Sepsis qSOFA Score

The quick SOFA score explained

The quick SOFA is aimed at predicting adverse outcome in patients outside intensive care units that have been diagnosed with an infection and are now suspected of sepsis.

The score is based on a study by the Sepsis 3 group which moves from the previous SIRS criteria (more limiting in functionality) in the definition of sepsis. The new, simplified criteria are:

■ Altered Mental Status (GCS <15) – assessed through bedside Glasgow coma scale with the 15 points cut off value between abnormal and normal.

■ Respiratory Rate ≥22 breaths per minute – increased respiratory rate.

■ Systolic Blood Pressure ≤100 mmHg – lowered SBP.

qSOFA is targeted at a rapid identification of patients with confirmed or suspected infections who are at risk of adverse outcomes, without having to wait for time consuming laboratory tests.

Clinical interpretation remains at the judgment of the medical professional, however, these are the guidelines provided:

■ Neither or one of the criteria met means that in-hospital mortality remains unlikely. The patient should be monitored and the score reassessed if condition does not improve.

■ When two or three criteria are met, there is a high risk of adverse outcome. Further from this application of SOFA score and serum lactate testing are required to evaluate organ dysfunction.

During the study, 70% of total mortality was linked to 24% of patients with two or three criteria met.

Comparing the predictive validity for in-hospital mortality, SOFA validity remains statistically greater than qSOFA or SIRS, however, in out of ICU suspected infections, the predictive validity of qSOFA is greater than that of SOFA and SIRS.

Limitations of qSOFA

Due to the fact that sepsis remains a broad condition in clinical practice, attempts to provide a definition emphasize generalizability.

Many critics argue that serum lactate measurement is an essential biochemical identifier of sepsis, therefore should be accounted for in the score. However, there has been some research on the matter, and including this as a fourth criterion does not provide relevant improvement to the score.

The score is only valid when interpreted by a clinician but even in this case, the fact that the patient does not meet the criteria does not mean that sepsis can be excluded.

The score can only be used in adult populations and still requires validation and contribution in studies from low, middle- income countries.

Sepsis and septic shock defined

Sepsis is defined as a "life-threatening organ dysfunction due to a dysregulated host response to infection" by the Third International Sepsis Consensus Definitions Task Force (19 critical care, infectious disease, surgical, and pulmonary specialists).

Organ dysfunction can be explained as an increase in the Sequential [Sepsis-related] Organ Failure Assessment (SOFA) score of 2 points or more. OD is also associated with an in-hospital mortality greater than 10%.

Septic shock is a subset of sepsis characterised by abnormalities in the circulatory, cellular and metabolic areas, which poses a greater mortality risk than sepsis (around 40%). Clinical requirement during septic shock (in the absence of hypovolemia) is of mean arterial pressure of 65 mmHg or greater and serum lactate level greater than 2 mmol/L (>18 mg/dL).

Original source

Singer M, Deutschman CS, Seymour CW, Shankar-Hari M, Annane D, Bauer M, Bellomo R, Bernard GR, Chiche JD, Coopersmith CM, Hotchkiss RS, Levy MM, Marshall JC, Martin GS, Opal SM, Rubenfeld GD, van der Poll T, Vincent JL, Angus DC. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016; 315(8):801-10.

Other references

1. Shankar-Hari M, Phillips GS, Levy ML, Seymour CW, Liu VX, Deutschman CS, Angus DC, Rubenfeld GD, Singer M; Sepsis Definitions Task Force. Developing a New Definition and Assessing New Clinical Criteria for Septic Shock: For the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016; 315(8):775-87.

2. Seymour CW, Liu VX, Iwashyna TJ, Brunkhorst FM, Rea TD, Scherag A, Rubenfeld G, Kahn JM, Shankar-Hari M, Singer M, Deutschman CS, Escobar GJ, Angus DC. Assessment of Clinical Criteria for Sepsis: For the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016; 315(8):762-74.