Categories of Anesthesia: Overview and Common Procedures

November 17, 2020

Anesthesia is a critical requirement of many different medical procedures and allows patients to undergo important operations without experiencing distress or pain. There are four broad categories of anesthesia: general anesthesia, regional anesthesia, local anesthesia and sedation.2 Physicians may elect to use one type or a combination of different types of anesthetics. Depending on the specific procedure being performed, the desired effects may include loss of awareness, muscle relaxation, autonomic regulation and analgesia.1  

General anesthesia results in a total loss of consciousness, awareness and sensation. 2 The medications used to produce this state are administered either intravenously or via gases or vapors.2 This category of anesthesia is commonly used during major surgeries such as heart surgeries and organ transplants. Anesthesia professionals often use a technique called “balanced anesthesia”, administering controlled quantities of different neurological depressants such as analgesics and inhalational anesthetics.3,4 By tailoring mixtures of different neurological agents to specific patients, providers are able to achieve the desired effect while minimizing risk to patient safety.3 

Regional anesthetics are injected near specific clusters of nerves, inhibiting pain signals in a specific area of the body while the patient remains conscious and awake. The major types of regional anesthetics are peripheral nerve blocks, epidural anesthetics and spinal anesthetics.5 Spinal and epidural anesthetics are injected into the spinal subarachnoid or epidural space and have the effect of blocking sensations from large areas of the body during procedures involving the lower abdomen, the hips, or the legs. Peripheral nerve blocks block pain sensations in a more localized region.6 The most common types are brachial plexus blocks and femoral nerve blocks, administered during surgery on the arms and legs, respectively.6 

Sedation, another one of the multiple anesthesia categories, generally involved intravenous medication administration and is commonly used during procedures that do not require the powerful effects of general anesthesia but require sedative effects that are not produced by regional anesthesia alone. 2,7 Depending on the specific procedure, anesthesia providers may control the level of sedation experienced by the patient. Light sedation causes drowsiness but allows the patient to communicate and follow directions whereas during deep sedation, the patient will remain conscious but asleep and will likely have no recollection of the procedure.7 The most common operations that utilize sedation are eye surgery, dental procedures, endoscopies, bronchoscopies, and colonoscopies.2,8 

The final of the main anesthesia categories is local anesthesia, which is generally used during minor outpatient procedures. Lidocaine is the most widely used local anesthetic and is delivered via injection to provide pain relief in a small area of the body.2 Certain dental procedures, suturing, skin biopsies and breast biopsies often will only require local anesthesia.9 

Over the past several decades, anesthesia has become remarkably safe as the field learns more about how to select the correct anesthetic, or combination of anesthetics, to correspond to both the procedure being conducted as well as to the specific patient being treated. Each category of anesthesia serves an important role in allowing physicians to perform surgical procedures while preventing patients from feeling discomfort or pain.  

References 

  1. Weatherspoon D. General anesthesia: Side effects, risks, and stages. www.medicalnewstoday.com. Published January 5, 2018. https://www.medicalnewstoday.com/articles/265592 
  1. General anesthesia – sedation – UCLA Anesthesiology & Perioperative Medicine – UCLA Health, Los Angeles, CA. www.uclahealth.org. https://www.uclahealth.org/anes/types-of-anesthesia 
  1. Brown EN, Pavone KJ, Naranjo M. Multimodal General Anesthesia: Theory and Practice. Anesth Analg. 2018;127(5):1246-1258. doi:10.1213/ANE.0000000000003668 
  1. ‌Types of Anesthesia. Canadian Association of General Surgeons. https://cags-accg.ca/patient-care/types-of-anesthesia/ 
  1. ‌Torpy JM, Lynm C, Golub RM. JAMA patient page. Regional anesthesia. JAMA. 2011;306(7):781. doi:10.1001/jama.306.7.781 
  1. Peripheral Nerve Blocks for Anesthesia. MyHealth.Alberta.ca Network. Published August 22, 2019. https://myhealth.alberta.ca/Health/pages/conditions.aspx 
  1. IV Sedation: Definition & Effects. American Society of Anesthesiologists, Pain Management & Surgery. https://www.asahq.org/madeforthismoment/anesthesia-101/types-of-anesthesia/ivmonitored-sedation/ 
  1. ‌‌Procedural Sedation. Hopkins Medicine. https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/procedural-sedation 
  1. ‌Local Anesthesia: Definition & Effects. American Society of Anesthesiologists, Pain Management & Surgery. https://www.asahq.org/madeforthismoment/anesthesia-101/types-of-anesthesia/local-anesthesia/ 

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