Sequential Organ Failure Assessment (SOFA) Score: Your Body's Red Flag for Organ Distress

What is SOFA?

The Sequential Organ Failure Assessment (SOFA) score is a scoring system that assesses the performance of several organ systems in the body (neurologic, blood, liver, kidney, and blood pressure/hemodynamics) and assigns a score based on the data obtained in each category. The higher the SOFA score, the higher the likely mortality.

It serves as a crucial instrument in determining both the clinical status of individual patients and the effectiveness of treatments, particularly in intensive care units (ICUs). To accurately assess treatment response, it is imperative to maintain consistency among assessors when using the SOFA score as an outcome measure in sepsis cases.

First, Let’s understand what is SEPSIS

Sepsis is a serious condition caused by bacteria, fungi, viruses and parasites. Bacteria are the most common cause of sepsis in which the body responds improperly to an infection. The infection-fighting processes turn on the body, causing the organs to work poorly. Sepsis may progress to septic shock. This is a dramatic drop in blood pressure that can damage the lungs, kidneys, liver and other organs. 

Sepsis can affect anyone, but people who are older, very young, pregnant or have other health problems are at higher risk.

Sign & Symptoms: Common signs of sepsis include

·        Fever

·        Fast heart rate

·        Rapid breathing

·        Confusion

·        Body pain

 It can lead to septic shock, multiple organ failure and death

To understand sepsis Stages lets dive in to details about stages in Sepsis patients

Sepsis can be divided into different stages: 

·        SIRS(systemic inflammatory response syndrome)

·        Sepsis

·        Severe Sepsis

·        Septic Shock(“Sepsis-3”).

 Sepsis is life-threatening. It happens when your immune system overreacts to an infection.

The diagnosis of sepsis has undergone a metamorphosis since the inception of standardized definitions in 1991. Shifting away from the systemic inflammatory response syndrome (SIRS) criteria previously utilized, in 2014 the Society of Critical Care Medicine and the European Society of Intensive Care Medicine convened a task force and, by an expert consensus process, agreed in 2016 on updated definitions and criteria to be tested clinically. The Third International Consensus Definitions for Sepsis and Septic Shock (“Sepsis-3”) redefined sepsis as “life-threatening organ dysfunction caused by a dysregulated host response to infection.”

Sepsis-3 also redefined septic shock as “hypotension not responsive to fluid resuscitation,” with the added requirement for vasopressors to maintain a mean arterial pressure (MAP) ≥ 65 mm Hg and a lactate > 2 mmol/L. These new definitions were adopted by the 2016 Surviving Sepsis Campaign: International Guidelines for the Management of Sepsis and Septic Shock.

Sepsis-3 cited new insights into sepsis pathobiology, the lack of sensitivity and specificity of SIRS criteria, and the excessive focus on inflammation as some of the reasons for the changes. The updated definitions in Sepsis-3 emphasize organ dysfunction in the setting of infection, which can be quantified using the sequential (sepsis-related) organ failure assessment (SOFA) score. For expansion of the criteria for scoring SOFA

Hope now you are clear what is sepsis and different stages of sepsis then let’s come back to our topic to understand more about SOFA Score

Why was the SOFA Score Developed?

 The SOFA score was designed as a research tool so that groups of patients (e.g., those with sepsis, and infection in the bloodstream which can lead to shock and death) could be categorized based on their risk of death. SOFA is quite accurate when used in sepsis cases and when applied to groups of patients. For example, if 100 severely ill septic patients requiring intensive care unit (ICU) treatment have a SOFA score greater than 11, over 90% of them will die (Vincent et al., 1996). One benefit of SOFA is that it requires only six common points of data to calculate. Comparable predictive systems require much more data. 

What is a normal SOFA score?

SOFA score is a quantitative scoring index that dynamically describes sepsis-related organ dysfunction, including respiratory system, coagulation system, liver function, cardiovascular system, central nervous system, and renal function. Scores ranged from 0 to 24 points.

Each organ system received a score ranging from 0 (normal) to 4 (most abnormal), with a minimum SOFA score of 0 and a maximum SOFA score of 24.

What does SOFA score indicate?

The Sequential Organ Failure Assessment (SOFA) score is a simple and objective score that allows for calculation of both the number and the severity of organ dysfunction in 5 organ systems (respiratory, coagulator, liver, cardiovascular, renal)

SOFA Score Analysis:

To understand SOFA lets take a real- time example where I used SEPSIS dataset analyses it and created visual using Tableau visualization tool.

This analysis shows detail about Total SOFA Score for each SIRS patient and further it broken down by Patient ID, SIRS, Sofa Liver Score, Sofa Coagulation Score, Sofa Renal Score, Sofa Resp Score and Total SOFA Score.

To calculate all score, I have given condition and created calculation field as per given in previous table.

• In analysis table we can see that there are different score as per organ functional condition.

• This adds up the scores from different organ systems, like heart, liver, and lungs.

• Each organ gets a score based on how well it's working.

• This part indicates whether a patient's organs are functioning properly or failing based on their overall SOFA score.

• Total SOFA: indicates When you add these scores together, you get a total SOFA score for each patient, showing how serious their organ problems might be.

• If the total SOFA score is 11 or less, it means the organs are likely working okay, so it says "Organ Functional".

• But if the total SOFA score is more than 11, it suggests the organs might be failing, so it says "Organ Failure".

  
  

 What are the Limitations of SOFA? 

Because SOFA was designed to look at populations, and not individual patients, it cannot accurately predict which patients will survive when the mortality rate is high (i.e., if mortality is 90%, which 10 patients will survive) or which patients will die if the mortality rate is low. Some of the factors used in scoring can be difficult to assess depending on the care being provided (e.g., it is difficult to assess a level of coma when a patient is receiving sedatives) and some of the medications listed are no longer used routinely (e.g., low dose dopamine or dobutamine). 

Conclusion: Sepsis is a serious condition, and it should not be ignored. Even in the absence of signs of organ failure and a timely diagnosis, the chances of death may be as high as 15%–30%, and in the case of severe sepsis, the chances may even be as high as 40%–60%. Thus, in the event of any signs or symptoms of any infectious disease, like wound infections, pneumonia, or meningitis, immediate medical attention should be sought. Early treatment of infections can reduce the chance of developing sepsis, especially in high-risk groups like children, the elderly, and immunocompromised individuals.

Thank you for reading my blog, Hope it is helpful for your study.