Shock – A Practical Approach

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Introduction
The approach to shock should be systematic, focussed and efficient
Establish there is sufficient evidence of hypoperfusion
2 or more of the following without sufficient alternative cause e.g. pain, anxiety, cold

  • Tachycardia
  • Decreased capillary refill > 4 secs
  • Hypotension (including fall of 20% or 20% lower than pre-morbid BP) – MAP < 65mmHg
  • Oliguria < 0.5ml/hr
  • Altered mentation
  • Lactate > 2 mmol/L

Confirm a likely cause
Attempt to identify the likely underlying aetiology and pathophysiology 

  • Hypovolaemic? – Evident blood loss? Trauma? Excessive fluid loss from GIT or drains?  Flat jugular veins
  • Cardiogenic? – Chest pain? New murmurs?  Injury pattern on ECG?   Elevated jugular veins?
  • Distributive? – Bounding pulse? wide pulse pressure? Sepsis? Spinal/epidural anaesthetic? Spinal cord lesion?
  • Obstructive? – Risk factors or clinical evidence for pulmonary embolus? Pericardial effusion on echo? Clinical or radiological tension pneumothorax?  Elevated jugular veins?

It is possible to augment the assessment with Bedside Cardiac Ultrasound
Management

  • If obstructive, treat immediate cause e.g. drain pneumothorax or tamponade
  • If a shocked patient already has signs of pulmonary oedema then fluid should be withheld and pressors considered
  • If the patient has clear evidence of hypovolaemia then fluid resuscitation is justified to restore haemodynamic parameters.  However, there is a role for limited fluid resuscitation and permissive hypotension if the cause is suspected to be active bleeding that requires early intervention to control it
  • If there is uncertainty, a judicious administration of 10m/kg fluid (to a maximum of 30ml/kg) should be trialled.  If no improvement occurs ,then pressors are recommended until more sophisticated means of monitoring are available
  • Treat the underlying cause e.g. antibiotics for sepsis, reperfusion therapy for myocardial infarction

Haemodynamic targets
Roughly are the ones that triggered a response (see above).  Major deviations should be corrected within minutes but as parameters normalise the corrections should be slowed over a period of hours to prevent complications of over-treatment.
*fluid resuscitation should replace like for like i.e. crystalloid for water/electrolyte loss, blood products for bleeding, albumin if protein rich fluid
Situations that may require modified targets
Examples

  • Heart failure
  • Renal failure
  • Diuretic use
  • Sepsis
  • Cor pulmonale

 
 
 

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