Hypotension
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.
If problem worsens significantly or a new problem arises, call for help and go back to START of 1-1 Key basic plan.
Glycopyrrolate 5 µg.kg⁻¹ (adult 200–400 µg)
Atropine 5 µg.kg⁻¹ (adult 300–600 µg)
Ephedrine 100 µg.kg⁻¹ (adult 3–12 mg)
Phenylephrine 5 µg.kg⁻¹ (adult 100 µg)
Metaraminol 5 µg.kg⁻¹ (adult 500 µg)
Adrenaline 1 µg.kg⁻¹ (adult 10–100 µg) in emergency only
Decreased venous return (e.g. vena cava compression / pneumoperitoneum)
Blood loss (unrecognised / undeclared / occult)
Vagal reaction to surgical stimulation
Embolism (gas / fat / blood / cement reaction)
Consider whether you could have made a drug error.
Pneumothorax and/or high intrathoracic pressure can cause hypotension.
Also consider:
Cardiac ischaemia → 3-12
Anaphylaxis → 3-1
Cardiac tamponade → 3-9
Local anaesthetic toxicity → 3-10
Sepsis → 3-14
Cardiac valvular problem
Endocrine cause (e.g. steroid dependency)