Cardiovascular Rounds

Early insights on using ECMO to treat Covid-19

by Daniel Roza

As medical professionals continue to develop consensus on the most effective treatments for Covid-19, extracorporeal membrane oxygenation (ECMO) is emerging as an alternative to ventilators for patients whose respiratory function is compromised.

Read our primer to learn about growth drivers and program development considerations for ECMO

While no official consensus or formal guidelines have been established on the efficacy of ECMO in Covid-19 patients, some providers have experienced success using the therapy. Cardiothoracic & Vascular Surgical Associates (CTVSA), a private physician practice that works with 12 hospitals across the Chicago area, has supported more than 70 Covid-19 patients using ECMO with a mortality rate of about 10%. The Cardiovascular Roundtable called Dr. Antone Tatooles, a CT surgeon at CTVSA, to learn about some of his early lessons for using ECMO to treat Covid-19 patients.

Potential benefits of ECMO over ventilators

Throughout the early phases of the Covid-19, media and medical attention focused on the role that ventilators played in treating patients with compromised respiratory function. However, the efficacy of ventilators is still in question for some, with reports demonstrating mortality for such patients ranging anywhere from 30% to 90%.

While it's too early to make a direct comparison between ECMO patients and those on ventilators, Dr. Tatooles and his colleagues have found that ECMO can have clear benefits over ventilators. For instance, while ECMO is extremely invasive, Dr. Tatooles believes that it can be less likely than ventilators, which inflict significant barotrauma, to cause infections. Additionally, patients do not necessarily have to be sedated while on an ECMO circuit—in fact, of the ECMO patients treated by CTVSA physicians, 80% are not on sedatives.

This difference is important because extensive use of sedatives comes with negative ramifications, particularly for patients with comorbidities such as kidney failure. Furthermore, with patients alert and awake, providers can begin the rehab process for recovering patients within the walls of the hospital, even when they are still on ECMO. In contrast, patients on ventilators must be weaned off sedatives gradually and are often discharged to post-acute care for recovery, which can introduce additional opportunities for complications.

That said, ECMO is a resource-intensive technology that requires round-the-clock staff and lengthy inpatient stays. According to Dr. Tatooles, a thoughtful, deliberate, evidence-based strategy is of the utmost importance to meet three main challenges associated with ECMO: patient selection, staff deployment, and resource allocation.

Flexible patient selection criteria reflect emerging evidence

In the absence of official patient selection criteria, the onus falls on providers and systems to determine the best candidates for Covid-19-related ECMO.

For CTVSA, Dr. Tatooles said the patient selection criteria evolved as providers learned more about how ECMO impacts outcomes. Initially, ECMO was offered as a last resort to patients who were dying or unable to be supported by ventilators. However, providers observed that patients who were put on ECMO earlier or who had fewer comorbidities such as renal failure tended to have better outcomes. As a result, patient inclusion criteria transitioned to prioritize patients with a BMI of less than 45 who have not spent extensive time on ventilators and are not experiencing kidney failure. While providers continue to modify the inclusion criteria based on emerging evidence, the guidelines at CTVSA align closely with guidelines at other systems, such as Michigan Medicine and the University of Mississippi Medical Center.

Creative use of hospital space minimizes capacity constraints

ECMO patients tend to have lengthy inpatient stays. Of the Covid-19 patients treated by CTVSA, the average length of stay is four weeks. As a result of potentially lengthy stays, providers and leaders had to think creatively to accommodate these patients at a time in which capacity was already under severe strain.

According to Dr. Tatooles, as ECMO began to emerge as a viable therapy, one of CTVSA's hospital partners allowed the ECMO team to take over the CV ICU. To treat more patients, the team doubled the number of beds in most rooms, expanding the floor's capacity from 20 beds to 30. (And in addition to expanding capacity, this measure helped save personal protective equipment (PPE), as providers could see more patients at one time.)

With the CV ICU dedicated solely to Covid-19 patients on ECMO, the system served urgent and emergent non-Covid-19 patients on the pediatric hospital campus next door. Finally, to maximize capacity across the region, the surgeons worked with two major medical centers in Chicago to share ECMO patients across the two institutions.  

Statewide sequester supplements nursing team

Of all the challenges CTVSA providers faced when delivering ECMO care, the scarcity of nurses was the hardest to overcome. ECMO patients require nurses around the clock to administer care, particularly if they were previously sedated on ventilators. To accommodate demand, nurses were sequestered from across the state of Illinois, particularly from areas less impacted by the epidemic. The surge of nurses helped the ECMO program support record numbers of patients.

As hospitals open up for elective procedures and nurses return to their home institutions, leaders are in the process of identifying surgical nurses who can continue to be a part of the ongoing ECMO team.

Looking ahead to prepare for future surges

Dr. Tatooles and his team are looking ahead to prepare not only for periodic surges as social restrictions in the area continue to ease, but also for a potentially higher-than-average flu season this fall and winter. For the physicians at CTVSA, the early experiences and lessons learned from the surge this April gives them a strong foundation from which to build.  

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