急诊剖宫产的麻醉选择和术中处理英文版课件.ppt

急诊剖宫产的 麻醉选择和术中处理,Definition,Abdominal delivery a surgical procedure that permits delivery of the infant through incisions in the abdominal and uterine wall.,Cesarean Section,Caedere SecoPompilius II 730 BCnot widely used until the 1920s,Indications for Cesarean Section,RepeatScheduledFailed attempt at vaginal deliveryDystociaAbnormal presentationTransverse lieBreechMultiple gestation,Fetal stress/distressDeteriorating maternal medical illnessPreeclampsiaHeart diseasePulmonary diseaseHemorrhagePlacenta previaPlacental abruption,Cesarean Section,60%unplannedMore extensive peripartum monitoringLower threshold for surgical intervention,What is an emergency Caesarean section?-Category 1&2,Category 1 Indication,Placental abruptionuterine rupturecord prolapseActively bleeding placenta praeviaIntrapartum hemorrhage Presumed fetal compromise with severely abnormal CTG and/or severe fetal acidosis,The 30-minute rule,a maximum decision-to-delivery time of 30 min for Category 1 situation Association of Anaesthetists of Great Britain and Ireland and ObstetricAnaesthesists Association.Guidelines for obstetric anaesthesia services;2005.Hillemanns P,Strauss A,Hasbargen U,et al.Crash emergency cesarean section:decision-to-delivery interval under 30 min and its effect on Apgar and umbilical artery pH.Arch Gynecol Obstet 2005;273:161165.anaesthetist informed delivery,Perianesthetic Evaluation,A directed history and physical examinationplatelet countAn intrapartum blood type and screen for all parturients reduces maternal complicationsPerianesthetic recording of the fetal heart rate reduces fetal and neonatal complications,A directed history and physical examination,Maternal health and anesthetic historyRelevant obstetric historyAirway and heart and lung examinationBaseline blood pressureBack examination when neuraxial anesthesia is planned or placed,Platelet count,A routine intrapartum platelet count does not reduce maternal anesthetic complicationsSuspected preeclampsia or coagulopathy Eclamptic-plt 80*109.l-1 Moodley J,Jjuuko G,Rout C.Epidural compared with general anaesthesia for Caesarean delivery in conscious women with eclampsia.British Journal of Obstetrics and Gynaecology 2001;108:37882.,Aspiration Prophylaxis,clear liquids up to 2h before induction of anesthesia A fasting period for solids 68 h(fat content?)Further restrictionmorbid obesity,diabetes,difficult airwaynonreassuring fetal heart rate patternAntacids,H2 Receptor Antagonists,and Metoclopramide reduces maternal complications,Perianesthetic Maternal Position,Aortocaval compression 3 mechanisms uteroplacental perfusion venous return C.O.and BPObstruction of uterine venous drainage uterine venous pressure and uterine artery perfusion pressureCompression of aorta or common iliac arteries uterine artery perfusion pressure,Perianesthetic Maternal Position,Avoid aortocaval compression Kinsella SM.Editorial.Lateral tilt for pregnant women:why 15 degrees?Anaesthesia 2003;58:8357.,Choices of Anesthesia,General anesthesiaRegional anesthesiaLocal anesthesia,Choices of Anesthesia,depends onthe indications for the surgerythe degree of urgencymaternal and fetus statusdesires of the patientSafest+most expedient,midwife,anesthetist,obstetrician,Regional anesthesia,85%emergency Caesarean section3%Regional anesthesia require conversion to GA,Regional anesthesia,Epidural anesthesiaspinal anesthesiaCombined Spinal/Epidural(CSE),Epidural,As fast as GATitrated dosing and slower onset risk of severe hypotension and reduced uteroplacental perfusionDuration of surgery not an issueLess intense motor blockadeLower extremity“muscle pump”may remain intact incidence of thromboembolic disease,Epidural,Risk of systemic local toxicityGreater placental transfer of drug than with spinal BUT does not affect neonatal Apgar score and of little clinical significance when appropriate doses usedRisk of high spinal,Epidural,The speed of onsetThe choice of local anesthetic Possible adjuvants,Epidural,0.5%bupivacaine 0.75%ropivacaine0.5%levobupivacaine2-chloroprocainelidocaine 1.8%lidocaine,0.76%bicarbonate and 1:200 000 epinephrine Allam J.Anaesthesia 2008;63:243249.,Epidural failure,24%fail to achieve a pain-free operation Kinsella SM.A prospective audit of regional anaesthesia failure in 5080 caesarean sections.Anaesthesia 2008;63:822832.Conversion to Spinal anesthesia?unpredictable high-spinal blocksa relative contraindication to give spinal anaesthesia following epidural analgesia in labour the dose of local anesthesia by 2030%and use addition of opioidsa normal dose of local anesthesia after 30 min since the last dose of epidural with no documented block,Spinal,SimpleRapid onsetDense blockadeNegligible maternal risk of systemic local toxicityMinimal transfer of drug to infantNegligible risk of local anesthetic depression of infant,Spinal,Rapid onset of sympathetic blockade abrupt,severe hypotensionLimited duration,Spinal,Bupivacaine(isobaric/hyperbaric)levobupivacaine,ropivacaine less motor blockade&toxicityaddition of opioid(Morphine,fentanyl or sufentanil)Reduce the needed dose of local anaesthesiashorten the time to readiness for surgeryenhances blockade of visceral painpostoperative analgesia,Spinal,Peoload coloadApplication of monitorsSupplemental oxygenLeft uterine displacementAggressive treatment of hypotension,Aggressive treatment of hypotension,Aggressive treatment of hypotension,Exaggerated LUDIV fluidsEphedrine and/or phenylephrine Reflex bradycardia(HR45-50bpm)anticholinergic agent,Combined Spinal Epidural(CSE),Initially described in 1981(epidural catheter at L1-2 and spinal at L3-4),CSE,Rapid onset and density of spinal anesthesia combined with versatility of epidural anesthesiaLow-dose spinalreduce the incidences of cardiovascular instabilityespecially useful in high risk cardiac patients,CSE,Inability to test epidural catheter18%rate of failureextra time consumption,General anesthesia,15%of CS was performed under general anesthesia in USMajority of CS were done under urgent or emergent situations,Indications for GA,Fetal distressSignificant coagulopathyAcute maternal hypovolemia and Homodynamic instability Sepsis or local skin infection failed regional anesthesiaMaternal refusal of regional anesthesia,GA,Rapid onsetControlled airway and ventilationhands are free for fluid management and hemodynamics control in cases of major bleedingAlmost never failsMinimal cooperation needed from the patient,GA,17 X higher anesthesia related mortality compared to regional anesthesiaRisk of difficult/failed intubation 10 X higher than in non-obstetric populationRisk of pulmunary aspirationContribute to uterine relaxation/atony,Extra time needed at end of procedure to wake up the the patientUsually faster onset of postoperative painRisk of malignant hyperthermiaRisk of intaoperative awarenessExposure of fetus to depressant effect of GAMore costly,Most important causes of mortality due to GA,Inability to intubateInability to ventilateAspiration pneumonitis,Suggested Technique for Cesarean Section,The patient is placed supine with a wedge under the right hip for left uterine displacement.Preoxygenation 100%O2 35 min The patient is prepared and draped for surgerya rapid-sequence induction with cricoid pressure propofol,2 mg/kg(or thiopental 4 mg/kg)succinylcholine,1.5 mg/kg Ketamine,1 mg/kg,is used instead of thiopental in hypovolemic or asthmatic patients.,Suggested Technique for Cesarean Section,Surgery is begun only after proper placement of the endotracheal tube is confirmed by capnography.Excessive hyperventilation(PaCO225 mm Hg)should be avoided because it can reduce uterine blood flow and has been associated with fetal acidosis.,Suggested Technique for Cesarean Section,50%N2O in oxygen with up to 0.75 MAC of a low concentration of a volatile agent is used for maintenanceA muscle relaxant of intermediate duration(mivacurium,atracurium,cisatracurium,or rocuronium)is used for relaxation,Suggested Technique for Cesarean Section,After delivered,2030 U of oxytocin is added to each liter of intravenous fluid.N2O concentration may then be increased to 70%and/or additional intravenous agents,such as additional propofol,an opioid or benzodiazepine,can be given to ensure amnesia,Suggested Technique for Cesarean Section,If the uterus does not contract readily,an opioid should be given,and the halogenated agent should be discontinuedMethylergonovine(Methergine),0.2 mg intramuscularly,may also be given but can increase arterial blood pressure 15-Methylprostaglandin F2(Hemabate),0.25 mg intramuscularly,may also be used,Suggested Technique for Cesarean Section,An attempt to aspirate gastric contents may be made via an oral gastric tube to decrease the likelihood of pulmonary aspiration on emergenceAt the end of surgery,muscle relaxants are completely reversed,the gastric tube(if placed)is removed,and the patient is extubated while awake to reduce the risk of aspiration.,Obstetric Hemorrhagic Emergencies,Obstetric Hemorrhagic Emergencies,Large-bore intravenous cathetersFluid warmerForced-air body warmerAvailability of blood bank resourcesEquipment for infusing intravenous fluids and blood products rapidly,Suggested Resources for Airway Management during Initial Provision of Neuraxial Anesthesia,Laryngoscope and assorted bladesEndotracheal tubes,with styletsOxygen sourceSuction source with tubing and cathetersSelf-inflating bag and mask for positive-pressure ventilationMedications for blood pressure support,muscle relaxation,and hypnosisQualitative carbon dioxide detectorPulse oximeter,Suggested Contents of a Portable Storage Unit forDifficult Airway Management for Cesarean Delivery Rooms,Rigid laryngoscope blades of alternate design and size from those routinely usedLaryngeal mask airwayEndotracheal tubes of assorted sizeEndotracheal tube guidesRetrograde intubation equipmentAt least one device suitable for emergency nonsurgical airway ventilationFiberoptic intubation equipmentEquipment suitable for emergency surgical airway access(e.g.,cricothyrotomy)An exhaled carbon dioxide detectorTopical anesthetics and vasoconstrictors,Summary,A distinction must be made between a true emergency requiring immediate delivery and one in which some delay is possible Spinal or epidural anesthesia is preferred to general anesthesia for cesarean section because regional anesthesia is associated with lower maternal mortality Hypotension is the most common side effect of regional anesthetic techniques and must be treated aggressively with vasopressors and intravenous fluid boluses to prevent fetal compromise,Summary,Regardless of the time of last oral intake,all obstetric patients are considered to have a full stomach and to be at risk for pulmonary aspiration Uterine displacement(usually left displacement)should be maintained Delivery units should have personnel and equipment readily available to manage airway emergencies,consistent with the ASA Practice Guidelines for Management of the Difficult Airway,Thanks!,