1、Nerve BlockSketch of this lessonGeneral introductionLocal anesthetic toxicityCervical plexus blockBrachial plexus blockSciatic blockDigital blockGeneral introductionHistory 1880s, Cocaine was injected to peripheral site for minor surgeries. 1885, Esmarch bandage used to arrest local circulation to p
2、rolong coaine-induced block. 1903, epinephrine as “chemical tourniquet” emerged.1920, the first definitive textbook, Regional anesthesia: Its Technic and Application, was authored by Gaston Labat in U.S.A. Became a well-accepted component of comprehensive anesthetic care, and expanded from operating
3、 suite to pain management.General introductionTechnique of nerve block is to localize the neural structures, usually by anatomy knowledge and elicited paresthesia.Development of nerve blockGeneral introductionIndication Surgical area, consciousness and cooperation, skill level of handler.Contraindic
4、ation Infection, tumor, serious malformation on the puncture site; coagulation disorder; allergy to local anesthetics.Local anestheticsAgentAgentConcentratioConcentration nMaximumMaximum (mg) (mg)Onset (min)Onset (min)Duration Duration (min)(min)Lidocaine* *1-1.5%40010-20120Mepivacaine1-1.5%40010-20
5、180Bupivacaine* *0.25-0.5%17515-30360Etidocaine0.5-1.0%30010-20360Dicaine0.15-0.25%10015-20120Ropivacaine* *0.25-0.5%17515-30240Chloroprocaine2-3%8006-1230Local anesthetic toxicityYou should know what complication You should know what complication could becould be caused by your procedure caused by
6、your procedure before you master the procedurebefore you master the procedure！未学打人，先学挨打！Local anesthetic toxicityLocal anesthetic toxicityConcept Concentration of local anesthetic in blood far exceeds the tolerance limitation of human body and cause adverse effect. Central nervous system and heart a
7、re vulnerable.Common cause Local anesthetic over dose; Accidentally vessel injection; Excessive absorbance of local anesthetic; Systemic pathology reduce the tolerance. Local anesthetic toxicityCNS toxicity (Biphasic effect) CNS is more susceptible to systemic action of local anesthetic than cardiov
8、ascular system is. (Dose 1:3) Early symptoms: dizziness, visual and auditory disturbance, disorientation, excitatory sign including shivering, muscular twitching. Hypertension. Ultimately, generalized convulsion will occur. After seizure activity ceases, respiratory depression even arrest may occur.
9、Local anesthetic toxicityCardiovascular toxicity Inhibit the myocardial sodium channel and cause negative inotropic action, reduction of CO, bradycardia, ventricular arrhythmia even cardiac arrest. Local anesthetic toxicityTreatment of local anesthetic toxicity 1. Stop injection immediately. 2. Oxyg
10、en supply and airway maintenance. 3. Midazolam 5mg / Propofol 80-100mg iv. 4. Respiratory assistance and sustaining the HR and Blood pressure. 5.When cardiac arrest occurs, CPR must be applied promptly. 6. Bupivacaine-induced cardiac arrest is more difficult to resuscitate. 20% intralipid is conside
11、rable to be applied.Local anesthetic toxicityProphylaxis of local anesthetic toxicity 1. Not exceed the dosage limitation, choose suitable dose according to evaluation of patients and the blockage site. 2. Aspiration before injection. 3. Use epinephrine to reduce the absorbance. 4. Administration of
12、 small dose benzodiazepine or barbital. 5. Correction of acidosis, hyperthermia, anemia and hypovolemia preoperatively.Cervical plexus blockIndication:Superficial and deep Operations in the region of neck and supra-clavicular fossa.枕小神经耳大神经颈横神经锁骨上神经Cervical plexus blockTechnique selection Superficia
13、l Vs Deep ?Pharmacologic choiceHigh concentration Vs Low ?颈襻Cervical plexus blockComplications 1. Superficial block rarely cause any complication; 2. Local anesthetic toxicity; 3. Intrathecal injection; 4. Phrenic nerve blockage; 5. Laryngeal recurrent nerve blockage; 6. Honors syndrome; 7. Hemorrag
14、e of vertebral arteryCervical plexus blockSuperficail cevical plexus block Cervical plexus blockDeep cervical plexus blockBrachial plexus blockAnatomy of brachial plexusAxillary blockIndicationForearm, hand and wrist surgery.Position Abduct the arm at shoulder Pharmacologic choice High volume low co
15、ncentration. 0.25%Ropivacaine+0.5%Lidocaine 30ml Analgesia last 4-6 hrs Axillary blockAdvantage:Most safe one of all. Shortage:Cross sectionAxillary blockSupraclavicular blockIndicationInpatient, skillful practitionerPositionSupine, arm aside, head turn to oppositePharmacologic choiceConsider the le
16、ngth of blockageSupraclavicular blockAdvantage:Rapid onset;Well motor blockage;Easy to approach.Shortage:Cause pneumothorax;Phrenic nerve blockage.Supraclavicular blockInterscalene blockAnatomyIndicationPositionInterscalene blockPharmacology choicesInterscalene blockParesthesiaseeking methodAdvantag
17、e:Upper armand shoulder blockagewith less LD;Safetyapproach.Shortage:Difficultto block ulnar n.;vertebral a. injection;spinal or epidural Injection; pneumothorax; phrenic n. block.Interscalene blockSagittal plane optimizes the needle angleSciatic blockDigital blockCase discussionFemale, 54y, Diagnos
18、is: humeral fracture.Surgery: Open reduction and internal fixation.Anesthesia: Interscalene block with 2% lidocaine 25ml with epinephrine (1:200,000)Maneuver: “Immobile needle”+careful aspiration.After 5 min, patient notes numbness of the operative arm but starts to complain of increasing dyspnea.Ca
19、se discussion1.What could be appropriate management?2.What are the most likely causes?What could be appropriate management?1.Apply full monitoring: EKG, NIBP, SPO2, 2.Supplemental oxygen.3.Preparation of general anesthesia induction: tracheal intubation, controlled ventilation.4.Vasopressors and atropine.5.Mental status and ventilatory exchange .What are the most likely causes?1.Spinal injection 2.Cervical epidural injection3.Phrenic n. block4.Pneumothorax5.Anxiety
