General Anaesthesia - An overview of the modern miracle
Table of Contents
General Anaesthesia Definition
The word “anaesthesia,” is comprised of two Greek words: "an" which means "without" and "aesthesis" which means "sensation".
General anaesthesia is a medically induced state of controlled unconsciousness in which a patient will not be arousable to a painful stimulus allowing surgery to be possible.
During a general anaesthetic, medications that are used to render you unconscious also impair other aspects of the bodies function. Commonly there is impairment of the ventilatory function, circulation and neuromuscular function. Cardiovascular function may be impaired.
Indications for General Anaesthesia
There are many surgical procedures today that have only been made possible due to the implementation of a general anaesthetic.
Surgical procedures that may require a general anaesthetic:
- muscle relaxation medications required the surgical procedure
- Regional anaesthesia is not possible for a particular surgery
- Surgery to take considerable time
- Significant blood loss expected
Patient factors that may require a General Anaesthetic:
The patient requires airway protection during the procedure
Patient unable to cope or unwilling for regional anaesthesia
General Anaesthesia Drugs
General anaesthetic medications can be divided into either intravenous or inhalational anaesthetic agents.
Intravenous Anaesthetic agents
Intravenous anaesthetics may be used solely for the anaesthetic or may be used at the commencement of anaesthesia prior to an inhalational anaesthetic agent being utilised.
The technique of administering an intravenous anaesthetic agent solely for the duration of the surgery is known as 'Total intravenous anesthesia' (TIVA). As it uses the intravenous route solely, no inhalational anaesthetic agent is required.
There are certain patient factors or surgery factors where TIVA is more suitable than the use of inhalational anaesthetic agents. Some indications for TIVA are as follows:
- Malignant hyperthermia risk
- History of severe postoperative nausea and vomiting
- Ear, nose and throat surgery or thoracic surgery requiring no endotracheal tube.
- Neurosurgery—to limit intracranial volume .
- Surgery requiring neurophysiological monitoring .
- Myasthenia gravis/neuromuscular disorders to avoid neuromuscular blocking agents.
- Anaesthesia in non-theatre environments .
- Transfer of anaesthetised patient between environments .
Types of intravenous drugs used for General Anaesthesia
Inhalational Anaesthetic agents
procedures but are more commonly used for induction only.
What are the side effects of General Anaesthesia?
Having a general anaesthetic is a very common occurrence in modern medicine. In the United States alone 60,000 people undergo general anaesthesia each day. Although some risks associated with having general anesthesia can be quite serious, the risks of these serious conditions are very small. In fact, having an anesthetic in Australia is one of the safest places in the world to have general anaesthesia due to the stringent training program for Anaesthetists. In this section, we will discuss the anaesthetic risks of general anaesthesia.
Most patients who have general anesthesia will describe experiencing a sore throat on awakening from general anaesthesia. This is due to an airway device called an endotracheal tube being utilised which sits near the back of the throat and passes through the vocal cords. The risk of developing a sore throat is anywhere from 1 in 2 to 1 in 3 people. People describe their sore throat as ranging from mild to severe and may last from several hours to a few days after surgery.
A sore throat, although uncomfortable, will most likely be not serious and will resolve by itself. To relieve a sore throat, drinking cold fluids and having 'throat lozenges' can be of benefit. If however you have a prolonged sore throat or your ability to speak is impaired you should seek medical advice.