1、 急诊剖宫产的 麻醉选择和术中处理费敏2010-3-26DefinitionoAbdominal delivery a surgical procedure that permits delivery of the infant through incisions in the abdominal and uterine wall.Cesarean Sectiono Caedere Secoo Pompilius II 730 BCo not widely used until the 1920sIndications for Cesarean Sectiono RepeatnSchedule
2、dnFailed attempt at vaginal deliveryo Dystociao Abnormal presentationnTransverse lienBreechnMultiple gestationo Fetal stress/distresso Deteriorating maternal medical illnessnPreeclampsianHeart diseasenPulmonary diseaseo HemorrhagenPlacenta previanPlacental abruptionCesarean Section60%unplannedo More
3、 extensive peripartum monitoringo Lower threshold for surgical intervention What is an emergency Caesarean section?-Category 1&2GradeDefinition(at time of decision to operate)Category 1 Immediate threat to life of woman or fetusCategory 2Maternal or fetal compromise,not immediately life-threateningC
4、ategory 3Needing early delivery but no maternal or fetal compromiseCategory 4At a time to suit the woman and maternity teamCategory 1 Indicationo Placental abruptiono uterine rupture o cord prolapse o Actively bleeding placenta praeviao Intrapartum hemorrhage o Presumed fetal compromise with severel
5、y abnormal CTG and/or severe fetal acidosis The 30-minute ruleo 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,Stra
6、uss 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.o anaesthetist informed deliveryPerianesthetic Evaluationo A directed history and physical examinationo platelet cou
7、nto An intrapartum blood type and screen for all parturients reduces maternal complicationso Perianesthetic recording of the fetal heart rate reduces fetal and neonatal complicationsA directed history and physical examinationo Maternal health and anesthetic historyo Relevant obstetric historyo Airwa
8、y and heart and lung examinationo Baseline blood pressureo Back examination when neuraxial anesthesia is planned or placedPlatelet count o A routine intrapartum platelet count does not reduce maternal anesthetic complicationso Suspected preeclampsia or coagulopathy o Eclamptic-plt 80*109.l-1 Moodley
9、 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 Prophylaxiso clear liquids up to 2h before induction of anesthesia o A fasting period for solids 68 h(fat con
10、tent?)o Further restrictionnmorbid obesity,diabetes,difficult airwaynnonreassuring fetal heart rate patterno Antacids,H2 Receptor Antagonists,and Metoclopramide reduces maternal complicationsPerianesthetic Maternal PositionAortocaval compression 3 mechanisms uteroplacental perfusion p venous return
11、C.O.and BPpObstruction of uterine venous drainage uterine venous pressure and uterine artery perfusion pressurepCompression of aorta or common iliac arteries uterine artery perfusion pressurePerianesthetic Maternal PositionoAvoid aortocaval compression Kinsella SM.Editorial.Lateral tilt for pregnant
12、 women:why 15 degrees?Anaesthesia 2003;58:8357.Choices of AnesthesiaoGeneral anesthesiaoRegional anesthesiaoLocal anesthesiaChoices of Anesthesia depends ono the indications for the surgeryo the degree of urgencyo maternal and fetus statuso desires of the patient +midwifeanesthetistobstetricianRegio
13、nal anesthesiao 85%emergency Caesarean sectiono 3%Regional anesthesia require conversion to GARegional anesthesiao Epidural anesthesiao spinal anesthesiao Combined Spinal/Epidural(CSE)Epidural p As fast as GAp Titrated dosing and slower onset risk of severe hypotension and reduced uteroplacental per
14、fusionp Duration of surgery not an issuep Less intense motor blockadep Lower extremity“muscle pump”may remain intact incidence of thromboembolic diseaseEpidural p Risk of systemic local toxicityp Greater placental transfer of drug than with spinal BUT does not affect neonatal Apgar score and of litt
15、le clinical significance when appropriate doses usedp Risk of high spinalEpiduralo The speed of onseto The choice of local anesthetic o Possible adjuvants Epiduralo 0.5%bupivacaine o 0.75%ropivacaineo 0.5%levobupivacaineo 2-chloroprocaineo lidocaine 1.8%lidocaine,0.76%bicarbonate and 1:200 000 epine
16、phrine Allam J.Anaesthesia 2008;63:243249.Epidural failureo 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.o Conversion to Spinal anesthesia?nunpredictable high-spinal blocksna relative co
17、ntraindication to give spinal anaesthesia following epidural analgesia in labouro the dose of local anesthesia by 2030%and use addition of opioidsoa normal dose of local anesthesia after 30 min since the last dose of epidural with no documented blockSpinal p Simplep Rapid onsetp Dense blockadep Negl
18、igible maternal risk of systemic local toxicityp Minimal transfer of drug to infantp Negligible risk of local anesthetic depression of infantSpinal p Rapid onset of sympathetic blockade abrupt,severe hypotensionp Limited duration Spinalp Bupivacaine (isobaric/hyperbaric)p levobupivacaine,ropivacaine
19、 less motor blockade&toxicityp addition of opioid(Morphine,fentanyl or sufentanil)nReduce the needed dose of local anaesthesianshorten the time to readiness for surgerynenhances blockade of visceral painnpostoperative analgesia Spinalo Peoload coloado Application of monitorso Supplemental oxygeno Le
20、ft uterine displacemento Aggressive treatment of hypotensionAggressive treatment of hypotensionAggressive treatment of hypotensionp Exaggerated LUDp IV fluidsp Ephedrine and/or phenylephrine Reflex bradycardia(HR45-50bpm)anticholinergic agentCombined Spinal Epidural(CSE)Initially described in 1981(e
21、pidural catheter at L1-2 and spinal at L3-4)CSE o Rapid onset and density of spinal anesthesia combined with versatility of epidural anesthesiao Low-dose spinalnreduce the incidences of cardiovascular instabilitynespecially useful in high risk cardiac patientsCSE p Inability to test epidural cathete
22、rp 18%rate of failurep extra time consumptionGeneral anesthesiao 15%of CS was performed under general anesthesia in USo Majority of CS were done under urgent or emergent situationsIndications for GAo Fetal distresso Significant coagulopathyo Acute maternal hypovolemia and Homodynamic instability o S
23、epsis or local skin infection o failed regional anesthesiao Maternal refusal of regional anesthesia GA o Rapid onseto Controlled airway and ventilationo hands are free for fluid management and hemodynamics control in cases of major bleedingo Almost never failso Minimal cooperation needed from the pa
24、tient GA p17 X higher anesthesia related mortality compared to regional anesthesiapRisk of difficult/failed intubation 10 X higher than in non-obstetric populationpRisk of pulmunary aspirationpContribute to uterine relaxation/atonypExtra time needed at end of procedure to wake up the the patientpUsu
25、ally faster onset of postoperative painpRisk of malignant hyperthermiapRisk of intaoperative awarenesspExposure of fetus to depressant effect of GApMore costlyMost important causes of mortality due to GAoInability to intubateoInability to ventilateoAspiration pneumonitisSuggested Technique for Cesar
26、ean Section o The patient is placed supine with a wedge under the right hip for left uterine displacement.o Preoxygenation 100%O2 35 min o The patient is prepared and draped for surgeryo a rapid-sequence induction with cricoid pressure propofol,2 mg/kg(or thiopental 4 mg/kg)succinylcholine,1.5 mg/kg
27、 Ketamine,1 mg/kg,is used instead of thiopental in hypovolemic or asthmatic patients.Suggested Technique for Cesarean Sectiono Surgery is begun only after proper placement of the endotracheal tube is confirmed by capnography.o Excessive hyperventilation(PaCO225 mm Hg)should be avoided because it can
28、 reduce uterine blood flow and has been associated with fetal acidosis.Suggested Technique for Cesarean Sectiono 50%N2O in oxygen with up to 0.75 MAC of a low concentration of a volatile agent is used for maintenanceo A muscle relaxant of intermediate duration(mivacurium,atracurium,cisatracurium,or
29、rocuronium)is used for relaxationSuggested Technique for Cesarean Sectiono After delivered,2030 U of oxytocin is added to each liter of intravenous fluid.o N2O concentration may then be increased to 70%and/or additional intravenous agents,such as additional propofol,an opioid or benzodiazepine,can b
30、e given to ensure amnesiaSuggested Technique for Cesarean Sectiono If the uterus does not contract readily,an opioid should be given,and the halogenated agent should be discontinuedo Methylergonovine(Methergine),0.2 mg intramuscularly,may also be given but can increase arterial blood pressure o 15-M
31、ethylprostaglandin F2(Hemabate),0.25 mg intramuscularly,may also be usedSuggested Technique for Cesarean Sectiono An attempt to aspirate gastric contents may be made via an oral gastric tube to decrease the likelihood of pulmonary aspiration on emergenceo At the end of surgery,muscle relaxants are c
32、ompletely reversed,the gastric tube(if placed)is removed,and the patient is extubated while awake to reduce the risk of aspiration.Obstetric Hemorrhagic EmergenciesObstetric Hemorrhagic Emergencieso Large-bore intravenous catheterso Fluid warmero Forced-air body warmero Availability of blood bank re
33、sourceso Equipment for infusing intravenous fluids and blood products rapidlySuggested Resources for Airway Management during Initial Provision of Neuraxial Anesthesiao Laryngoscope and assorted bladeso Endotracheal tubes,with styletso Oxygen sourceo Suction source with tubing and catheterso Self-in
34、flating bag and mask for positive-pressure ventilationo Medications for blood pressure support,muscle relaxation,and hypnosiso Qualitative carbon dioxide detectoro Pulse oximeterSuggested Contents of a Portable Storage Unit forDifficult Airway Management for Cesarean Delivery Roomso Rigid laryngosco
35、pe blades of alternate design and size from those routinely usedo Laryngeal mask airwayo Endotracheal tubes of assorted sizeo Endotracheal tube guideso Retrograde intubation equipmento At least one device suitable for emergency nonsurgical airway ventilationo Fiberoptic intubation equipmento Equipme
36、nt suitable for emergency surgical airway access(e.g.,cricothyrotomy)o An exhaled carbon dioxide detectoro Topical anesthetics and vasoconstrictorsSummaryo A distinction must be made between a true emergency requiring immediate delivery and one in which some delay is possible o Spinal or epidural an
37、esthesia is preferred to general anesthesia for cesarean section because regional anesthesia is associated with lower maternal mortality o Hypotension is the most common side effect of regional anesthetic techniques and must be treated aggressively with vasopressors and intravenous fluid boluses to
38、prevent fetal compromiseSummaryo 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 o Uterine displacement(usually left displacement)should be maintained o 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
