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

2015; Elsevier BV; Volume: 100; Issue: 6 Linguagem: Inglês

10.1016/j.athoracsur.2015.02.104

1552-6259

C. Bermúdez, Diana Zaldonis, Ming-Hui Fan, Joseph M. Pilewski, M. Crespo,

Organ Transplantation Techniques and Outcomes

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. 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. 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 because of the technical difficulties of the procedure and risk of severe bleeding adverse events [1Bermudez C.A. Rocha R.V. Zaldonis D. et al.Extracorporeal membrane oxygenation as a bridge to lung transplant: midterm outcomes.Ann Thorac Surg. 2011; 92 (discussion 31–2): 1226-1231Abstract Full Text Full Text PDF PubMed Scopus (132) Google Scholar, 2Javidfar J. Bacchetta M. Bridge to lung transplantation with extracorporeal membrane oxygenation support.Curr Opin Organ Transplant. 2012; 17: 496-502Crossref PubMed Scopus (40) Google Scholar]. Mechanical support, including mechanical ventilation (MV), before redo lung transplantation is associated with higher mortality [3Kawut S.M. Lederer D.J. Keshavjee S. et al.Outcomes after lung retransplantation in the modern era.Am J Respir Crit Care Med. 2008; 177: 114-120Crossref PubMed Scopus (101) Google Scholar]. Here, we describe a case in which prolonged extracorporeal CO2 removal was performed by use of the Hemolung respiratory assist system (RAS) device (ALung Technologies Inc., Pittsburgh, PA) to improve the patient's clinical status and allow redo lung transplantation. We treated a 33-year-old man who underwent a double lung transplantation for cystic fibrosis in 2012. He had an excellent clinical course after his first transplantation, regaining full physical activity. In late 2013, he experienced acute respiratory failure caused by adenovirus pneumonia that led to refractory severe hypercarbic respiratory failure requiring hospitalization, tracheostomy, and prolonged MV (>30 days). After improvement in his clinical condition, including the ability to ambulate with the assistance of a portable mechanical ventilator, he was transferred to our institution because of his high-risk status. Upon arrival, he was admitted to the intensive care unit (ICU) because of his persistent hypoxemia and hypercarbia requiring MV with high oxygen requirements (up to 100% FiO2). Despite full MV, he experienced profound hypercarbia (paCO2 >100 mm Hg) with metabolic encephalopathy and worsening acidosis requiring increasing doses of vasopressors. The patient's neurologic condition, secondary to high CO2 retention, prohibited mobilization. He became increasingly difficult to provide ventilation, with dangerously high airway pressures (plateau pressure 55 to 60 cm H20) on low tidal volume ventilation. Because high CO2 levels were the primary cause of the patient's hemodynamic instability and the predominant cause of his respiratory failure, and because he was a poor candidate for ECMO support because of his frail clinical condition, volume overload, and need for a redo transplantation, we considered an emergency use of the Hemolung RAS device (approved by our Institutional Review Board) with the intention to improve the patient's overall clinical, hemodynamic, and neurologic condition and to allow his consideration as a candidate for transplantation. Simultaneously, continuous venovenous hemodiafiltration was initiated to prevent further fluid overload. The Hemolung RAS is an integrated respiratory support system that uses a hemodialysis-like circuit to remove CO2 [4Batchinsky A.I. Jordan B.S. Regn D. et al.Respiratory dialysis: reduction in dependence on mechanical ventilation by venovenous extracorporeal CO2 removal.Crit Care Med. 2011; 39: 1382-1387Crossref PubMed Scopus (96) Google Scholar, 5Burki N.K. Mani R.K. Herth F.J. et al.A novel extracorporeal CO(2) removal system: results of a pilot study of hypercapnic respiratory failure in patients with COPD.Chest. 2013; 143: 678-686Crossref PubMed Scopus (176) Google Scholar]. The Hemolung consists of a cylindrical bundle of hollow fibers adjacent to a rotating impeller to provide active mixing, which augments gas exchange efficiency and facilitates a compact device design (Fig 1). Venous blood is withdrawn through a double-lumen catheter (also used for blood return) by a centrifugal pump and flows past the fiber bundle. Sweep gas is drawn through the hollow fibers by a vacuum pump that creates a diffusion gradient for gas exchange across the membrane. This CO2 removal system differs from ECMO systems in that it is a low-flow system, propelling blood at 500 to 600 mL/min, as compared with typical ECMO flow rates of 4 to 6 L/min, and requires a smaller catheter (15.5F vs 17–29F for ECMO). The Hemolung was implanted through the right jugular vein by use of the Seldinger technique. A dual-lumen 15.5F catheter was placed in the superior vena cava. The small-diameter catheter permitted bedside insertion. We confirmed proper positioning radiologically, using a portable radiograph before the initiation of support. A 3,000-U initial bolus of heparin was administered for anticoagulation and then was titrated to maintain a partial thromoboplastin time of 45 to 60 seconds. Hemolung support was initiated at 470 to 540 mL/min flow and 500 rpm motor speed, which was slowly increased to 1,000 to 1,400 rpm (Fig 2). A notable decrease in systemic CO2 levels was observed within 24 hours, with progressive decreases over 4 to 6 days (Fig 3). During support, the patient received maintenance MV with decreased oxygen requirements to maintain arterial oxygen levels above 60 mm Hg (Fig 4). He was weaned from vasopressors, which were no longer required after 4 days of support. CO2 removal averaged 93 ± 7 mL/min during days 2 through 20 of support. Systemic CO2 levels remained below 100 mm Hg (averaging 79 ± 9 mm Hg on days 2–20) (Fig 3). After 9 days of support, the patient was accepted as a candidate for redo lung transplantation because of his considerable clinical improvement. He was awake, could be mobilized to sit on the edge of the bed, and maintained a better fluid balance with continuous venovenous hemodiafiltration.Fig 3CO2 removal and gas exchange during 20 days of Hemolung support.View Large Image Figure ViewerDownload (PPT)Fig 4(A, B) Mechanical ventilation and (C) hematologic parameters during 20 days of Hemolung support. (LDH = lactate dehydrogenase; PEEP = positive end-expiratory pressure; RR = respiratory rate; TV = tidal volume.)View Large Image Figure ViewerDownload (PPT) Donor lungs became available from a donor meeting the standard criteria 20 days after the initiation of Hemolung support. Standard preservation and surgical techniques were used for transplantation. The Hemolung device was removed at the time of the transplantation, and a double lung transplantation was performed with the use of cardiopulmonary support. After transplantation, the patient's chest was left open for 3 days because of a size mismatch. The patient required MV for 7 days immediately after the transplantation. He remained in the ICU for 12 days. Hemolung support was not required at any point after transplantation. The patient required treatment for acute cellular rejection and was discharged 89 days after transplantation with adequate lung function, in good clinical condition, and ambulating independently. The patient did not encounter airway or other respiratory adverse events and is currently active and able to walk 1.5 to 2 miles without assistance. There was significant improvement in lung function from a forced expiratory volume in 1 second of 0.92 L before transplantation to 3.05 L 9 months after transplantation. The postoperative adverse event of renal failure requiring dialysis is still present; kidney transplantation is being considered. In this case, we report the use of the Hemolung RAS as a prolonged bridge to lung transplantation, and the first use of the Hemolung as a bridge to redo lung transplantation. Additionally, this is the first use of the device in a patient in the United States. A handful of case series have described the use of the Hemolung for up to 8 days in patients with chronic obstructive pulmonary disease, but reports describing its use in patients requiring respiratory support for other conditions are sparse [5Burki N.K. Mani R.K. Herth F.J. et al.A novel extracorporeal CO(2) removal system: results of a pilot study of hypercapnic respiratory failure in patients with COPD.Chest. 2013; 143: 678-686Crossref PubMed Scopus (176) Google Scholar, 6Bonin F. Sommerwerck U. Lund L.W. Teschler H. Avoidance of intubation during acute exacerbation of chronic obstructive pulmonary disease for a lung transplant candidate using extracorporeal carbon dioxide removal with the Hemolung.J Thorac Cardiovasc Surg. 2013; 145: e43-e44Abstract Full Text Full Text PDF PubMed Scopus (28) Google Scholar]. Although ECMO has served as an adequate support to bridge patients to lung transplantation, its use has been limited by the large cannulas and high circulating volumes required, inflammatory response in the presence of a large-area membrane oxygenator, and risks of bleeding and thrombolytic adverse events [1Bermudez C.A. Rocha R.V. Zaldonis D. et al.Extracorporeal membrane oxygenation as a bridge to lung transplant: midterm outcomes.Ann Thorac Surg. 2011; 92 (discussion 31–2): 1226-1231Abstract Full Text Full Text PDF PubMed Scopus (132) Google Scholar, 2Javidfar J. Bacchetta M. Bridge to lung transplantation with extracorporeal membrane oxygenation support.Curr Opin Organ Transplant. 2012; 17: 496-502Crossref PubMed Scopus (40) Google Scholar]. The Hemolung offers an attractive and less invasive alternative for CO2 removal that can be implemented at the bedside. It could be used in some patients waiting for lung transplantation to reduce the risk of adverse events. Further study of the potential benefits of extracorporeal CO2 removal as an alternative to ECMO is both important and warranted, especially in patients who require mechanical support as a bridge to lung transplantation including redo cases. The authors wish to thank ALung Technologies for providing the Hemolung device and Shannon Wyszomierski for editorial support.