clinical monitoring

Last reviewed 01/2018

Clinical monitoring of the depth of anaesthesia relies on the presence of autonomic reflexes:

• ophthalmic:
• pupil size, reducing with increasing depth, but may dilate in very deep anaesthesia
• opioids and anticholinergics alter pupil size by a central action and so make this index less valid
• cardiovascular:
• the trend in heart rate and arterial blood pressure is followed
• it may be modified by drugs, haemorrhage and body fluid abnormalities
• respiratory:
• the trend in rate, depth and rhythmicity of breathing
• effect of ventilation
• hiccuping or bronchospasm may indicate light anaesthesia
• skin:
• sweating can be a sign of light anaesthesia; reduced by anticholinergic agents
• colour; good perfusion indicated by pink hue
• capillary refill time; an indirect index of tissue perfusion
• temperature; particularly important in infants