Short and longer term health related outcomes in patients receiving extracorporeal membrane oxygenation (ECMO)
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thesis
posted on 2017-05-22, 04:15authored byTramm, Ralph
Extracorporeal membrane oxygenation (ECMO) is a rescue therapy for patients in Intensive
Care Units (ICUs) that are critically ill and at great risk of dying from acute lung or heart
failure. It consists of specialised cannulae that connect to the body circulation, as well as
circuit tubing, a membrane that oxygenates the blood and removes carbon dioxide externally
from the body and a blood pump that drives circuit blood flow. ECMO can support the
lungs and the heart for hours to weeks until the underlying condition has resolved.
Survivors of critical illness, such as surviving ECMO patients, face a magnitude of short and
long term physical, cognitive, and mental health impairments that also affect the caring family.
Patients treated with ECMO are the sickest patients in ICU and are at high risk to develop
health impairments. These new or worsening problems have been defined as Post Intensive
Care Syndrome of the patient (PICS) and the family (PICS-F). This PhD thesis investigated
these syndromes in ECMO survivors and their families.
The systematic review of high quality evidence from randomised controlled trials (RCTs), that
compared survival of ECMO patients to control groups, was the starting point of this thesis.
The quality of evidence was low to moderate, with clinical heterogeneity preventing metaanalysis
of studies. Further evidence from ongoing RCTs is required to determine the
effectiveness of ECMO.
A risk factor profile of ECMO patients was developed with a focus on post-traumatic stress
disorder (PTSD). The profile was applied to a retrospective ECMO cohort. Psychiatric
histories, admission to ICU and drug therapy were identified risk factor clusters. Complex
and profound illness severity, as well as prolonged ICU stay exposed ECMO patients to
almost all known risk factors for PTSD and other mental and physical health risks.
This risk profile was then applied to prospective patient outcomes during a cohort study. The
study examined adverse health outcomes, health status, cognitive functioning and risk of
anxiety, depression and PTSD 3, 6 and 12 months after discharge. The analysis revealed that
physical function was greatly impaired in survivors compared to mental health, but trended to
resolve over time. Psychiatric risk factors showed an irregular pattern but both health
impairments and psychiatric risk factors remained elevated 12 months after discharge. Only
half of the participants scored non-impaired cognitive tests.
The final part of this thesis explored the acute care experiences of patients and relatives 12
months after discharge. ECMO patients experienced deconditioning, immobility, dependency
and death-threats during deterioration, admission and delusional experiences in the ICU.
Relatives were confronted with uncertainties of the survival of a loved one and carried most
of the acute psychological burden while patients were sedated.
In summary, the collated evidence presented in this thesis strongly mandates that all available
support systems must be activated to help ECMO survivors and their families to overcome
the existing multiple risks and health impairments that PICS and PICS-F may cause in the
year after discharge.