The clinical assessment and treatment of intensive care unit-acquired weakness

• Main Author: Connolly, Bronwen
• Other Authors: Hart, Nicholas ; Moxham, John
• Published: King's College London (University of London) 2014
• Subjects: 362.17
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.676922

Admission to the intensive care unit with critical illness can result in significant and wide-ranging impairments for survivors, which often persist for many years following resolution of the index illness and are now recognised as ‘post intensive care syndrome’. One component of this syndrome, peripheral skeletal muscle wasting and dysfunction that develop during critical illness are described as intensive care unit-acquired weakness (ICU-AW) and account for residual deficits in physical functional ability in post ICU patients. This thesis comprised studies examining the clinical assessment and treatment of patients with ICU-AW investigating the Medical Research Council sum-score (MRC-SS) tool, the most commonly reported technique for diagnosing ICU-AW, use of ultrasound to measure peripheral skeletal muscle architecture during critical illness, and exercise-based rehabilitation for critical illness survivors with ICU-AW. Moderate levels of inter-observer agreement and limited clinical predictive value using the MRC-SS for ICU-AW diagnosis were demonstrated, highlighting the challenges of the volitional manual muscle testing approach. Investigation of ultrasound to assess peripheral skeletal muscle architecture provided data to support technical application of this tool as a potential surrogate marker for strength in ICU patients where direct measurement may be limited. Post hospital discharge exercise-based rehabilitation for critical illness survivors with ICU-AW was explored in a pilot feasibility randomised controlled trial. Whilst no improvement in outcome was evident, process evaluation revealed methodological factors for further investigation in the design and conduct of a larger-scale trial, including development of an intervention effective beyond the extent of natural recovery observed. Follow-up of patients without ICU-AW highlighted the limitations of adopting the MRC-SS threshold to categorise diagnosis and ongoing rehabilitation requirements. A national UK survey revealed failure to implement published guidance on rehabilitation following critical illness following hospital discharge due to lack of funding, resources and managerial prioritisation, and suggests the need for a robust evidence base to support service delivery to address the currently unmet clinical need in this patient population.