Charles F. Evans

Ambulatory veno-venous extracorporeal membrane oxygenation: Innovation and pitfalls

OBJECTIVE End-stage lung disease and severe acute lung injury are complex entities that remain challenges to manage. Therapies include early institution of mechanical ventilation with positive end-expiratory pressure, permissive hypercapnia, pulmonary vasodilators, and complex fluid regimens. Veno-venous extracorporeal membrane oxygenation is an available treatment option for these patients but, in its conventional form, can be associated with significant complications. We present our early experience with an attempt to optimize extracorporeal membrane oxygenation, emphasizing reduced adjunctive mechanical ventilatory support and aggressive rehabilitation, with a goal of ambulation. This strategy has been enabled by the introduction of a dual-lumen draw and return cannula placed via the internal jugular vein. METHODS The first 10 patients (mean age of 45.3 years, 8 male) treated with this strategy between January 1, 2009, and October 1, 2009, were retrospectively reviewed. The ambulatory extracorporeal membrane oxygenation strategy was initiated with an aim of minimal mechanical ventilation and aggressive rehabilitation. The patients were intended to be weaned from all respiratory support or bridged to transplantation. RESULTS The mean duration of extracorporeal membrane oxygenation was 20 (9-59) days, with average mean blood flows of 3.5 (1.6-4.9) L/min, and levels of CO(2) removal and O(2) transfer of 228 (54-570) mL/min and 127 (36-529) mL/min, respectively. Six of 10 patients were weaned from respiratory support (N = 4) or underwent transplantation (N = 2) and survived to discharge from the hospital. The remaining 4 patients died of sepsis (N = 3) and withdrawal of care after renal failure (N = 1). Four of the 6 surviving patients were extubated and ambulatory while still on extracorporeal membrane oxygenation. During that time, 3 of the 4 patients exercised at the bedside, with the remaining patient able to undergo full cardiopulmonary rehabilitation, including treadmill walking. CONCLUSIONS Improvements in the durability of membrane blood oxygenators and pumps have prompted renewed consideration of extracorporeal membrane oxygenation in patients with severe lung disease. This report describes an attempt to augment extracorporeal membrane oxygenation with the goal of ambulation by minimizing mechanical ventilatory support and using aggressive in-and-out-of-bed rehabilitation.

Class III Obesity is Not a Contraindication to Venovenous Extracorporeal Membrane Oxygenation Support

BACKGROUND The use of venovenous extracorporeal membrane oxygenation (ECMO) has increased as a bridge to recovery for acute respiratory distress syndrome (ARDS) refractory to conventional support. Morbid obesity can pose a significant challenge to obtaining indexed flows, and outcomes in this population are not well described. METHODS Patients requiring ECMO for ARDS between January 2009 and November 2012 were retrospectively reviewed. Demographics, ECMO variables, and outcomes were assessed. Morbid obesity and super obesity were defined as a body mass index (BMI) greater than 40 kg/m(2) and greater than 50 kg/m(2), respectively. RESULTS Fifty-five patients with ARDS were placed on ECMO during the study period. Twelve were morbidly obese with a BMI of 49.0 kg/m(2) (interquartile range [IQR]: 45.4-57.3 kg/m(2)). Pre-ECMO mechanical ventilatory support and indices of disease severity were similar between the 2 groups, as were cannulation strategy and duration of ECMO support. Nine (75%) morbidly obese patients and 27 (63%) non-morbidly obese patients were successfully weaned from ECMO support, and patient survival to time of discharge was 67% and 58%, respectively. In the subset of super obese patients (n = 6; BMI, 57.3 kg/m(2) [IQR: 51.3-66.5 kg/m(2)]), recovery and midterm survival was 100%. CONCLUSIONS In this review, class III obesity was not associated with poorer outcomes, and based on these data, ECMO support should not be withheld from this patient population.

Venovenous Extracorporeal Membrane Oxygenation as a Bridge to Lung Transplantation: Successful Transplantation After 155 Days of Support

We present a case of a woman with acute respiratory distress syndrome and irrecoverable lung function that was successfully bridged to lung transplantation after 155 consecutive days of venovenous extracorporeal membrane oxygenation.

Long-Term Venovenous Extracorporeal Membrane Oxygenation Support for Acute Respiratory Distress Syndrome

BACKGROUND Given substantial advances in venovenous extracorporeal membrane oxygenation (ECMO) technology, long-term support is increasingly feasible. Although the benefits of short-term ECMO as a bridge to recovery in acute respiratory distress syndrome (ARDS) are well described, the utility and outcomes of long-term support remain unclear. METHODS Patients requiring ECMO for ARDS between January 2009 and November 2012 were retrospectively reviewed and analyzed separately for those requiring ECMO support for less than 3 weeks or for 3 weeks or longer. Demographic factors, ECMO variables, and outcomes were assessed. RESULTS Fifty-five patients with ARDS received ECMO during the study period, with 11 patients requiring long-term ECMO support and a median duration of 36 (interquartile range: 24 to 68) days. Recovery was the initial goal in all patients. Pre-ECMO mechanical ventilatory support, indices of disease severity, and the ECMO cannulation strategy were similar between the two groups. Eight (73%) patients receiving long-term support were bridged to recovery, and 1 patient was bridged to transplantation after a refractory course. Eight (73%) patients receiving long-term support and 25 (57%) patients receiving short-term support survived to 30 days and hospital discharge. CONCLUSIONS Previously, long-term ECMO support was thought to be associated with unfavorable outcomes. This study, however, may provide support for the efficacy of ECMO support even for 3 weeks or more as a bridge to recovery or transplantation.

Surgical Management of Mitral Valve Infective Endocarditis

Active mitral valve infective endocarditis is a challenging clinical problem with a high rate of mortality. Surgery is currently performed in more than 40% of patients, and selecting those patients who will benefit from surgical intervention and performing a technically sound operation at the proper time are keys to optimizing outcomes. Moderate-to-severe and severe mitral regurgitation, large, mobile vegetations, paravalvular abscess, embolic events, failure of antibiotic therapy, and infection with a fungal organism are indications for prompt operation. The use of computed tomography imaging is important to determine whether there are noncardiac sources of infection, and transesophageal echocardiography is essential to delineate valvular dysfunction, identify paravalvular abscesses, rule out involvement of other valves, and plan operative therapy. In most cases, surgery should not be delayed because of cerebrovascular emboli. Mitral valve repair is favored over replacement whenever possible, is associated with superior short- and long-term outcomes, and should be possible in most cases. Operative mortality is <10% and 5-year survival is >80%.

Venous Thromboembolic Complications of Lung Transplantation: A Contemporary Single-Institution Review

BACKGROUND The incidence and consequences of deep venous thrombosis (DVT) and pulmonary embolism (PE) have not been described recently in lung transplant recipients. We sought to characterize DVT and PE in a contemporary series of lung transplant recipients and describe their association with clinical outcomes. METHODS The records of all lung transplant recipients from July 1, 2008, to June 30, 2013, were reviewed and analyzed. DVT was diagnosed by venous duplex ultrasonography. PE was diagnosed by computed tomography angiography, nuclear ventilation/perfusion scanning, or pulmonary angiography. RESULTS The study comprised 117 patients who underwent 123 transplants. The median age was 63 years (range, 17 to 77 years). Forty-five patients (39%) had evidence of lower extremity DVT, 53 (45%) had no evidence of lower extremity DVT, and 19 (16%) were not tested. Fifty-three (45%) had evidence of upper extremity DVT, 30 (26%) had no evidence of upper extremity DVT, and 34 (29%) were not tested. Eighteen (15%) had evidence of PE, 82 (70%) had no evidence of PE, and 17 (15%) were not tested. A multivariable, stepwise Cox proportional hazards model revealed that the presence of lower extremity DVT (hazard ratio, 2.43; 95% confidence interval, 1.29 to 4.64), use of cardiopulmonary bypass (hazard ratio, 2.21; 95% confidence interval, 1.04 to 4.68), and unilateral lung transplantation (hazard ratio, 2.13; 95% confidence interval, 1.07 to 4.25) were associated with diminished survival. CONCLUSIONS The incidence of DVT and PE in lung transplant recipients is high. Posttransplant surveillance and treatment based on findings are warranted.

Long-Term Outcomes following Alemtuzumab Induction in Lung Transplantation

OBJECTIVES Alemtuzumab is a commonly used induction agent for solid-organ transplantation. Its use in lung transplantation with reduced immunosuppressive regimens, however, has yet to be well characterized. METHODS From November 2006 to March 2008, 20 consecutive lung transplantation patients received alemtuzumab induction with a reduced maintenance immunosuppression regimen. Twenty consecutive case-controls who underwent transplantation between 2005 and 2006 were treated with a standard immunosuppression regimen without induction. Outcome variables were patient survival, acute rejection, infection, and bronchiolitis obliterans syndrome. RESULTS Mean follow-up time was 1400 days in the alemtuzumab group and 1210 days in the control group. Double lung transplantation was performed in 21 patients (12 in the alemtuzumab group and 9 in the control group). There was no difference in survival between the alemtuzumab (n = 10) and control (n = 10) groups. There was also not a significant difference in time-adjusted death based on Kaplan-Meier analysis. The mean number of any grade of rejection event per patient was not significantly different (alemtuzumab 2.3 ± 2.7 vs. control 3.2 ± 2.35; P = .22). There was a trend toward the reduced incidence of infection requiring intravenous antibiotics per patient (alemtuzumab 2.4 vs. control 3.8; P = .08). The incidence of bronchiolitis obliterans syndrome was similar in both groups (alemtuzumab 55% vs. control 70%; P = .25). CONCLUSIONS Alemtuzumab induction with reduced immunosuppression offers a comparable 5-year survival and rejection rate compared to standard-dose immunosuppression regimen.

Externally visible thrombus partially predicts internal thrombus deposition in extracorporeal membrane oxygenators

Aim: We sought to quantify the location and volume of thrombus in used hollow-fiber membrane oxygenators and correlate the volume of thrombus with patient demographics, flow characteristics and anticoagulation parameters. Methods: Hollow-fiber membrane oxygenators (Quadrox D, Maquet, Rastatt, Germany) were collected after clinical use in ECMO circuits and divided into sections. Each section was digitally imaged and analyzed using ImageJ software. The location and total volume (cm3) of thrombus was calculated for different sections. In an effort to predict thrombus formation, we correlated thrombus volume with possible aggravating and mitigating variables. Results: We collected 41 oxygenators from 27 patients. Twenty-seven (66%) were configured in the veno-venous mode and 14 (34%) in the veno-arterial mode. The median duration of use was 131 hours (interquartile range 61–214 hours). Eighteen (44%) were removed when the patient recovered, six (15%) were removed after withdrawal of care and seventeen (41%) were exchanged. The median volume of thrombus was 11.4 cm3 (interquartile range 2.2–44.5 cm3). Conclusions: A multivariable linear regression model suggested that the combination of median flow, configuration of ECMO and visible thrombus partially predicted internal thrombus volume (adjusted R2=0.39).

Successful Management of Penetrating Injury to the Aortopulmonary Window

previously healthy 35-year-old man presented with Apenetrating injuries to the left hand and anterior chest after an assault with a nail gun. The nails entered along the lateral left palm and left parasternal border (Fig 1). The patient remained hemodynamically stable and demonstrated no respiratory distress, hemoptysis, tachypnea, or hypoxia. Computed tomographic angiography demonstrated a 7.7-cm nail protruding through the left aspect of the manubrium with the nail tip projecting into the aortopulmonary window, under the aortic arch and above the main pulmonary artery, with no evidence of vessel injury. Given the location and length of the nail,