Sepsis is a life-threatening medical emergency defined by organ dysfunction resulting from the body’s dysregulated response to an infection. This systemic overreaction damages tissues and organs, potentially leading to shock, multiple organ failure, and death. Since patient outcomes depend on the speed of intervention, early detection is important. The sepsis risk score is a standardized, non-diagnostic tool designed to flag patients showing signs of deterioration, ensuring rapid assessment and treatment.
The Purpose of Sepsis Risk Scores
Sepsis risk scores overcome the limitations of relying solely on a clinician’s subjective judgment in fast-paced healthcare settings. These tools serve as objective, standardized warning systems for patient triage and the activation of rapid response protocols. Their goal is to identify patients who are at an increased likelihood of poor outcomes, such as death or prolonged intensive care.
The medical community has moved away from older, less-specific screening criteria, such as the Systemic Inflammatory Response Syndrome (SIRS). The SIRS criteria were overly sensitive, flagging many patients who had a normal inflammatory response but were not actually progressing to organ dysfunction. This shift led to the adoption of simpler, more focused tools usable quickly at the bedside, even outside of a specialized intensive care unit (ICU) setting.
The scores allow for risk stratification, classifying patients based on their probability of decline. When a patient’s score crosses a specific threshold, it triggers an immediate escalation of care, including prompt investigation, administration of antibiotics, and fluid resuscitation. Since every hour of delay in treatment initiation increases the risk of mortality, these standardized scores are a necessary component of modern sepsis management.
Core Physiological Indicators and Scoring Systems
The most widely used scoring systems rely on easily measurable physiological parameters that reflect the body’s attempt to compensate for infection and organ injury. The Quick Sequential Organ Failure Assessment (qSOFA) score is a simplified tool using three bedside variables to identify patients at high risk of death or prolonged ICU stay. These components include an altered mental status, a systolic blood pressure of 100 millimeters of mercury (mmHg) or less, and a respiratory rate of 22 breaths per minute or greater.
Each of these three components is assigned one point, and a score of two or more is considered a positive screen, indicating a high risk of poor outcomes and prompting further investigation. A high respiratory rate suggests the patient is compensating for metabolic acidosis or circulatory failure. Low blood pressure is a sign of circulatory system failure, and altered mental status reflects reduced oxygen delivery to the brain or toxin accumulation.
The National Early Warning Score 2 (NEWS2) is a more comprehensive system using a broader set of physiological indicators. NEWS2 incorporates six parameters: respiratory rate, oxygen saturation, supplemental oxygen use, systolic blood pressure, heart rate, temperature, and level of consciousness. Each variable is assigned a score ranging from zero to three points based on its deviation from the normal range.
By using a wider range of measurements, NEWS2 provides a detailed picture of general physiological deterioration, including sepsis risk. An aggregate score of five or more points triggers an urgent clinical review and rapid response activation. Studies often show NEWS2 is superior to qSOFA in detecting sepsis complicated by organ dysfunction because it captures subtle abnormalities across different organ systems.
Identifying High-Risk Vulnerable Groups
While sepsis can affect anyone, certain patient populations carry a higher baseline risk, making early and objective scoring important. Age is a significant factor; adults aged 65 and older and infants are more susceptible to developing sepsis and experiencing severe outcomes. Older adults often have co-morbidities and may not exhibit typical signs of infection, leading to delayed recognition.
Individuals with pre-existing chronic medical conditions also face elevated risk because their organ systems are already compromised. This includes people with diabetes, chronic kidney disease, chronic lung disease, and certain cancers. For instance, patients with end-stage kidney disease on chronic dialysis are highly vulnerable to infections that quickly progress to sepsis.
A weakened immune system, whether due to conditions like HIV or treatments such as chemotherapy and chronic steroid use, increases the likelihood of an infection escalating. These patients often struggle to mount a visible inflammatory response, meaning typical signs of sepsis may be masked or atypical. For these vulnerable groups, objective sepsis risk scores are vital for identifying deterioration when clinical presentation might otherwise be misleading.