Hypotension - Guidelines for Crises in Anaesthesia



Hypotension is commonly due to unnecessarily deep anaesthesia, the autonomic effects of neuraxial block, hypovolaemia or combined causes.

You should rapidly exclude a problem in adequate oxygen delivery, airway and breathing first.



❶ Adequate oxygen delivery

 • Pause surgery if possible.

 • Increase fresh gas flow AND give 100% oxygen AND check measured FiO2.

 • Visual inspection of entire breathing system including valves and connections.

 • Rapidly confirm reservoir bag moving OR ventilator bellows moving.

❷ Airway

 • Check position of airway device and listen for noise (including larynx and stomach).

 • Check capnogram shape compatible with patent airway.

 • Check airway AND airway device are patent (consider passing suction catheter).

❸ Breathing

 • Check chest symmetry, rate, breath sounds, SpO2, measured VTexp, ETCO2.

 • Feel the airway pressure using reservoir bag and APL valve <3 breaths.

 • Exclude high intrathoracic pressure as a cause.

❹ Circulation

 • Check heart rate, rhythm, perfusion, recheck blood pressure.

 • If heart rate <60 bpm consider giving anticholinergic drug (Box B).

 • Consider giving vasopressor (Box C) and positioning (e.g. move head down).

 • Consider fluid boluses (250 ml adult, 10 ml.kg-1 paediatric).

 • If heart rate >100 bpm sinus rhythm, treat as hypovolaemia: give i.v fluid bolus.

 • If heart rate >100 bpm and non-sinus → 2-7 Tachycardia.

❺ Depth

 • Ensure correct depth of anaesthesia AND analgesia (consider risk of awareness).

❻ Exclude potential surgical causes (Box D) – discuss with surgical team.

❼ Consider causes in Box E and call for help if problem not resolving quickly.



DON’T FORGET!

• Consider whether you could have made a drug error.

• Pneumothorax and/or high intrathoracic pressure can cause hypotension.

• Also consider:

  o Cardiac ischaemia → 3-12

  o Anaphylaxis → 3-1

  o Cardiac tamponade → 3-9

  o Local anaesthetic toxicity → 3-10

  o Sepsis → 3-14

  o Cardiac valvular problem

  o Endocrine cause (eg steroid dependency)



By Association of Anaesthetists @ https://twitter.com/AAGBI

Quick Reference Handbook - Guidelines for crises in anaesthesia 



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