Anesthesia FAQs: Side Effects, Types, Procedures and More

Modern medicine would not be possible without anesthesia. Early anesthesia can be traced back to ancient times. During the Eastern Han Dynasty, a Traditional Chinese medicine (TCM) physician, Hua Tuo, invented Mafeisan, an oral herbal general anesthetic, for performing surgeries. Although there has been controversy over the existence of Mafeisan and even Hua Tuo in Chinese literature, it has proven that anesthesia has a long history and creates numerous possibilities for different kinds of operations.

What are the Principles of Anesthesia?

You feel pain because your nerves are stimulated and send sensory/pain signals to the centres in the brain. Anesthesia temporarily blocks the transmission of these signals, so you do not feel any pain during the procedure.

Chemical compounds, such as diethyl ether and nitrous oxide, can make people lose their consciousness and become the early form of anesthesia - inhalational anaesthetics. With medical advancement, intravenous anesthetics were developed and applied later on.

Who Administers Anesthesia?

Depending on the complexity of the surgery and your needs, general anesthesia, referring to large-scale operations, will be conducted by an anesthetist. For simpler operations, your surgeon will perform the procedures directly.

How Many Types of Anesthesia Are There?

There are three types of anesthesia categorised by the scale of surgery and the area to be treated. The choice of anesthesia depends on the patients' underlying disease, laboratory findings, general condition, surgery type and duration.

1. General Anesthesia

   General anaesthesia is a state of controlled unconsciousness. During a general anaesthetic, medicines are used to send you to sleep, so you are unaware of surgery and do not move or feel pain while it is performed.

   General anaesthetic can be administered through intubation, inhalation with a face mask, inhalation with a laryngeal mask and injection. Due to muscle relaxation, you will not be able to on your own. A ventilator must be used to provide oxygen to you during the operation. It is common to use in major operations, such as thoracotomy and laparotomy.

2. Local Anesthesia

   Apart from injections, local anesthesia can be administered with topical (applied to skin or eyes) liquid, spray or patch for numbing a small section of the body. It applies to minor operations, including dental procedures and mole removal. You are awake during the course.

3. Regional Anesthesia

   Regional anesthesia is a type of pain management for surgery that numbs a large part of the body. It can be further divided into:

   1. Spinal Anesthesia: Inject anesthetic directly into the cerebrospinal fluid that surrounds the spinal cord.
   2. Epidural Anesthesia: Inject anesthetic into the space between the spinal column and outer membrane of the spinal cord (epidural space) in the middle or lower back.
   3. Peripheral Nerve Blocks: Inject anesthetic near a specific nerve or bundle of nerves to block sensations of pain from a specific area of the body. It is commonly used for surgery on the arms and hands, the legs and feet, or the face.

    

Epidural and spinal blocks are also called half-body anesthesia, mainly using for the lower part of the body. It is usually applied in childbirth, hip surgery and prostate surgery. Whether you have an epidural or a spinal, you will probably also receive sedatives or analgesics intravenously or together with the anesthetic to make you fall asleep.

What Are the Procedures of Anesthesia?

Local anesthesia can be performed directly in the ward, but regional and general anesthesia needs to be undergone in an operating room with the following procedures:

• Deliver the anesthesia medications through an intravenous line in your arm or breathing from a mask.
• During an operation, someone from the anesthesia care team monitors your breathing, temperature, heartbeat, blood pressure, blood oxygen level continuously while you sleep for adjusting the medications.
• As soon as the operation finishes, the anaesthetic drugs will be stopped and you will regain consciousness.

What Does it Feel Like After Anesthesia?

Estimates vary, but about 1 or 2 people in every 1,000 may be partially awake during general anesthesia and experience what is called unintended intraoperative awareness what is called unintended intraoperative awareness. It is even rarer to experience pain.

What Are the Side Effects of Anesthesia?

The side effects associated with general anaesthesia may occur during or after the surgical procedure. However, the actual side effects and risks vary among individuals and patient groups, and most of them are short-term.

The side effects of general anesthesia include:

• Short term confusion or memory loss, more common among the elderly
• Dizziness
• Urination problems
• Bruising or soreness due to the injection of drugs
• Nausea and vomiting
• Trembling and feeling cold
• Sore throat

Does Anesthesia Lower Your Memory?

Whilst there is a known short-term effect of anaesthesia on memory, anesthesia generally does not create permanent memory problems. Prolonged memory, cognitive and focus disruption may be caused if you record abnormally low blood pressure, severe blood loss or insufficient blood oxygen during the surgery. However, this situation is rare.

How to Prepare for Anesthesia?

Before you receive general anesthesia, your anesthesiologist will talk with you and ask questions about your health history, prescription medications, allergies, past experiences with anaesthesia and living habits. Your doctor has to seek your consent before performing anesthesia.

To ensure your safety, you should do the following things as advised by the Hospital Authority:

• Stop smoking for as long as possible
• Stop any herbal medicine for at least two weeks before your operation
• See a dentist for treatment if you have any loose teeth or crowns
• Stop or commence certain types of medication according to the advice of your anesthetist

In order to prevent aspiration of food or liquid into your lungs during anaesthesia, you should not eat for at least 6 hours before your operation. You can safely drink water until 2 hours before the procedure.

What You Need to Know After Anesthesia

Apart from the aforementioned side effects, some patients may experience pain at the wound or injection site. Your doctors will prescribe pain-relieving drugs for you according to your conditions.

Does Anesthesia Have Any Complications?

In general, modern anesthesia is safe, and the risk of death directly associated with general anesthesia itself is minimal. According to the statistics from the Hospital Authority, the occurrence of serious complications, such as stroke, serious allergy to drugs, heart attack and nerve damage, is 1 in 10,000, while the possibility of death is 0.000061%.

Complications may occur despite all precautions, mainly depending on patient conditions and surgeries undergone but not receiving anesthesia.