Imagine a condition that causes between 20 and 30 million deaths worldwide each year. However, many people have not heard of it, and even fewer understand what it is. I was one of them. The condition is called sepsis and it’s the reason many adults, children, and families, are grieving for their loved ones.
Our immune system protects our bodies from a variety of things, including viruses, bacteria, and toxins, so having a healthy one is important. Sometimes, however, an immune system can weaken or fail. It can even work against us, causing autoimmune disorders, which can put one at greater risk for sepsis and lead to septic shock.
Sepsis and Progression of Sepsis
Sepsis, also known as septicemia or blood poisoning, occurs when the body has a severe response to an infection. Instead of the immune system defending the body, it releases chemicals, potentially leading to mass inflammation and damage to the kidneys, lungs, liver, or other major organs.
Figure. 2 Sepsis Stages
Sepsis can be identified into four stages (figure 2):
1. SIRS (Systematic Inflammatory Response Syndrome)
Sepsis can be hard to diagnose at its early stages because its symptoms are similar to many other conditions, but SIRS still helps at a certain level to identify.
Identifying SIRS in a patient includes the following criteria:
Temperature > 38.5ºC or < 35ºC (body temperature alterations which are known as hyperthermia or hypothermia)
Heart rate >90 beats/min (Tachycardia)
Respiratory rate >20 breaths/min or PaCO2 < 32 mmHg (Tachypnoea)
WBC >12,000 cells/mm3 or < 4000 cells/mm3, or >10 percent immature (band) forms (leukocytosis or leukopenia)
Finding two or more of any of these criteria in a patient indicates the possibility of sepsis.
An infection reaches the bloodstream and causes inflammation in the body.
3. Severe Sepsis
The infection is severe enough to affect organ function.
4. Septic Shock
There’s a significant drop in blood pressure that can lead to respiratory or heart failure, stroke, dysfunction of other organs, and possibly death.
When Sepsis Becomes Septic Shock
Sepsis treatment usually requires intravenous (IV) fluids and antibiotics. It is essential that the treatment begin as early as possible. The chance of sepsis progressing to severe sepsis and septic shock, causing death, rises by 4% to 9% for every hour treatment is delayed.
Severe sepsis occurs when one or more of your organs stop working effectively. For example, you could need a ventilator to help you breathe or dialysis to filter toxins from your blood. Any organ can be affected.
People with severe sepsis are already very ill, but if your blood pressure starts to drop, you become even sicker. You go into septic shock. The medical definition of “shock” is a drop or fall in blood pressure. When it is associated with sepsis, it is called septic shock.
Severe Sepsis and Septic Shock:
Both of these are conditions in which multiorgan dysfunction is due to INFECTION only.
The only difference between these two is the presence of volume-resistant hypotension in septic shock.
The tendency to develop one (or both) of these conditions is NOT a function of the organism involved in the actual infectious process but rather, the degree of HOST RESPONSE.
Septic Shock Signs, Symptoms, & Complications:
Figure. 3 Septic Shock Signs, Symptoms, & Complications
Septic shock is a severe drop in blood pressure that results in highly abnormal problems with how cells work and produce energy. Progression to septic shock increases the risk of death. Signs of progression to septic shock include:
The need for medication to maintain systolic blood pressure ≥ 65 mmHg.
High levels of lactic acid in your blood (serum lactate). Having too much lactic acid in your blood means that your cells aren’t using oxygen properly.
Difficulty breathing with increasing oxygen requirement.
Lab abnormalities — kidney or liver dysfunction, blood count abnormalities.
Confusion or change in mental status.
At this stage, immediate medical attention is critical.
Septic Shock Symptoms:
Depending on a patient’s progression through the phases of sepsis, symptoms range from mild to severe. The most common symptoms include:
Low blood pressure (Hypotension)
Temperature exceeding 101 º F
Fever and chills
Increased heart rate
Septic Shock Complications:
Septic shock is a very serious medical condition. It’s the most severe stage of sepsis. Septic shock can lead to:
Septic Shock Treatment:
People who are in septic shock need urgent intensive care. The medical team has to approach treatment from different angles for it to be successful:
IV fluids to raise blood pressure.
Treat the infection: Your doctors must find out what caused the infection that triggered the sepsis and give the appropriate antibiotics.
Oxygen, either by mask or nasal cannula or with a ventilator, helps raise oxygen levels in the blood.
Surgery may be necessary to remove the source of infection, such as gallstones or an inflamed appendix.
Analysis with Sepsis Data using Tableau:
Let’s understand a bit of data….
The Sepsis dataset has 43 biomarkers which can broadly be classified into:
Vital Signs or Clinical
Just like biomarkers, patients can be categorized under 3 conditions:
Patients without sepsis, on admission (Sepsis Label 0).
Patients without sepsis on admission, but later developed Sepsis in ICU (Sepsis Label 0 to 1). we can call them Onset Sepsis patients.
Patients with sepsis, on admission (Sepsis Label 1).
Part-I: SIRS Analysis
SIRS Analysis part has already been done so I am not going to explain it here in detail. Below the table, I created in tableau based on SIRS symptoms (explain above) Trigger hour as well as an hour before the trigger hour gave name Previous hour. If any two of the SIRS conditions are satisfied that means the patient falls under the SIRS criteria, and they have the trigger started so we can compare it with the previous hour. We can see many patients who already started showing symptoms at least once and so with this and considering the other factors we can give priority to those patients who need more care or who need immediate care.
Color-coded was given based on SIRS conditions for the Trigger hour and the Previous hour.
Figure. 4 SIRS Analysis (Hourly)
Part II: Septic Shock Analysis
The sepsis dataset has 40,336 total patients count. Out of that 98.02% of patients have no sepsis, and 1.98% of the patients have sepsis. Figure.5 shows the total patient counts for Sepsis, SIRS, and Septic Shock out of that total Patient counts.
Figure. 5 Patient Count for SIRS, Sepsis, and Septic Shock
Severe sepsis with acute circulatory failure is characterized by persistent hypotension (SBP <90 mm Hg, MAP <60 mm Hg, or a decrease in SBP by >40 mm Hg) despite adequate fluid resuscitation.
Identifying septic shock in a patient includes the following criteria:
SBP<90 mm Hg, MAP<60 mm Hg or SBP>40 mm Hg
Respiratory rate ≥ 22 breaths/mins
The chance of sepsis progressing to severe sepsis and septic shock, causing death, rises by 4% to 9% with every hour of treatment delay. Laboratory tests can help assess organ dysfunction and contribute to the clinical diagnosis and appropriate medical management of sepsis, but lab results might take a little longer to get so for immediate pre-diagnose, the other 3 important vital signs (SBP, MAP, and RR) need to take into consideration.
The below visualization (figure. 6) helps doctors to know if patients are reaching the critical stage. Visualization contains Trigger hour, Previous hour, and biomarkers like SBP, MAP, Respiratory, and Lactate. Patients who satisfy septic shock conditions have either a sudden drop in blood pressure or a high respiratory rate or it can be both. The respiratory rate is high for all septic shock patients for their previous hour also, but they’re not many significant signs of BP drop in the previous hour, so doctors and nurses need to monitor sepsis patients continuously if the patient has a respiratory rate ≥22 with other imbalance vital signs.
Figure. 6 Hourly comparisons of biomarkers
High levels of lactic acid in your blood (serum lactate) is also important biomarker to diagnose if the patient identifies septic shock. Having too much lactic acid in your blood means that your cells aren’t using oxygen properly. In figure. 7, I highlighted lactate values that show high lactate (>2) and very high lactate (>4) with color codes for these septic shock patients. 9.3% of septic shock patients have high lactate in this data set.
Figure. 7 Hourly Comparisons of biomarkers
From the below Sunburst chart (figure 8) we can see the number of patients who exhibits septic shock symptoms each hour. There is a total of 473 septic shock patients in this dataset which is 16.13% of sepsis patients.
Figure 8: Count of Patients with Septic Shock symptoms (Hourly)
Using the above comparison, we can see how patients quickly develop the symptoms of septic shock. Here in this dataset, there are a total of 9 patients who satisfy all four conditions together (Figure 9) on the higher side which shows these severe septic shock patients need urgent intensive care.
Figure. 9 Severe Septic Shock Patients
Chances of survival for severe sepsis and septic shock are greatly dependent on the infection source and how far along the infection has progressed, but the septic shock symptom recognition helps ensure to get urgent intensive care immediately, it can be survivable. Early treatment can and does save lives.