General Anesthesia2019-03-29T18:43:55+08:00

What is General Anesthesia?

General anesthesia is a state of total unconsciousness that is a result of the use of general anesthetic drugs. Several drugs are given to the patient that have different effects with the goal of ensuring unconsciousness, amnesia and analgesia.

Effects of General Anesthesia

The objectives of anesthesia include anesthesia (lack of awareness of surrounding events), akinesia (keeping the patient still to allow surgery to take place), muscle relaxation (to enable access through muscles to bones and body cavities) and autonomic control (to prevent dangerous surges in hemodynamics).

Candidates for General Anesthesia

General anesthesia is ideal for patients who need to undergo more extensive procedures or procedures that are not amenable to regional anesthesia.

Your Consultation

Before the surgery, the anesthetist will interview the patient to determine the best combination and drugs and dosages and the degree of how much monitoring is needed to ensure a safe and effective procedure. The patient will fill out a form where important information such as age, weight, medical history, current medications, previous anesthetics and fasting time are asked. The anesthetist will review this information and will select the proper anesthetics based on it.

The doctor will then assess the patient’s airway, involving inspection of the mouth opening and visualisation of the soft tissues of the pharynx. The doctor will also check the condition of teeth and location of dental crowns and caps, as well as the neck flexibility and head extension. And if an endotracheal tube is indicated and airway management is considered difficult, then alternative placement methods like fiberoptic intubation may be used.

The General Anesthesia Procedure

General anesthesia can either be induced by intravenous (IV) injection or breathing a volatile anesthetic through a facemask (inhalational induction). The effect of anesthesia is faster with an IV injection than with inhalation, taking about 10 to 20 seconds to induce total unconsciousness. With this, there is an advantage of avoiding the excitatory phase of anesthesia, which reduces complications related to induction of anesthesia. The anesthetist may choose inhalational induction when IV access is difficult to obtain, when difficulty maintaining the airway is anticipated, or because of patient preference. The IV induction agents that are commonly used include propofol, sodium thiopental, etomidate and ketamine.


After the procedure, the patient will be given a management plan for post-operative pain relief, which may be in the form of regional analgesia, oral or parenteral medication. Oral pain relief medications are ideal for minor surgical procedures. While moderate levels of pain need the addition of mild opiates such as codeine. But major surgical procedures might require a combination of modalities to confer adequate pain relief.


The major risks with general anesthesia include death, myocardial infarction and stroke. Other less serious complications are nausea or vomiting, sore throat, headache, shivering, and delayed return to normal mental functioning.

General anesthesia can also cause malignant hyperthermia, a rare, inherited muscular condition in which exposure to some (but not all) general anesthetic agents results in acute and potentially lethal temperature rise, hypercarbia, metabolic acidosis, and hyperkalemia.


What are the different types of anesthesia?

Anesthesia can be categorized by the degree to which it suppresses the patient’s consciousness and protective reflexes. Greater amounts of anesthesia are required for larger procedures. From least to most, the levels of anesthesia include local, conscious sedation, regional and general.

What are the advantages of general anesthesia?

First of all, general anesthesia makes no psychological demand of the patient. It allows complete stillness for prolonged periods of time and permits surgery to take place in widely separated areas of the body at the same time. Also, it facilitates complete control of the airway, breathing and circulation. General anesthesia can be adapted easily to procedures of unpredictable duration or extent and it usually can be administered rapidly.

When and why is general anesthesia used?

General anesthesia is a state of total unconsciousness that is a result of the use of general anesthetic drugs. Several drugs are given to the patient that have different effects with the goal of ensuring unconsciousness, amnesia and analgesia.

How safe is general anesthesia?

Nowadays, doctors have a better understanding of how anesthesia affects the individual and can choose from many anesthetic drugs depending on the needs of the patient. It also helps that advances in monitoring equipment have dramatically reduced anesthesia-related complications. Such advances include a device that determines whether a breathing tube placed in your windpipe is properly positioned during general anesthesia. The device also measures whether you are getting enough ventilation during general anesthesia. There are other monitors that keep track of your heart rate, circulation, blood pressure, temperature, body fluid balance and other body functions.

Is it possible to die because of anesthesia?

Death due to anesthesia is most commonly related to surgical factors or pre-existing medical conditions which include major haemorrhage, sepsis, and organ failure (eg. heart, lungs, kidneys, liver). The common causes of death that are directly related to anesthesia include aspiration of stomach contents, suffocation (due to airway management), allergic reactions to anesthesia (specifically and not limited to anti-nausea agents) and other deadly genetic predispositions, human error and equipment failure.

How soon can I return to my normal activities?

After the procedure, you should rest for 24 hours and avoid driving or operating machinery for at least a day.