Development and Clinical Use of an Artificial Lung
Nathan L. Kister
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Brittany A. Zwischenberger
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Jeremiah T. Martin
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Joseph B. Zwischenberger
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N. L. Kister B. A. Zwischenberger J. T. Martin J. B. Zwischenberger (&) Division of Cardiothoracic Surgery, Department of Surgery, University of Kentucky
, 800 Rose Street,
MN260
, Lexington,
KY 40536-0298, USA
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This article is part of the Topical Collection on Artificial Organ CT Surgery
In the 1970s, the use of cardiopulmonary bypass at the bedside for critically ill patients with respiratory failure began and was termed extracorporeal membrane oxygenation (ECMO). Later, in the 1980s, applications for extracorporeal technology expanded, and included oxygenation, CO2 removal, and hemodynamic support. However, early studies regarding the use of ECMO for acute lung failure provided less than optimistic results. Today, recent research has created a renewed interest in such technology. There have been progressive advancements in artificial lung technology, and ECMO serves as a form of life support and as a bridge to transplantation for critically ill patients when traditional supportive care is no longer effective. These progressive advancements in artificial lung technology provide another tool in the critical care physician's arsenal to combat this often fatal injury.
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Despite the continued evolution and advancements in critical
care medicine, acute respiratory failure continues to cause
significant morbidity and mortality worldwide. Vasilyev
et al. [1] found in an intercontinental trial that the in-hospital
mortality rates for acute lung injury approached 45 %. While
positive pressure ventilation has been the cornerstone of
managing patients with significant lung injury, there have
been progressive advancements in artificial lung technology
which may provide another tool in the critical care
physicians arsenal to combat this often fatal injury.
Early studies regarding the use of extracorporeal
membrane oxygenation (ECMO) for acute lung failure provided
less than optimistic results [2]. Recent research, however,
has created a renewed interest in such technology. Studies
such as the CESAR trial and recent experience with H1N1
pandemics have shown the potential benefit and possible
superiority of ECMO to traditional ventilator support [3,
4]. This article aims to review the development, current
use, and potential future direction of artificial lung
technology in the adult patient with lung failure.
The term artificial lung has for the most part been used to
refer to venovenous ECMO (VV-ECMO) although some
other support devices which function to assist or replace the
oxygenation and ventilation functions of the lung may be
grouped under this terminology [5]. ECMO is a broad term
that encompasses many different variations of extracorporeal
oxygenation. The two main types of ECMO are venoarterial
(VA) and venovenous (VV). VA-ECMO is most commonly
used for patients with both heart and lung failure and functions
more as the traditional cardiopulmonary bypass machine in
which oxygenated and pressurized blood is returned to the
systemic circulation. VV-ECMO more appropriately
functions as an artificial lung as it replaces the respiratory
component of the lung but does not replace the patients intrinsic
cardiac function. Hence the discussion of this article will focus
on the clinical aspects of VV-ECMO rather than the complete
cardiopulmonary support of VA-ECMO.
The need for artificial lung technology to replace the
respiratory functions of the lungs (oxygenation and
ventilation) is usually secondary to acute lung injury which may
be induced by any variety of pulmonary insults, including
surgery, trauma, or infection. Only patients whose lung
function is expected to make a recovery should be
considered candidates for VV-ECMO. Recent advances in
technology which allow for patients to be maintained on
ECMO for longer periods of time are now questioning
whether the artificial lung can be used as a bridge to
transplant in patients with end-stage lung disease until
donor organs become available [6].
In patients with acute lung injury, mortality can range
anywhere from 34 to 58 % [3]. The vast majority of
patients with acute respiratory failure are managed with
positive pressure ventilation. Ventilators alone or in
combination with other rescue strategies are often able to
provide support in the form of oxygenation and ventilation
but only if the lung parenchyma itself is not too severely
damaged to perform these basic functions. Unfortunately,
positive pressure ventilation comes with risks including
pneumonia, need for sedation and immobility, and further
damage to the lung parenchyma itself through barotrauma,
which can escalate the injury to an already compromised
lung tissue. VV-ECMO has shown promise in replacing the
respiratory function of the lung, while at the same time
allowing the native lung tissue to heal without the harsh
and unnatural positive pressure ventilation.
For patients who have reached e (...truncated)