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GENERAL ANESTHESIA

2.3.1 Definition Anesthesia means a state with no pain. General anesthesia is a condition characterized by loss of perception of all sensations due to drug induction. In this case, in addition to the loss of pain, consciousness is also lost. General anesthetics consist of a heterogeneous group of chemical compounds which reversibly depress the CNS with nearly the same spectrum and can be controlled. General anesthetic drugs can be administered by inhalation and intravenously. General anesthetic drugs given by inhalation (volatile gases and liquids), the most important of which are N2O, halothane, enflurane, methoxyflurane, and isoflurane. General anesthetic drugs used intravenously, namely thiobarbiturates, narcotic-analgesics, other alkaloid compounds and similar molecules, and some special drugs such as ketamine. To determine the prognosis, the ASA (American Society of Anesthesiologists) makes a classification based on the pre-anesthesia patient's physical status which divides the patient into 5 groups or categories as follows:  ASA 1, namely the patient is in good health who requires surgery.  ASA 2, namely patients with mild to moderate systemic abnormalities either due to surgical disease or other diseases. For example, patients with ureteral stones with hypertension being controlled, or patients with acute appendicitis with leukocytosis and fever.  ASA 3, namely patients with severe systemic disorders or diseases caused by various causes. For example, patients with perforated appendicitis with septicemia, or patients with obstructive ileus with myocardial ischemia.  ASA 4, namely patients with severe systemic disorders that directly threaten their lives.  ASA 5, namely patients with severe systemic disorders who are no longer able to be helped, whether operated on or not within 24 hours the patient will die. Examples are elderly patients with cranial base hemorrhage and hemorrhagic shock due to hepatic rupture. The ASA classification is also used in emergency surgery by including an emergency sign (E = emergency), for example ASA 1 E.

2. Pre-surgical assessment 1) Anamnesis A history of whether the patient has received anesthesia before is very important to find out if there are things that need special attention, such as allergies, nausea, vomiting, muscle pain, itching, or shortness of breath after surgery so that the next anesthesia can be planned properly. Some researchers recommend that drugs that have caused problems in the past should not be reused, for example halothane should not be reused within 3 months or succinylcholine which causes prolonged apnea also should not be repeated. Smoking habits should be stopped 1-2 days before. 2) Physical examination Examination of the teeth, opening the mouth, or a relatively large tongue is very important to know whether it will complicate laryngoscopy intubation. A short, stiff neck will also complicate laryngoscopy intubation. Routine systemic examination of the general state of course should not be missed such as inspection, palpation, percussion and auscultation of all the patient's organ systems. 3) Laboratory examination Laboratory tests are carried out for appropriate indications according to suspected disease. Examinations performed included blood tests (Hb, leukocytes, bleeding time, and clotting period) and urinalysis. At the age of patients over 50 years there is a recommendation for an EKG and chest photo. 4) Fitness for anesthesia The classification commonly used to assess a person's physical fitness is originating from The American Society of Anesthesiologists (ASA). This physical classification is not a tool for estimating anesthetic risk because side effects of anesthesia cannot be separated from side effects of surgery.  Class I: Organic, physiological, psychiatric, biochemical healthy patients.  Class II: Patients with mild or moderate systemic disease.  Class III: Patients with severe systemic disease limiting routine activities.  Class IV: The patient with severe systemic disease is unable to carry out routine activities and the disease poses an imminent threat to life.

 Class V: Patients with severe systemic disease who can no longer be helped, whether they are operated on or not, will die within 24 hours.In cito or emergency surgery, the letter E is usually written.

5. Oral input Laryngeal reflexes are decreased during anesthesia. Regurgitation of gastric contents and debris in the airways is a major risk in patients undergoing anesthesia. To minimize this risk, all patients scheduled for elective surgery under anesthesia should abstain from oral intake (fasting) for a specified period prior to induction of anesthesia. In adult patients generally fasting 6-8 hours, small children 4-6 hours, and in infants 3-4 hours. Lean food is allowed 5 hours before induction of anaesthesia. Drink water, sweet tea for up to 3 hours, and for medicinal purposes drink water in limited quantities, 1 hour before induction of anesthesia.

3. Premedication Before the patient is given anesthetic drugs, the next step is donepremedicationnamely the administration of drugs before the induction of anesthesia is given with the aim of facilitating induction, maintenance, and awakening from anesthesia including:

1. Create a sense of comfort for the patient a) Eliminating worry through pre-anesthesia visits, understanding the problems encountered, ensuring the success of the operation. b) Provide calm (sedative). c) Create amnesia. d) Reducing pain (non-narcotic or narcotic analgesics). e) Prevent nausea and vomiting.
2. Facilitate or expedite induction. Administration of sedative or narcotic hypnotics.
3. Reducing the amount of anesthetic drugs. Administration of sedative or narcotic hypnotics.
4. Suppresses unwanted reflexes (vomiting or drooling)
5. Reduces secretion of salivary glands and stomach Administration of the drug subcutaneously will not be effective within 1 hour, intramuscularly must be waited at least 40 minutes. In very emergency cases with

S : scopes - Stethoscope to listen to lung and heart sounds. Laryngoscope select blades or blades ( blades ) according to the age of the patient. The lamp must be bright enough. Q : Tubes - Tracheal tube choose according to age. Age < 5 years without balloon ( cuffed ) and > 5 years with balloons ( cuffed ). A : airways - pharyngeal tube ( guedel , oro-tracheal airway ) or nasal-pharyngeal tube ( naso-tracheal airway ). This pipe is to hold the tongue when the patient is unconscious to keep the tongue from blocking the airway. Q : Tape - Plaster for pipe fixation so that it is not pushed or pulled out. I : Introducer - Mandrin or stylet of wire wrapped in plastic (cable) that easily bends for guides to allow easy insertion of the tracheal tube. C : Connectors - Connection between the pipe and anesthesia equipment. S : Suction - suction mucus, saliva, and others. Types of induction of general anesthesia are: a. Intravenous induction  Most done. Intravenous indications are done carefully, slowly, gently, and under control. The bolus induction drug is injected at a rate of between 30-60 seconds. During induction of anesthesia, the patient's breathing, pulse, and blood pressure should be monitored and oxygen should always be administered. Performed on cooperative patients.  Intravenous induction drugs:  Tiophental (pentothal, tiophenton) preparationampoules of 500 mg or 1000 mg. Before use it is dissolved in sterile distilled water to a concentration of 2.5% (1 ml = 25 mg). Only used for intravenous at a dose of 3-7 mg/kg injected slowly spent in 30-60 seconds. Depending on the dose and rate of injection, tiophental will cause the patient to be in a state of sedation, hypnosis, anesthesia or respiratory depression. Tiophental reduces cerebral blood flow, liquor pressure, intracranial pressure, and is thought to protect the brain from O2 deficiency. Low doses are anti-analgesic. Contra indication:

1. Children under 4 years

2. Shock, anemia, uremia and debilitated patients
3. Respiratory disorders: asthma, shortness of breath, mouth and respiratory tract infections
4. Heart disease
5. Liver disease
6. Patients who are too fat so it is difficult to find a good vein. b. Intramuscular induction Until now, only ketamine (ketalar) can be administered intramuscularly at a dose of 5- mg/kg and after 3-5 minutes the patient is asleep. c. Inhalation Induction  N2O(laughing gas, laughing gas, nitrous oxide, nitrous oxide) It is a gas, colorless, has a sweet odor, is non-irritating, non-flammable, and weighs 1.5 times the weight of air. Administration must be accompanied by at least 25% O2. It is a weak anesthetic and strong analgesic, so it is often used to reduce pain before childbirth. Inhalation anesthetics are rarely used alone, often in combination with one of the other anesthetic fluids such as halothane.  Halothane (fluothane) Also as an induction for laryngoscope intubation, provided that the anesthesia is deep enough, stable, and before the action is given an analgesic spray of 4% or 10% lidocaine around the pharynx-larynx. Halothane induction requires an O2 boost gas or a mixture of N2O and O2. Induction begins with O2 flow > 4 ltr/min or a mixture of N2O:O2 = 3:1. Flow > 4 ltr/min. If the patient coughs, the concentration of halothane is lowered, then when it is calm, it is increased again until the concentration is needed. Overdosage can cause respiratory depression, decreased sympathetic tone, hypotension, bradycardia, peripheral vasodilation, vasomotor depression, myocardial depression, and inhibition of baroreceptor reflexes. It is a weak analgesic but a strong anesthetic. Halothane inhibits the release of insulin thereby increasing blood sugar levels.  Enflurane

Physical damage that can occur as a complication of anesthesia include: blood vessels, intubation, and superficial nerves.

2. Blood vessel Technical errors in venipuncture can cause bruising, drug exavation which can cause overlying skin ulceration, local infection, thrombophlebitis and damage to adjacent structures, especially arteries and nerves. Several drugs including Benzodiazepines and Propanidide cause thrombophlebitis. Prolonged venous cannulation is more likely to cause thrombophlebitis and infection. 3. Intubation Damage often occurs to the lips and gums as a result of tracheal intubation by an inexperienced person. Tooth decay will be more serious if accompanied by the possibility of inhalation of fragments followed by a lung abscess. If left undetected, nasotracheal intubation can cause unpleasant epistaxis and sometimes a tube can form a passage under the nasal mucosa; nasal intubation often fractures the concha. Damage to the tonsillar and larynx structures (especially the vocal cords) is fortunately common, but the rough handling of the posterior oral structures contributes to postoperative sore throat. 4. Superficial Nerve Continuous direct pressure will damage the nerves, such as the lateral popliteal as it surrounds the head of the fibulae, which causes " foot drop ”, facial when it crosses the mandible, which paralyzes the facial muscles, ulnar when it crosses the medial epicondyle, which causes paralysis and loss of sensation in the hand and the radial nerve as it circles the humerus posteriorly, which causes “wrist drop”. The brachial plexus can be damaged by stretching it over the humeral head if the arm is abducted or externally rotated too far. 5. Respiratory Respiratory complications that may arise include undetected hypoxaemia, atelectasis, bronchitis, bronchopneumonia, lobar pneumonia, hypostatic pulmonary congestion, pneumonia, and superinfection. Respiratory failure is primarily a postoperative phenomenon, usually due to a combination of events. Muscle weakness after recovery from inadequate relaxants,

central depression with opioids and anesthetics, inhibition of cough and inadequate alveolar ventilation secondary to wound pain combine to causeRestrictive respiratory failure with CO2 retention and later CO2 narcosis, especially if PO2 is maintained with oxygen administration.

6. Cardiovascular Cardiovascular complications that can occur include hypotension, hypertension, cardiac arrhythmias, and heart failure. Hypotension is defined as systolic blood pressure less than 70 mmHg or a decrease of more than 25% from the previous value. Hypotension can be caused by hypovolemia caused by bleeding, anesthetic drug overdose, cardiovascular disease such as myocardial infarction, arrhythmia, hypertension, and drug-induced hypersensitivity reactions, muscle relaxants, and transfusion reactions. 7. Heart The cause of postoperative hepatitis can be caused by halothane. The incidence of active Hepatitis A virus in the general population is probably much more prevalent, estimated to be around 100–400 per million at any one time. Repeated Halothan anaesthesia at 6 week intervals should probably be avoided. 8. Body temperature As a result of peripheral venodilation that is still elicited by anesthesia, it causes a decrease in core body temperature. During prolonged surgery, especially with exposed vesera, severe hypothermia may occur, resulting in delayed return of consciousness, breathing and inadequate peripheral perfusion. Respiratory problems will be complicated, if the need for oxygen increases as a result of shivering during the postoperative period.