Short and longer term health related outcomes in patients receiving extracorporeal membrane oxygenation (ECMO)

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