Shock Flashcards
What the 6 types of shock
Types of shock : SHOCAN
1. Hypovolaemic
2. Septic
3. Obstructive
4. Neurogenic
5. Cardiogenic
6. Anaphylactic
What is the definition of Shock
“Acute circulatory failure, with inadequate tissue perfusion causing cellular hypoxia”
Will pt with shock always have abnormal blood pressure
No - can have normal BP
Clinical features vary dependant on ….
Is “Hypotension” and “shock” interchangeable
Clinical features vary dependant on the mechanism
- “Hypotension” and “shock” are NOT interchangeable
What are pre and after-load?
Pre-load: before the heart
After-load : after the heart
AETIOLOGY:
Which types of shock are pre-load and give examples
Hypovolaemia:
- Haemorrhage
- Fluid loss
- Dehydration
Which types of shock involve the heart and give examples
Cardiogenic:
- MI
- CCF
- Arrhythmia
Obstructive - prevent the contraction
- PE
- Tamponade
- Pneumothorax
Which types of shock are after-load and give examples
Vasodilatory: prevents blood (or leaking) from reaching tissues and organs
- Sepsis
- Neurogenic
- Anaphylactic
- Adrenal insufficiency - this is y SNS is impor.
PATHOPHYSIOLOGY:
What are the initial steps in the shock cascade
*Circulatory failure leads to hypoperfusion which causes hypoxia
*Cells switch to anaerobic energy production –> lactic acidosis
PATHOPHYSIOLOGY:
What are the compensatory steps in the shock cascade?
- Body attempts to rectify hypoxia and lactic acidosis by:
–> * hyperventilation - to raise pH
—> *release of adrenaline and noradrenaline from adrenals - to increase pressure
—> *renin-angiotensin system activation (RAAS) - stimulates a rise in BP and so kidneys increases water retention - Blood diverted to essential organs (heart, brain, lungs) and away from the skin, GI tract
PATHOPHYSIOLOGY:
What are the progressive steps in the shock cascade?
*Compensatory mechanisms begin to fail.
- Decreased perfusion of the cells leads to Na+/K+ pump failure
–> Intracellular sodium increases and potassium leaks out - cells can’t function - Leakage of water/protein into surrounding tissues –> Blood viscosity increases
- Essential organs now compromised due to reduced perfusion
- If the gut is compromised, bacteria may enter the bloodstream, resulting in the release of endotoxins - usually gram- negative bacteria
PATHOPHYSIOLOGY:
What happens in the refractory step of the shock cascade?
*Essential organs fail
–> brain damage
–> multiorgan failure
–> death
Which step in the shock cascade must medicine be successful when treating shock
must be successful during the compensatory step to prevent progression to multi-organ failure
Which are the 5 clinical features of shock can we can observe?
Observations of shock:
1. Tachypnoea
2. Tachycardia
3. Hypotension
4. Hyper or hypothermia
5. Poor urine output - good indicator to increase fluid intake
What are the 7 clinical SIGNS OF DECREASED TISSUE PERFUSION in pt with shock?
- Cool peripheries
- Poor filling of peripheral veins
- Cool to the touch
- Warm to the touch —> sepsis/neurogenic shock
- Metabolic acidosis
- Elevated lactate
- Restlessness or decreased conscious level
what are the 3 steps in the GENERAL APPROACH TO SHOCK
- Resuscitate
- Diagnose
- Treat underlying cause
What are the general principles used to manage sick patient
ABCDE principle
A = Airway and oxygenation
B= Breathing and ventilation
C = Circulation and shock management
D = Disability due to neurological deterioration
E = Exposure and examination
What is common cause of shock
HYPOVOLAEMIC SHOCK
What is Hypovolaemic shock?
Low cardiac output direct reflection of reduced venous return (preload) - low blood volume so the cardiac output is low
How do we measure Hypovolemic shock
By measuring the cardiac out
CO = SV x HR
How do we measure Hypovolemic shock
By measuring the cardiac out
CO = SV x HR
What are the 4 causes of hypovolemic shock?
- Haemorrhage
- Loss of GI fluid
- Burns
- Renal loss - the distal tubule and collecting duct
HYPOVOLAEMIC SHOCK - HAEMORRHAGE:
What are the 4 ways of losing blood via haemorrhages other than visual blood loss
‘Blood on the floor and four more”
1. Intrathoracic
2. Retroperitoneal - beyond the abdomen - kidney and aorta
3. Pelvis
4. Intrabdominal
What are the 4 HYPOVOLAEMIC SHOCK - HAEMORRHAGE classifications and what are the percentages of blood loss in each class?
Classification of shock:
I). 15% (<500ml blood loss)
II). 15-30% (500-1000ml blood loss)
III). 30-40% (1000-2000ml blood loss)
IV). >40% (>2000ml blood loss) - reversibility is uncertain
HAEMORRHAGE MANAGEMENT:
What are the 3 HAEMORRHAGE MANAGEMENTs
- Advanced Trauma Life Support (ATLS) algorithm if the history of trauma - most of western world deals with trauma
- Trauma CT “the afghanogram”
- Baseline (and multiple repeat)
lactate, pH and haemoglobin levels
What are the 5 principles of haemorrhage management?
Principles of haemorrhage management:
- ID the source of the haemorrhage - pelvis, brain blood on the floor and 4 more
- Stop haemorrhage (pressure, tourniquet, surgical intervention)
- Replace blood products (1:1:1 resuscitation)
- Tranexamic acid - prevent clotting
- Avoid using lots of crystalloids (adds to haemodilution and have no clotting ability - have to balance)
HYPOVOLAEMIC SHOCK - LOSS OF GI FLUID :
What are the 3 methods of losing GI fluid ?
- Vomiting & diarrhoea
- Fistulae - an abnormal connection between two body parts or an organ and the external body
- Sequestration of fluid in bowel lumen due to obstruction - not in circulation
What is the DEHYDRATION MANAGEMENT:
Assess pt with the ABCDE approach
what are 5 DEHYDRATION MANAGEMENTs
- Baseline obs (HR, b/p, central capillary refill)
- Gain IV access
- Baseline bloods including lactate & electrolytes
- Fluid challenge intake (crystalloid)
- Monitor urine output hourly- aim for >0.5ml/kg/hr
What are the 3 main types of fluids used in dehydration management? and name a pro for each one.
ISOTONIC:
- NaCl 0.9%
Pro: Corrects ECF loss
- Ringer’s Lactate
Pro: Generates Bicarbonate - reduces risks of hyperchloraemia and is a physiological - Dextrose 5%
Pro: Glucose is rapidly metabolised
HYPOVOLAEMIC SHOCK - BURNS:
What are the three degrees of burns and the extent of skin damage
- Superfical - 1st degree
only in the epidermis layer - Partial thickness - 2nd degree
in the epidermis and dermis layers - Full-thickness - 3rd degree
in the epidermis, dermis and the subcutaneous layer and almost in the muscle
HYPOVOLAEMIC SHOCK - BURNS:
Burns management ?
ABCDE assessment of patient
–> remember that airways swell rapidly in inhalation injury
Assess the percentage of burns using Lund & Browder chart
What is the formula used for burns fluid resuscitation?
- Use Parkland formula for fluid resuscitation:
4ml x Burns Surface Area (%) x weight (kg) = total crystalloid volume
- Give 1⁄2 of the volume in the first 8hrs
- Give 1⁄2 of the volume in subsequent 16hrs
what is CARDIOGENIC SHOCK
Primary impairment of cardiac function may result from myocardial infarction/ischaemia, acute arrhythmias, acute cardiomyopathy, acute valvular lesions and myocardial contusion (blunt trauma to the chest)
What are the PRESENTATIONs of CARDIOGENIC SHOCK
- Chest pain,
palpitations,
syncope - fainting bcs of low BP
No reduction in circulating volume leads to additional features:
- Elevation of central jugular venous pressure - vein is bulky
- Pulmonary oedema
What does an acute myocardial infraction cause
acute myocardial infarction results in a reduction in SV and CO and increased Left ventricular end-diastolic pressure LVEDP, Pulmonary edema and hypoxia
These cause the release of inflammatory biomarkers and catecholamines
which then causes Vasoconstriction –> increasing myocardial work and oxygen demand resulting in Cardiogenic shock!
What are the medicine steps used during an acute myocardial infarction to prevent it lead to shock
Inotropes, vasopressors and MCS: prevent HTN and the reduction of SV and CO
Revascularisation: to prevent ischemia
Oxygenation and mechanical ventilation: prevent increase in LVEDP, P.edema and Hypoxia
Which histories can cause Cardiogenic shock ?
History may indicate the cause of cardiogenic shock:
- PMHx of angina,
MI,
HTN, hypercholesterolaemia, T2DM
Cardiogenic shock Management?
Assess pt using the ABCDE approach
Baseline bloods (including troponin)
ECG
Avoid large volumes of IV fluidwill lead to overload May need ionotropic support
Treat underlying cause
What is OBSTRUCTIVE SHOCK?
Name 3 examples of Obstructive shock
Secondary impairment to cardiac function results from physical obstruction to cardiac output
- Cardiac tamponade - space in the cardiac lining - myocardial cavity is filled with blood- heart is squashed so it cant expand
- Tension pneumothorax - the heart is getting squashed
- Major pulmonary embolism -blockage in the pulmonary artery
PRESENTATION OBSTRUCTIVE SHOCK
Tamponade and tension pneumothorax are usually associated with a history of thoracic trauma
(usually penetrating but can happen in blunt mechanisms)
*Remember the classical presentation of PE and risk factors
What are the 3 factors in the cardiac tamponade : Beak Triad
Beak triad
- hypotension
- jugular venous distension
- Muffled heart sounds
Cardiac tamponade and tension pneumothorax share 2 presentations but what is the main difference?
both present with - hypotension
- jugular venous distension
but with tension pneumothorax there are absent breath sounds whilst cardiac tamponade has muffled heart sounds
What is NEUROGENIC SHOCK
What happens during neurogenic shock ?
Spinal transection/injury with loss of sympathetic outflow beneath the level of injury
- Vasodilation
- Rapid increase in size of the vascular bed - blood is in the peripheries not in the heard and organs
- Reduced venous return - less tonal control
- Reduced cardiac output
NEUROGENIC SHOCK MANAGEMENT ?
What are the ABCDE management approaches ?
A. secure airway
B. if the injury affects C3-5, the diaphragm may become affected so “3 and 5 keep the diaphragm alive”
pt needs ITU admission, careful observation +/- mechanical ventilation
C. may be bradycardic, warm peripheries, hypotensive, use of inotropes & vasopressors on ITU
D. confused if brain perfusion affected, focal neurological signs (sensory or motor impairment)
E. remember to assess anal tone & perineal sensation
What should be avoided in Neurogenic shock management?
Avoid large amounts of IV fluid- will lead to
pulmonary oedema
ANAPHYLACTIC SHOCK:
What is the reaction mediated by ?
and what does it cause :
- Reactions mediated by IgE from mast cell degranulation
Causes :
-> Release of histamine and serotonin
-> Rapid vasodilation
-> Fall in systemic vascular resistance
-> Hypotension
Presentations of Anaphylactic shock
Signs and symptoms:
Skin: itchy skin or a raised red skin rash (hives) and flushing
swollen eyes, lips, hands and feet.
CNS: feeling lightheaded or faint, unconsciousness, headache and anxiety
Swelling of the mouth, throat or tongue, which can cause breathing and swallowing difficulties.
wheezing.
GI: abdominal pain, diarrhoea, nausea and vomiting
Pelvic pain
Heart: Slow or fast HR and low BP
People with a history of allergies and known triggers are more likely to experience which type of shock?
Anaphylaxis
ANAPHYLACTIC SHOCK MANAGEMENT ?
What are the steps/actions used in ABCDE approach?
FIRST: Immediately remove the trigger
A = manoeuvres/adjuncts/early definitive airway
B = high flow O2, examine chest, nebulised bronchodilators
C= assess b/p, gain IV access, take bloods
Administer:
- IM adrenaline 1:1000 0.5mlrepeat every 5 mins
- IV chlorphenamine 10mg
- IV hydrocortisone 200mg
- IV fluids
D = assess GCS
E= rash, erythema, triggers
SEPTIC SHOCK:
What if the CONSENSUS CONFERENCE DEFINITIONs for SEPSIS
Systemic Inflammatory Response Syndrome (SIRS)
Two or more of:
- Pyrexia (>38deg) or hypothermia (<36deg)
- Tachycardia (>90bpm)
- Tachypnoea (RR >20)
- White cell count >12 or <4
- Acutely altered mental state
- Blood glucose >6.6
Sepsis = SIRS + documented source of infection
What is severe sepsis?
Severe sepsis = SIRS + altered organ perfusion/evidence of dysfunction
Including:
- CVS (lactate >1.2mmol/L)
- Resp (PaO2 <9.3kPa)
- Renal (urine output <120ml over 4 hours)
- CNS (GCS <15)
What is sepsis shock?
Septic shock = refractory hypotension in addition to SIRS, in presence of invasive infection
What are the signs/symptoms of sepsis shock?
and what are they caused by?
Signs/symptoms caused by the release of endogenous inflammatory mediators (nitric oxide, bradykinin, histamine, prostaglandins & cytokines)
–> Vasodilation
–>Vessel permeability
–>Myocardial depression
History may give indication of infective source
What history of sign/symptoms are treatments can be used to identify sepsis shock?
–> Breathlessness, productive cough
–> Abdo pain, D&V
–> Frequency, dysuria, suprapubic pain
–>Headache, neck stiffness, coma
–> Recent surgery, trauma
When should we call for help ?
SEPSIS acronym
S = slurred speak
E = extreme shivering and muscle pain
P = passing no urine
S = Severe breathlessness
I = It feels like you’re going to die
S = Skin mottled/ discoloured
SEPTIC SHOCK MANAGEMENT:
what are the 6 steps?
“Sepsis six”
Doing these 6 steps within the first-hour help with survival
1. High oxygen flow
2. Take blood cultures
3. Give IV antibiotics
4. Give a fluid challenge
5. Measure Lactate
6. Measure urine output
