Transcript Treat for Shock

Shock: Clinical features and
pathophysiology
Mahesh Nirmalan
Critical Care Unit, Manchester
Royal Infirmary
Objectives
• Life-threatening condition
– Immediate or delayed mortality
– Multiple aetiology
• Recognition and Assessment
• Physiological consequences of shock
– clinical features
– Document and report on progression
Definition of Shock
• Inadequate tissue perfusion
• Decreased oxygen supply
• Anaerobic metabolism
• Accumulation metabolic waste
Causes of Shock
• Severe or sudden blood loss
• Large drop in body fluids
• Myocardial infarction
• Major infections
• High spinal injuries
• Anaphylaxis
• Extreme heat or cold
Types of Shock
• Hypovolemic Shock:
– haemorrhagic
– or non haemorrhagic
• Other causes of shock
– Cardiogenic Shock
– Septic Shock
– Neurogenic Shock
– Anaphylactic Shock
Harvest of Death: T H O’Sullivan
Hypovolaemic Shock
• Haemorrhage: Overt or occult
• Reduction in circulating volume
• Reduction in venous return and CO
• O2 supply-demand imbalance
• Lactic acidosis
• Reduction in venous oxygen saturation
• Non haemorrhagic hypovolaemia
– Severe burns, vomiting and diarrhoea
Cardiac output (l)
CO, MAP and SvO2
6
CO
C(n=9)
S(n=10)
G(n=10)
4
2
0
Baseline CO Initiation of End of shock
Post
shock phase phase CO resuscitation
CO
CO
MAP
80
40
SvO2
80
SvO2(%)
MAP(mm Hg)
120
60
40
20
0
0
Baseline
Initiation of End of shock
Post
shock phase shock phase resuscitation
Baseline
Initiation of End of shock
Post
shock phase
phase
resuscitation
Effect of EDV and
contractility on SV
Changes in CO and MAP in haemorrhage
Clinical Signs of Acute
Hemorrhagic Shock
% Blood loss
< 15
15-30
Clinical Signs
Slightly increased heart rate, local
swelling, bleeding
Increased heart rate, increased diastolic
blood pressure, prolonged capillary refill
30-50
Above findings plus: hypotension,
confusion, acidosis, decreased urine output
> 50
Refractory hypotension, refractory
acidosis, death
Signs of Shock
• Cold, clammy and pale skin
• Rapid, weak, thready pulse
• Shallow, rapid breathing
• Oliguria
• Reduction in MAP
• Cyanosis
• Loss of consciousness
Non-Haemorrhagic Shock
• Cardiogenic Shock
• Septic Shock
• Neurogenic Shock
• Anaphylactic Shock
Cardiogenic Shock
• Primary myocardial failure
• Arrhythmia
• Tamponade
• Contusion
• Pump failure
• Reduction in cardiac output:
– Decreased blood supply
– Decreased oxygen delivery
Cardiogenic Shock
• Assess for:
– Signs of heart failure
– Signs of tamponade
– Cardiac dysrrhythmia
– Myocardial infarction
– Tachycardia
– Muffled heart sounds or third heart sound
– Engorged neck veins with hypotension
– Dyspnoea
– Oedema in feet and ankles
Septic Shock
• Bacterial, viral, fungal infection
• Gram negative and gram positive bacteria
• High output failure: “warm shock”
– Fever, tachycardia, tachypnoea, leucocytosis
• Inadequate oxygen extraction
– High SvO2, Metabolic acidosis
• “Cold shock”
• Atypical presentation in immunocompromised patients
• Diabetes, Cirrhosis, immunosuppression
Septic Shock in trauma
patients
• Develops 2 - 5 days after injury
occurs
• Carries a poor prognosis
• Assess for:
– Penetrating abdominal injuries
– Signs of infection
– Warm pink skin and dry elevated body
temperature
– Tachycardia
– Wide pulse pressures
Neurogenic Shock
• Caused by:
– Spinal cord injury
– Certain drugs
– Brain stem, spinal or torso trauma
• Venous pooling and arteriolar dilatation
• Signs and Symptoms:
– Hypotension without tachycardia
– Warm pink skin
– Low blood pressure & minimal response to fluids
Anaphylactic shock
Anaphylactic Shock
• Rapid onset
• Primary systems:
– Cardiovascular, Respiratory
– Skin, Gastrointestinal, coagulation
• Face, pharynx and laryngeal oedema
• Adrenaline is life saving
Anaphylactic Shock
• Diffuse vasodilatation
• Increase size of vascular bed
• Blood is trapped in small vessels and viscera
• Temporary loss in total circulatory volume
• Sudden severe allergic reaction to:
– Drugs, Toxins, Foods, Plants
Symptoms
• Apprehension and flushing
• Wheezing or shortness of breath & cough
• Rapid, weak pulse
• Cyanosis
• Generalized itching or burning
• Watering and itching of the eyes
• Hypotension
• Coma
Stages of shock
• Compensated shock
–
Autotransfusion
• Decompensated shock
– Blood moves to more
vital organs
• Irreversible shock
– Multiple system / organ
damage
– Even with treatment, death
is the result
Plasma [Lactate]
A priori groups
Plasma[lactate] (mmol/l)
6
8
C(n=9)
S(n=10)
G(n=10)
5
Post hoc groups
7
6
4
C(n=9)
Lactate<3(n=8)
Lactate>3(n=12)
5
4
3
3
2
2
1
1
0
0
Baseline
Initiation of
shock phase
End of shock
phase
Post
resusitation
Baseline
Initiation of
shock phase
End of shock
phase
Post
resusitation
Evaluation of Shock
• Internal or external hemorrhage
• Underlying cardiac problems
• Sepsis
• Trauma to spine cord
• Contact with known allergic substance
• Determine amount of blood loss
• How long has casualty been bleeding?
Level of Consciousness
Report and record
• Alert
• Verbal response to stimuli
• Pain response to stimuli
• Unresponsive to any stimuli
Early Signs of Shock in Non
Complicated Patients
• High index of suspicion
• Minimum tachycardia
• No measurable changes occur in blood
pressure
• Pulse pressure is potentially very useful
Definitive management
Where?
By whom?
Invasive monitoring
• Essential in the definitive treatment
• Direct arterial pressure
• Central venous pressure
• Cardiac output
Direct arterial pressure
CVP AND CIRCULATING VOLUME?
Treatment of Shock
Increase tissue perfusion and
oxygenation status
• Maintain airway
• Control bleeding
• Baseline vital signs
• Level of consciousness
Treatment of Shock
• Positioning
• ABCD approach
• Fluid therapy
• Drug therapy
• Keep patient at normal temperature
– Prevent hypothermia
– Minimize effect of shock
• On-going assessment - every 10-15 minutes
Specific measures
• Hypovolaemia: Blood transfusion
• Electrolyte/acid base imbalance
• Sepsis: Antibiotics, ?steroids
• Neurogenic: Steroids
• Anaphylactic: Adrenalin
Summary
• Life threatening: Early goal directed therapy and regular
monitoring by trained staff will change outcome.
• Early detection : DON’T RELY ON BP
• High index of suspicion
• Monitor casualties susceptible to shock