How is a patient prepared for anaesthesia?

Initial Assessment

The anaesthetist makes an initial assessment by checking the following:

  • Cardiovascular System
  • Obesity - associated with a higher risk of complications during the operation
  • Respiratory System
  • Airway is checked for ease of intubation.
  • Kidney Function
  • Past Medical History
  • Liver Disease
  • Hepatitis Status
  • HIV Status (if relevant)

The ASA Status (American Society of Anaesthetists scoring system I-IV) is then used to rate the patient's general health.


Most commonly no medication is used, but medication can be given in the following circumstances:

  • Benzodiazepines for the anxious patient
  • H2 receptor antagonists for the prevention of aspiration pneumonitis. The medication is given both the night before and the morning of the operation.
  • Topical local anaesthetic can be used at sites of venous cannulation for children and adults with needle phobias.
  • Anti-cholinergic agents to dry secretions or to prevent bradycardia.
  • Analgesics for pain relief.
  • Oral drugs for effect in the postoperative period.

Pre-operative Factors

  • Most patients are starved for at least four hours before their operation. The aim of this is to decrease the volume of secretions to reduce the risk of aspiration.
  • It is important to monitor the fluid status of children as they are at greater risk of dehydration (they are more susceptible to fluid and heat loss).
  • It is important to correct any electrolyte disturbances.
  • Smoking before the operation is associated with several peri-operative problems such as excessive sputum production, bronchospasm, coughing and increased carbon monoxide in the blood.
  • Obesity is associated with an increase in morbidity and makes every technical procedure more difficult.