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\begin{document}

\title{Response to ``The Use of Extracorporeal Membrane Oxygenation in Clinical
Practice'' Letter to Editor}



\author[1]{Harrison Lang}%
\author[1]{Mitchell Milanuk}%
\author[2]{John Brady}%
\author[1]{Karin Trujillo}%
\author[3]{Elizabeth Lyden}%
\author[1]{HelenMari Merritt Genore}%
\affil[1]{University of Nebraska Medical Center College of Medicine}%
\affil[2]{University of Pittsburgh Medical Center}%
\affil[3]{University of Nebraska Medical Center}%


\vspace{-1em}



  
  \date{May 24, 2024}


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\begin{abstract}
This is a response to the Letter to Editor received regarding the
article ``Outcomes of Non-Cardiotomy Patients Requiring Postoperative
Extracorporeal Membrane Oxygenation.''%
\end{abstract}%



\sloppy


Dear Dr Harky:

Thank you for your inquiry regarding our manuscript\textsuperscript{1}.
Our retrospective database captures all ECMO patients from 2006 through
Jan 2017. Postoperative ECMO for non-cardiotomy patients has been a
recent endeavor and includes 20 perioperative patients supported over a
six-year period (2010-2016). These patients were compared with ELSO
outcomes and within our own database (practices/selection criteria are
most similar within our institution).

We agree it is difficult to make recommendations about decisions for
support based on a small cohort of orthotopic liver transplant (OLT)
patients, including the referenced case series of eight patients with
38\% survival (2/4 VV an 1/4 VA survived
hospitalization)\textsuperscript{2}. Cannulation ranged from 0 to 180
days after transplantation. Our manuscript focused only on perioperative
support, occurring within index hospitalization, with median time to
support 0 days. This may represent a different \emph{type} of patients,
as the initial postoperative period includes unique hemodynamic
challenges.

Two other OLT reports include 32 and 18 patients\textsuperscript{2}.
These larger \emph{VV-only} cohorts report 15\% and 44\% survival. It is
unclear how close in proximity of OLT support was initiated. Within The
smaller 8 patient case series blends VA and VV support: overall survival
was 3/8 patients (25\% VA and 50\% VV). In our small experience,
perioperative salvage ECMO for OLT has been unsuccessful (0/4).

Our manuscript addresses demographic and preoperative characteristics of
the smaller subgroups. We do also discuss the type of ECMO utilized.

\textbf{OLT:} Indications were ``cardiac arrest (n = 2), intraoperative
cardiogenic shock (n = 1), and postoperative respiratory failure (n =
1). Two patients required VA-ECMO in the setting of ECPR, one patient
required VV-ECMO, and one patient fell into the ``Other'' category as
they were supported with RVAD with VV in-line oxygenator.''

\textbf{Thoracic:} ``Indications were\ldots{}respiratory failure (n 8)~
and cardiogenic shock (n 2). Three patients required VA-ECMO, six
patients required VV-ECMO, and one patient fell into the ``Other''
category.'' We do not have intraoperative details prior to ECMO
initiation.

We agree the use of either VA or VV ECMO respresent distinct underlying
disease processes. The PNC-ECMO and control cohorts were divided into VA
and VV ECMO before comparing short and long-term survival rates between
the cohorts.

Each case is considered uniquely via multidisciplinary approach with
discussion between primary surgeon and anesthesiologist, cardiothoracic
surgeon, intensivist, nurses, perfusionists and the patient/family. A
team-based approach to difficult situations is essential; we agree this
improves outcomes\textsuperscript{3}. Likewise, a quality conference
occurs at regular intervals to discuss ECMO mortalities and morbidities
in an interprofessional setting.

In closing, we agree completely that further studies are needed to
define which postoperative patients may benefit. Our manuscript is meant
to add to the body of literature available, not to provide guidelines.
Thank you for your insightful points and reflections.

~

References:

1.~~~~ Lang H, Milanuk M, Brady J, et al. Outcomes of noncardiotomy
patients requiring postoperative extracorporeal membrane oxygenation. J
Card Surg. 2020;1--8.
\href{https://doi.org/10.1111/jocs.14598\%20\%20\%202}{https://doi.org/10.1111/jocs.14598~}

2.~~~~ Braun H, Pulcrano M, Weber D et al. The Utility of ECMO After
Liver Transplantation: Experience at a High-volume Transplant Center and
Review of the Literature. Transplantation. 2019 Aug;103(8):1568-1573.

3.~~~~ Na SJ, Chung CR, Choi HJ, et al. The effect of multidisciplinary
extracorporeal membrane oxygenation team on clinical outcomes in
patients with severe acute respiratory failure. Ann Intensive Care.
2018;8(1):31. 2018 Feb 27. doi:10.1186/s13613-018-0375-9

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