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Sepsis
Sepsis

Sepsis

Sepsis is a dysregulated hyper-inflammatory response to infection that causes life-threatening organ dysfunction. It’s overall mortality is 30-40% and is the leading cause of death in ICU.

Pathophysiology

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WBCs respond to an infectious agent by releasing cytokines, interleukins and TNF, which subsequently hyper activate the immune system. The immune reaction causes NO to be released and we get systemic vasodilation (causing BP to drop drastically). Our endothelial lining also becomes more permeable as we allow for extravasation of WBCs → oedema and hypovolaemia.

We also get activation of our coagulatory cascade → fibrin deposition throughout the circulatory system which compromises our perfusion further. As our platelets are used up we get thrombocytopaenia and haemorrhages too (DIC). Lactate rises due to hypoperfusion (as anaerobic respiration produces lactate).

☑️ Criteria

We use the SOFA score to categorise patients with suspected sepsis.

2 criteria are needed to diagnose sepsis:

  1. Infection - either known or suspected
  2. Organ dysfunction features.

If a patient has a SOFA score of >2 indicates sepsis. We can also use the SOFA score to assess a patients response to treatment.

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A shortened version is the qSOFA score, which allows for rapid assessment of potential sepsis based on clinical signs alone. It has 3 criteria:

  1. Respiratory rate >22
  2. Altered mental state
  3. Systolic BP <100mmHg

If a patient scores >2 then they should be managed and investigated for sepsis.

There are also red flag criteria and amber flag criteria which were made by NICE which should also be considered:

Red flag criteria
Amber flag criteria
• Responds only to voice or pain/ unresponsive
• Relatives concerned about mental status
• Acute confusional state
• Acute deterioration in functional ability
• Systolic B.P <= 90 mmHg (or drop >40 from normal)
• Immunosuppressed
• Heart rate > 130 per minute
• Trauma/ surgery/ procedure in last 6 weeks
• Respiratory rate >= 25 per minute
• Respiratory rate 21-24
• Needs oxygen to keep SpO2 >=92%
• Systolic B.P 91-100 mmHg
• Non-blanching rash, mottled/ ashen/ cyanotic
• Heart rate 91-130 OR new dysrhythmia
• Not passed urine in last 18 h/ UO < 0.5 ml/kg/hr
• Not passed urine in last 12-18 hours
• Lactate >=2 mmol/l
• Temperature < 36ºC
• Recent chemotherapy
• Clinical signs of wound, device or skin infection

🔢 Classification

Severe sepsis

This is when we get organ dysfunction as a result of sepsis and tissue hypoperfusion.

Hyperlactataemia (>2mmol/L)

Septic shock

This occurs when:

  • Systolic BP <90 despite fluid resuscitation
  • Hyperlactataemia (lactate >4mmol/L)

It needs to be transferred to HDU or ICU and treated with inotropes to improve the BP and organ perfusion.

⚠️ Risk factors

  • Very young or very old patients (<1 or >75)
  • COPD and diabetes
  • Chemotherapy, immunosuppressants, steroids
  • Surgery, burns, trauma
  • Pregnancy/peripartum
  • Indwelling catheter/central lines

😷 Presentation

We use the NEWS score to pick up the signs of sepsis (temp, HR, BP, RR, O2 sats, consciousness level).

Some key things to look out for are:

  • Breathlessness
  • Confusion or drowsiness
  • Fever, sweats, chills
  • Headache
  • Nausea and vomiting

Patients may also have:

  • Signs of infection
  • Non-blanching rash (due to meningococcal septicaemia)
  • Oliguria
  • Cyanosis
  • New onset arrhythmias

On examination we may observe:

  • Tachycardia
  • Hypotension
  • Pyrexia
  • Peripheral vasodilation
  • Hypoxia
  • Tachypnoea

🔍 Investigations

🩸
Bloods:
  • FBC - to assess WCC and neutrophils. May show leucocytosis (>12,000) or leucopenia (<4,000).
  • U&Es - to assess kidney function and AKI status.
  • LFTs - to assess LFTs and possible source of infection.
  • CRP - to assess inflammation.
  • Clotting - to assess for DIC.
  • Cultures - to look for bacteraemia.
  • Blood gas - to assess lactate, pH, and glucose levels.

Other investigations include:

  • Urine dipstick ± culture
  • Chest X-ray
  • Swab surgical wounds and other wounds
  • CT scan (if intra-abdominal infection suspected)
  • Lumbar puncture (to assess meningitis or encephalitis)
  • Stool culture
7️⃣
The 7 C’s for a pyrexic surgical patient
  1. Chest (infection)
  2. Cut (wound infection)
  3. Catheter (UTI)
  4. Collections (abdominal, pelvic abscesses etc.)
  5. Calves (DVT)
  6. Cannula
  7. Central line

🧰 Management

The underlying cause needs to be identified and treated. However, if the red flags are present, the sepsis six needs to be initiated immediately:

Give 3

  1. Broad spectrum antibiotics - based on local guidelines until switching to targeted therapy once the source is identified.
  2. IV fluid challenge - 500-1000ml initial crystalloid bolus over 15 minutes.
  3. High flow oxygen - 15laim to keep sats >94% (or 88-92% in COPD patients)

Take 3

  1. Blood cultures - prior to antibiotic administration.
  2. Serum lactate
  3. Urine output hourly - aiming for >0.5ml/kg/hour.

A 7th factor is source control to remove the cause.

The Surviving Sepsis campaign recommends noradrenaline as the first-line agent in treating septic shock which is unresponsive to fluid resuscitation, supplemented by vasopressin and adrenaline.

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