Anesthesia Basics

The Different Types of Anesthesia

There are four types of anesthesia: general anesthesia, regional anesthesia, local anethesia, and sedation. 

General Anesthesia is when the patient is fully unconscious and has no awareness. In order to administer this type of anesthesia, anesthetic gases or vapors are given through a breathing tube/mask. Medications can also be given through IV lines to induce sleep, relax the patient's  muscles, and/or treat pain. 

Regional Anesthesia makes part of the body numb. The anesthesiologist injects the anesthesia near the nerves that provide sensation to that area. The patient is normally awake during this type of anesthesia. 

Local Anesthesia is usually injected through a needle or applied as a cream to numb a small area. It is generally used as pain relief. 

Sedation is when medications are given through an intravenous line (IV) to make patients feel drowsy or relaxed. There are three different types of sedation. 

• • Mild Sedation: This is when the patient is awake and can respond to questions or instructions.

  • Moderate Sedation: This is when the patient may doze off, but can be awakened easily. 

  • Deep Sedation: This type of sedation is in between moderate sedation and general anesthesia. 

The Different Stages of Anesthesia

There are usually four stages of general anesthesia: induction, excitement/delirium, surgical anesthesia, and overdose. 

The first stage of anesthesia is induction. This stage lasts from when you first take the medication until you go to sleep. You're calm and able to talk for a while, and your breathing is slow, but regular. You also lose the ability to feel pain. 

The second of anesthesia is delirium or excitement. During this stage, you might have uncontrolled movements, fast heartbeat, irregular breathing, and you might vomit, which could cause choking. This is usually the most dangerous stage. 

The third stage of anesthesia is surgical anesthesia. This is when your eyes stop moving, your muscles fully relax, and you would stop breathing without the help of machines. Surgery can happen at this stage. 

The fourth stage of anesthesia is overdose. This stage happens when too much anesthesia is adminstered, causing the brain to stop telling your heart to beat and your lungs to work. This stage of anesthesia is fatal, but extremely rare with modern technology. 

Types of Anesthetic Drugs

There are three different types of drugs used for anesthesia: analegesics (pain relievers), anxiolgtics (sedatives), or paralytics (muscle relaxtants).

Analgesics or pain relievers are medications that help to relieve pain. Analegesics are divided into three subcatergories depending on how they are administered. 

• Acetaminophen (Tylenol): This type of analegesic is usually given as a pill or injectewd into the bloodstream through an IV. It is commonly used in post-operation settings with narcotic analegesics. 

• Non-steroidal Anti-inflammatory (NSAID): This type of analegesic helps with post-operation pain and is usually given through an IV line or an intramuscular injection. NSAIDs are not commonly used because they increase the risk of bleeding following certain procedures. 

• Narcotics: These analegesics are very potent pain relievers, adminstered through IV lines, oral methods, or transdermal methods. Common narcotics include morphine, fentanyl, hydromorphone, merperidine, and oxycodone, all of which are safe if taken in small doses.  These drugs are usually administered during the operation and post-operation. The patient must be monitiored carefully when given narcotics because they can reduce the drive to breathe. 

Anxiolgtics or sedatives are medications that help to relax or alleviate anxiety and relav the body. Higher doses of anxiolgtics can induce sleep, and cause anterograde amnesia for a few hours. Anxiolgtics are given post-operation and through an IV line, orally through a liquid, or through the nose using a spray. 

Paralytics or muscle relaxtants induce complete relaxation of the muscles and help to facilitate intubations and surgery. They are only given to patients that are fully unconscious and in a monitored setting. At the end of surgery, reversal drugs are administered to undo the effects of the paralytics. 

Anesthesia Delievery Methods

How anesthesia is administered depends on what type of anesthesia you are recieving. 

Local anesthesia is only used for minor surgeries, when the anesthesiologist injects the medication into the area they will be operating on. 

Regional anesthesia is usually used for childbirth or after abdominal or chest surgery. It may also be used as the main anesthetic in abdominal or leg surgery. In order to administer regional anesthesia, local anesthesia is first injected, and then regional anesthesia is injected. 

General anesthesia is used for major surgeries, where you must be unconsious. The medicine amy be inhaled through a breathing mask/tube or injected into the bloodstream through an IV line.