduced tidal volume on PaCO₂ , [HCO₃ ] and plasma pH were then simulated assuming carbon dioxide removal rates from the ECCO₂ R device measured in the clinical studies. Agreement of such model predictions with clinical data was good whether the ECCO₂ R device was positioned proximal or distal to the CVVH device in the extracorporeal circuit. Although carbon dioxide removal rates from the ECCO₂ R device measured in one previous clinical study were higher when it was placed proximal to the CVVH device, suggesting that such in-series positioning was optimal, the current mathematical model demonstrates that proximal positioning of the ECCO₂ R device also results in lower bicarbonate (and, therefore, total carbon dioxide) removal from the distal CVVH device. Thus, the removal of total carbon dioxide by such extracorporeal circuits is relatively independent of the position of the in-series devices. It is concluded that the described mathematical model has quantitative accuracy; these results suggest that the overall acid-base balance when using ECCO₂ R and CVVH devices in a single extracorporeal circuit will be similar, independent of their in-series position.

Evaluation of a New Extracorporeal CO2 Removal Device in an Experimental Setting

Background: Ultra-protective lung ventilation in acute respiratory distress syndrome or early weaning and/or avoidance of mechanical ventilation in decompensated chronic obstructive pulmonary disease may be facilitated by the use of extracorporeal CO₂ removal (ECCO₂R). We tested the CO₂ removal performance of a new ECCO₂R (CO₂RESET) device in an experimental animal model. Methods: Three healthy pigs were mechanically ventilated and connected to the CO₂RESET device (surface area = 1.8 m², EUROSETS S.r.l., Medolla, Italy). Respiratory settings were adjusted to induce respiratory acidosis with the adjunct of an external source of pure CO₂ (target pre membrane lung venous PCO₂ (P_preCO₂): 80–120 mmHg). The amount of CO₂ removed (VCO₂, mL/min) by the membrane lung was assessed directly by the ECCO₂R device. Results: Before the initiation of ECCO₂R, the median P_preCO₂ was 102.50 (95.30–118.20) mmHg. Using fixed incremental steps of the sweep gas flow and maintaining a fixed blood flow of 600 mL/min, VCO₂ progressively increased from 0 mL/min (gas flow of 0 mL/min) to 170.00 (160.00–200.00) mL/min at a gas flow of 10 L/min. In particular, a high increase of VCO₂ was observed increasing the gas flow from 0 to 2 L/min, then, VCO₂ tended to progressively achieve a steady-state for higher gas flows. No animal or pump complications were observed. Conclusions: Medium-flow ECCO₂R devices with a blood flow of 600 mL/min and a high surface membrane lung (1.8 m²) provided a high VCO₂ using moderate sweep gas flows (i.e., >2 L/min) in an experimental swine models with healthy lungs.

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.