Lecture 3.1 - Sepsis

Septic Shock and Ileus

• Septic shock can cause ileus, which is delayed by the use of narcotics and sedatives.

Hepatic and Renal Dysfunction

• The hepatic reticuloendothelial system is the first line of defense against bacteria and their products, and liver dysfunction leads to a spillover of these products into the systemic circulation.
• Acute kidney injury (AKI) is associated with: • Systemic hypotension • Cytokines (e.g. TNF) • Activation of inflammatory cells, which indirectly and directly contribute to renal tubular injury

Sepsis Risk Groups

• Extremes of age
• Impaired immune systems due to illness or drugs (e.g. chemotherapy)
• Recent surgery or other invasive procedures
• Breach of skin integrity (e.g. cuts, burns, blisters, or skin infections)
• IVDU
• Indwelling lines or catheters
• Women who are pregnant, have given birth, or had a termination of pregnancy or miscarriage in the last 6 weeks
• Neonates

Clinical Assessment

• Assess people with suspected infection to identify: • Possible source of infection • Factors that increase the risk of sepsis • Any indicators of clinical concern (e.g. new onset abnormalities of behavior, circulation, or respiration)
• Use a structured set of observations/early warning score to assess people in a face-to-face setting to stratify risk
• Assess: • Temperature • Heart rate • Respiratory rate • Blood pressure • Level of consciousness • Oxygen saturation
• Ask the person, parent, or carer about frequency of urination in the past 18 hours

Examination

• Pale
• Temperature 36°C, pulse 110/min, BP 90/70 mmHg
• Respiratory rate 30/min
• Widespread purpuric (non-blanching) rash
• Mentally alert, Glasgow Coma Scale 15

NEWS2 Scoring System

• Sepsis is defined as: • Aggregate NEWS2 score of 7 or above • OR a patient with a lower NEWS2 score (5 or 6) but also with:
  • Lactate > 2 mmol/L
  • Chemotherapy in the last 6 weeks
  • Other organ failure evident (e.g. AKI)
  • Patient looks extremely unwell
  • Patient is actively deteriorating

Sepsis 6 Bundle

• Sepsis 6 works to minimize the increased mortality risk by: • Restoring the circulation • Assessing risk • Monitoring the effect of treatment • Switching off the infective trigger
• The sepsis 6 bundle should be delivered as quickly as possible, but for the sickest patients with red flag sepsis always within the first hour following recognition of sepsis

Oxygen Therapy

• Imbalance between oxygen demand and supply
• If the patient is shocked or critically ill, the initial oxygen therapy is a reservoir mask at 15 L/min
• Adults: • Target oxygen saturation of 94-98% • 88-92% for those at risk of hypercapnic respiratory failure
• Children: • Give oxygen if SpO2 < 92%

Bloods and Cultures

• Glucose: • Stress response causes gluconeogenesis, glycogenolysis, and insulin resistance • Increases risk of secondary infection
• FBC: • WCC:
  • Trend
  • Differential
  • Aetiology • Plt:
  • Acute phase increase then sign of progressing organ dysfunction • Hb:
  • Helpful to maximize oxygenation

Lactate

• In sepsis and other pathological conditions, lactate is a marker of anaerobic respiration
• A raised arterial lactate is usually due to one of four types of problems: • Insufficient oxygen delivery due to circulatory failure (the ‘macro circulation’) • Insufficient oxygen delivery due to microcirculation (the capillary beds are not working properly) • Inability of the tissue to use oxygen (e.g. mitochondrial dysfunction) • Excessive oxygen demand (e.g. tonic-clonic seizures, or excessive exercise)
• Therefore, response to fluids gives an indication of severity and underlying pathophysiology

Antibiotic and Suitable Control

• Ensure mechanisms are in place to deliver antibiotics fast
• Take microbiological samples before prescribing an antimicrobial (where possible)
• For all people with suspected sepsis where the source of infection is clear, use existing local antimicrobial guidance
• If not clear, use broad-spectrum antibiotics
• Revise according to results
• Think about the source: abscess, obstruction

IV Fluids

• O2 delivery = O2 content of blood x cardiac output
• Cardiac output = stroke volume x heart rate
• The stroke volume is dependent on: • Preload • Afterload
• The aims of fluid therapy are: • To correct absolute and relative hypovolemia • To bring the patient's pulse, blood pressure, mental state, lactate, and urine output within target • To do this judiciously, and to avoid pushing the patient into overload
• Crystalloids are the preferred first-line fluid for resuscitation
• Monitor: • UO:
  • In early stages, this is key
  • Easy to measure/ask about
  • The urine output is an excellent window on the circulation