Integral to efforts to improve the recognition and diagnosis of wound infection – and the management of wound bioburden – is our awareness of wound-related sepsis. Spurred on by this, Richard White, Professor of Tissue Viability, and Director at DDRC Wound Care, Plymouth Science Park, reviews its risks and outcomes, and draws attention to recent diagnostic and treatment guidelines, with the ultimate aim of reducing morbidity and mortality.
In 2013 the NHS identified sepsis management as a clinical priority. Sepsis is defined as a systemic inflammatory response (or SIRS) initiated by infection. It is no longer to be called septicaemia and is not an infection per se.
In the UK, NHS statistics show that the incidence and mortality are increasing dramatically (PHSO 2013). Reasons given for this include antibiotic resistance, increased bacterial virulence, and an ageing population. The economic burden is similarly high, making improvement in diagnosis and care clinical priorities.
Gaps in care delivery have been identified, and there is evidence of an opportunity for cost-effective quality improvement. Those clinicians involved in wound management, whether acute or chronic, have a major part to play.
Wounds of all aetiologies represent a risk for the development of severe sepsis, defined in this piece. Appropriate and timely management of wound bioburden and infection is integral to the avoidance of morbidity due to sepsis.
It’s widely recognised that patients with burns, traumatic soft tissue injuries, and surgical wounds can develop life-threatening infections – it is less so for most ‘chronic’ wound patients. It’s one of the main causes of morbidity and mortality worldwide, with an annual incidence of 60 per 100,000 patients in the UK and 300 per 100,000 in America. This results in over 44,000 deaths per annum according to the UK Sepsis Trust. It’s estimated to be the third most common cause of death in America, where the incidence has been increasing by eight to 13 per cent annually over the past decade.
n pathological terms sepsis is an immune-inflammatory condition in which cytokines elicit a systemic response to infection.
The clinical picture varies with the degree of infection: the criteria of hyperthermia (38.3°C), acutely altered mental state, heart rate >90/min, white cells <4 or >12 x 109/l, plus tachypnoea >20/min. (Table 1) Severe sepsis and septic shock are further complications with additional criteria. (NCEPOD 2015; White et al 2015)
The risk factors for sepsis have been divided into two groups: a) risk factors for infection, and b) risk factors for organ dysfunction.
As a result, for wound patients, age, perfusion, nutritional status, immune status, site and depth of wound, and comorbidities, among other factors, constitute infection risk. (White et al 2015)
More than half of all severe sepsis cases occur in patients over 65 years, or those with diabetes. In this context it is obvious that aged patients with a pressure ulcer and double incontinence are ‘at risk’, as are patients with large body surface area burns. These examples, to the experienced wound clinician, will be widely-known risk factors. The variability in susceptibility to sepsis is attributed to genetic factors. Sepsis, together with bacteraemia, is recognised as a major hazard in patients with chronic wounds, being reported variously in diabetic foot ulcers, pressure ulcers, and leg ulcers. (White and Witts 2016)
Cellulitis is a common inflammatory condition which involves cutaneous tissues. It is associated with locally wounded / damaged skin with Gram-positive bacterial infection. Typical organisms implicated are group A Streptococci and Staphylococci. Its incidence is increased in diabetes and vascular insufficiency. It has been hypothesised that if chronic wound patients are ‘provided with early intervention and comprehensive treatment… they will be spared the morbidities of pain, amputation, and even death’.
Pressure ulcers occur in all age groups – most commonly in the elderly and those with impaired mobility. Many pressure ulcer patients will have concomitant pathologies which may further complicate the clinical picture.
The UK incidence of pressure ulcers is 12 per cent, of which some 20 per cent developed sepsis, i.e. approximately 2.4 per cent of the total. The mortality of this fraction is not given, but it will be very high.
In patients with sepsis solely associated with pressure ulcers, bacteraemia was documented in 76 per cent, and mortality was 48 per cent in spite of antibiotic therapy. In pressure ulcer patients, the diagnosis of osteomyelitis underlying the ulcer is difficult, complicated by the inherent difficulty in diagnosis and the complexity of the tissue pathology.
In such cases, the presence of pyrexia and leucocytosis, without drainage, are indicators of joint involvement.
Diabetes has long been known to predispose the sufferer to infection; this includes local sepsis. Indeed, such patients constitute approximately 20 per cent of all diagnosed with sepsis.
Osteomyelitis and sepsis in the diabetic foot have been described.
As many diabetic foot ulcers are in origin pressure ulcers, it is the influence of sepsis upon the outcome of foot ulceration that is of clinical significance. (Skrepnek et al 2015)
The presentation of sepsis associated with leg ulceration is rare. A recent report illustrated the typical presentation of a venous ulcer with active group A Streptococcal infection (GAS) and toxic shock. In this case the patient exhibited many of the characteristic sepsis signs, including metabolic acidosis (elevated lactate, indicating the need for urgent fluid resuscitation).
The others include blood cultures (although these can be negative even in severe sepsis), arterial blood gases, CRP acute phase protein level noting the rate of elevation, and white cell counts as a marker of systemic inflammation.
Every clinician should be aware of, and recognise, sepsis and its potential for morbidity and mortality. The simple criteria of a) hyperthermia, b) acutely altered mental state, c) increased heart rate, plus d) tachypnoea, should be evident to all healthcare professionals and alert them to the possibility of ongoing serious acute illness. The death rate from sepsis and its complications is far too high. To reduce this, a change in clinical practice is essential. The modern, evidence-based requirements for early and accurate diagnosis and appropriate intervention are well-documented.
While we can’t be precise on the contribution of wounds in general to sepsis, it is quite clear that any wound has the potential to lead to an increased clinical risk. As ever, early recognition, appropriate referral, and intervention are likely to reduce morbidity.
The recent publication of the NICE guideline on sepsis (NICE 2016) is of great significance to all involved in wound management, education, or research. As yet, few will have read it so here are some of the salient points: as the mortality rate associated with sepsis is so high (almost 30 per cent of all cases diagnosed will die from the disease), it is reasonable to assume that recognition of early symptoms is often missed by healthcare professionals. The guideline acknowledges this and states, ‘Ensure all healthcare staff and students involved in assessing people’s clinical condition are given regular, appropriate training in identifying people who might have sepsis. This includes primary, community care and hospital staff including those working in care homes.’
Being a guideline makes this statement discretionary, however the document goes on to state, ‘Local commissioners and / or providers have a responsibility to enable the guideline to be applied when individual health professionals and their patients or service users wish to use it. They should do so in the context of local and national priorities for funding and developing services, and in light of their duties to have due regard to the need to eliminate unlawful discrimination, to advance equality of opportunity and to reduce health inequalities.’
What must be done to enact the guideline locally is clearly stated; the responsibility lies with all healthcare professionals, regardless of clinical setting. Sepsis must no longer remain some vague condition with which other clinicians must concern themselves, it is for everyone working with patients, in every setting. Can you now afford to be unaware any longer?