The practice of anaesthesia has become very safe, but risks remain.

The thought of undergoing general anaesthesia can be a source of great anxiety for many people. General anaesthesia is a medically induced, reversible state of unconsciousness, achieved by using a combination of medications which include pain-killers. These medications work by blocking the signals that pass along your nerves to your brain, rendering you completely unconscious and insensitive to pain during surgery.

“The practice of anaesthesia has become very safe; however, there always remains the risk of complications with any anaesthesia rendered. The risks can be minor or major, and patients with pre-existing heart, lung or kidney problems may have a higher risk of complications,” says Dr Leong Kwok Wah, Consultant, Department of Anaesthesiology, Singapore General Hospital (SGH), a member of the SingHealth​ group.

Factors like smoking, diabetes and obesity may also increase the risk of complications from general anaesthesia. However, not all surgeries require general anaesthesia.

You only need local anaesthesia for surgical procedures such as a root canal treatment or cataract operation. An anaesthetic is used to numb a small surface area of the body and you remain fully awake and pain-free during the surgery. Local anaesthesia lasts a short time.

A larger area of the body is numbed during regional anaesthesia as in the case of a caesarean section or knee or hand surgery. You remain fully conscious but pain-free.

Risk of complications from anaesthesia

General anaesthesia may cause rare complications such as heart attack and stroke, and mental confusion and lung infections in older people and in those with serious medical conditions.

But patients need not be overly anxious as an anaesthetist, a specialist medical doctor with many years of additional training in anaesthesiology, will be present throughout the surgery. “The anaesthetist will monitor your vital signs, such as blood pressure, heart rate and breathing, and ensure that you are safe and comfortable throughout the surgery,” says Dr Leong.

Common side effects of anaesthesia

Common side effects of both general and regional anaesthesia may include:

  • Pain or bruising at site of injections or drips
  • Shivering
  • Dizziness
  • Post-operative nausea and vomiting

Additional side effects of general anaesthesia may include:

  • Sore throat
  • Damage to teeth or dental work
  • Damage to lips or tongue
  • Facial or eyelid abrasions
  • Body aches

Additional side effects of regional anaesthesia may include:

  • Headache
  • Backache
  • Bleeding
  • Infection
  • Prolonged nerve blockade

The minor side effects are usually temporary and disappear in less than 24 hours. Any post-surgical pain is treated with pain relief medications.

Read on for 5 tips to minimize your risk of complications from general anaesthesia.

Ref: S13