الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 169 |  |  |
| | | from | 169 | | |
Abstract
Extracorporeal membrane oxygenation (ECMO) is a form of
partial pulmonary and/or cardiopulmonary bypass used for short
term (days to weeks) support of patients in severe pulmonary
and/or cardiac failure. ECMO is a form of mechanical assist
therapy that employs an extracorporeal blood circuit including an
oxygenator and a pump.
There are two main types of ECMO: veno-arterial (VA) and
veno- venous (VV). VA ECMO provides both cardiac and
respiratory support, whereas VV ECMO only provides respiratory
support. In adults, VA ECMO is used primarily for refractory
cardiogenic shock. In contrast, VV ECMO is favored in patients
with isolated severe respiratory failure in the absence of major
cardiac dysfunction.
More efficient membrane oxygenators and novel cannulation
strategies have broadened the indications for which ECMO may
offer a benefit, including hypercapnic respiratory failure,
cardiogenic shock and cardiac arrest. Ultimately, more studies are
needed to determine the appropriate use and clinical impact of
ECMO on respiratory and cardiac failure.
Once ECMO support has been started, the goal is to preserve all
organs and recover those injured. A daily metabolic panel verifies
proper perfusion and oxygenation. Arterial gases and coagulation
panel readings must be obtained hourly; especially during the first
hours of support. ECMO flows should be adjusted according to
the patient needs. On one hand, flows should be sufficient to keep
165
a good systemic perfusion measured by urine output, lactic acid
levels and mixed venous saturation. On the other hand, ECMO
flows should not be high enough to prevent lung circulation.
Transesophageal echocardiography (TEE) is the primary form of
imaging required during insertion and commencement of ECMO,
monitoring patient response, and detecting complications.
Systemic anticoagulation is initiated to prevent circuit clotting.
Unfractionated heparin is the current international standard for
anticoagulation during ECMO. The anticoagulant effect is
monitored using activated clotting time (ACT) or partial
thromboplastin time (PTT).
Most contraindications are relative, balancing the risks of the
procedure vs. the potential benefits.The absolute
contraindications to ECMO are irreversible lung disease with no
indication for lung transplantation and severe brain damage
associated with major cerebral infarction or severe intracranial
bleeding.
The most frequently observed medical complications are
hemorrhage and infection. Bleeding is the most common
complication and can occur at cannulation sites and can also be
life threatening with intracranial hemorrhage. Coagulase-negative
Staphylococci and Candida species are common causes of
ECMO-related blood stream infection