Recovery From ICUAW Following Severe Respiratory and Cardiac Failure

To identify determinants of recovery from ICUAW and to discover the effects of ICUAW on physical function and health-related quality of life (HRQoL) after critical illness. This phenomenon has become more evident over recent years and still requires extensive research.

ICUAW is an umbrella term for more specifically polyneuropathy and myopathy. Recent research has found that 50% of patients undergoing elective cardiac surgery lose significant muscle mass (9.6% in the wasters group) within the first seven days. These patients are receiving relatively uncomplicated surgery yet still suffering from muscle breakdown, which cannot be described by inactivity alone. The investigators wish to observe ICUAW in a real-life context, however, where cases are always severe. ICUAW can lead to a significant increase in mortality and morbidity. Risk factors for ICUAW include neuromuscular blocking agents, hyperglycaemia, inactivity and sepsis. The correlation between a patient group with severe cardiorespiratory failure and patient-centred outcomes during recovery such as functional ability and health-related quality of life (HRQoL) has been little studied.

Severe cardiac and respiratory failure can both be supported by a mechanical cardio-respiratory support (MCS) including extra-corporeal membrane oxygenation (ECMO); therefore referral for this intervention can be used as a marker of the severest form of cardiorespiratory failure. Both conditions are associated with a high incidence of collateral multi-organ dysfunction and mortality; as well as long-term morbidity, loss of independence and reduced quality of life. Patients with acute cardiac and respiratory failure referred to St Bartholomew's hospital for consideration of MCS will be recruited by advice/guidance from a personal and professional consultee.

Rectus femoris cross-sectional area (RFcsa) will be measured by ultrasound during the first week of admission and at pre-determined time points. The RFcsa will be correlated with indices of muscle strength, physical function and HRQoL. The investigators will also take blood and urine samples on arrival and at pre-defined intervals during the patients' admission for circulating and respiratory markers of sepsis, oxidative stress and organ injury. A muscle biopsy will be taken from the operation field if the patient is centrally cannulated when initiating ECMO.

The primary Objective is to identify determinants of recovery from ICUAW and to discover the effects of ICUAW on physical function and health-related quality of life (HRQoL) after severe cardiorespiratory failure. Specifically, to observe the cross-sectional area of the Rectus Femoris (RFcsa) and correlate this with muscle strength and HRQoL during recovery. RFcsa, hand-held dynamometry, knee straightening dynamometry, Free Fat Mass Index, standing and lying vital capacity, MRC-SS sum score and short physical performance battery (SPPB) will be observed. Also, HRQoL will be measured using the reintegration to normal living index (RNLI), hospital and anxiety depression score (HADS)and the EQ-5D-5L (EuroQol research foundation). Additionally, we have composed a 10 item questionnaire to assess pre-morbid functional status. The primary endpoint will be once all these data are gathered and analysed.

The secondary aim is to understand the molecular and genomic profile of blood samples and the histology of the muscle biopsies. The objective will be supported with additional data from urine analysis (albumin-creatinine ratio) and vascular endothelial cells. The secondary endpoint will be once these data are collected and analysed.

• The secondary aim is to understand the molecular profile (bloods). [Time frame: Up to approximately 1 year]
• Urine Analysis [Time frame: Up to approximately 1 year]
• Muscle Biopsy [Time frame: Intra operatively]
• Vascular endothelial cell sampling [Time frame: Day 0.]
• Cardiac post operative morbidity score (C-POMS) will be used to calculate total morbidity risk. [Time frame: Time Frame: Day 3, day 5, day 8 and day 15 post ECMO initiation.]