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1、Common Complications in Obstetric Anesthesia and How to Avoid Them.TomArcher,MD,MBAUCSDAnesthesiaResidentLectureSeriesJanuary23,2013My definition of “common”A complication you will see at least once in a career in which you do some OB anesthesia.If you do OB anesthesia regularly, you will see most o
2、f the following complications many, many times.CommonOBAnesthesiaComplicationsDifficultyplacingspinalorepidural,causingpatientdistress.“Sketchy-dural”(poorepidural)Post-duralpunctureheadache(PDPH)HypotensionafterneuraxialblockCommon OB Anesthesia ComplicationsHigh spinal or epidural respiratory fail
3、ure +/- hypotensionLow spinal or epidural anesthesia failureIntraoperative pain (incomplete block)Cant intubate (and cant ventilate?) under GA.Common OB Anesthesia ComplicationsFetal bradycardia after CSE or epiduralPost-delivery lower extremity neuropathyI am not going to discuss:Localanestheticorc
4、ontaminanttoxicitytonerves(rareinmodernpractice).Directneedletraumatonerverootsorspinalcord(rare).Epiduralabscessorhematoma(rare).AspirationDifficultyplacingspinalorepidural,withpatientdistress.Difficulty placing spinal or epidural, with patient distress.We have all been there, many times. At least
5、I have.20-60 minutes of effort.Patient is in tears. You are sweating.You have called for help. They couldnt do it either.Is this inevitable, or is there a way to reduce the frequency of such events?Making epidural placement easier for patient and doctor“Management of expectations”: “5-10% of the tim
6、e the epidural does not work properly. We will do our best” Dont promise perfection!Achieve patient rapport and cooperation.Demonstrate posture.Reinforce positioning patients straighten up over time when in pain. IV fentanyl makes a big difference.Making epidural placement easier for patient and doc
7、torIf you anticipate difficult placement (e.g. an obese patient) consider IV fentanyl and ultrasound before you start.Dont wait until patient is in tears to give fentanyl and to use ultrasound.Can ultrasound make neuraxial block easier?Many practitioners say it is an unnecessary waste of time. I dis
8、agree, at least in selected cases.Ultrasound can help identify:MIDLINE (true location of spinous processes)DEPTH TO LIGAMENTUM FLAVUMSPINAL ROTATION, IF PRESENT ParamedianSagittalParamedianSagittalObliqueTransverseMostusefulviewsSpinousprocessesarenotalwaysdirectlycephaladfromglutealcleftTenseparasp
9、inousmusclescanbemistakenforspinousprocessesLinerunningcephaladfromglutealcleftPLLDLFSkinsurfaceEmittedsoundReflectedsoundUltrasoundprobe,lateralviewVerticalskinmarkTransverseprocessPLLDLFSkinsurfaceEmittedsoundReflectedsoundBestinsertionangleisdeterminedforeachpatientbymaximizingbrightnessofposteri
10、orlongitudinalligament(PLL)ontheultrasoundscreenandrememberingthatangleforactualneedleinsertion.Bestangleisusually5-15degreescephaladfromalineperpendiculartotheskin.Ultrasoundprobeisangleduntilposteriorlongitudinalligamentisthebrightest.Dura/ligamentumflavumcomplexPosteriorlongitudinalligamentInterl
11、aminarforamen(blackshapeinsidewhiterectangle)Verticalskinmark#1,centeredonprobeUnderlyingspinousprocess(darkblue)LinerunningcephaladfromglutealcleftHorizontalskinmark#2,centeredonlevelofprobe(betweenspinousprocesses)Insertionpointistheintersectionofhorizontalandverticallinesthroughskinmarks.PLLDLFSk
12、insurface10cmUltrasoundprobeBestinsertionangleUltrasoundenablesustomeasuredistancetotheligamentumflavumtowithinacentimeterorso.Estimate,ifincorrect,isalmostalwaystoosmall,duetocompressionofadiposetissueduringthemeasurement.“Sketchy-dural”(poorepidural)“Sketchy-dural”They happen, no matter how good y
13、ou are.“Management of expectations.” Dont promise the patient a perfect epidural.That said, here is my advice to minimize impact of sketchy-durals on our care“Sketchy-dural”Be honest with yourself. Many sketchy-durals are simply not in the right place. Check what is really going on, with ice systemi
14、c fentanyl can mask a non-epidural.Have a low threshold for replacement. “Sketchy-dural”A disadvantage of IV fentanyl is that the analgesia it provides can mask a poor epidural.Ask the patient how her legs feel. The answer should be “numb” or “tingly”. “Fine” is NOT a good answer it means there is n
15、o block!Epidurals requiring more than one MD bolus have a higher failure rate for CS.“Sketchy-dural”What exactly is the problem? Talk with and examine the patient.Just doesnt work at all? replaceOne sided? bolus with less-affected side down. Next step pull back one cm. Next step replace“Hot spot” bu
16、t otherwise OK? Position side with “hot spot” downwards and bolus with stronger local anesthetic + epinephrine + fentanyl.“Sketchy-dural”Think about other causes of “abnormal” pain fetal head pressing on nerves, uterine rupture, placental abruption, “intradural placement.”There should be no pain (or
17、 much sensation at all) with an epidural injection.Discomfort in the back during epidural injections suggests intramuscular or subcutaneous injection.“Sketchy-dural”Consider ultrasound the second time (or the first time!) to confirm:MIDLINE (true location of spinous processes)DEPTH to ligamentum fla
18、vumROTATION of the spinal column“Sketchy-dural” goes to CS.Can you do a spinal on top of a “sketchy-dural”?Yes, but do it carefully and understand that high spinal may occur. CSE with low intrathecal dose, or titrated epidural are options.Post dural puncture headache(“Spinal headache”)Post dural pun
19、cture headache(PDPH)Third most common cause of lawsuit in OB anesthesia.Can be disabling and distressing, particularly for a mother trying to take care of a newborn and a household.Post dural puncture headache(PDPH)Third most common cause of lawsuit in OB anesthesia.Can be disabling and distressing,
20、 particularly for a mother trying to take care of a newborn and a household.PDPHMidline frontal and/or occipital. Not lateralized!May extend into neck (stiff neck)Worse with upright posture (usually immediate onset, may be delayed 20 minutes)Relief with flat posture (usually immediate).PDPHMay be as
21、sociated with diplopia (abducens palsy) and muffled hearing or tinnitus.May be associated with N+V.But is it really PDPH?The key question: Could it be something else?If you Rx PDPH and it is something else you incur two problems: unnecessary treatment risk AND missed Dx.It could be: lactation HA, mi
22、graine, subdural hematoma, brain tumor, AVM, cortical vein thrombosis, dural sinus thrombosis, etc.Yes, it is PDPHConservative therapy vs. Blood patch?Conservative therapy: NSAIDs, other oral analgesics, caffeine, fluids, salty foods.Epidural blood patch (EBP): 10-30 mL of patients blood injected in
23、to epidural space.EBP complications: back pain, leg paresthesias (common), epidural abscess or adhesive arachnoiditis (rare).In favor of EBPSevere disability, 24 hours of Sx.Patient confined to bed unable to functionAssociated signs + Sx of decreased ICP (abducens palsy, hearing changes, N+V)In favo
24、r of conservative therapyUncertain Dx.Patient uncomfortable but able to function.If they are sitting up in bed, or walking, when I enter the room, I am hesitant to do a blood patch.PDPH etiologyTraditional theory: loss of CSF leads to brain “settling down” in skull, with resultant traction on dura a
25、nd nervesVasodilation theory: loss of CSF leads to translocation of CSF to lumbar area with upright posture. Volume in skull must remain constant, hence vasodilation + HA.Therapeutic efficacy of caffeine and vasoconstrictors supports vasodilation theoryHypotension after labor epiduralHypotension aft
26、er labor epiduralOccurs VERY commonly. 30-40% of the time?Consider low dose prophylactic phenylephrine or ephedrine after block placement. Hypotension after labor epidural95% of fetal distress after epidural is due to hypotension. The other 5% may be “uterine hypertonus” due to rapid pain relief (di
27、scussed later).Both things might be happening.When there is fetal distress palpate uterus!Hypotension after labor epiduralRoutine therapy for hypotension (in absence of uterine hyperstimulation) is:Position change (Left or right side down).Fluid bolusVasopressorsOxygen, if there is fetal bradycardia
28、.Hypotension with labor epiduralTreat hypotension early, treat often.Prevention with low-dose vasopressor has very little downside.Is there a role for non-invasive cardiac output measurement in labor to detect occult IVC obstruction? Physiology of post-block hypotensionSympathetic efferents exit spi
29、nal cord from T1 to L2.Lowsympathectomy:Blockade of T5-L2Splanchnic vasodilation and pooling. Reduced venous return (CO), especially with IVC obstruction. Reduced SVR.17Sympathetic efferents exit spinal cord from T1 to L2.Highsympathectomy:Blockade of T1-T4 warm vasodilated hands, further reduced SV
30、R, Horners syndrome, ? bradycardia. Blockade of T5-L2Splanchnic vasodilation and pooling. Reduced venous return (CO), especially with IVC obstruction. Reduced SVR.18T5-L2sympathectomycausespoolingofbloodinthesplanchnicvessels,reducingvenousreturnandCO.20Splanchnicvasculaturehasalphaandbetareceptorsa
31、tmultiplesites.Beta2dilateshepaticveinsAlpha1+2constrictsplanchniccapacitancevesselsAlpha1+2constrictsplanchnicarteriesFiguremodifiedbyArcherTL21Decreased venous return and cardiac output due to sympathectomy is exacerbated by obstruction of IVC.22ManbitimagesIfIVCisopen,venousreturnisunimpededandca
32、rdiacoutputismaximized.23Givenlate!DiagrammodifiedbyArcherTL29Avoid cardiac arrest after neuraxial blockTalkwithpatientduringtestdose.“Heartpounding,legsnumborweak?”HaveAmbubagandpressorsimmediatelyavailable.Allow2-3minutesfortestdosetobepositive.Considerdosingepiduralfentanyl100mcgmaftertestdosesin
33、ceitwillaugmentblockbutnot“burnanybridges.”Staywithpatient15-30minutesafterinitiationofblocktor/ohypotension,hyperstimulationorexcessblock.Docharting.Startinfusion.Makesurenursewillstaywithpatientafteryouleave.30Cardiac arrest in labor room do the CS in the labor room!“Four minute rule” start CS wit
34、hin 4 minutes of arrest. Deliver baby within 5 minutes to avoid neonatal brain damage.“Our findings imply that perimortem cesarean delivery during actual arrest would require more than 5 minutes and should be performed in the labor room rather than relocating to the operating room.”ObstetGynecol.201
35、1Nov;118(5):1090-4.Laborroomsettingcomparedwiththeoperatingroomforsimulatedperimortemcesareandelivery:arandomizedcontrolledtrial.LipmanS,DanielsK,CohenSE,CarvalhoB.33High spinal (or epidural)Sympathetic efferents exit spinal cord from T1 to L2.Highsympathectomy:Blockade of T1-T4 warm vasodilated han
36、ds, further reduced SVR, Horners syndrome, ? bradycardia. Blockade of T5-L2Splanchnic vasodilation and pooling. Reduced venous return (CO), especially with IVC obstruction. Reduced SVR.18High or Total SpinalA circulatory as well as respiratory emergency.You will have to assist or control ventilation
37、.You must recognize situation immediately and act rapidly and with confidence so that patient does not panic (too much).High or Total SpinalSay three things:“Youre going to be OK.”“This happens sometimes when the spinal goes too high.”“Im going to help you breathe.”High or Total SpinalDo this:Unwrap
38、 circle system tubing and mask and close down pop-off valve.Put mask on face and assist ventilation. Explain what you are doing. Patient is panicking. High or Total SpinalDo this:Feel for a pulse and if weak (or just empirically) give ephedrine 10-25 mg. Atropine for bradycardia.Check BP, but all th
39、at really matters is ventilation and a good pulse.High or Total SpinalShould you intubate?It depends, but ventilation trumps intubation.Ventilation even trumps aspiration.My rule of thumb: LOC, total apnea intubate. But stabilize BP and oxygenation first, even before intubation!Low spinalLow spinalH
40、yperbaric (bupivacaine) solution will “pool” in the dural sac below the sacral promontory if patient is allowed to sit for too long after the intrathecal injection.Trendelenburg position often used “to move level up” but no proof it really works.Low spinalCough often used “to move level up”- but no
41、proof it really works.Tburg + flexion of thighs on the abdomen straightens lumbar curve and raises intra-abdominal pressure.I believe this works.HyperbaricsolutioninjectedherecanpoolhereSeatedinjectionandprolongeduprightpostureallowpoolingofhyperbaricsolutionModifiedfromDelaneyRadiologistsSupineposi
42、tionSacralpromontorycanbeabarriertocephaladspreadAvoiding a low spinalHave patient lie down rapidly after intrathecal injection. Have her position herself on the OR table. Trendelenberg? Cough?Flexion of thighs on the abdomen to flatten lumbar curve and to increase intra-abdominal pressure.Imagefrom
43、Boba,Inc.Repeat the spinal?Bupivacaine takes 15-20 minutes for full effect, so dont rush it.Beware of high or total spinal if you repeat the injection. Hows the airway?Epidural may be better.Fetal bradycardia after neuraxial analgesiaFetal bradycardia after neuraxial analgesiaClassic scenario for hy
44、pertonic uterus is: Patient has oxytocin augmentation of labor and severe pain. CSE with lipid soluble narcotic is given rapid pain relief. Fetal bradycardia occurs 10-30 minutes after the block. Loss of beta stimulus?May or may not be accompanied by hypotension, but hypertonic uterus is a separate
45、phenomenon, requiring uterine relaxation. Correction of BP is not enough!MinimalcollateralvenousreturntoheartvialumbarandazygossystemOpenIVCUncompressedaortaandiliacarteriesFigure2Uterinecontractionsperiodicallydepriveplacentaofperfusion.UpperbodyUterinecontractionsFetalO2supplyTakYeungLeung,MDa,b,(
46、Professor),TerenceT.Lao,MDa(Professor)UterinehyperstimulationduetoexcessiveoxytocinaugmentationoflaborSolutionisNOTalwaysemergencyCS.Rather,itisINTRAUTERINERESUSCITATIONusingTIMEandTERBUTALINEorNTGDetecting uterine hyperstimulationKey “maneuver” is to think of the possibility and to evaluate uterine
47、 tone by palpation or IUPC during fetal bradycardia.Recognition of uterine hyperstimulation and reversal with terbutaline SC or NTG SL or IV can avoid an unnecessary CS!Intraoperative pain during CSIntraoperative pain during CS“Management of expectations” dont promise a pain-free experience. Discuss
48、 intraoperative pain management options ahead of time. What will patient tolerate?Mild discomfort fentanyl + local infiltration?Intraoperative pain during CSMore discomfort Fentanyl, midazolam + ketamine (low dose and maintain responsivenss). Keep your suction at the ready.Severe discomfort RSI/ GA.
49、Choice of neuraxial technique when airway is bad.Consider avoiding CSE if airway is bad: epidural may fail, leaving patient with surgery underway and disappearing block.If airway is bad, straight epidural or continuous spinal anesthesia may be a better choice than CSE, since you know it works from t
50、he outset, before surgery starts.Cant intubate under GACant intubate under GAA few comments only:1) Pregnancy involves weight gain and airway edema.2) Pre-eclampsia and pushing make 1) worse.3) Nose bleeds easily in pregnancy.Cant intubate under GA4)Positioneverypatientassumingyouwillhavetointubateh
51、er(e.g.ramp,Glidescope,etc,availableifneedforeseen).5)AvoidCSEifairwayisunfavorableforintubation.Thereasonis:epiduralpartofCSEmayfailwhenyoutrytoactivateit.6)Continuousepiduralorspinalisbetterifairwayisbad.Thatwayyouknowanesthesiawillworkaslongasyouneedit,before surgery starts.Management of “cant in
52、tubate” situationElective procedure awaken patient and secure airway by other means (e.g. AFOI).Emergency procedure LMA?, careful ventilation, good paralysis (avoids coughing and retching).Post-delivery lower extremity neuropathyPost-delivery lower extremity neuropathy“Post-delivery” does not = “Due
53、 to anesthesia”Vast majority of post-delivery neuropathies are due to nerve stretch, pressure, compression or ischemia not due to needle damage or local anesthetic toxicity.“Obstetric palsy” from fetal head, forceps or positioning. Often seen without anesthesia.Post-delivery lower extremity neuropat
54、hySo, relax when you see these patients!You probably did not (directly) cause it- and it will almost certainly resolve over time.On the other hand listen well, be sympathetic and get proper consultation and therapy. Do not be dismissive of the problem!Post-delivery lower extremity neuropathyTake a g
55、ood history and do a good physical.Rule out signs and symptoms of meningitis, spinal hematoma or infection.Do not hesitate to get Neurology consultation.Stay in touch with the patient.Obstetric palsyFrom nerve compression within the pelvis, by fetal head, forceps or retractors.Often blamed on neurax
56、ial anesthesia.Pelvicbrimistheredline.Fetalheadis“engaged”whenbiparietaldiameterisbelowpelvicbrim.Fetalheadorforcepscandamagenerves(lumbosacraltrunkorobturator)atsacralpromontoryportionofpelvicbrim.PelvicbrimPeripheralnervesinthepelvis.PelvicbrimDoteAnatomyTopicsCitedinWongetalVulnerablenervesinpelv
57、is:Lateralfemoralcutaneous(atinguinalligament)LumbosacraltrunkObturatorFemoralSciaticSafeguardstoMinimizePeripheralNerveCompressionBewatchfulforpatientpositioningthatcontributestonervecompressionAvoidprolongeduseofthelithotomyposition;regularlyreducehipflexionandabduction.Avoidprolongedpositioningth
58、atmaycausecompressionofthesciaticorperonealnerve.F.ReynoldsinChestnutSafeguardstoMinimizePeripheralNerveCompressionPlacethehipwedgeunderthebonypelvisratherthanthebuttock.Uselow-doselocalanesthetic/opioidcombinationsduringlabortominimizenumbnessandallowmaximummobility.Encouragetheparturienttochangepo
59、sitionregularly.F.ReynoldsinChestnutPeripheral Neuropathy Syndromesin Obstetrics“Meralgia Paresthetica” lateral femoral cutaneous nerve (pure sensory) numbness of lateral thigh. Common in pregnancy.Femoral nerve damage from prolonged hip flexion weak quadriceps. Cant straighten leg and climb stairs.
60、Peripheral Neuropathy Syndromesin ObstetricsFootdropImpairedfootdorsiflexiondueto:Commonperonealnerveatfibula(legholders)Lumbosacraltrunkatpelvicbrim(fetalhead)Impaireddorsi-andplantar-flexionoffootandnumbnessbelowknee:Sciaticnervedamage.PressureonbuttockduringlongCS?Diabeticpatient?ImpairedadductionofthighandinnerthighnumbnessobturatorpalsyatpelvicbrimThe EndExtra slidesSpinal nerve “roots” are within the spinal canal. Dorsal root ganglion is at intervertebral foramen.
