The Risks of Anaesthesia

Please inform your anaesthetist if a complication persists for more than 48 hours.


Common Complications

(1 to 10% of cases)
Minimal treatment usually

  • Nausea and Vomiting
  • Sore Throat
  • Shivering/Feeling cold
  • Headache
  • Dizziness
  • Itching
  • Pain during injection of drugs
  • Swelling/bruising at the infusion site
  • Confusion
  • Memory Loss

Rare Complications

(Less than 1 in a 1000 cases)

  • Injury: teeth, mouth, tongue
  • Painful muscles
  • Difficulty urinating
  • Difficult breathing
  • Visual disturbances
  • Worsening underlying medical condition
  • Hoarse voice, vocal cord injuries
  • Pressure related injuries

Very Rare Complications

(1 in 10 000 – 200 000 cases)

Often serious, long term damage

  • Eye injuries

  • Nerve injuries causing paralysis

  • Lung infection

  • Awareness of the operation

  • Bleeding

  • Stroke

  • Allergic reaction/ Anaphylaxis

  • Unexpected reaction to drugs

  • Inherited reactions to drugs (Malignant hyperthermia,

  • Choline Apnoea, Porphyria)


Brain Damage or Death

(Less than 1 in 250 000 cases)

  • Due to other complications getting more severe
  • Heart attacks
  • Emboli (Clots)
  • Lack of oxygen

Complications related to Upper or Lower Limb Block (Regional anaesthesia)


Common Complications

  • Motor Block
  • Horners Syndrome
  • Failed Block

Rare Complications

  • Haematoma
  • Local discomfort

Very Rare Complications

  • Intravenous administration
  • Pneumothorax
  • Spinal or epidural
  • Sepsis
  • Nerve damage

Complications arising from PROCEDURES that may be performed during your anaesthetic

Intravenous line

Pain, swelling, bleeding, inflammation, infection, clots, repeated insertions

Central line

Pain, swelling, bleeding, inflammation, infection, repeated insertions, puncture of lungs, artery or nerve roots.

Arterial Line

Pain, swelling, bleeding, inflammation, infection, repeated insertions, loss of blood flow to the hand leading to the death of fingers/ toes.

Airway Management

Damage to teeth, lips, tongue, palate, throat, vocal cords, hoarseness, inhalation of stomach contents, pneumonia, obstruction of breathing failure to maintain the airway requiring an operative procedure.

Complications related to EPIDURAL/ SPINAL anaesthesia


Common Side Effects

  • Pain and bruising where the epidural was inserted
  • Nausea, vomiting, itching, shivering
  • Temporary difficulty in passing urine – this may require a urine catheter
  • Temporary leg weakness
  • Insufficient pain control that may need more medication, removing of the epidural, repeat insertion of epidural or extra intravenous medication (1 in 7 patients)

Uncommon Side Effects

  • A significant drop in blood pressure (1 in 50 patients)
  • Severe headache (1 in 100 patients) requiring a blood patch (an epidural insertion with a transfusion of your own blood into the epidural space)

Rare Side Effects

  • Temporary nerve damage, lasting less than 6 months — leg weakness or a numb patch on your foot or leg (1 in 24 000 patients)
  • Higher than the expected spread of medication which can affect breathing muscles (1 in 13 000 patients)

Very Rare Side Effects

  •  Epidural abscess (1 in 50 000 patients)
  • Meningitis (1 in 100 000 patients)
  • Accidental unconsciousness (1 in 100 000 patients)
  • Blood clot with spinal cord damage (1 in 170 000) requiring surgical removal
  • Permanent nerve damage with possible paralysis (1 in 80 000 patients to 1 in 250 000 patients)
  • Equipment failure (e.g. breakage of needles/ catheters requiring surgery to remove them)
  • Toxicity of medication/Allergic reactions/ Seizures/ Cardiac Arrest/ Death