Epoxy silane sulfobetaine block copolymers for simple, aqueous thromboresistant coating on ambulatory assist lung devices.

Developing an ambulatory assist lung (AAL) for patients who need continuous extracorporeal membrane oxygenation has been associated with several design objectives, including the design of compact components, optimization of gas transfer efficiency, and reduced thrombogenicity. In an effort to address thrombogenicity concerns with currently utilized component biomaterials, a low molecular weight water soluble siloxane-functionalized zwitterionic sulfobetaine (SB-Si) block copolymer was coated on a full-scale AAL device set via a one pot aqueous circulation coating. All device parts including hollow fiber bundle, housing, tubing and cannular were successfully coated with increasing atomic compositions of the SB block copolymer and the coated surfaces showed a significant reduction of platelet deposition while gas exchange performance was sustained.

Design and In Vitro Evaluation of an Artificial Placenta Made From Hollow Fiber Membranes.

For infants born at the border of viability, care practices and morbimortality rates vary widely between centers. Trends show significant improvement, however, with increasing gestational age and weight. For periviable infants, the goal of critical care is to bridge patients to improved 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.

Month-long Respiratory Support by a Wearable Pumping Artificial Lung in an Ovine Model.

Background: A wearable artificial lung could improve lung transplantation outcomes by easing implementation of physical rehabilitation during long-term pretransplant respiratory support. The Modular Extracorporeal Lung Assist System (ModELAS) is a compact pumping artificial lung currently under development. This study evaluated the long-term in vivo performance of the ModELAS during venovenous support in awake sheep.

In vivo testing of the low-flow CO 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 CO removal devices remove CO independent of the lungs thereby controlling the hypercapnia and permitting non-invasive or lung-protective ventilation techniques.

Blood Recirculation Enhances Oxygenation Efficiency of Artificial Lungs.

Ambulating patients on extracorporeal membrane oxygenation (ECMO) or extracorporeal CO2 removal (ECCO2R) improves outcomes. These systems would further simplify ambulation if made more compact. This study investigates blood recirculation to decrease device size by increasing efficiency.

Acute In Vivo Evaluation of the Pittsburgh Pediatric Ambulatory Lung.

Respiratory failure is a significant problem within the pediatric population. A means of respiratory support that readily allows ambulation could improve treatment. The Pittsburgh Pediatric Ambulatory Lung (P-PAL) is being developed as a wearable pediatric pump-lung for long-term respiratory support and has previously demonstrated positive benchtop results.

Bench Validation of a Compact Low-Flow CO Removal Device.

Background: There is increasing evidence demonstrating the value of partial extracorporeal CO removal (ECCOR) 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. ECCOR removes CO 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.

Effects of Hollow Fiber Membrane Oscillation on an Artificial Lung.

Gas transfer through hollow fiber membranes (HFMs) can be increased via fiber oscillation. Prior work, however, does not directly translate to present-day, full-scale artificial lungs. This in vitro study characterized the effects of HFM oscillations on oxygenation and hemolysis for a pediatric-sized HFM bundle.

In Vivo 5 Day Animal Studies of a Compact, Wearable Pumping Artificial Lung.

Recent studies show improved outcomes in ambulated lung failure patients. Ambulation still remains a challenge in these patients. This necessitates development of more compact and less cumbersome respiratory support specifically designed to be wearable.

In Vitro Characterization of the Pittsburgh Pediatric Ambulatory Lung.

Acute and chronic respiratory failure are a significant source of pediatric morbidity and mortality. Current respiratory support options used to bridge children to lung recovery or transplantation typically render them bedridden and can worsen long-term patient outcomes. The Pittsburgh Pediatric Ambulatory Lung (P-PAL) is a wearable pediatric blood pump and oxygenator (0.

In vitro and in vivo evaluation of a novel integrated wearable artificial lung.

Background: Conventional extracorporeal membrane oxygenation (ECMO) is cumbersome and is associated with high morbidity and mortality. We are currently developing the Pittsburgh Ambulatory Assist Lung (PAAL), which is designed to allow for ambulation of lung failure patients during bridge to transplant or recovery. In this study, we investigated the in vitro and acute in vivo performance of the PAAL.

Fiber Bundle Design for an Integrated Wearable Artificial Lung.

Mechanical ventilation (MV) and extracorporeal membrane oxygenation (ECMO) are the only viable treatment options for lung failure patients at the end-stage, including acute respiratory distress syndrome (ARDS) and chronic obstructive pulmonary disease (COPD). These treatments, however, are associated with high morbidity and mortality because of long wait times for lung transplant. Contemporary clinical literature has shown ambulation improves post-transplant outcomes in lung failure patients.

Effect of impeller design and spacing on gas exchange in a percutaneous respiratory assist catheter.

Providing partial respiratory assistance by removing carbon dioxide (CO2 ) can improve clinical outcomes in patients suffering from acute exacerbations of chronic obstructive pulmonary disease and acute respiratory distress syndrome. An intravenous respiratory assist device with a small (25 Fr) insertion diameter eliminates the complexity and potential complications associated with external blood circuitry and can be inserted by nonspecialized surgeons. The impeller percutaneous respiratory assist catheter (IPRAC) is a highly efficient CO2 removal device for percutaneous insertion to the vena cava via the right jugular or right femoral vein that utilizes an array of impellers rotating within a hollow-fiber membrane bundle to enhance gas exchange.

Evaluation of a respiratory assist catheter that uses an impeller within a hollow fiber membrane bundle.

Respiratory assist using an intravenous catheter may be a potential treatment for patients suffering from acute or acute-on-chronic lung failure. The objective of this study was to evaluate a novel respiratory catheter that uses an impeller within the fiber bundle to enhance gas exchange efficiency, thus requiring a smaller fiber bundle and insertional size (25 Fr) and permitting simple percutaneous insertion. Bench testing of gas exchange in deionized water was used to evaluate eight impeller designs.

Flow visualization study of a novel respiratory assist catheter.

Respiratory assist using intravenous catheters may be a potential therapy for patients with acute and acute-on-chronic lung failure. An important design constraint is respiratory catheter size, and new strategies are needed that enable size reduction while maintaining adequate gas exchange. Our group is currently developing a percutaneous respiratory assist catheter (PRAC) that uses a rotating bundle of hollow fiber membranes to enhance CO(2) removal and O(2) supply with increasing bundle rotation rate.

Evaluation of fiber bundle rotation for enhancing gas exchange in a respiratory assist catheter.

Supplemental oxygenation and carbon dioxide removal through an intravenous respiratory assist catheter can be used as a means of treating patients with acute respiratory failure. We are beginning development efforts toward a new respiratory assist catheter with an insertional size <25F, which can be inserted percutaneously. In this study, we evaluated fiber bundle rotation as an improved mechanism for active mixing and enhanced gas exchange in intravenous respiratory assist catheters.

Blood biocompatibility assessment of an intravenous gas exchange device.

To treat acute lung failure, an intravenous membrane gas exchange device, the Hattler Catheter, is currently under development. Several methods were employed to evaluate the biocompatibility of the device during preclinical testing in bovines, and potential coatings for the fibers comprising the device were screened for their effectiveness in reducing thrombus deposition in vitro. Flow cytometric analysis demonstrated that the device had the capacity to activate platelets as evidenced by significant increases in circulating platelet microaggregates and activated platelets.

Evaluation of a pumping assist lung that uses a rotating fiber bundle.

A paracorporeal respiratory assist lung (PRAL) is being developed for supplemental gas exchange to allow the native lungs of acute lung failure patients to heal. The device consists of a rotating annular microporous hollow fiber membrane bundle. The rotation augments the gas exchange efficiency of the device at constant flow-rate thereby uncoupling gas exchange and flow rate.

Flow visualization study of a pulsating respiratory assist catheter.

Our group is currently developing an intravenous respiratory assist device that uses a centrally located pulsatile balloon within a hollow fiber bundle to enhance gas exchange rate via active mixing mechanism. We tested the hypothesis that the non-symmetric inflation and deflation of the balloon lead to both nonuniform balloon-generated secondary flow and nonuniform gas exchange rate in the fiber bundle. The respiratory catheter was placed in a 1-in.

Evaluation of local gas exchange in a pulsating respiratory support catheter.

An intravenous respiratory support catheter, the next generation of artificial lungs, is being developed in our laboratory to potentially support acute respiratory failure or patients with chronic obstructive pulmonary disease with acute exacerbations. A rapidly pulsating 25 ml balloon inside a bundle of hollow fiber membranes facilitates supplemental oxygenation and CO2 removal. In this study, we hypothesized that non-uniform gas exchange in different regions of this fiber bundle was present because of asymmetric balloon collapse and the interaction of longitudinal flow.

Acute in vivo testing of a respiratory assist catheter: implants in calves versus sheep.

A respiratory catheter that is inserted through a peripheral vein and placed within the vena cava is being developed for CO2 removal in patients with acute exacerbations of chronic obstructive pulmonary disease (COPD). The catheter uses a rapidly pulsating balloon to enhance gas exchange. In this study, the CO2 removal performance of our catheter was assessed in acute sheep implants and compared with calf implants, primarily because sheep have cardiac outputs (CO) that are more comparable with human CO and lower than calves.