Proper anesthesia not only prevents patients from feeling pain during a procedure but also provides an amnesic affect. According to the SurgeryEncyclopedia.com, general anesthesia induces unconsciousness, prevents pain sensation and paralyzes the body. There are many types of general anesthesia and they can be given either intravenously or inhaled as gases (see Reference 1).
Inhalation Anesthetics
Inhalation anesthetics are delivered to the system by inhaling anesthetic gases mixed with oxygen, according to SurgeryEncyclopedia.com. Gases are often used in conjunction with intravenous medications as well as opioid or narcotics for pain control. Halothane is a gas that produces unconsciousness but provides little pain control. It may have toxic effects on adult livers and cause liver necrosis (see Reference 1). Enflurane produces a rapid onset of anesthesia and is not toxic to the liver. Kidney failure is a contraindication to use. Sevoflurane is easy to administer through a mask, as it does not irritate the airway, but its byproducts can cause kidney damage. Desflurane can increase the heart rate, but its advantage is a rapid awakening with few adverse effects (see Reference 1).
Intravenous Anesthetics
Propofol, thiopental, etomidate and methohexital are medications that are pushed through an intravenous line. Propofol is a hypnotic anesthetic that works quickly to induce anesthesia, according to RxList.com. Propofol is a favored intravenous anesthetic because of its rapid induction of anesthesia and the ability to reverse the anesthetic affect when surgery is complete. According to RxList.com thiopental is used as an adjunct intravenous medication when other anesthetics are used. It can be used alone for brief procedures lasting less than 15 minutes. When used for general anesthetic, patients must be monitored for low blood pressure and a decrease in cerebral blood flow according to "The Washington Manual of Surgery". Methohexital can be used as an induction agent prior to the use of other anesthetic agents (see Reference 4). Intubation is necessary in order to manage the subsequent respiratory arrest that occurs (see Reference 4).
Neuromuscular Blockade
Neuromuscular blockade is required in many procedures, as it facilitates intubation and respiratory ventilation. Succinylcholine is a rapidly acting, rapidly metabolized blockade agent. Malignant hyperthermia is a rare but fatal side effect. Other blockade agents include mivacurium, rocuronium and pancuronium. Many of these agents are derived from curare. Use of these agents is particularly helpful during abdominal surgery when it is necessary to relax the abdominal wall muscles. Neuromuscular blockade can be reversed with the use of neostigmine and edrophonium (see Reference 4).
References
- SurgeryEncyclopedia.com: General Anesthesia
- RxList.com: Propofol
- RxList.com: Thiopental
- "The Washington Manual of Surgery." Mary E. Klingensmith, MD and et al, Editor. 2008
