Darryl Abrams

Pilot Study of Extracorporeal Carbon Dioxide Removal to Facilitate Extubation and Ambulation in Exacerbations of Chronic Obstructive Pulmonary Disease

RATIONALE Acute exacerbations of chronic obstructive pulmonary disease (COPD) requiring invasive mechanical ventilation (IMV) are associated with significant morbidity and mortality. Extracorporeal carbon dioxide removal (ECCO₂R) may facilitate extubation and ambulation in these patients and potentially improve outcomes. OBJECTIVES We assessed the feasibility of achieving early extubation and ambulation in subjects requiring IMV for exacerbations of COPD using single-site ECCO₂R. METHODS Five subjects with exacerbations of COPD with uncompensated hypercapnia requiring IMV were enrolled in this single-center, prospective, feasibility trial using a protocol of ECCO₂R, extubation, and physical rehabilitation. The primary endpoint was extubation within 72 hours of starting ECCO₂R. MEASUREMENTS AND MAIN RESULTS Mean preintubation pH and PaCO₂ were 7.23 ± 0.05 and 81.6 ± 15.9 mm Hg, respectively. All subjects met the primary endpoint (median duration, 4 h; range, 1.5-21.5 h). Mean duration of extracorporeal support was 193.0 ± 76.5 hours. Mean time to ambulation after extracorporeal initiation was 29.4 ± 12.6 hours. Mean maximal ambulation on extracorporeal support was 302 feet (range, 70-600). Four subjects were discharged home, and one underwent planned lung transplantation. Two minor bleeding complications occurred. There were no complications from mobilization on extracorporeal support. CONCLUSIONS ECCO₂R facilitates early extubation and ambulation in exacerbations of COPD requiring IMV and has the potential to serve as a new paradigm for the management of a select group of patients. Rigorous clinical trials are needed to corroborate these results and to investigate the effect on long-term outcomes and cost effectiveness over conventional management.

Extracorporeal membrane oxygenation as a novel bridging strategy for acute right heart failure in group 1 pulmonary arterial hypertension.

Patients with group 1 pulmonary arterial hypertension (PAH) and decompensated right heart failure (RHF) were not previously considered for extracorporeal membrane oxygenation (ECMO) as bridge to transplantation (BTT) or bridge to recovery (BTR) because options were limited by long transplantation wait times and perceived inability to wean ECMO. In a retrospective review, we describe our center’s multidisciplinary mechanical–medical approach to ECMO as a bridging therapy for PAH (2009–2012). Suitability for ECMO was determined using a defined algorithm. Six patients (age, 32 ± 11 years) underwent mechanical–medical bridging. Two transplant-eligible patients underwent successful BTT. The four patients ineligible for transplantation underwent BTR with escalation of targeted medical therapies before weaning off ECMO. Three of four BTR patients survived to ECMO decannulation (duration, 12 ± 7; range, 7–23 days). In this single-institution experience, mechanical–medical BTT and BTR with ECMO and targeted PAH therapies were used as a novel treatment strategy to successfully manage acute RHF in PAH.

Upper-body extracorporeal membrane oxygenation as a strategy in decompensated pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a disease with significant morbidity and mortality, particularly during an acute decompensation. We describe a single-center experience of three patients with severe Group 1 PAH, refractory to targeted medical therapy, in which an extubated, nonsedated, extracorporeal membrane oxygenation (ECMO) strategy with an upper-body configuration was used as a bridge to recovery or lung transplantation. All three patients were extubated within 24 hours of ECMO initiation. Two patients were successfully bridged to lung transplantation, and the other patient was optimized on targeted PAH therapy with subsequent recovery from an acute decompensation. The upper-body ECMO configuration allowed for daily physical therapy, including one patient, who would otherwise have been unsuitable for transplantation, ambulating over 850 meters daily. This series demonstrates the feasibility of using ECMO to bridge PAH patients to recovery or transplantation while avoiding the complications of immobility and invasive mechanical ventilation.

Blood Conservation in Extracorporeal Membrane Oxygenation for Acute Respiratory Distress Syndrome

BACKGROUND Extracorporeal membrane oxygenation support (ECMO) typically requires multiple blood transfusions and is associated with frequent bleeding complications. Blood transfusions are known to increase morbidity and mortality in critically ill patients, which may extend to patients receiving ECMO. Aiming to reduce transfusion requirements, we implemented a blood conservation protocol in adults with severe acute respiratory distress syndrome (ARDS) receiving ECMO. METHODS This was a retrospective study of adults receiving ECMO for ARDS after initiation of a blood conservation protocol that included a transfusion trigger of hemoglobin of less than 7.0 g/dL, use of low-dose anticoagulation targeting an activated partial thromboplastin time of 40 to 60 seconds, and autotransfusion of circuit blood during decannulation. The primary objective was to evaluate transfusion requirements during ECMO support. Clinical outcomes included survival, neurologic function, renal function, bleeding, and thrombotic complications. RESULTS The analysis included 38 patients; of these, 24 (63.2%) received a transfusion while receiving ECMO. Median hemoglobin was 8.29 g/dL. A median of 1.0 units (range, 250 to 300 mL) was transfused during ECMO support over a median duration of 9.0 days, equivalent to 0.11 U/d (range, 27.5 to 33.3 mL/d). The median activated partial thromboplastin time was 46.5 seconds. Bleeding occurred in 10 patients (26.3%); severe bleeding occurred in 2 patients (5.3%). Twenty-eight patients (73.7%) survived to hospital discharge. CONCLUSIONS Implementation of a blood conservation protocol in adults receiving ECMO for ARDS resulted in lower transfusion requirements and bleeding complications than previously reported in the literature and was associated with comparable survival and organ recovery.

One Hundred Transports on Extracorporeal Support to an Extracorporeal Membrane Oxygenation Center

BACKGROUND Extracorporeal life support technology has gained acceptance as a salvage mode for patients in respiratory or cardiac failure. Patients who are sick enough to require extracorporeal membrane oxygenation (ECMO) support are often too unstable for transfer to a hospital with ECMO capabilities. We highlight the progressive development of an ECMO transport team and the manner in which it provides reliable transport with excellent outcomes. METHODS All data were collected retrospectively from our hospitals electronic medical record. Patient outcomes are reported through April 2, 2014. RESULTS Our institution began an ECMO transport program in 2008, with the initial phase involving transport of highly selected patients for short distances. With experience we refined our intake and evaluation process. We also consolidated care for ECMO patients into two intensive care units and developed a dedicated ECMO intensivist position. As the program has matured, patient selection has become more inclusive and we have extended our capabilities to include interstate and international transport. All 100 patients were successfully placed on ECMO and transported to our center. Seventy-nine patients were placed on venovenous ECMO, 19 on venoarterial ECMO, and 2 on venovenous arterial ECMO. The median transport distance was 16 miles and ranged from 2.5 to 7,084 miles. CONCLUSIONS Extracorporeal membrane oxygenation transport can be performed safely and reliably with excellent outcomes with a dedicated team that maintains stringent adherence to well-designed management protocols.

Emerging Indications for Extracorporeal Membrane Oxygenation in Adults with Respiratory Failure

Recent advances in technology have spurred the increasing use of extracorporeal membrane oxygenation (ECMO) in patients with severe hypoxemic respiratory failure. However, this accounts for only a small percentage of patients with respiratory failure. We envision the application of ECMO in many other forms of respiratory failure in the coming years. Patients with less severe forms of acute respiratory distress syndrome, for instance, may benefit from enhanced lung-protective ventilation with the very low tidal volumes made possible by direct carbon dioxide removal from the blood. For those in whom hypercapnia predominates, extracorporeal support will allow for the elimination of invasive mechanical ventilation in some cases. The potential benefits of ECMO may be further enhanced by improved techniques, which facilitate active mobilization. Although ECMO for these and other expanded applications is under active investigation, it has yet to be proven beneficial in these settings in rigorous controlled trials. Ultimately, with upcoming and future technological advances, there is the promise of true destination therapy, which could lead to a major paradigm shift in the management of respiratory failure.

Recirculation in venovenous extracorporeal membrane oxygenation.

Recirculation, a phenomenon in which reinfused oxygenated blood is withdrawn by the drainage cannula without passing through the systemic circulation, decreases the efficiency with which venovenous extracorporeal membrane oxygenation (ECMO) provides oxygenation. The precise amount of recirculation may be difficult to quantify. However, interventions should be attempted to reduce recirculation when oxygen delivery is suboptimal and recirculation is suspected. Several techniques, including the use of dual-lumen cannulae, have been successful in minimizing recirculation in venovenous ECMO. This article will provide an overview of the factors that affect recirculation, methods that may be used to quantify recirculation, and interventions that may reduce recirculation, thereby increasing ECMO efficiency.

Hybrid configurations via percutaneous access for extracorporeal membrane oxygenation: a single-center experience.

Use of extracorporeal membrane oxygenation (ECMO) in adults has surged in recent years. Typical configurations are venovenous (VV), which provides respiratory support, or venoarterial (VA), which provides both respiratory and circulatory support. In patients supported with VV ECMO who develop hemodynamic compromise, an arterial limb can be added (venovenous-arterial ECMO) to provide additional circulatory support. For patients on VA ECMO who develop concomitant respiratory failure in the setting of some residual cardiac function, an oxygenated reinfusion limb can be added to the internal jugular vein (venoarterial-venous ECMO) to improve oxygen delivery to the cerebral and coronary circulation. Such hybrid configurations can provide differential support for various forms of cardiopulmonary failure. We describe 21 patients who ultimately received a hybrid configuration at our institution between 2012 and 2013. Eight patients (38.1%) died during ECMO support, four patients (19.0%) died after decannulation but before hospital discharge, and nine patients (42.9%) survived to hospital discharge. Our modest survival rate is likely related to the complexity and severity of illness of these patients, and this relative success suggests that hybrid configurations can be effective. It serves patients well to maintain a flexible and adaptable approach to ECMO configurations for their variable cardiopulmonary needs.

Extracorporeal carbon dioxide removal for refractory status asthmaticus: experience in distinct exacerbation phenotypes

Extracorporeal carbon dioxide removal (ECCO2R) may be indicated for refractory status asthmaticus when severe dynamic hyperinflation or life-threatening respiratory acidosis persists despite optimal medical and ventilator management. Most prior reports describe the application of ECCO2R to rapid-onset asthma exacerbation, requiring a short duration of extracorporeal support. We report two patients with refractory status asthmaticus managed with ECCO2R, emphasizing the use of modern extracorporeal technology, cannulation technique and management protocols, which may improve the risk-to-benefit profile of this strategy. This report highlights the challenges in managing patients with distinct asthma exacerbation phenotypes. The potential need for prolonged device support may alter provider expectations and offers a new perspective of the role of ECCO2R for status asthmaticus.

What is new in extracorporeal membrane oxygenation for ARDS in adults

The use of extracorporeal membrane oxygenation (ECMO) in severe acute respiratory distress syndrome (ARDS) has increased considerably over the last several years, attributable to advances in extracorporeal technology, renewed interest, and accumulating evidence. Yet the role of ECMO in severe ARDS is still being defined. Looking ahead, the future of ECMO for ARDS may potentially involve an expanding role.