HistoryAmbroise Par (1510-1590) squeezing limbBenjamin Bell (1749-1806) nerve compressionDominique J. Larrey (1766-1842) cold environmentsBenjamin Ward Richardson (1828-1896) ether spray

Topical AnesthesiaCocaine (Erythroxylon coca)IncaBernabe Cobo (1582-1657), toothache (1544)Albert Niemann (1834-1861) isolated the and gave the name cocaineVasili von Anrep (1852-1918) first to remark on its local anesthetic propertiesSigmund Freud (1856-1939) cocaine for substitute for opioidsCarl Koller (1858-1944) producing local anesthesia for operations on the eye.

Regional AnesthesiaNew applications for cocaine.November 1884 subcutaneous injectionDecember 1884, William Halsted and Richard Hall, blocks of the sensory nerves of the face and arm.Spinal anesthesia (1885) Leonard Corning a substitute for etherization in genito-urinary or other branches of surgery.

August Bier and Theodor Tuffier, described a spinal anesthesiaHeinrich Quincke described technique of lumbar puncture.Prof. August Bier, Dr. Hildebrandt perform a lumbar puncture, A strong blow with an iron hammer against the tibia was not felt as pain. Strong pressure and pulling on a testicle were not painful.Clinical effect and complication from spinal anesthesia

1944 Edward Tuohy, Tuohy needle1949, Martinez Curbelo perform the first continuous epidural anesthetic.Caudal anesthesia.Jean Athanase Sicard, relief of back pain.Fernand Cathelin, alternative to spinal anesthesiaAchille M. Dogliotti the loss-of-resistance technique.

Physiologic Effect of Spinal & Epidural Anesthesia

CardiovascularBlockade of Sympathetic Preganglionic NeuronsPredominant action is venodilationReduces:Venous returnStroke volumeCardiac outputBlood pressureT1-T4 BlockadeCauses unopposed vagal stimulationBradycardiaAssociated with decrease venous return & cardioaccelerator fibers blockade

HypotensionTreatmentPrimary treatmentIncrease the cardiac preloadLarge IV fluid bolus as preloading 10-20 ml/kgSecondary treatmentPharmacologicEphedrine VS Phenylephrine

RespiratoryHealthy patientsAppropriate spinal blockade has little effect on ventilationHigh spinalDecrease functional residual capacity (FRC)Paralysis of abdominal musclesIntercostal muscle paralysis interferes with coughing and clearing secretionsApnea is due to hypoperfusion of respiratory center

GastrointestinalResult of sympathetic blockadeUnopposed parasympathetic activitySecretions increase, sphincters relax, and the bowel becomes constrictedNausea, associated with:Blocks higher than T5HypotensionOpioid premedicationHistory of motion sickness

Endocrine-MetabolicInhibit many of the endocrine-metabolic changes associated with the stress response. lower abdominal > lower extremity > upper abdominal and thoracic procedures

Spinal CordSpinal CordAdultBegins: Foramen MagnumEnds: L1NewbornBegins: Foramen MagnumEnds: L3Terminal End: Conus MedullarisFilum Terminale: Anchors in sacral regionCauda Equina: Nerve group of lower dural sac

Spinal AnesthesiaIndicationsOperation of lower extremitiesLower abdominal surgerySome upper abdominal surgery

Preparation & MonitoringAs in GAPatient Positioning for spinal anesthesiaLateral decubitusSitting Prone (hypobaric technique)

DrugsLocal AnestheticHyperbaric Local anestheticIsobaric Local anestheticHipobaric Local anestheticAdjuctEpinephrineOpioidsNaHCO2ProstigmineClonidine

Assessment of Sensory BlockadeAlcohol swabMost sensitive initial indicator to assess loss of temperaturePin prickMost accurate assessment of overall sensory block

Spinal Anesthesia LevelsSpinal Anesthesia Levels (You must know dermatomes)

Spinal AnesthesiaContraindicationsAbsoluteRefusalInfectionCoagulopathySevere hypovolemiaIncreased intracranial pressureSevere aortic or mitral stenosisRelativePost-Stroke

Spinal AnesthesiaComplicationsFailed block

Back pain (most common)

Hematoma

Nerve Injury

Regional Anesthesia in the Anticoagulated PatientBasic Labs:Platelet counts > 50,000 (minimum), prefer > 100,000Prothrombin time (PT) & Partial thrombin time (PTT)Note that PT & PTT require approx. 60-80% loss of coagulation activity before becoming abnormalThrombin timeHemoglobin & HematocritBleeding time

Regional Anesthesia in the Anticoagulated PatientHeparin: Reverse with FFP or ProtamineIV discontinue 4 hours prior to blockSQ can block one hour prior to doseDo not D/C cath until 4 hours after heparin D/Cd & obtain normal lab valuesLow Molecular Weight Heparin: No ReversalStop 10 days prior to surgeryPost op D/C cath 2 hours prior or 10 hours after first doseCoumadin: Reverse with Vit K or FFPStop 7 days prior to surgeryCheck PT/INR

Regional Anesthesia in the Anticoagulated PatientPlavix: No ReversalStop 5-10 days prior to surgeryNSAIDS: No ReversalMay be safe for regional blockIdeal to stop 5 days prior to surgeryASA: No ReversalStop 7-10 days prior to surgery

Spinal headache (PDPH)More common in women ages 13-40Larger cutting edge needle size, increase severityOnset typically occurs first or second day post-opTreatment:Bed restFluidsCaffeineBlood patch

Epidural Anesthesia

Epidural SpaceSpace that surrounds the spinal meningesPotential spaceLigamentum FlavumBinds epidural space posteriorlyWidest at level L2 (5-6mm)Narrowest at Level C5 (1-1.5mm)

Epidural AnesthesiaTest dose: 1.5% Lido with Epi 1:200,000Tachycardia (increase >30bpm over resting HR)High blood pressureLight headednessMetallic taste in mouthTinitusPerioral numbness

Epidural AnesthesiaComplicationsPenetration of a blood vesselHypotension (nausea & vomiting)HeadacheBack painIntravascular catheterizationWet tapInfection

Caudal AnesthesiaAnatomySacrumTriangular bone5 fused sacral vertebraeNeedle InsertionSacrococcygeal membraneNo subcutaneous bulge or crepitous at site of injection after 2-3ml

Caudal AnesthesiaPost Operative ProblemsPain at injection site is most commonSlight risk of neurological complicationsRisk of infectionDosagesThoracolumbar 1 ml/kgLumbosacral 0.5 ml/kg

Peripheral Nerve Block

DisadvantageINJECTION!!!!!!!!!!!!!BLIND Technique!!!!!!! Low successful rate!! If nerve stimulation, - USGTime consuming!!!!!Local Anesthetic toxicity!!!!!

AdvantageLess GA drugs side effectPatent airwayPost operative pain control

Upper Extremity BlockIntravenous Regional Anesthesia (Bier Block)

Brachial Plexus BlockadeInterscalene blockSupraclavicular blockInfraclavicular block