Understanding Shock and Sepsis

• Sepsis, Shock & Multi-organ Dysfunction are key points

Learning Objectives

• The content comprises of shock elements
• Discussion of how shock leads to multi-organ dysfunction
• Analysis of clinical assessments
• Analysis of the pathophysiology of sepsis
• How to apply pathophysiology to sepsis treatment

Shock

• Shock is an acute circulatory failure
• It is life threatening
• Inadequate oxygen delivery to the body's cells is a characteristics
• Can be described as 'Inadequate Tissue & Organ Perfusion'
• Glucose is combined with Oxygen to create Energy (ATP) along with carbon dioxide (CO2) and water (H20)

Effective Blood Flow

• There are 3 key elements for effective blood flow:
• Effective Pump is needed
• Must have an effective circulatory stystem
• Needs adequate blood volume

Cardiac Output

• Cardiac Output is an important blood flow element
• Cardiac output is determined by stroke volume and heart rate
• Stroke volume is affected by Preload, Afterload, and Contractility
• Blood pressure depends on cardiac output and systemic vascular resistance

Preload, Afterload & Contractility

• The relationship between preload and stroke volume relates to Frank Starlings Law
• Frank Starlings Law: The greater the volume of blood to fills the heart during diastole, the greater the force of contraction during systole

Systemic Vascular Resistance

• The size (diameter) of arteries affects blood flow
• Wide = Vaso-dilation
• Narrow= Vaso-constriction
• The body can widen or constrict vessels to maintain homeostasis
• The renin-angiotensin-aldosterone system (RAAS) regulates arterial blood pressure
• RAAS relies on several hormones that increase blood volume and peripheral resistance
• Kidneys retain plasma & release hormones to squeeze vessels tighter (Constrict)

Shock Types

• There are several types of shock:
• Hypovolaemic shock comes from haemorrhage or other fluid loss
• Cardiogenic is from myocardial infarction or arrhythmia
• Distributive is from neurogenic processes, or is septic or anaphylactic
• Obstructive shock if from tamponade or tension pneumothorax
• Dissociative results from severe anaemia or 02 carrying capacity depletion

Anaerobic Metabolism

• Decreased O2 in cells causes Anaerobic metabolism
• Increase in lactic acid production leads to metabolic acidosis
• Cell and tissue death results
• Organ failure occurs

Sepsis

• Sepsis is when the body's response to infection injures its own tissues and organs
• Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection
• Septic Shock is a subset of sepsis with circulatory and cellular/metabolic dysfunction that raises mortality risk

Sepsis Data

• Sepsis ranges from infection, to multi organ failure, to septic shock, ultimately to death
• Approximately 50,000 deaths per year are attributed to sepsis
• Earlier identification and treatment of sepsis across the UK could save 14,000 lives
• Faster treatment could also result in 400,000 fewer days in hospital stays for patients
• This could save the UK economy as much as £2.8 billion per annum

Sepsis-Pathophysiology

• Sepsis results from immunologic overactivity that is mediated by leukocytes
• Leukocytes (white blood cells) initially come from bone marrow and/or thymus
• They circulate in peripheral blood and go to inflammation site early on
• There are circulating monocytes, tissue macrophages, neutrophils and dendritic cells, natural killer cells, eosinophils, basophils, and mast cells in leukocytes
• Leukocytes fight invading pathogens via phagocytosis which removes cellular debris and promotes a tissue repair environment
• Sepsis then reflects a circulatory dysfunction caused by immunologic overactivity

Inflammation

• Over-production of Cytokines and inflammatory mediators by immune system cells
• This causes capillary permeability and decreases Intra-vascular volume
• Vaso-dilation results
• This leads to a drop in Blood Pressure
• Less rich blood flow reaches organs
• Heart rate increases to maintain cardiac output due toadrenaline release-sympathetic response

Disseminated Intravascular Coagulopathy (DIC)

• Increased capillary permeability and pro-inflammatory mediators cause clotting and lysis alterations
• These changes cause microthrombi to form in capillaries restricting oxygen availability to tissues
• Cells switch from aerobic to anaerobic metabolism which results in lactic acid build-up and metabolic acidosis

Consequences of Sepsis

• Lack of circulating volume reduces organ perfusion
• This leads to organ failure/multiple organ failure
• Can result in death if untreated

Arterial Blood Gas (ABG) Values

• Test Value Normal values
• pH is 7.23, with normal values 7.35-7.45
• PaO2 is 9.85 with normal values of 11-13 kPa
• PaCO2 is 3.2 with normal values of 4.7-6.0 kPa
• HCO3 is 12.6 with normal values of 22-26 mmol/l
• BE is -16.7 with normal values of -2 to + 2
• Lac is 6.2 when normal values are <2 mmol/l

Sepsis Symptoms

• In adults it includes:
• acting confused, slurred speech or being incoherent
• blue, grey, pale or blotchy skin, lips or tongue
• A rash that does not fade when a glass is rolled over it
• difficulty breathing, breathlessness or breathing very fast

Sepsis Symptoms: Babies and Children

• Includes:
• blue, grey, pale or blotchy skin, lips or tongue
• A rash that does not fade with glass test
• difficulty breathing with grunting noises or stomach sucking under their ribcage
• breathing very fast or breathlessness also -weak, high-pitched cry that's not like their normal cry
• not responding like they normally do, or not interested in feeding or normal activities
• being sleepier than normal or difficult to wake

Clinical Assessment: Generalised indicators of Sepsis

• Key indicators are:
• A - often maintains own airway during early stages of sepsis, cyanosis
• B - tachypnoea (high RR), poor SpO2 trace
• C - tachycardia, hypotension, prolonged CRT, hyperthermic but cool peripheries.
• D - AVPU dependent on level of deterioration
• E -Widespread haemorrhagic rash (purpuric is when the rash is non-blanching) is leakage of blood from vessels

Sepsis: Clinical Treatment

• GIVE O2 TO KEEP SATS ABOVE 94%
• TAKE BLOOD CULTURES
• GIVE IV ANTIBIOTICS
• GIVE A FLUID CHALLENGE
• MEASURE LACTATE
• MEASURE URINE OUTPUT

Key Considerations

• The problem with Sepsis is disbalance/not volume: Treat with fluid & vasopressors for vascular squeeze because vessels are floppy
• Inotropes are given for contractility
• Aim to have .5mls/kg/hour of urine as minimum to perfuse kidneys so waste lactate is excreted
• MAP (Mean Arterial BP) accounts for fluid and resistance

Common Drugs Used

• Broad spectrum antibiotics are typically applied
• Crystalloid fluid 500ml bolus, administered over 15 minutes or less
• Human albumin solution (HAS) 4% or 5% are applied to patients with sepsis and shock
• Give Oxygen to achieve saturations above 94%
• Noradrenaline (vasopressor) and Dobutamine (inotrope) are first line drugs for ineffective fluid resuscitation

Acronyms for Sepsis

• Use "3 in, 3 out"
• IN:
• Fluid
• Antibiotics
• Oxygen
• OUT
• Full venous bloods
• Urine output
• Measure lactate
• BUFALO is helpful
• Bloods
• Urine output
• Fluids
• Antibiotics
• Lactate
• Oxygen

ODP Role

• ODPs are an appropriate professional for sepsis patients
• You should:
• Recognise symptoms based on A-E assessment
• Call if you suspect
• Know the location of policies for treatment
• Support anaesthetist with airway management
• Work within MDT for patient assessment, treatment and transfer to critical care

Explore the primary characteristics of shock, including elements for effective blood flow and vasodilation. Cover sepsis, septic shock, and the immune response, including the role of leukocytes and phagocytosis. Understand DIC and lactic acid build-up in sepsis.