anesthesiaoverview课件

Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,ANESTHESIA:OVERVIEW,Anesthesia is the use of medications and close monitoring to provide comfort and maintain vital life functions during surgery or other medical procedures.,Anesthesia is concerned not only with the administration of anesthesia for surgery but also with many other areas of patient care,including critical care medicine,management of chronic pain,and respiratory therapy.,Anesthesia:reversible,drug-induced,loss of sensation,in the,entire,body or in a,part,of it,Local anesthetic agents:agents that,block sensory and,motor nerve conduction,to produce temporary loss of,sensation without a loss of consciousness,General anesthetics:,CNS depressants,with action that can,be induced and terminated more rapidly than sedative hypnotics,Preanesthetic medication:may include sedatives,opioids,tranquilizers and anticholinergic agents,What determines the type of anesthesia used?,Your medical history.,The results of your physical exam.This is done to evaluate your current health and identify any potential risks or complications that may affect your anesthesia care.,The results of tests such as blood tests or an,electrocardiogram,The reason for your surgery and the type of surgery.,.,Physical status classification of the American society of Anestheriologist,class,Physical status,1,Patient has no organic physiologic,biochemical,or psychiatric disturbance,2,Patient has mild to moderate systemic disturbances that or may not be related to the disorder requiring surgery(eg,essential hypertension,diabetes mellitus),3,Patient has severe systemic disturbances that may or may not be related to the disorder requiring surgery(eg,heart disease that limits activity,poorly controlled essential hypertension),4,Patient has severe systemic disturbance that is lifethreatening with or without surgery(eg,congestive heart failure,persistent angine pectoris),5,Patient is moribund and has little chance for survival,but surgery is to be performed as a last resort(resuscitative effort)(eg,uncontrolled hemorrhage,as from a ruptured abdominal aneurysm),E,Patient requires emergency operation,Anesthesia is divided into four basic categories:,general,anesthesia,regional,anesthesia,local,anesthesia,sedation,Today we just learn,General anesthesia,There are several drugs and gases that can be combined or used alone to produce general anesthesia.,When anesthetics reach the bloodstream,the drugs that affect the,brain,pass through other blood vessels and organs so they are often affected too.Therefore,patients must be carefully monitored.,General anesthesia is used for more extensive procedures or for procedures that arent amenable to regional anesthesia.The medications used in general anesthesia are given intravenously or by inhalation.The drugs circulate in your bloodstream to all areas of your body,including your brain.It,results in amnesia,paralysis and analgesia.,They can suppress all of your protective reflexes,such as coughing,gagging and even breathing.Consequently,a general anesthetic requires the use of a mask or breathing tube during the surgery.,Inhaled General Anesthetics,Nitrous oxide,Halothane,Enflurane,Isoflurane,Sevoflurane,Desflurane,Xenon,(rarely used),Anesthesia Machine,IV General Anesthetics and Sedative Agents,Thiopental,Methohexital,Propofol,Etomidate,Ketamine,Diazepam,Midazolam,Lorazepam,These drugs quickly reach the brain and their effect is dependent on several factors including the volume in which the drug is distributed in the body,the fat-solubility of the drug,and how quickly the body eliminates the drug.,It is not completely clear exactly how general anesthetics work at a cellular level,but it is speculated that general anesthetics affect the spinal cord(resulting in immobility),the brain-stem reticular activating system(resulting in unconsciousness)and the cerebral cortex(seen as changes in electrical activity on an electroencephalogram).,Four,stages,of Anesthesia and increasing depth of CNS depression,1.,Analgesia:awareness of pain without amnesia,2.Excitement:delirium and excited with amnesia,3.Surgical anesthesia:unconscious,no pain reflexes,regular respiration and BP maintained,4.Medullary depression:severe respiratory and CV,depression;death without CV and respiratory support,STAGE,RESPIRATION,EYES PUPIL,REFLEX,ONE-Analgesia,Regular small volume,Central small,Two-excitement,irregular,Divergent large,Eyelash absent,Three-anesthesia,Plane I,Regular large volume,Central small,Eyelid absent and conjunctival depressed,Plane II,Regular large volume,Central medium,Corneal depressed,Plane III,Regular becoming diaphragmatic,small volume,Central medium,Laryngeal depressed,Plane IV,Irreg diaphragmatic small volume,Central large,Carinal depressed,Four-overdose,apnea,Central full dilatation,Cardiac depressed,Curved(Macintosh),1.The tip of the blade is advance into the space between the base of the tongue a