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Sepsis is the commonest cause of death from infection. This is a statement that is often quoted, but why is this so? What is sepsis? How do we treat it, how do we monitor progress and what happens when things get worse?
Wikipaedia tells us that ‘infection is the invasion of an organism's body tissues by disease-causing agents, their multiplication, and the reaction of host tissues to the infectious agents and the toxins they produce.’ Bacterial infections are most commonly considered when thinking about infection, but are not the commonest cause: viral infections are far commoner. However, there are also fungi (such as candida), parasites (such as malaria) and arthropods (such as ticks). Infection by itself is usually self-limiting, may be uncomfortable, but rarely fatal.
Sepsis on the other hand is a major problem. Sepsis is defined most recently by the Third International consensus meeting as ‘life-threatening organ dysfunction caused by a dysregulated host response to infection.’¹ So sepsis is the body’s response to an infection. Different organisms are more or less likely to cause sepsis, but any infective organism can cause it. Specific infections may result in local organ dysfunction without generating a systemic host response.
Diagnosis of sepsis can be difficult. The consensus document recommends the Quick Sequential Organ Failure Assessment (q-SOFA), but this is still hotly debated. What is not in doubt is that there should be a low threshold for considering sepsis in a patient with an unexplained illness particularly one who is deteriorating.
Treatment is the appropriate antimicrobial.² In bacterial sepsis - an antibiotic, fungal sepsis – an antifungal and so on. Most of the time, it is not clear what type of organism has triggered the sepsis, and so a broad spectrum antibiotic is given. The choice of this agent is usually heavily influenced by the local microbiology department, who will know the prevalence of local infective agents. This varies within the country and also between countries. The antimicrobial should be given as early as possible, the ‘golden-hour’ used in management of trauma has been adopted in sepsis. Therefore, unless there are good reasons, the antimicrobial should be administered within an hour of sepsis being suspected. The second major limb of treatment is source control. If the infection has an identified anatomical site, then this should be debrided/aspirated or otherwise dealt with. An example is necrotising fasciitis, where it is insufficient to merely give broad spectrum antibiotics, the affected area of fascia needs to be widely debrided for the patient to have a chance of survival – this can lead to rapid limb amputation as the author has seen.
Once treatment has been initiated, then how is the patient to be monitored? How do we determine whether they are improving or deteriorating? Over the last 2 decades, early warning scores have been developed. First the ‘Early Warning Score’ (EWS) in 2000, then Modified Early Warning Score (MEWS) in 2005, then National Early Warning Score (NEWS) in 2012 and currently NEWS- 2 from 2017. A huge amount of data has been collected on patients and these scores provide an objective way of assessing physiological condition. NEWS is a robust system. National Confidential
Enquiry on Patient Outcome and Death (NCEPOD) say ‘The National Early Warning Score... should be used in all acute healthcare settings in the NHS to improve communication between clinicians regarding the level of a patient’s deterioration.’³ Serial NEWS measurements allow clinicians to track whether the patient is improving or deteriorating. Guidelines require actions to be taken when the score crosses a particular threshold and these actions are backed by a great deal of evidence. There has to be a very good reason why a patient who has suddenly hit a NEWS of 7 is not immediately referred for critical care assessment! NEWS, when used properly, saves lives and conversely, if it is ignored, costs lives and causes harm.
This leads to Intensive Care. Intensive Care Medicine (ICM) has been a specialty in the UK for 2 decades now, with its own Faculty since 2010. As a specialty, it is distinct from general medicine, anaesthesia and emergency medicine, although most UK intensivists are also trained in one of these areas. On the ICU, critical care staff can provide advanced organ support that is not available anywhere else in the hospital looking after the sickest patients. Organ support therapies require close supervision with minute to minute assessment of the patient. Patients are graded as Level 2 – one organ support, or Level 3 – multiorgan support (Level 0 & 1 cover care on a general ward). The General Provision for Intensive Care Services (GPICS) is national guidance for what constitutes an intensive care service.⁴ It covers staffing, the physical structure, as well as support services. The intensivist will often be asked to support treating teams on the wards. As Prof Ken Hillman said, critical care should be without walls.⁵
Septic patients with a deteriorating NEWS will often need to be cared for in ICU. Patients in septic shock will definitely need ICU level support. Septic shock is sepsis with a low blood pressure, defined as a Mean Arterial Pressure (MAP) less than 65mmHg that is unresponsive to fluid therapy. These patients will need inotropes or vasopressor drug infusions to keep the MAP >65mmmHg and this therapy can only be provided in ICU.
Over the last 2 decades, there has been a steady improvement in survival from sepsis. This has, in part, been related to ICM becoming a specialty in its own right and clear definitions of what is sepsis, with evidence based guidance on treatment. Early recognition and treatment is key with immediate access to the critical care team to provide the right level of care at the right time.
As well as the big drive to recognise sepsis, it is imperative to treat early with antimicrobials and escalate in a timely manner to critical care. The tools are there, and are readily available to every clinician of every grade.
References
[1] Singer, Mervyn, Clifford S. Deutschman, Christopher Warren Seymour, Manu Shankar-Hari, Djillali Annane, Michael Bauer, Rinaldo Bellomo, et al. ‘The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3)’. JAMA 315, no. 8 (23 February 2016): 801. https://doi.org/10.1001/jama.2016.0287.
[2] Rhodes, Andrew, Laura E. Evans, Waleed Alhazzani, Mitchell M. Levy, Massimo Antonelli, Ricard Ferrer, Anand Kumar, et al. ‘Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock: 2016’. Intensive Care Medicine, 18 January 2017. https://doi.org/10.1007/s00134-017-4683-6.
[3] ‘Themes and Recommendations Common to All Hospital Specialities’. NCEPOD, 2018.
[4] https://www.ficm.ac.uk/surveys/guidelines-provision-intensive-care-services
[5] Hillman, Ken. ‘Critical Care without Walls’. Current Opinion in Critical Care 8, no. 6 (December 2002): 594–99.
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