急诊剖宫产的麻醉选择和术中处.ppt

1、急诊剖宫产的 麻醉选择和术中处理,费敏 2010-3-26,Definition,Abdominal delivery a surgical procedure that permits delivery of the infant through incisions in the abdominal and uterine wall,Cesarean Section,Caedere Seco Pompilius II 730 BC not widely used until the 1920s,Indications for Cesarean Section,Repeat Scheduled

2、 Failed attempt at vaginal delivery Dystocia Abnormal presentation Transverse lie Breech Multiple gestation,Fetal stress/distress Deteriorating maternal medical illness Preeclampsia Heart disease Pulmonary disease Hemorrhage Placenta previa Placental abruption,Cesarean Section,60% unplanned More ext

3、ensive peripartum monitoring Lower threshold for surgical intervention,What is an emergency Caesarean section? -Category 1 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.

4、Arch Gynecol Obstet 2005; 273:161165. anaesthetist informed delivery,Perianesthetic Evaluation,A directed history and physical examination platelet count An intrapartum blood type and screen for all parturients reduces maternal complications Perianesthetic recording of the fetal heart rate reduces f

5、etal and neonatal complications,A directed history and physical examination,Maternal health and anesthetic history Relevant obstetric history Airway and heart and lung examination Baseline blood pressure Back examination when neuraxial anesthesia is planned or placed,Platelet count,A routine intrapa

6、rtum platelet count does not reduce maternal anesthetic complications Suspected 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

7、 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 restriction morbid obesity, diabetes, difficult airway nonreassuring fetal heart rate pattern Antacids, H2 Receptor Antagonists, and Metoc

8、lopramide reduces maternal complications,Perianesthetic Maternal Position,Aortocaval compression 3 mechanisms uteroplacental perfusion venous return C.O. and BP Obstruction of uterine venous drainage uterine venous pressure and uterine artery perfusion pressure Compression of aorta or common iliac a

9、rteries 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 anesthesia Regional anesthesia Local anesthesia,Choices of Anesthe

10、sia,depends on the indications for the surgery the degree of urgency maternal and fetus status desires of the patient Safest + most expedient,midwife,anesthetist,obstetrician,Regional anesthesia,85% emergency Caesarean section 3% Regional anesthesia require conversion to GA,Regional anesthesia,Epidu

11、ral anesthesia spinal anesthesia Combined Spinal/Epidural (CSE,Epidural,As fast as GA Titrated dosing and slower onset risk of severe hypotension and reduced uteroplacental perfusion Duration of surgery not an issue Less intense motor blockade Lower extremity “muscle pump” may remain intact incidenc

12、e of thromboembolic disease,Epidural,Risk of systemic local toxicity Greater placental transfer of drug than with spinal BUT does not affect neonatal Apgar score and of little clinical significance when appropriate doses used Risk of high spinal,Epidural,The speed of onset The choice of local anesth

13、etic Possible adjuvants,Epidural,0.5% bupivacaine 0.75% ropivacaine 0.5% levobupivacaine 2-chloroprocaine lidocaine 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

14、 audit of regional anaesthesia failure in 5080 caesarean sections. Anaesthesia 2008; 63:822832. Conversion to Spinal anesthesia? unpredictable high-spinal blocks a relative contraindication to give spinal anaesthesia following epidural analgesia in labour the dose of local anesthesia by 2030% and us

15、e addition of opioids a normal dose of local anesthesia after 30 min since the last dose of epidural with no documented block,Spinal,Simple Rapid onset Dense blockade Negligible maternal risk of systemic local toxicity Minimal transfer of drug to infant Negligible risk of local anesthetic depression

16、 of infant,Spinal,Rapid onset of sympathetic blockade abrupt, severe hypotension Limited duration,Spinal,Bupivacaine (isobaric / hyperbaric) levobupivacaine ,ropivacaine less motor blockade & toxicity addition of opioid(Morphine ,fentanyl or sufentanil) Reduce the needed dose of local anaesthesia sh

17、orten the time to readiness for surgery enhances blockade of visceral pain postoperative analgesia,Spinal,Peoload coload Application of monitors Supplemental oxygen Left uterine displacement Aggressive treatment of hypotension,Aggressive treatment of hypotension,Aggressive treatment of hypotension,E

18、xaggerated LUD IV fluids Ephedrine 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

19、 anesthesia Low-dose spinal reduce the incidences of cardiovascular instability especially useful in high risk cardiac patients,CSE,Inability to test epidural catheter 18% rate of failure extra time consumption,General anesthesia,15% of CS was performed under general anesthesia in US Majority of CS

20、were done under urgent or emergent situations,Indications for GA,Fetal distress Significant coagulopathy Acute maternal hypovolemia and Homodynamic instability Sepsis or local skin infection failed regional anesthesia Maternal refusal of regional anesthesia,GA,Rapid onset Controlled airway and venti

21、lation hands are free for fluid management and hemodynamics control in cases of major bleeding Almost never fails Minimal cooperation needed from the patient,GA,17 X higher anesthesia related mortality compared to regional anesthesia Risk of difficult/failed intubation 10 X higher than in non-obstet

22、ric population Risk of pulmunary aspiration Contribute to uterine relaxation/atony,Extra time needed at end of procedure to wake up the the patient Usually faster onset of postoperative pain Risk of malignant hyperthermia Risk of intaoperative awareness Exposure of fetus to depressant effect of GA M

23、ore costly,Most important causes of mortality due to GA,Inability to intubate Inability to ventilate Aspiration 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

24、is prepared and draped for surgery a 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 onl

25、y 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

26、MAC of a low concentration of a volatile agent is used for maintenance A 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 intra

27、venous 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

28、 the halogenated agent should be discontinued Methylergonovine (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 aspira

29、te gastric contents may be made via an oral gastric tube to decrease the likelihood of pulmonary aspiration on emergence At 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

30、,Obstetric Hemorrhagic Emergencies,Obstetric Hemorrhagic Emergencies,Large-bore intravenous catheters Fluid warmer Forced-air body warmer Availability of blood bank resources Equipment for infusing intravenous fluids and blood products rapidly,Suggested Resources for Airway Management during Initial

31、 Provision of Neuraxial Anesthesia,Laryngoscope and assorted blades Endotracheal tubes, with stylets Oxygen source Suction source with tubing and catheters Self-inflating bag and mask for positive-pressure ventilation Medications for blood pressure support, muscle relaxation, and hypnosis Qualitativ

32、e carbon dioxide detector Pulse 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 used Laryngeal mask airway Endotracheal tubes of assorted size Endotracheal tube guides Retrograde intubation equipment At least one device suitable for emergency nonsurgical airway ventilation Fiberoptic intubatio