Week 1: Sepsis Flashcards
Define sepsis
A potentially life threatening condition caused by a dysregulated host response to infection, resulting in an acute systemic immune response.
Leads to fatal organ and tissue injury
Define septic shock
Sepsis, with a significant increase in mortality risk due to circulatory and cellular/metabolic abnormalities.
When blood pressure drops to a dangerously low level =<65mmHG and lactate remains => 2mmol/L after intervention and organ failure starts after an infection.
How common is septic shock?
Occurs in 30% of sepsis patients
What are the outcomes like for sepsis patients?
Mortality ranges from 10-30% for sepsis patient, higher 50% in septic shock.
Many survivors will suffer from hsopital readmission, early death, physical and neurocognitive dysfunction, mood disorders and low quality of life.
Why are sepsis death statistics important to public health?
Leading cause of death in hospitalised patients
Nearly 20% of all global deaths.
What are some risk factors for sepsis?
Extreme age
Male sex
Black patients
Chronic diseases - HIV and cancer
Immunosuppressed patients
Prior organ dysfunction
Delay in treatment and diagnosis
Recent surgery or invasive procedure
Pregnancy women, recent birth or miscarriage
What are the two classification or sepsis regarding aetiology?
Hospital acquired
Community acquired
What are the most common types of infection in sepsis?
Pneumonia
Intra-abdominal infections
Genitourinary infections (UTIs)
Follwed by endocarditis, meningitis and skin infections
How useful are blood cultures in sepsis diagnosis?
1/3 of blood cultures for sepsis patients will come back positive.
What are the most common gram-positive pathogens causing sepsis?
Staphylococcus aureus
Staphylococcus pneumonia
What are the most common gram negative pathogens that cause sepsis?
E.coli
Klebsiella spp
Pseudomonas aeruginosa
What type of pathogens are often responsible for causing sepsis?
79% bacterial
20% fungal
1% viral
What is the difference between microvascular and macrovascular?
Microvascular involves small vessels such as capillaries
Macrovascular involves large vessels such as arteries or veins.
Describe the pathophysiological process by which sepsis brings about vascular changes in the body.
Pathogen from infection. PAMPs recognised by PRRs triggering the inflammatory response.
This leads to tissue damage and necrotic cell death.
Release of DAMPs further activates leukocytes and promotes inflammation.
Microvascular changes include endothelial cell dysfunction, coagulation and complement activation.
Macrovascular changes include vasodilation and hypotension.
What are the pathophysiological consequences of the vascular changes in sepsis?
Microvascular and macrovascular changes result in vascular leak cuasing edema and intravascular volume depletion.
This reduces the oxygen supply to the tissue leading to increased glycolysis (hence higher lactate levels), leads to a build up a reactive oxygen species causing mitochondrial damage and organ damage.
How does sepsis affect the kidneys?
Can cause acute kidney injury due to:
Decreased urinary output
Uremia (waste products build up in blood)
Ileus (aversion to oral intake due to lack of emptying GIT)
How can liver failure be identified in sepsis?
Elevated liver enzymes
What makes up the sepsis 6?
Take blood cultures - Give IV antibiotics
Take lactate levels - Give oxygen
Take Urine Output - Give IV fluids
What is the purpose of taking blood cultures in the sepsis 6? What else might you also do to fit this purpose?
Peripheral blood sample to identify source of infection
May also take a urine dispstick, CSF sample or chest X-ray (pneumonia)
What is the example guidance of how to screen for sepsis?
- combined NEWS of 5+, single NEWS 3 or patient looks unwell
- Possibly an infection?
- one red flag present
- Or two amber flags and lactate level above 2mmols/L or Acute Kidney INJury
What is considered a red flag for sepsis?
Systolic BP below 90mmHg
Heart rate above 130 bpm
RR above 24 bpm
Require oxygen
Non-blanching rash
Not passed urine in the last 18hours
Urine output less than 0.5ml/kg/hr
Lactate => 2mmol/L
Chemotherapy within 6 weeks
How soon after sepsis diagnosis should treatment begin?
Within 1 hour
What is the qSOFA screening tool used for Sepsis?
Used to help diagnose a patient with sepsis
If two of the three are present suggests sepsis
1. Respiratory rate of 22/min or above
2. Altered mental status (glasgow coma of less than 15)
3. Systolic BP of 100mgHg or less
What screening tool is recommended by NHS England for sepsis?
NEWs score
Lactate levels
Give an indication of how problematic sepsis is in the UK?
5 people die every hour in the UK from sepsis
-45,000 deaths per year
27% of ICU emissions
1% of the NHS budget
Using the screening systems, a patient is identified as requiring screening for sepsis if….
- Look unwell or someone is worried they are detriorating
2.Had recent chemotherapy - Has a NEWS2 score of five and above
4.Patient is at risk of neutropenia
5.Evidence of organ dysfunction - A recent infection/injury
What are the different screening tools that may be used for sepsis?
SOFA
qSOFA
SIRS
NEWS2
MEWS
What is included in the SOFA score when screening for sepsis?
Cardiovascular system - blood pressure and dopamine
Respiratory system - Partial pressure of oxygen
Liver - billirubin levels in blood
CNS - GCS
REnal - serum creatine measured and urine output levels
What is included in the SIRS tool when screening for sepsis?
SIRS is defined as when two or more of the following are present in the patient
-abnormal temperature
-abnormal heart rate
-abnormal respiratory rate
- new confusion or drowsiness
- abnormal WBC count
- elevated blood glucose
What is the normal respiratory rate?
12-16 bpm
What is the normal blood glucose level?
4-7mmol/L
What is the normal white blood cell count?
4-11x10^9/L
On the NEWS Score what is considered a normal measurement?
Respiration rate:12-20
SpO2: over 96
Systolic BP = 111-219
Pulse = 51-90
Temperature= 36.1 to 38
What is the difference between type 1 and type 2 respiratory failure?
Type 1: hypoxemic - not enough oxygen
Type 2: Hypercapnia - too much carbon dioxide
What variables does the MEWS score include?
Respiratory rate
Heart rate
Systolic blood pressure
Temperature
Hourly urine for two hours
What is the purpose of red flag sepsis?
Not a formal diagnostic tool
Bedside tool which suggest the patient is likley to have some level of organ dysfunction
Warns that s sepsis screening tool should be used
What is meant by the golden hour is sepsis screening?
Quality standard is to treat all sepsis patients within one hour of suspected sepsis
What should be assessed in everyone with suspected sepsis?
Temperature
Heart rate
Respiratory Rate
Level of consciousness
Oxygen saturation
Mottled skin/cyanosis
Non-blanching rash or breach of skin
Frequency and amount of urination
What are the three key processes in the pathology of sepsis?
Vasodilation
Capillary leak
Blood clotting
What is the process behind vasodilation in sepsis?
H2 activates endothelial cells lining blood vessels
Release NO
causing dilation
What is the processes behind capillary leak in sepsis?
Inflammation - vasodilation adn increased permeability
Leads to accumulation of fluid in the tissues
Loss of fluid from blood stream leads to low blood pressures
Fluid in lungs can impair breathing and oxygen exchange
Lead to hypovolemic shock
What is the process behind blood clotting in sepsis?
Cytokines activate clotting cascade to limit infection
Damaged endothelial cells can also lead to clot formation
What are the main pathological processes in sepsis ?
Blood pressure drops, heart rate increases to compensate.
Poor perfusion to tissue, cells switch to anaerobic metabolism and generate lactic acid
Build up of lactic acid causes lactic acidosis and a drop in pH making the body more acidic.
Blood flow to essentail organs decreases, inlcuding kidneys
No longer excrete H+ ions and reabsorbed HCO3- to balance pH
Impaired liver metabolsim, acid not elimiated from body remains acidic.
What is multiple organ dysfunction syndrome?
Multiple organs fail due to impaired blood flow and function
What are the key clinical presentations of sepsis?
Fever or hypothermia
Tachycardia
Tachypnea
Altered Mental Status
Hypotension - result in cold clammy skin and reduced urine output
What are the common reasons why blood cultures of septic patients are negative?
Have antibiotics before blood cultures are taken
Causative microorganism have no or limited proliferation in conventional blood cultures
Diagnosis of organism requires special media or cell cultures conditions
What is the laboratory process of diagnosing sepsis?
Blood cultures are taken and cultured in aerobic or anaerobic conditions
Microorganisms present metabolise nutriens in culture releasing CO2 which changes a dye in the bottom of the container
This change can be detected by a sensor
This indicates a microrganism has grown and can be taken for further diagnostic tests
What are the limitations of blood cultures as a method of sepsis diagnosis?
Delays in the transport of sample - faults e.g dropped
Method of collection can be painful
If taken after antibiotics may be less accurate
Some organisms fail to grow in blood culture
Hard to get the necessary volume or blood.
Slow process before diagnosis
What is the most common microorganism causing sepsis in hospitals?
- E.coli
- Staphylococcus aureus
3.Streptococcus spp - Klebsiella spp
What is the most common microorganism causing sepsis in the community?
Staphylococcus aureus
Enterococcus spp
Candida spp
E.coli
How affective is the Sepsis 6 in the treatment of sepsis?
If given within an hour of suspected sepsis can reduce mortality risk by almost 50%.
Identify
E.coli
Gram negative (pink)
Bacillus
Identify
Neisseria meningitidis
Gram negative (pink)
Diplococci
Identify
Staphyloccus aureus
Gram positive (purple)
Clumps of cocci
Identify
Streptococcus pneumonia
Gram positive (purple)
Cocci lancet shaped typically in pairs
Identify
Group B strep
Gram positive (purple)
Cocci typically in chains
