Approximately 110,000 people (estimated from the UK Intensive Care National Audit and Research Centre [ICNARC] Case Mix Programme [CMP] Summary Statistics) spend time in critical care units in England and Wales each year, the majority surviving to be discharged home. The general perception among patients, families and most healthcare professionals is that these people undergo a rapid convalescence and recover to their previous life, in terms of both quantity and quality.
Until relatively recently, there was little understanding of what really happens to all of these people. In the United Kingdom, a handful of hospitals established specialist follow-up clinics, staffed initially by doctors and nurses who also worked in critical care, and who thus understood the context of the patients' clinical stories. Research on the longer-term consequences of critical illness has shown that significant numbers of patients surviving critical illness have important continuing problems. For many, discharge from critical care is the start of an uncertain journey to recovery characterised by, among other problems, weakness, loss of energy and physical difficulties, anxiety, depression, post-traumatic stress (PTS) phenomena and, for some, a loss of mental faculty (termed cognitive function). Family members become informal caregivers, and this itself can exert a secondary toll of ill-health; family relationships can become altered and financial security imperilled. Recovery from illness is highly individual, and few studies have been able to demonstrate a close relationship between features of the acute illness and longer-term impact. Logically, patients who have had prolonged episodes of critical illness are likely to have greater long-term difficulties, however patients with relatively short intensive care stays may also need substantial help.
The optimisation of recovery as a therapeutic objective, rather than mere survival, has developed increasing prominence. Identified as an important area during the creation of NICE's guideline on acutely ill adults in hospital, the Department of Health charged NICE 'To develop a short clinical guideline on rehabilitation after a period of critical illness requiring a stay in an ITU', and this series of documents represents the result of the process.
To the non-specialist, the terminology around critical illness can be confusing. Critical care is now used as a term that encompasses intensive care or intensive therapy; provided in intensive care units (ICUs) or intensive therapy units (ITUs), together with what used to be called high-dependency care provided in high-dependency units (HDUs). Intensive care, or level 3 care, generally involves the support of one or more failing organ system, usually including the lungs, whereas high dependency care, or level 2 care, supports one system. Recently the distinctions have become blurred, hence the increasing use of the term criticalcare.
For simplicity, we have chosen to divide the potential consequences of critical illness into 'physical', and 'non-physical' domains, the latter to encompass all the non-physical symptoms one might envisage, such as anxiety, depression, post-traumatic stress disorder (PTSD), and cognitive dysfunction.
There is no particular requirement for a specified period of mechanical ventilatory support as an entry criterion for this pathway. Comments from the initial stakeholder meeting drew attention to the numbers of trauma patients, who receive mechanical ventilatory support for brief periods of time and yet who have the potential to benefit greatly.
The Guideline Development Group (GDG) also recognised the strain suffered by many families, and the commitment involved in helping the recovering patient. There is a tension between providing information to help families cope, and recognising that many patients may not wish specific information to be shared; patient autonomy must be respected.
Many families suffer financial strain as well as strain on their health and emotional resources. It was recognised that information around social services and benefits is often difficult to obtain and understand by those who need it, and decisions made around this area occasionally seem arbitrary; however, although there is clear room for improvement, it was difficult to see how this could be incorporated into the guideline beyond generalities, given how often such guidance would need to be changed.
For many patients the recovery after critical illness is relatively straightforward and it is important not to lose sight of this. What is clear is that tens of thousands of patients leave critical care to go home each year, and it is likely that poor-quality recovery represents a substantial problem. Given the individual impact on patients, and ripple effects on families and society in general, poor-quality rehabilitation and impaired recovery from severe illness should be regarded as a major public health issue.
The GDG has made a series of specific research recommendations, which are detailed later in the document. Additionally, of particular strategic importance is the lack of detailed understanding of the pathophysiology of the muscle wasting that is a feature of critical illness, and this area needs to be addressed. Critical illness polyneuropathy and myopathy are related and important problems. Alongside this, a better understanding of the impact of critical illness on the brain, and its relationship to sedation, neuroinflammation, delirium and future cognitive impairment is a priority. There is scope here for interventional trials in the near future. A thorough understanding of the socioeconomic consequences of critical illness at both individual and society levels is also needed to inform broader policy. As the majority of the recommendations in this guideline are consensus based, this guideline should stimulate, rather than stifle, research, and the impact of the introduction of the recommendations, along with alternative approaches, should be thoroughly evaluated.
From my perspective as GDG Chair, the development process has been a challenge. It is one thing to know that a problem exists, and quite another to translate knowledge of a problem into an evidence-based management guideline, that can be implemented in the NHS for the benefit of patients. The GDG and the technical team have worked extremely hard picking their way through a difficult and somewhat patchy evidence base; I am grateful for their commitment and effort. Our ambition is that this guideline will lead to substantial benefits for recovering patients and their families. We hope that when this guideline is reviewed, the evidence base for specific interventions and service delivery models is more substantial.
Consultant and Senior Lecturer in Intensive Care Medicine, Imperial College Healthcare NHS Trust
Guideline Development Group Chair