Septic Shock

Shock can be classified into 3 different types: Hypovolaemic Shock, Cardiogenic Shock, and Septic Shock. Whilst the management of shock varies based on the type of shock it is, the resulting effect of all 3 types of shock is the same – decreased tissue perfusion.

Distributive Shock

  • impaired distribution of circulating blood volume
  • vasodilation
  • capillary leaks

Distributive Shock is sub-classified into 3 other types of shock: septic shock, anaphylactic shock and neurogenic shock. In this blogpost we will be focusing on Septic Shock.

Septic Shock

While sepsis is defined as a life-threatening organ dysfunction caused by dysregulated host response to infection, a septic shock is defined as a subset of sepsis in which underlying circulatory, cellular and metabolic abnormalities and profound enough to substantially increase the risk of mortality.

  • microorganism entry into the patient’s body
  • dysregulated host response characterised by excessive peripheral vasodilation, causing maldistribution of blood volume, over-perfused peripheral areas and under-perfused central areas
  • is the major cause of admission in the critical care setting

Septic Shock may originate from the community (>80% of cases) or during a stay in a healthcare facility. Common sites for origin of septic shock include:

  • lung
  • abdomen
  • bloodstream
  • renal
  • gastrointestinal tract
  • bone
  • soft tissue
  • surgical wounds

Infective organisms may include:

  • Gram negative bacteria eg. Klebsiella, Escherichia coli, and Pseudomonas aeruginosa
  • Gram positive bacteria eg. Staphylococcus aureus and Streptococcus pneumoniae
  • Viruses
  • Fungi
  • Parasites

Predisposing Factors

Intrinsic FactorsExtrinsic Factors
age extremesinvasive devices eg. catheter use
malnutritionimmunosuppressing drug therapy eg. steroids
co-existing diseases eg. malignancies, AIDS and Diabetesimmunosuppressive therapy eg. chemotherapy
wounds
surgical or invasive procedures

NOTE: all critically ill patients are at an increased risk of developing septic shock.

Septic Shock Signs & Symptoms

  • general malaise
  • fever OR hypothermia
  • tachycardia
  • tachypnoea
  • altered mental status
  • hypotension
  • impaired gas exchange
  • mottled skin
  • prolonged capillary refill
  • oliguria – urinary output less than 400 ml per day or less than 20 ml per hour

Investigations

  • CBCs
  • ABGs
  • c-reactive protein
  • clotting profile – prothrombin time and INR
  • urea & electrolytes
  • liver function tests
  • urinary function tests
  • serum lactate – helps identify cryptic septic shock

Septic Shock Diagnosis

Rapid recognition and resuscitation is crucial for survival, and so, deteriorating patients should be investigated for infection in a timely manner.

SepsisSeptic Shock
presence of infectionadequate fluid resuscitation not enough
acute change in SOFA score of 2 points or more from baselinevasopressors required to keep MAP at >65mmHg and Serum Lactate at >2mmol/L

Sequential Organ Failure Assessment Score (SOFA)

SOFA is a bedside tool that helps identify patients with infection at an increased risk of death or prolonged ICU stay. SOFA is considered to be positive when the patient has at least 2 of the following 3 criteria:

  • respiratory rate of >22 breaths/minute
  • altered mental state with a GCS <15
  • systolic blood pressure <100mmHg
septic shock
Retrieved from https://www.crit.cloud/summaries–reviews/the-bat-and-the-sofa-the-3rd-consensus-definitions-for-sepsis-are-out on 20th January 2023

Multiple Organ Dysfunction Syndrome (MODS)

MODS refers to a clinical syndrome characterised by acute potentially reversible dysfunction of two or more organs or organ systems not directly involved in the primary disease process. It is the ultimate complication of Septic Shock.

Airway Support

  • stabilise the patient’s airway
  • maintain oxygen saturation >94% (unless patient has COPD)
  • mechanical ventilation may be required to improve oxygenation and neutralise metabolic acidosis

Identifying Source of Sepsis + Treatment

  • Microbiology – blood, sputum, CSF, urine, wound swab specimens should be sent immediately for Culture & Sensitivity (2 sets of blood cultures should be taken, the 2nd one being with increased sensitivity for detecting bacteraemia); IMPORTANT: take cultures BEFORE antibiotics are administered (even though broad antibiotics should be started within 1 hour)!
  • Radiology – x-ray and CT scan should be performed to check for signs of infection
  • IV Antibiotics – start broad spectrum IV antibiotics within one hour to cover likely causative agents such as resistant organisms like MRSA, VREs and Klebsiella, or endogenous infections by colonising bacteria
  • Adjust Antibiotic Regime – upon identification of specific pathogens
  • Eliminate Sepsis Source within 12 Hours – debride any infected or nectrotic tissue, drain abscesses and secretions, and remove infective invasive devices

Fluid Resuscitation

Fluids are required to counteract absolute hypovolaemia (sweating, diarrhoea, hyperventilation) and relative hypovolaemia (vasodilation and peripheral blood pooling).

  • start crystalloids within one hour using the fluid challenge – 30ml/kg over 3 hours, titrating according to response
  • if necessary, colloids may be administered to patients who had to receive large volumes of crystalloids
  • CAUTION: watch out for fluid and chloride overload

Inotropes and Vasopressors

If fluid administration is unsuccessful in maintaining physiological parameters and adequate perfusion (MAP should be maintained at >65mmHg), or in the case of myocardial dysfunction, inotropes and vasopressors may be required.

  • administer noradrenaline to revere inappropriate vasodilation, lower risk of tachycardia and arrhythmias with less adverse metabolic effects
  • adrenaline may also be added as an adjunct if required
  • dobutamine may also be added if the patient remains unstable; this may also help counteract excessive vasoconstriction, especially within the peripheries

Corticosteroid Use

  • corticosteriods (hydrocortisone 200mg/day) may be indicated due to their anti-inflammatory effects in patients unresponsive to fluids and vasopressors NOTE: corticosteroids should not be discontinued abruptly!

Nutrition

  • nutritional support is particularly important for patients with septic shock since this helps improve their immune response
  • in case of patients with wounds, a high protein diet is recommended since it helps speed up the healing process
  • maintain the patient’s blood glucose level at <10mmol/L but avoid excessive glucose control to prevent hypoglycaemia

General Support

  • maintain temperature control to decrease metabolic demands
  • provide skin care and pressure ulcer prophylactic measures
  • provide prophylactic therapy to prevent venous thromboembolism
  • prevent over-sedation
  • aim to prevent ventilator-acquired pneumonia and infections related to lines/catheter use
  • provide blood transfusions only if the patient’s Hgb is <7mmol/L, or in case of bleeding, myocardial ischaemia, and severe hypoxia
Give high-flow oxygen via non-rebreathe bag. Take blood cultures and consider source control. Give IV antibiotics according to local protocol. Start IV fluid resuscitation Hartmann’s or equivalent. Check lactate. Monitor hourly urine output consider catheterisation. within one hour….plus Critical Care support – Retrieved from https://slideplayer.com/slide/12865670/ on 20th January 2023
septic shock
Retrieved from https://slideplayer.com/slide/17346484/ on 20th January 2023

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