- In a retrospective study of 279 adults, implementation of a multidisciplinary approach to extracorporeal membrane oxygenation (ECMO) at Massachusetts General Hospital improved survival to discharge, from about 38% in 2009–2013 to 53% in 2014–2017
- The number of patients treated with venovenous ECMO significantly increased during the study period, from 19% before the team was formed to 41% afterward
- The number of patients treated with venoarterial ECMO decreased from 76% to 51%
- Over time, ECMO patients came to be placed in designated ICUs, which seems to have improved clinician skills and comfort levels in caring for this complex patient population
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Recent retrospective studies have demonstrated that a higher annual hospital volume of patients undergoing extracorporeal membrane oxygenation (ECMO) is associated with improved survival to discharge. This research has not examined, though, whether the greater experience itself is what improves outcomes.
Cardiac anesthesiologists and cardiac surgeons at Massachusetts General Hospital recently conducted the largest single-institution study of ECMO outcomes. In the Journal of Cardiothoracic and Vascular Anesthesia, Cardiothoracic Anesthesiologists Adam A. Dalia, MD, MBA, and Gaston D. Cudemus, MD, of the Division of Cardiac Anesthesiology, and Mauricio Villavicencio, MD, director of ECMO in the Division of Cardiac Surgery at Mass General, and colleagues report that instituting a formal ECMO team, guided by a set of protocols, dramatically improved in-hospital survival of this complex patient population.
No More Silos
When ECMO was initiated at Mass General, patients were cared for in various ICUs by specialized intensivists who functioned in "silos." In 2014, the hospital instituted an ECMO team consisting of cardiac surgeons, cardiac anesthesiologists, intensivists, cardiologists, ICU nurses, perfusionists, respiratory therapists, nutritionists, physical therapists, occupational therapists and an ethics committee member. At that time, Mass General also implemented an ECMO initiation algorithm, along with order sets and protocols. Those are included in the journal article.
By searching an institutional database, the research team identified 279 adults who were placed on venoarterial (VA) or venovenous (VV) ECMO between 2009, when data collection began, and 2017. They divided the patients into those treated between 2009 and 2013, before the team was formed (n=130), and those treated between 2014 and 2017 (n=149).
Rates of survival to hospital discharge were as follows:
- Entire cohort: 37.7% for patients treated before the team was formed and 52.3% for those treated afterward (= .02)
- VA ECMO patients: 37.4% and 48.6%
- VV ECMO patients: 40% and 63%
- Mixed ECMO: patient numbers were too small to analyze for comparison
There was substantial staff turnover throughout the study period, which suggests to them that the improved survival was not solely a result of increased provider experience.
Choice of VV Versus VA ECMO
The number of patients treated with VV ECMO increased drastically during the study period, from 19% before the team was formed to 41% afterward (= .01). The number of VA ECMO patients significantly decreased, from 76% to 51% (P < 0.01).
There could be multiple reasons for the trend, the researchers acknowledge, but they believe it suggests a more prudent selection of therapeutic modalities and possibly better patient selection.
Before the ECMO team was created, patients cannulated for ECMO could be placed in any of four ICUs, depending on the patient's current location and hospital bed resources. One of the changes made over time has been to send patients exclusively to ICUs experienced in ECMO care. VA ECMO patients are now cared for within the cardiac surgical ICU, and VV ECMO patients are cared for within the medical ICU.
Anecdotally, the authors found the consolidation of ICU placement to be a key contributor to improved outcomes. Dedicated ICUs allow physicians to focus on ECMO-specific training for nurses and other health care professionals, which has improved clinicians' skills and comfort level in caring for ECMO patients.
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