An example of a complex intervention in acute stroke rehabilitation currently under investigation in an international RCT is very early mobilisation (VEM). Very early mobilisation is defined as starting mobilisation (i.e. sitting out of bed, standing or walking) within 24 hours of onset of stroke symptoms and to continue this at frequent intervals throughout the patients stay in the acute stroke unit (ASU). Very early mobilisation encourages activity in these acute stages (within 14 days) and is delivered by the multidisciplinary team (MDT), most usually nurses, physiotherapists and occupational therapists. Very early mobilisation is a complex intervention due to its multidimensional nature. It has several
interacting components i.e. an education component and a prescribing
component. It incorporates a number of behaviours required by those delivering or receiving the intervention i.e. the number and complexity of skills used by physiotherapists to provide the intervention to stroke patients. The delivery of very early mobilisation is likely to be patient specific (tailored to the individual needs of the patient) and context specific (delivered within a dynamic and complex healthcare system). This has implications for the definition,
standardisation and monitoring of VEM. Very early mobilisation has potentially wide-ranging and interacting effects, making the evaluation of VEM more
challenging than that of a drug. Therefore, VEM is an appropriate illustration of a complex intervention and was used as the clinical example in this thesis.
Although early mobilisation of acute stroke patients is recommended in clinical guidelines,2 42 43 VEM remains controversial and specific recommendations cannot be made until further evidence to guide practice is available. Mobilisation
practices vary between countries with patients mobilised within 24 hours of symptom onset the convention in some countries while in others the mobilisation of patients routinely occurs four to seven days after stroke. Delaying
mobilisation is based on the belief that cerebral perfusion pressure in the penumbra region needs to be maintained, therefore a horizontal position may increase intracranial blood flow to ischaemic tissue and reduce the infarct.44 The emergence of the very early and more intensive rehabilitation intervention in humans has posed controversy.
Some development work of VEM has been undertaken in relation to establishing current activity levels of acute stroke patients and testing the feasibility of VEM in a clinical setting.45 46 The cyclic nature of the MRC framework indicates that developing theory and an evidence base is an iterative process and should not end when commencing the main evaluation. Other areas of development may include exploring the predictable variations of important rehabilitation
outcomes such as mobility (Chapter 2), establishing activity levels in other countries (Chapter 3) and investigating methods for monitoring activity-based interventions in real-life (Chapter 3).
Specific evaluation of VEM is more limited. One study has suggested that VEM is the single most distinctive characteristic of stroke unit care and the strongest predictor of improved outcome.47 A Cochrane review which included studies that investigated VEM versus delayed mobilisation after stroke concluded that there was insufficient evidence to make recommendations on the use of VEM in stroke.
The individual patient data from these included studies provide the opportunity to synthesis the best available evidence to estimate the clinical effectiveness and cost-effectiveness of VEM (Chapter 4 and Chapter 6, respectively).
A very early rehabilitation trial (AVERT) phase III is now well underway to
determine the clinical and cost-effectiveness of VEM in stroke care.4 Therefore, it is important that during these development and evaluation stages, early consideration is given to the implications for the future implementation of VEM, if the results of AVERT phase III are in favour of the intervention (Chapter 5).
Aim and objectives
Complex interventions, defined as those that incorporate multiple interacting components, are difficult to define, measure and implement. Early
rehabilitation is a complex intervention and although recommended in clinical guidelines it remains controversial and lacks definition. A Very Early
Rehabilitation Trial phase III is currently underway to determine the clinical and cost-effectiveness of VEM in acute stroke, however the results are not due until 2013. Even if the AVERT phase III trial shows positive findings in support of VEM, it will remain unclear how best to define, monitor and implement the
intervention in routine practice.
The aim of this thesis was to develop and evaluate a complex intervention in stroke by adopting the MRC complex intervention framework as the
methodological approach and using VEM as the clinical example. The clinical effectiveness and cost-effectiveness of VEM was evaluated whilst simultaneously considering the implications for future implementation.
To address this aim, developmental work was conducted to identify and comprehend the predictable variations in outcome post-stroke (Chapter 2). A pre-implementation level of physical activity was established and methods to monitor activity levels were investigated to allow the assessment of the future implementation of activity-based interventions such as VEM (Chapter 3). The evaluation stage investigated the clinical and economic impact of a VEM
(Chapter 4 and 6). Evaluation also included the early stages of implementation as outlined in the Model for Effective Implementation.36 Relevant practice issues (problems or best practice) were identified and an analysis of current practice was undertaken (Chapter 5). This thesis covers only the early stages of
implementation and provides the basis for further work to address the
implementation stage of the MRC framework which is focused on the longer-term aspects of implementation such as surveillance and longer-term outcomes (see Figure 1-1). The development and evaluation stages of this thesis have strong connections to implementation.
The objectives for this thesis are as follows:
Objective one
To identify, using statistical models, the baseline factors that are predictive of mobility early after stroke in order to understand the predictable variations in outcome.
Objective two
To establish, using an observational study design, pre-implementation physical activity levels in acute stroke patients in order to monitor the future
implementation of activity-based interventions such as very early mobilisation.
Objective three
To estimate, using individual patient data from two completed feasibility
studies, the clinical impact of very early mobilisation in order to understand the implications of implementing very early mobilisation.
Objective four
To establish, using a qualitative process evaluation study design, healthcare professionals’ beliefs towards implementing very early mobilisation in order to understand the potential barriers and facilitators to very early mobilisation.
Objective five
To estimate, using economic evaluation, the economic impact of very early mobilisation in order to understand the implications of implementing very early mobilisation.
Structure of the thesis
The example of a complex intervention used throughout the thesis is VEM. There are seven Chapters: Chapters 3 and 5 use primary research methods and
Chapters 2, 4 and 6 use secondary research methods. Chapters 2 to 6 have an introduction, methods, results, discussion and conclusion section. At the beginning of each Chapter an overview to justify the reason for the research contained in the Chapter and how it links to the previous Chapter and the topic of implementation. Chapter 1 provides an overall background to the main topics of this thesis; stroke rehabilitation, complex interventions, implementation and VEM. Chapters 2 and 3 included the research for the developmental stage of the MRC framework and address objectives one to two. Chapters 4 to 6 include the research for the evaluation stage of the MRC framework and address objectives three to five. Chapter 7 provides an overall conclusion for the thesis.
Chapter 1 introduces the clinical and economic impact of stroke, the
importance of stroke rehabilitation and describes very early mobilisation, the example of a complex intervention, to be used in this thesis.
Chapter 2 consists of a systematic review of studies aimed at predicting mobility post-stroke and the development of statistical predictive models. This addresses objective one.
Chapter 3 is an observational study aimed to establish pre-implementation activity levels of acute stroke patients in order to monitor the future implementation of very early mobilisation. This addresses objective two.
Chapter 4 is an individual patient data meta-analysis of two feasibility trials previously conducted to investigate the clinical impact of very early
mobilisation. This addresses objective three.
Chapter 5 is a qualitative process evaluation aimed to identify the barriers and facilitators to implementing very early mobilisation. This addresses objective four.
Chapter 6 consists of a systematic review of economic evaluations of stroke rehabilitation and an economic evaluation to model the economic impact of very early mobilisation. This addresses objective five.
Chapter 7 summaries the findings from each of the Chapters, discusses the clinical application of the available evidence and provides a critique of the methods used. The thesis also makes some suggestions for the future study of very early mobilisation and more generally, complex interventions.