口腔颌面外科学：口腔颌面部麻醉

1、General Anesthesia in oral and maxillofacial surgery1What is general anesthesia(GA)? GA is anesthetics-induced reversible suppression on CNS.2What is general anesthesia(GA)?GA has the following manifestations :Essential Components of AnesthesiaA. pain relief (analgesia) B. blocking memory of the pro

2、cedure (amnesia) C. producing unconsciousness (Hypnosis)D. inhibiting normal body reflexes to make surgery safe and easier to perform E. relaxing the muscles of the body3General Anesthesia, Sleep, and Coma. N Engl J Med. 2010 December 30; 363(27): 26382650What is general anesthesia(GA)?GA was absent

3、 until the mid-1800sWilliam Morton administered ether to a patient having a neck tumor removed at the Massachusetts General Hospital, Boston, in October 1846. The discovery of the diethyl ether as GA was the result of a search for means of eliminating a patients pain perception and responses to pain

4、ful stimuli.4 (CH3CH2)2O What is general anesthesia(GA)?Prior to introduction of GALeg amputation5What is general anesthesia(GA)6Robert Liston,1794-1847What is general anesthesia(GA)?Frozen anesthesiaAlcoholBleedingHua Tuo（141208）7Local AnestheticsWhat is general anesthesia(GA)?Safety of GAPeriopera

5、tive Mortality (2010 to 2014) :2,866,141 cases and 944 deaths (33 per 100,000). Anesthesia-related Mortality: 1/13881/85708 1/50000 (in China)8(Whitlock, Feiner et al. 2015)What is general anesthesia(GA)?Development of Anesthesia First noteworthy step in modern anesthesia: 19th century Medical Miles

6、tones - The Past 500 Years The New England Journal of Medicine (2008)9GA in oral and maxillofacial surgery10Indications of oral and maxillofacial surgeryExtractions of decayed teeth that cannot be restored Surgical removal of impacted teeth Extraction of nonvital teeth Preprosthetic surgery to smoot

7、h and contour the alveolar ridge Removal of teeth for orthodontic treatment Removal of root fragments 11GA in oral and maxillofacial surgeryIndications of oral and maxillofacial surgeryRemoval of cysts and tumors Biopsy Treatment of fractures of the mandible or maxilla Surgery to alter the size or s

8、hape of the facial bones Surgery of the temporomandibular joint Reconstructive surgery Cleft lip and cleft palate repairs Salivary gland surgery Surgical implant procedures 12GA in oral and maxillofacial surgeryGA in oral and maxillofacial surgeryCharacteristic 1：Anesthesia and performing surgery in

9、terfere with each other.13GA in oral and maxillofacial surgeryCharacteristic 1：Anesthesia and performing surgery interfere with each other.14Anesthesia for oral and maxillofacial surgeryCharacteristic 2： Its difficult to keep airway unobstructed. The patients Operative site （aspiration pneumonia） Op

10、erator 15Anesthesia for oral and maxillofacial surgeryCharacteristic 2：. 16Anesthesia for oral and maxillofacial surgeryCharacteristic 2：Difficult airwayASA: when sign of inadequate ventilation could not be reversed by mask ventilation or oxygen saturation could not be maintained above 90% or if a t

11、rained Anaesthetist usinig conventional larangoscope takes more than 3 attempts or more than 10 minutes are required to complete tracheal intubation.17GA in oral and maxillofacial surgeryCharacteristic 3：The high proportion of pediatric and old patientsCharacteristic 4：Be associated with more surgic

12、al bleeding1819GA in oral and maxillofacial surgeryCharacteristic 4：Bleeding: 9500mlBlood Transfusion RBC34u，blood plasma 3200ml, Transfusion: 8000mlOthers202122GA in oral and maxillofacial surgeryCharacteristic 5： Respiratory complications are more common during anesthesia recovery period. Monitori

13、ng of SpO2,ECG,Pet-CO2,BP23GA in oral and maxillofacial surgeryNational Board Dental Examination24Methods of GA in oral and maxillofacial surgery25GA in oral and maxillofacial surgeryAnesthetics divide into 2 classesInhalation AnestheticsGasses Usually Halogenated Intravenous AnestheticsInjectionsAn

14、esthetics or induction agents26GA in oral and maxillofacial surgeryAnaesthesias methods Inhalation anesthesia; Intravenous anesthesiaCombined intravenous and inhaled anesthesia (CIIA)Total intravenous anesthesia (TIVA) 27Inhalation anesthesiaThrough airwayMaintenance (most); induction (some)Mechanis

15、m: interact with the brain cell membrane, details are not clear28Inhalation anesthesiaMAC (minimum alveolar concentration) The concentration (at 1atm) required to prevent movement in 50% of subjects following a surgical stimulus. (50%Effect Dose/ED50)Oil-gas partition coefficient Anesthetic potency

16、MACMAC is also an index for depth of anesthesia29How to determine its controllability?Blood-gas partition coefficient (solubility) The lower the blood-gas partition coefficient the easier for the partial pressure in alveolar, blood and brain to get equilibrium the easier to control its concentration

17、 in brain30Physicochemical property (1) oil-gas partition coefficient anesthetic potency (2) blood-gas partition coefficient controllability 31reversereverseMACWhich has the best anesthetic potency?Which takes effect fastest?Molecular weightOil-gasBlood-gasMACnitrous oxide441.40.47105enflurane184981

18、.91.7isoflurane184981.41.15sevoflurane20053.40.652.0desflurane16818.70.426.0 xenon131.31.90.1471ether7465121.9halothane1972242.40.7532Metabolism of inhalation anesthetics Major: eliminated by lungMinor: metabolized in liver metabolic rate, media product and the final productetherN2Ohalothaneenfluran

19、eisofluranesevofluranedesflurane2.1-3.60.00415-202-50.22-30.0233decide toxicityNitrous Oxide (N2O)MAC: 105%, low anesthetic potency, inhalation conc.:50-70% (FiO20.3) , in combination with other agentB/G: 0.47, fastRespiratory system: non-irritant, no injuryCardiovascular system: almost no-depressio

20、n Diffuse hypoxia: inhale 100% O2 5-10minIncrease cavity pressure: forbidden in colon obstruction34EnfluraneProperties：clear colourless volatile anesthesia, pleasant smellMAC 1.7, B/G 1.9, Metabolism 2%Cardiovascular: Myocardial contractility reduced Systemic vascular resistanceBP Sensitivity of myo

21、cardium to catecholamine Respiratory: non-irritant; dose dependent inhibitionMuscle relaxationInduction and maintenance, unavailable in USAPatient with epilepsy history should be avoided35IsofluraneProperties ：clear colourless volatile anesthesia, pungent odorCardiovascular: mild depression of myoca

22、rdial contractilitysystemic vascular resistanceBP little sensitization of myocardium to CatecholamineRespiratory: dose dependent inhibition36SevofluraneProperties ：clear colourless volatile anesthetic; pleasant smellMAC 2% B/G 0.65 (rapid induction in children) Metabolism 2%Cardiovascular: similar t

23、o isofluraneRespiratory: dosedependent inhibition, no irritate to airwayMuscle relaxation: similar to isofluraneBoth Induction and maintenanceDecomposition in soda lime and when temperature rises37DesfluraneProperties: clear colorless volatile anesthesia MAC 6.0-7.25% B/G 0.42 (very rapid onset) Met

24、abolism 0.02%Cardiovascular: similar to isoflurane but no coronary steal Respiratory: no pungent odor but irritantMuscle relaxation: stronger than isofluraneNausea and vomitingSpecial vaporizer, expensive38Halothane39Properties: clear colorless volatile anesthesia; pleasant smellMAC 0.75 B/G 2.4 Met

25、abolism 20 %Cardiovascular: Myocardial contractility reduced Systemic vascular resistanceBP Increase sensitization of myocardium to catecholamineRespiratory: non-irritant; pleasant smell; dilate bronchial; inhibitionMuscle relaxationInduction and maintenanceHalothane associated hepatitis: seldom in

26、use now, unavailable in ChinaIntravenous anestheticsIdeal Intravenous anestheticWater-soluble, no pain on injectionRapid onset, rapid recovery, little accumulation, little depression on respiratory-cardiovascular system. No nausea and vomiting, no interact with muscle relaxant, no release of histami

27、ne.40Intravenous anestheticsInduction dose(mg/kg)CVSRSCNS(CBF)Side-effectOther commentspropofol1.5-2.5hypotensiondepressionyesPain on injectionMovementTIVAetomidate0.15-0.3Less depressiondepressionyesPain on injectionmovementSuppress steroid synthesisthiopentone4-6hypotensiondepressionyesrareDelayed

28、 recovery after repeated useketamine1-2 (iv)6-10(im)minimalminimalNohallucinationAnalgesiaDissociated anesthesiamidazolam0.1-0.3hypotensiondepressionyesamnesia41ThiopentoneSedation&hypnosis lost consciousness2.5% 4-6mg/kgOnset 30sAnalgesic effect poorCNS cerebral metabolic rate anticonvulsantCardiov

29、ascular myocardial contractility vasodiltation, BPRespiratory VT RR bronchial muscle toneIndications induction/anticonvulsant/anesthesia.42Propofol43PropofolOut-patient anesthesiaInduction: 2mg/kg; maintenance: TCI/TIVASupplement to local anesthesia Sedation in ICUSide effect :cardiovascular& respir

30、atory suppression, excitatory phenomenon, pain on injection, allergy 44PropofolInduced priapism in some individuals Short-term effects include mild euphoria, hallucinations, and disinhibition.Long-term use has been reported to result in addiction.45PropofolTCI/TIVA (Target Control Infusion & Total I

31、ntravenous Anaesthesia ) 46Muscle relaxants Skeletal muscle relaxants/ No anesthetic effect Cannot make patient lost consciousness Cannot produce amnesia/ Suitable condition for surgery Avoid hazardous of deep anesthesia No analgesiainterfere with the normal action of ACH at the motor end plate, blo

32、ck the receptors on the postsynaptic muscle membrane 47Muscle relaxants Classification:Depolarizing muscle relaxants Suxamethonium (Succinylcholine, scoline)Nondepolarizing muscle relaxants Pancuronium Vecuronium Atracurium48Muscle relaxants agents intubating dose onset action duration (mg/kg) (min)

33、 (min) Scoline 1-2 0.5 3-8 琥珀胆碱 Tubocurarine 0.6 4-6 30-40 筒箭毒碱 Pancuronium 0.1 3-6 30-60 泮库溴胺 Atracurium 0.6 3-5 15-35 阿曲库胺 Vecuronium 0.1 2-3 25-30 维库溴胺49Muscle relaxants肌松药 advantage side effect metabolisam histamine releaseScoline rapid fasciculation,K+ cholinesterase （-） pressure Tubocurarine A

34、sthma kidney 、bile （+）Pancuronium HR liver kidney bile （） Atracurium Hoffmann Hoffmann血浆胆碱酯酶 （+） Vecuronium liver kidney bile （-） Cis-atracurium Hoffmann Hoffmann血浆胆碱酯酶 50Anaesthetic Analgesic 51 agents potency t1/2continuous infusion onset time Tmax TI Morphine 1 70-90 Fentanyl 100 100min 1-2min 3.

35、6min 270-400 Sufentanil 1000 30min 1.3-3min 4.8min 25000Remifentanil 134 3min 30sec 1.2min 33000Lethal injectionLethal injection 52Performing GAPreoperative EvaluationDetecting Disease in Preoperative Evaluation; Importance of the Preoperative Medical History;Components of the Preoperative Medical H

36、istoryCardiovascular Disease(Hypertension/Ischemic Heart DiseaseHeart Failure/Rhythm Disturbances and Electrocardiographic Abnormalities)Pulmonary DisordersEndocrine DisordersRenal DiseaseHepatic DisordersPsychiatric DisordersMusculoskeletal and ConnectiveTissue Diseases53Preoperative EvaluationASA-

37、PS54Airway evaluation55Assessment of airwayPrevious anaesthetic problems and general appearance of the patient. Neck, face, maxilla and mandible with jaw movements.Head extension and movements, teeth, oropharanx and soft tissue of the neck .56Performing a GAPreparing and induction Anesthesia Machine

38、 Checkout (Capnograph, pulse oximeter, oxygen analyzer, respiratory volume monitor, and breathing system pressure monitor with high and low pressure alarms)57Performing a GAInductionIntravenous anestheticAnaesthetic AnalgesicMuscle relaxant58Rapid Sequence Induction 快速序贯性全麻诱导Endotracheal intubation 5960DADAA of ASA61Laryngeal Mask Airway (LMA). Fiber optic62Mi