Faculty Bibliography

OBJECTIVE:There is a shortage of donor lungs relative to need, but overall donor organ utilization remains low. The most common reason for refusal is organ quality, but the standards applied to selection vary. In this study we sought to characterize differences in lung utilization according to quality across several clinically distinct recipient pools. METHODS:Data on donor lungs recovered (April 2006 to September 2019) were extracted from the Scientific Registry of Transplant Recipients database. Organs were classified as ideal, standard, or extended quality according to their poorest metric among selected parameters. Subanalyses were performed on the basis of procedure type, age, lung allocation score, era, and alternative definitions of extended quality. Recipient traits and survival according to organ quality were assessed. RESULTS:Of 156,022 lungs analyzed during the study period, 25,777 (16.5%) were transplanted. There was no difference in quality distribution for single and bilateral transplants. Young candidates were more likely to receive ideal (14.7% vs 12.3%) or standard (9.5% vs 8.2%) lungs, but not extended lungs (75.9% vs 79.5%; all P < .01). Absolute differences in distribution according to lung allocation score quartile were small (<2%). Extended quality donor utilization increased over time. Survival according to donor category was similar at 1 and 3 years post transplant in unadjusted and Cox regression analyses. CONCLUSIONS:Extended quality lungs comprise an increasing share of transplants in a national sample. Organ selection varies according to recipient age and lung allocation score. However, absolute differences in quality distribution are small, and adverse effects on outcomes are limited to organs with multiple extended qualifying characteristics.

Objectives/UNASSIGNED:Proning patients with acute respiratory distress syndrome (ARDS) has been associated with increased survival, though little data exists evaluating the safety and feasibility of proning ARDS patients on extracorporeal membrane oxygenation (ECMO). Methods/UNASSIGNED:, 2020 was performed. All proning events were evaluated for complications, as well as change in compliance, sweep, oxygenation and flow. The primary outcome of this study was the rate major morbidity associated with proning while on ECMO. Results/UNASSIGNED:of 86 pre to 103 post (p<0.0001). Mean ECMO flow was unchanged. Conclusions/UNASSIGNED:Proning in patients with ARDS on ECMO is safe with an associated improvement in lung mechanics. With careful planning and coordination, these data support the practice of appropriately proning patients with severe ARDS, even if they are on ECMO.

OBJECTIVE:This pilot study sought to evaluate the feasibility of our donation after circulatory death (DCD) heart transplantation protocol using cardiopulmonary bypass (CPB) for normothermic regional reperfusion (NRP). METHODS:Suitable local DCD candidates were transferred to our institution. Life support was withdrawn in the operating room (OR). On declaration of circulatory death, sternotomy was performed, and the aortic arch vessels were ligated. CPB was initiated with left ventricular venting. The heart was reperfused, with correction of any metabolic abnormalities. CPB was weaned, and cardiac function was assessed at 30-minute intervals. If accepted, the heart was procured with cold preservation and transplanted into recipients in a nearby OR. RESULTS:Between January 2020 and January 2021, a total of 8 DCD heart transplants were performed: 6 isolated hearts, 1 heart-lung, and 1 combined heart and kidney. All donor hearts were successfully resuscitated and weaned from CPB without inotropic support. Average lactate and potassium levels decreased from 9.39 ± 1.47 mmol/L to 7.20 ± 0.13 mmol/L and 7.49 ± 1.32 mmol/L to 4.36 ± 0.67 mmol/L, respectively. Post-transplantation, the heart-lung transplant recipient required venoarterial extracorporeal membrane oxygenation for primary lung graft dysfunction but was decannulated on postoperative day 3 and recovered uneventfully. All other recipients required minimal inotropic support without mechanical circulatory support. Survival was 100% with a median follow-up of 304 days (interquartile range, 105-371 days). CONCLUSIONS:DCD heart transplantation outcomes have been excellent. Our DCD protocol is adoptable for more widespread use and will increase donor heart availability in the United States.

BACKGROUND:Severe coronavirus disease 2019 (COVID-19) can cause acute respiratory failure requiring mechanical ventilation. Venovenous (VV) extracorporeal membrane oxygenation (ECMO) has been used in patients in whom conventional mechanical ventilatory support has failed. To date, published data have focused on survival from ECMO and survival to discharge. In addition to survival to discharge, this study reports 1-year follow-up data for patients who were successfully discharged from the hospital. METHODS:A single-institution, retrospective review of all patients with severe COVID-19 who were cannulated for VV-ECMO between March 10, 2020 and May 1, 2020 was performed. A multidisciplinary ECMO team evaluated, selected, and managed patients with ECMO support. The primary outcome of this study was survival to discharge. Available 1-year follow-up data are also reported. RESULTS:A total of 30 patients were supported with VV-ECMO, and 27 patients (90%) survived to discharge. All patients were discharged home or to acute rehabilitation on room air, except for 1 patient (3.7%), who required supplemental oxygen therapy. At a median follow-up of 10.8 months (interquartile range [IQR], 8.9-14.4 months) since ECMO cannulation, survival was 86.7%, including 1 patient who underwent lung transplantation. Of the patients discharged from the hospital, 44.4% (12/27) had pulmonary function testing, with a median percent predicted forced expiratory volume of 100% (IQR, 91%-110%). For survivors, a 6-minute walk test was performed in 59.3% (16/27), with a median value of 350 m (IQR, 286-379 m). CONCLUSIONS:A well-defined patient selection and management strategy of VV-ECMO support in patients with severe COVID-19 resulted in exceptional survival to discharge that was sustained at 1-year after ECMO cannulation.

Intra-aortic balloon pumps (IABPs) can be used to provide hemodynamic support in patients with end-stage heart failure as a bridge to transplantation (BTT). The IABP is commonly inserted via the common femoral artery, which can limit patients' mobility. The Ramsey protocol, developed by a critical care physical therapist, allows patients with femoral IABPs to ambulate with the assistance of a tilt table. The aim of this study was to determine the safety and feasibility of a modified Ramsey protocol for early mobilization of patients with femoral IABPs as BTT. This is a retrospective single-center review of patients with femoral IABPs as BTT using a tilt table protocol from May 2019 to May 2020. Primary outcomes were time to successful ambulation, number of successful ambulation events, and ambulation-associated adverse events, including IABP augmentation, waveform, positioning changes, and vascular complications at the insertion site. Twenty-four patients (mean age 55 ± 16 years) underwent femoral IABP insertion as BTT and were mobilized following our protocol. Nineteen patients (79.2%) successfully ambulated with a median of three sessions (interquartile range, 2-4) per patient. The median time from IABP insertion to ambulation was 3 days (interquartile range, 2-5). Twenty-one patients underwent heart transplantation, of which all 19 who ambulated were successfully bridged to transplantation. Early mobilization in select patients with femoral IABPs can be performed safely and successfully, avoiding the deleterious effects of bed rest that have been historically seen in this patient population.

Bleeding remains a major source of morbidity associated with veno-venous extracorporeal membrane oxygenation (VV-ECMO). Moreover, there remains significant controversy, and a paucity of data regarding the ideal anticoagulation strategy for VV-ECMO patients. All patients undergoing isolated, peripheral VV-ECMO between January 2009 and December 2014 at our institution were retrospectively reviewed. Patients (n = 123) were stratified into one of three sequential eras of anticoagulation strategies: activated clotting time (ACT: 160-180 seconds, n = 53), high-partial thromboplastin time (H-PTT: 60-80 seconds, n = 25), and low-PTT (L-PTT: 45-55 seconds, n = 25) with high-flow (>4 L/min). Pre-ECMO APACHE II scores, SOFA scores, and Murray scores were not significantly different between the groups. Patients in the L-PTT group required less red blood cell units on ECMO than the ACT or H-PTT group (2.1 vs. 1.3 vs. 0.9; p < 0.001) and patients in the H-PTT and L-PTT group required less fresh frozen plasma than the ACT group (0.33 vs. 0 vs. 0; p = 0.006). Overall, major bleeding events were significantly lower in the L-PTT group than in the ACT and H-PTT groups. There was no difference in thrombotic events. In this single-institution experience, a L-PTT, high-flow strategy on VV-ECMO was associated with fewer bleeding and no difference in thrombotic events than an ACT or H-PTT strategy.

INTRODUCTION: Extracorporeal membrane oxygenation (ECMO) provides life-saving support in severe coronavirus disease-19 (COVID-19) infections resulting in acute hypoxemic respiratory failure refractory to conventional medication support. We examine the trend of inflammatory markers, including D-dimers, in COVID-19 patients requiring extracorporeal support.
METHOD(S): We retrospectively analyzed 29 patients with COVID-19 infection requiring veno-venous (VV) ECMO. Demographics, pre-ECMO characteristics, complications, and blood product requirements were compared between patients with D-dimer levels < 3,000 versus >3,000 ng/ mL using independent two-sample Student's t-tests for continuous variables and chi-squared test for categorical variables. Inflammatory marker levels for patients before and after circuit exchanges were compared using paired samples t-tests.
RESULT(S): COVID-19 patients with pre-cannulation D-dimer levels >3,000 ng/mL had a significantly shorter time from admission to cannulation (4.78 vs 8.44 days, p=0.049) compared to those with D-dimer < 3,000 ng/mL. Furthermore, patients with D-dimer >3,000 ng/mL had a trend of lower pH (7.24 vs 7.33), higher pCO2 (61.33 vs 50.69), and higher VIS scores (7.23 vs 3.97) at time of cannulation, however these were not statistically significant. This cohort of patients also required longer duration of ECMO support (51.44 vs 31.25 days). 13 patients required at least one ECMO-circuit exchange and 16 patients did not require any exchanges. There was a consistent drop in D-dimer values after every circuit exchange, which was not observed in any of the other examined inflammatory markers including Ferritin, LDH, or CRP.
CONCLUSION(S): Elevated D-dimer levels (>3,000 ng/mL) likely reflect increased disease severity in COVID-19, and predict a longer ECMO course. Once on ECMO, however, the D-Dimer level consistently decreased with circuit exchange and may reflect thrombus within the oxygenator rather than disease severity