Difference between Local and General Anesthesia

March 22, 2017 by Editorial Team

Anesthesia is a temporary way to relax a patient and block pain during medical procedures. The two most common types of anesthesia are local and general anesthesia. What is the difference between the two? This article will discuss the uses of and the difference between local and general anesthesia.

Descriptions

Local vs General Anesthesia
Local anesthesia is done before minor dental surgeries

Local anesthesia is a type of anesthesia that blocks the transmission of nerve impulses to and from a specific area of the body. It does not cause the patient to be unconscious but it can create a numbing sensation in the area where the anesthetic drug is applied and where the surgery is performed.

Local anesthesia can be done by directly applying an anesthetic drug into the site. The anesthetic drug can be in different forms:

  • Topical – the anesthetic drug can be applied directly to the skin or membrane. It can be in a form of a gel, spray, cream, or ointment. It is used for minor procedures in the mouth, ears, nose, eyes, sexual organs, etc.
  • Injection – the anesthetic drug is usually not injected into the bloodstream but into the muscles.

Local anesthesia may be paired with the administration of sedatives to make the patient feel relaxed, less anxious, or even fall asleep during a minor operation or surgery. If the patient does fall asleep, the automatic body functions such as breathing, heartbeat, and blood pressure are still active.

The effect of the anesthetic drug in local anesthesia wears off after a few hours. It is normally used for outpatient procedures where the patient is allowed to go home the same day. Common examples of local anesthesia are done in minor dental procedures (the local anesthetic is injected into the gums) and eye surgery (the local anesthetic is in the form of eye drops).

Local anesthesia is generally safe, having only a few known side effects. However, when administered in high doses, local anesthetics can cause system toxicity. This may affect the patient’s heart rate, breathing, and even brain function.

General anesthesia
General anesthesia administered by anesthetic vapors

General anesthesia, on the other hand, is a type of anesthesia that makes the patient fall into a state of unconsciousness. The body and brain are “asleep” so the patient has no awareness, feelings, or memory of the events while in anesthesia.

General anesthesia can be administered in different forms:

  • Intravenous injection – this involves sticking a needle into a vein and injecting the anesthetic drug.
  • Gas – vapors or gases are inhaled by the patient through a breathing mask or tube.

Since the patient’s body is completely asleep, the body’s automatic functions are suppressed. This is why the patient is usually intubated when under general anesthesia. This involves inserting a flexible tube into the windpipe to help the patient breathe. An anesthesiologist should be present all throughout the medical procedure to monitor the patient’s vital functions (blood pressure, breathing, heartbeat) and should determine if additional doses of anesthetic drugs are needed or not. Upon recovery, the breathing apparatus will be removed.

General anesthesia is done in medical procedures that can be unbearably painful for the patient or if the patient needs to be asleep for the procedure. It is usually done in abdominal, thoracic, and brain surgeries.

Upon awakening, the patient may be disoriented, confused, and his throat may be slightly sore because of the tube. It may take a few hours for the effects of the anesthetic drugs to fade. General anesthesia may cause forgetfulness, nausea, and headaches.

Local vs General Anesthesia

What, then, is the difference between local and general anesthesia?

Local anesthesia simply causes a sensation of numbness in the surgical site. It is usually done for minor surgeries where the patient can go home right after the procedure. On the contrary, general anesthesia causes the patient fall into a state of unconsciousness. It is done in major surgeries that are too painful for the patient or if the patient needs to be asleep during the procedure.

Both local and general anesthesia can be applied through injections. However, local anesthesia can also be done by applying anesthetic spray, gel, cream, or ointment to the specific area of the body, whereas general anesthesia can be done by administering anesthetic vapors or gas to the patient.

In local anesthesia, the patient may be administered sedative drugs to make him fall asleep or to help the patient feel relaxed and less anxious. If the patient does fall asleep, the body functions are still active. On the other hand, the automatic body functions are suppressed in general anesthesia. The brain and the body are both asleep, therefore a breathing apparatus must be inserted into the windpipe to help the patient breathe properly.

Local anesthesia has a few known side effects. When administered in high doses, it may cause system toxicity. Conversely, general anesthesia may cause confusion, disorientation, a mild sore throat, forgetfulness, nausea, and headaches.

Comparison Chart

Local AnesthesiaGeneral Anesthesia
A type of anesthesia that blocks the transmission of nerve impulses to and from a specific area of the body; does not cause the patient to be unconsciousA type of anesthesia that makes the patient fall into the state of unconsciousness
Can be done by directly applying an anesthetic drug to the site; can be in the form of a topical spray, liquid, gel, cream, or ointmentCan be done by an intravenous injection of anesthetic drugs or by having the patient inhale anesthetic vapors (or a combination of the two)
May be paired with the administration of sedatives to make the patient feel relaxed, less anxious, or even fall asleep during a minor operation or surgery; if the patient falls asleep, the automatic body functions are still active; patient does not need any breathing apparatusThe body’s automatic functions are suppressed; the patient may need an intubator to help him breathe; the anesthesiologist should be present throughout the procedure to monitor the patient’s vital functions and determine if additional doses are needed
Normally used for outpatient procedures where the patient is allowed to go home the same day; usually for minor dental procedures (the local anesthetic is injected into the gums) and minor eye surgery (the local anesthetic is in the form of eye drops)Used for medical procedures that can be unbearably painful for the patient; also used if the patient needs to be asleep for the procedure; usually for abdominal, thoracic, and brain surgeries
Can cause system toxicity when local anesthetics are administered in high doses; may affect the patient’s heart rate, breathing, and brain functionMay cause confusion, disorientation, a mild sore throat, forgetfulness, nausea, and headaches