Shock Flashcards
Definition of Shock
Hypotension (Systolic
Cellular consequences of shock
Anaerobic metabolism causes lactic acidosis
Membrane permeability increases - Na & water enter cells causing them to swell leading to death
Treatment is aimed at restoring cellular normality
Clinical signs of shock
Tachycardia & Vasoconstriction
Cardiac output drops –> Narrow pulse pressure, MAP drops, blood flow to organs decreases
Cases where shock may not be shock (6)
At extremes of age
Athletes or Pregnant women
Certain medications or OD
Hypothermia or people with pacemakers
Causes of Shock
Haemorrhagic –> Hypovolaemic due to internal or external bleeding
Non-haemorrhagic –> Tension pneumothorax, cardiogenic, neurogenic or septic shock
Tension pneumothorax
A surgical emergency where increasing pressure of air in the pleural space causes lung collapse and mediastinal shift compressing the Vena cava reduces CO by blocking venous return –> HR+RR+JVP up, BP down
Absent breath sounds, hyper-resonant with tracheal shift
Cardiogenic Shock (6,4)
Acute Pump Failure - most commonly MI but also HF, myocardial contusion, tamponade, Air embolus, cardiomyopathy
Investigate with ECG, cardiac enzymes, echo and CVP
Neurogenic shock
Due to spinal cord injury and loss of sympathetic tone - BP drops without increase in HR - warm peripheries
Will not respond to fluid resuscitation
Septic shock
Focus of infection which has spread systematically - cytokine storm causing BP crash with tachy and wide pulse pressure
Warm peripheries - treat with fluid and abx
Haemorrhagic shock
Loss of blood (no shit) - normal blood volume is 7% of body weight in adult and 9% in children
Classed I-IV - management guided by pt’s response
Class I haemorrhage
15% of volume/ 750mls
BP, HR, RR, urine output all normal. Slightly anxious
Like donating blood - no treatment required/crystalloid
Class II haemorrhage
15-30%/ 750-1500mls
HR/RR up, pulse pressure down, urine output down
CNS - anxiety & hostility - Tx crystalloid & maybe blood
Class III haemorrhage
30-40%/1500-2000ml
HR/RR up, systolic pressure and urine output down
Anxious and confused - Tx with crystalloid and blood
Class IV haemorrhage
> 40% lost/ >2000ml
Immediately life threatening - HR, RR & BP drop or v. high
Olgiouric, Confused and lethargic
Treat with lots of blood and surgical intervention
Management of shock
A+B- oxygenate and ventilate to preserve organ perfusion
C - Control blood loss and replace volume
D - focus on maintaining brain & kidney perfusion
E - Prevent hypothermia by using warmed fluids, treat any secondary injuries
Assessment of shock
Need significant vascular access - 2 big IV lines, central lines, IO line –> cross match blood
Rapid warmed fluid bolus - 1-2L hartmanns for adults and 20mls/kg hartmanns for children –>monitor response
Volume replacement in shock
Warmed crystalloid is main - hartmanns or saline
Crossmatched RBCs if possible or O-ve blood
Management is directed by response to fluid challenge
Acid-base changes in shock
Use ABGs to monitor acidosis - acidosis in adults is due to poor perfusion, in children poor ventilation
Treat –> control bleeding, oxygenate and ventilate, restore volume - Do not give bicarbonate
A rapid responding patient
<20% blood loss - responds to inital fluid bolus
Remains stable afterwards - still needs surgical assessment and regular monitoring
A transiently responding patient
20-40% blood loss - initially improves but deteriorates after initial fluid bolus –> needs continued fluid and blood and surgical intervention to stop ongoing haemorrhage
A non-responding patient
> 40% blood loss - does not response to bolus or ongoing therapy - requires immediate transfer to theatre
Must exclude non-haemorrhagic causes
Skin temperature in shock
Cold peripheries –> hypovolaemic, cardiogenic,
Warm peripheries –> septic and neurogenic
Fluid shift in shock
External loss or internal loss (pelvis, lungs, abdomen)
Tissue fluid
Inotropes in shock management
Adrenaline Noradrenaline Ephedrine Dobutamine Dopexamine Dopamine
Adrenaline
It is a non-specific adrenoreceptor agonist and cause be used in Cardiac arrest, anaphylaxis, asthma, croup, LAs
SE: palpitations, tachycardia, arrhythmias, anxiety, panic attacks, tremor, HTN, headaches and pulmonary oedema
Noradrenaline
Used as a vasopressor to treat critical hypotension – acting on Alpha receptors – at high doses it can lead to limb ischemia - used in septic and neurogenic shock as it has fewer side effects than dopamine.
Ephedrine
Increase BP and act as bronchodilators. But it can cause tachycardia, arrhythmias, angina, vasoconstriction and HTN.
Dobutamine
A sympathomimetic used in HF and septic or cardiogenic shock – it directly stimulates B1 receptors. Powerful Inotropic action so is not useful in IHD. Can cause HTN, angina, arrhythmia (cautious if AF present) and tachycardia.
Dopexamine
A dopamine analogue and Beta-agonist which can be used as an inotrope in shock especially septic shock as it is a powerful splanchnic vasodilator so it protects the bowels.
Dopamine
Used in severe hypotension or bradycardia.at the cardiac dose (5-10ug/kg/min) acts as an inotrope but at 10-20ug/kg/min it acts as vasoconstrictor which can be useful in septic shock but can also lead to kidney damage or arrhythmias.
ECG changes in Hypothermia
Will be bradycardic with a ‘J’ or osborne wave - a hump at the end of the QRS complex. Can also have 1st degree heart block, long QT interval and atrial/ventricular arrhythmias.
Symptoms of allergic reactions
Mild - urticara, angio-oedema, conjunctivitis (nausea, abdo pain, burning or itching in the lips/mouth/throat)
Moderate - Bronchospasm, tachy, pallor (coughing, sweating, irritable, loose bowel motions)
Severe - S. Bronchospasm, Laryngeal oedema, shock Arrest (collapse, difficulty in breathing, vomiting, uncontrolled shitting)
Doses of Adrenaline in anaphylaxis
12yrs - 500mg (0.5ml 1/1000)
Mortality of acute respiratory distress syndrome
50-75% overall
Pneumonia 86%
Trauma 38%
