Infection Prevention and Sepsis

Critically ill and injured patients are unusually vulnerable to infection: broken skin, indwelling catheters and tubes, immune dysregulation, and prolonged intensive care all open routes for organisms to take hold. When such an infection provokes a dysregulated, life-threatening host response, it becomes sepsis. This topic links the prevention of healthcare-associated infection to the recognition and understanding of sepsis as its most dangerous consequence.

Definition

Sepsis is life-threatening organ dysfunction caused by a dysregulated host response to infection; infection prevention in critical care comprises the practices - notably device-insertion and maintenance bundles - that reduce the incidence of healthcare-associated infections that can precipitate it.

Scope

The entry covers the major device-associated infections of intensive care - bloodstream, urinary, and respiratory - the bundle-based strategies shown to prevent them, and the concept and pathophysiology of sepsis. It is a reference account of how infection is prevented and how sepsis is understood, not antimicrobial or management guidance for an individual patient.

Core questions

• Why are critically ill and injured patients especially prone to infection?
• Which preventive bundles reduce device-associated infections, and on what evidence?
• What distinguishes sepsis from uncomplicated infection?
• How does the host response in sepsis drive organ dysfunction?

Key concepts

• Healthcare-associated infection
• Central line-associated bloodstream infection
• Catheter-associated urinary tract infection
• Ventilator-associated pneumonia
• Care bundles
• Dysregulated host response
• Organ dysfunction and septic shock

Mechanisms

Sepsis arises when the host response to an infection becomes dysregulated: pro-inflammatory and anti-inflammatory pathways are activated together, the endothelium becomes leaky, microvascular flow is disrupted, and coagulation is deranged, producing the tissue hypoperfusion and organ dysfunction that define the syndrome (Angus & van der Poll, 2013). Prevention works upstream of this cascade by reducing the chance that organisms enter in the first place - sterile insertion and diligent maintenance of vascular and urinary catheters, and measures that limit ventilator-associated pneumonia - so that fewer infections occur and fewer progress to sepsis.

Clinical relevance

Healthcare-associated infections and sepsis are leading causes of late death and prolonged stay in critically ill and injured patients, and infection-prevention bundles are among the most cost-effective interventions in critical care. This entry describes why prevention matters and how sepsis is conceptualized; it is educational and is not a basis for diagnostic or antimicrobial decisions in an individual.

Epidemiology

Sepsis is a major global cause of death and a common pathway to mortality in the intensive care unit, and device-associated infections account for a substantial share of healthcare-associated infections worldwide. Quantitative incidence varies widely by setting and surveillance method, so specific rates are best taken from contemporary surveillance reports rather than stated as fixed figures here.

Evidence & guidelines

The Surviving Sepsis Campaign guidelines (Evans et al., 2021) consolidate the consensus on recognizing and treating sepsis and septic shock. For prevention, the Keystone ICU project (Pronovost et al., 2006) demonstrated large, sustained reductions in central line-associated bloodstream infection from a checklist-based bundle, and the IDSA guideline on catheter-associated urinary tract infection (Hooton et al., 2010) codifies prevention of the most common device-associated infection. Angus and van der Poll (2013) provide the pathophysiological framework for sepsis.

History

The modern concept of sepsis evolved from the systemic inflammatory response syndrome definitions of the 1990s to the 2016 consensus reframing of sepsis as infection-associated organ dysfunction. In parallel, the patient-safety movement of the 2000s - exemplified by checklist-based bloodstream-infection prevention - showed that much healthcare-associated infection is preventable, linking infection control firmly to critical-care outcomes.

Debates

How should sepsis be defined and screened for?

Successive definitions have shifted from systemic inflammatory response criteria to organ-dysfunction-based criteria, and the best bedside screening approach across different settings remains an area of active discussion.

Key figures

• Derek Angus
• Peter Pronovost

Seminal works

• angus-2013
• pronovost-2006
• evans-2021

Frequently asked questions

What is the difference between an infection and sepsis?

An infection is the presence and multiplication of organisms in the body. Sepsis is when the body's response to that infection becomes dysregulated and damages its own tissues and organs, making it life-threatening.

Why is infection prevention emphasized so strongly in intensive care?

Critically ill and injured patients have many entry points for organisms - catheters, breathing tubes, and wounds - and a high risk of progressing to sepsis. Prevention bundles, such as sterile line insertion and maintenance, have been shown to cut these infections substantially, which is why they are a core focus.