3 HISTORY1847 : Introduction of inhalational agents James Young Simpson on Jan 19, 1847 first used chloroform to anaesthetize a woman with a deformed pelvis for delivery. Early 20th century: Expanded use of opioids “Twilight sleep” was a technique developed by Von steinbuchel. It combined opioids with scopolamine to make women amnesic during labor . Mid 20th century ( ): Refinement of regional anaesthesia
4 INTRODUCTIONUntil 19th Century: Performed only for the most desperate situations, with very high mortality rates.Early 20th Century: Mortality rates 10%, but still performed only for the most severe cases of contracted pelvisIn India the caesarean rates have increased from 21.8% in to 25.4% in *(* Bhasin SK, Rajoura OP, Sharma AK,et al. A high prevalence of caesareansection rate in East Delhi. Indian J Community Med 2007;32:222-4)
5 CAESAREAN SECTIONIt is defined as the birth of an infant through incision in the abdomen(laparotomy) and uterus(hysterotomy).(derived from the latin word caedere which imply to cut)
6 INDICATIONS FOR CAESAREAN SECTION AbsoluteMaternalCephalo-pelvic DisproportionNon progression of labourFetal:Fetal DistressNon-cephalic presentationsMultiple gestationsPregnancy RelatedAbruptio PlacentaGrade 3 or 4 Placenta PreviaCervical obstructive lesionsLarge vulvar condylomataRelativeMaternalRelative CPDMaternal preferenceFetal:Twins with first in non cephalic presentationPregnancy RelatedLesser degrees APHPrevious Caesarean
7 COMPLICATIONS OF CS Hemorrhage Uterine atony Uterine laceration Broad ligament hematomaInfectionEndometritisWound infectionPost op complicationsCardiovascular: venous thromboembolismGastrointestinal: ileus, adhesions, injuryGenitourinary: bladder or ureter injuryRespiratory: atelectasis , aspirationChronic painFuture riskPlacenta previa,placenta accreta, uterine ruptureBefore we proceed to the anaesthetic management, we must know the complications associated with the procedure
8 PAIN PATHWAYS During Caesarean Section: Pain due to Incision – Pfannensteil / MidlinePain due to stretching to the skin and subcutaneous tissuesIntraperitoneal dissection and manipulationAdditional somatic pain due to diaphragmatic stimulationInvolves dermatomes up to T8 and visceral pain pathways up to T4 levelsImplications: Aim is to achieve T4 dermatomal level
9 Techniques of Anaesthesia: 1. Regional Anaesthesia Subarachnoid Block ANAESTHESIA FOR CASEAREAN SECTIONTechniques of Anaesthesia:1. Regional AnaesthesiaSubarachnoid BlockEpidural AnaesthesiaCombined Spinal-Epidural Anaesthesia2. General anaesthesia3. Local anaesthesia
10 Anaesthesia for Caesarean Section Depends on:Indication for CSUrgency of the procedureMaternal and fetal healthMaternal desiresIf time not a factor RA preferredEpidural for Labour Analgesia in-situ Extension of BlockRA contraindicated, or Emergency procedure GAThe surgical indication and therefore the speed of delivery. Anaesthetic considerations include the presence of an epidural catheter, the anticipation of difficult airway, contraindications to regional techniques or potential technical difficulties like spinal deformity and maternal preference.If time not a factor, RA is preferred for both planned and semi emergency situationsEmergency cases without anticipated difficult airway, SAB is givenIf Epidural catheter for labour analgesia in situ, block extended to levels adequate for caesareanIn Fetal Distress, Subarachnoid block is safe. Even if hypotension occurs, fetal circulation isn’t compromisedIf speed of delivery is of essence, RA is contraindicated or in severe maternal haemorrhage GA is administered.
11 Classification of caesarean section according to urgency Category 1- requiring IMMEDIATE delivery -a threat to maternal or fetal life Category 2- requiring URGENT delivery -maternal or fetal compromise that is not immediately life threatening Category 3- requiring EARLY delivery -no maternal or fetal compromise Category 4-ELECTIVE delivery -at time suited to the woman and maternity staff
12 Category 1 sections should be delivered within 15 minutes Examples of category 1 include- 1.Major haemorrhage 2.Profound and persistent fetal bradycardia 3.Prolapsed cord 4.Shoulder dystocia 5.Uterine rupture
13 REGIONAL ANAESTHESIA Definitive benefits over GA, including No risk of aspirationNo risk of failed intubation or ventilationLess blood lossLess fetal exposure to drugsBetter neurobehavioral score of fetus at birthAnalgesia can be extended to postoperative period
14 SPINAL ANAESTHESIA SAB most common and preferred technique for CS. Advantages of SAB DisadvantagesSimplicity of technique Limited DurationReliabilityRapid onset HypotensionDense neural blockLess shivering Prolonged Motor blockMinimal fetal exposure to drugs Nausea & Vomiting
15 EPIDURAL ANAESTHESIA Advantages Level Titrable Slower onset of sympathetic blockBlock height and Duration ExtendableLess intense motor blockPost operative analgesiaLess Chances of DVTDisadvantagesSlow onset of anaesthesiaIncreased failure ratesAccidental IV injectionCatheter migrationIncreased chances of total / high spinalTechnically difficultThe use of epidural anaesthesia for C.S has increased as a result of greater use of epidural analgesia during labour. Shivering increases oxygen demand, cardiac work and co2 production.
16 COMBINED SPINAL EPIDURAL ANAESTHESIA Rapid and predictable onset of SABAbility to augment anaesthesiaCSE TECHNIQUESUse of conventional doses of hyperbaric drugsSequential CSE techniqueExtradural volume extension (EVE) technique
17 COMBINED SPINAL EPIDURAL ANAESTHESIA Benefits:Lower intrathecal dose of LAIncreased success rates for correct epidural placementMore intense block, less intra operative pain compared to epiduralDisadvantages:Untested epidural catheterHypotensionHypotension is due to delay in making the patient supine from sitting position and enhanced spread of intra thecal LA following epidural injection
19 CONSIDERATIONS IN REGIONAL ANAESTHESIA Preloading/ co-loadingAnti aspiration prophylaxisPositioning in RAChoice of LAChoice of vasopressorsEpidural test doseComplications of RA i.e. Nausea and vomiting, Hypotension, Accidental intravascular injection or dural tap under Epidural anaesthesia, PDPH, LA toxicityBefore we move to the conduct of RA or GA , we would like to discuss the considerations under RA or GA
20 PRELOADING /CO-LOADING Preloading- rapid adminisration of crystalloids (1-1.5l) prior to initiation of intrathecal injection.Co-loading- rapid administration of crystalloids(20 ml/kg) initiated at the time of intrathecal injection.Crystalloids/ colloidsImplication – Initiation of anaesthesia should not be delayed in order to administer a fixed volume of fluid.Role of i.v fluids: decrease the frequency of neuraxial anaeshesia associated hypotension.A balanced salt solution – ringer lactate is preferred
21 Anti aspiration prophylaxis Increased risk of Gastric Aspiration in pregnancy↓ gastric motility↓ LES tone↑ gastric emptying time.↑ Intragastric pressure
22 Antiaspiration Prophylaxis: Planned CS: Ranitidine 150 mg and Metoclopramide 10 mg PO night before and minutes before surgeryEmergency CS :0.3M Sodium Citrate, 30mL PO 30 Min before Surgery.Ranitidine 50 mg IV + Metoclopramide, 10 mg IV prior to surgery.Na citrate does not dercrease the volume and dose need to be repeated if the surgery is prolonged .
23 POSITIONING IN RA Minimum left lateral tilt of 25º left lateral displacement to be maintained with a wedge under the right buttock .1o cm34 cm2.5 cm
24 POSITIONS FOR RA Lateral position better uteroplacental blood flow more comfortableminimises patient movement during needle insertionSitting positionDistance from skin to epidural space is shorterInterspinous spaces difficult to appreciateRestricted use : i.e. umbilical cord prolapse, footling presentation.Stands controversial
25 CHOICE OF LOCAL ANAESTHETIC FOR SAB DrugDosage (mg)Range (ml)Duration (min)Bupivacaine(H)(0.5%)7.5-151.5-360-120Ropivacaine15-25Lidocaine(H)(5% )60-8045-75choice of LA depend on the expected duration of surgery, post operative analgesia and preference of the anaesthetist. Bupivacaine is the DOC , LIGNOCAINE IS ASSOCIATED WWITH TNS. Ropivacaine is 40% less potent with less duration of sensory and motor blockade.chestnut’s obstetric anaesthesia (4th edition)
26 Local anaesthetics for epidural anaesthesia DrugDose rangeDuration(min)Bupivacaine 0.5%mgRopivacaine 0.5%Lignocaine 2% with epinephrine 5µg/mlmg75-100chestnut’s obstetric anaesthesia (4th edition)
27 DECREASE IN LOCAL ANAESTHETIC REQUIREMENT DURING PREGNANCY 1.↑ Neural susceptibility to LA2. Epidural plexus engorgement3. CSF changes a)↓CSF protein (↑unbound drug)b)↑ CSF pH (↑ unionised drug)4. Apex of thoracic kyphosis higher5.Pelvic widening & resultant head down tilt in lateral position
31 Side effects OF OPIOID ADJUVANTS PruritisDelayed respiratory depressionNausea and vomitingUrinary retentionReactivation of varicella zoster
32 Spinal Needles Quincke type Spinal Needles Whitacre type Spinal Needles
33 CHOICE OF VASOPRESSORS Ephedrine:mixed alpha and beta adrenergic receptor agonistIncrease blood pressure without a decrease in uterine blood flowDOSE – 10 mg prophylaxis5- 10 mg therapeuticS/ETachyphylaxisCan lower umbilical cord pH by1.Readily cross placenta cause fetal tachycardia2. Stimulate fetal metabolism by direct b-adrenergic effectmaternal tachycardia
34 Phenylephrine: (first line agent) alpha-receptor agonist Equally effective as ephedrinebetter umbilical cord pHbetter preserves uterine blood flowDose : µgS/E - maternal bradycardiaPhenylephrine is preferred as
35 Why phenylephrine? Does not have beta adrenergic agonist action thus No beta adrenergic action in fetus and thus better maintain fetal metabolismLeast chances of fetal acidosis or hypoxia, as reflected by better maintained umbilical cord pH.
36 EPIDURAL TEST DOSERole – To check the intrathecal and intravascular placement of epidural catheter3 ml LA + 15µg Epinephrin (1:200,000)Response - ↑HR- 30 bpm, ↑SBP – 20 mmHg in 45 sec.Test dose is less specific in labouring patientsPoints against routine use –Aspiration of multiorifice catheter is 98% sensitiveLow concentration of LARecommended 2 stage safety check is ASPIRATE and OBSERVE FOR 5 MIN.Epidural test dose is imp in obstetric patients as the incidence of accidental intravascular puncture is high. IN LABOUR LESS SPECIFIC as cyclic changes in maternal heart rate complicates its interpretation , test dose immediately after contractions.
37 RECOMMENDED SAFETY PROCEDURE BEFORE INJECTION OF TEST DOSE Perform aspiration testIn labour- 2 ml of % LA with out ADRFor C.S – 3 ml of % LA with 15µg (1: 200,000) ADRIn PIH, IUGR, DM or Fetal distress – Bupivacaine in 5 ml incrementsTest dose failure or Total spinal block – Treat promptlyPrince G et al: Obstetric epidural test dose. A reappraisal. Anaesthesia 1986.
38 Regional Anaesthesia – Complications HYPOTENSION : Def: ↓ in SBP of more than 20%-30% from baseline OR a SBP lower than 100 mm hg. Prevention : Left uterine displacement Prehydration Prophylaxis with vasopressor Leg elevation or wrapping Treatment : i.v fluids vasopressors
39 Regional Anaesthesia – Complications NAUSEA AND VOMITINGCAUSES –1.HypotensionhypotensionGut ischemia brain stem hypoperfusionRelease of emetogenic Stimulation of vomitingSubstance CentreVomiting
40 Treatment 2. Increased vagal activity 3. Surgical stimuli- exteriorisation of uterus4. Bleeding5. Drugs : ureterotonic agentsTreatmentPrevention of hypotensionMetoclopramideOndansetron
41 Regional Anaesthesia – Complications Post Dural Puncture HeadacheRisk factors:Age<40WomenPregnancyUse of wider guage and dura cutting spinl needle.Symptoms:Frontal / Occipital headachePositionalVarying severityNeck StiffnessOcular or Auditory symptomsOnset within 48 hoursPost Dural Puncture HeadacheFrontal or Occipital headache. Severity varies – Mild to debilitating.Symptoms worse when upright. Relieved in supine.Onset in first 48 hours. Last less than a week
42 Regional Anaesthesia – Complications PathophysiologyTreatment:Early: Psychological supportprevent dehydrationDrugs: NSAIDs, Caffeine, SumatriptanEpidural Saline PatchEpidural Blood Patch mL autologous blood used.Leakage of CSFTraction on pain sensitive structures2 people will wash up.Sumatirptan is a serotonin agonist with cerebral vasoconstrictor action. Given s/c
43 Regional Anaesthesia – Complications High Spinal Anaesthesia:Rostral spread of intrathecal dose, or Inadvertent intrathecal administration of epidural doseClinical Features:Complete motor and sensory palsy,Hypotension, Bradycardia,Unconsciousness,Loss of protective airway reflexes,respiratory arrestTreatment: Prompt tracheal intubation and ventilation with 100% oxygen, maintenance of maternal circulation
44 Regional anaesthesia – Complications ACCIDENTAL DURAL PUNCTUREIncidence-3% (in obstetric patients)Steps to be followed in case of accidental dural puncture*1.Injection of CSF from the epidural syringe back into the SAS through epidural needle2.Insertion of epidural catheter into the SAS3.Injection of NS through intrathecal catheter before removal4.Administration of continous intrathecal labour analgesia5.Leaving the intrathecal catheter in situ for a total of hours*Kuczkowski K M et.al. Acta Anaesthesiol scand :2003
45 Regional Anaesthesia – Complications LA toxicity:IV injection of LA.Bupivacaine most cardiotoxic,Toxicity enhanced in pregnancy.Clinical Features: Convulsions, ArrhythmiasCardiovascular collapseTreatment – for CNS Symptoms-symptomaticoxygen supplementation ,tracheal intubationPrevention – Epidural test dose with adrenalin 15µg.
46 ROLE OF INTRALIPIDRole - local anesthetic-induced cardiac arrest that is unresponsive to standard therapy, in addition to standard cardio-pulmonary resuscitationMechanism: . may serve as a “lipid sink”, providing a large lipid phase in the plasma, enabling capture of the local anaesthetic molecules and making them unavailable to tissues.-Dose regime:Intralipid 20% ,1.5 mL/kg i.v over 1 minute ,followed by 0.25 mL/kg/min,Repeat bolus every 3-5 minutes up to 3 mL/kg total dose untilcirculation is restoredMaximum dose - 8 mL/kg
47 Case 1 24 yr old, primigravidae, ASA grade I, with complaints of Amenorrhea for 9 monthsLeaking per vaginum for 2 hoursPain abdomen for 2 hoursObstetric history- WNLGPE – WNLPlan - Emergency LSCS in view of cephalopelvic dispropotion in labour.
48 PATIENT PREPARATION Single shot spinal anaesthesia Preanaesthetic evaluation –history-clinical examinationFasting was 8 hours.Informed consent takenInj Ranitidine (50 mg i.v.), Inj metoclopramide(10 mg i.v.) 30 min prior to surgeryMonitoring i.e.ECG, NIBP ,Pulse oximetry.Coloading : 1.5 l ringer lactatePositioning : Left lateral Displacement maintained with a Wedge under right buttock.
49 Sitting position25 G quincke needle; in L3-L-4 space ;10 mg(2 ml) of 0.5%bupivcaine HT4 level achieved .Oxygen by face mask to provide an FioNo hypotension reported.Pfannensteil Incision made, baby delivered within 15 min.Injection oxytocin (5U i.v. f/b 15 U slow i.v. in 500 ml RL)I/O - No complications.Post op : level – T6
50 ANAESTHESIA FOR CAESAREAN SECTION ROLE OF INTRAUTERINE RESUSCITATION MODERATOR: DR GEETANJALI
55 WHY DIFFICULT AIRWAY? Risk factor for airway complication in pregnancy Airway edemaWeight gainEnlarged breastFull dentitionDecreased LES toneReduced gastric emptying during labourRapid desaturation due to Increased oxygen consumption and reduced FRC.
56 AIRWAY ASSESSMENT1.Mallampatti classification 2.Atlanto occipital joint extension 3.Thyromental distance 4. Mandibular protrusion test Benumof’s 11 point sytem for evaluation of airway
57 AIRWAY ASSESSMENT1.Mallampatti classification 2.Atlanto occipital joint extension 3.Thyromental distance 4. Mandibular protrusion test Benumof’s 11 point sytem for evaluation of airway
58 CONSIDERATIONS IN GA Airway assesment Positioning Anti-aspiration prophylaxisPreoxygenationRSISkin incision – uterine incision time, Uterine incision – baby delivery timeUterotonic agentsExterioratization of uterusComplications i.e. Awareness, hypotension, Uterine atony, Blood loss, PONV, Difficult airway.
59 POSITIONINGCorrect positioning to maximise the chance of succesful intubation
60 RAMP POSITION in morbidly obese patients -ideal position leads to horizontal alignment between the external auditary meatus and sternal notch -achieved by use of blankets or commercially available devicesimprove oygenation and laryngoscopic view of glottis
62 CONSIDERATIONS IN GA Airway assessment Positioning Anti-aspiration prophylaxisPreoxygenationRSISkin incision – uterine incision time, Uterine incision – baby delivery timeUterotonic agentsExterioratization of uterusComplications i.e. Awareness, Pulmonary aspiration, Neonatal depression PONV, Difficult airway, hypotension, Uterine atony, Blood loss,
63 Conduct of general anaesthesia Preparation in OT:Machine checkDifficult Airway cart with short handle laryngoscopesOropharyngeal airwayOne extra styletted endotracheal tubeMagill forcepLaryngeal mask airwayIntubating Laryngeal mask airwayTrained assistant to be availableFiberoptic bronchoscopeVerify that surgeons are ready to begin the surgery
64 Conduct of General anaesthesia PreoxygenationAim : increase in oxygen content and maximise the time to desaturation.1. conventional method : normal tidal volume for 3 minutes2. 4 vital capacity breaths over 30 seconds(In emergency)vital capacity breaths over one minute.Rapid Sequence InductionThiopental 4-5 mg/kgContinued application of Cricoid Pressure (10 N when awake,increase to 30N after loss of consciousness.)Succinylcholine mg/kg; wait for seconds.
66 Recommended technique for General Anaesthesia Problem-Difficult laryngoscopy and failed intubation in group of patients who are already at risk of rapidly developing hypoxemia
67 Conduct of Anaesthesia - General Anaesthesia Sellick’s Manoeuvre:Dedicated Assistant20-30 N (2-3 Kg) ForceDirected backwardsContinued till airway secured and cuff is inflated
68 CLINICAL IMPLICATIONS INTRAVENOUS AGENTSAGENTF:MCLINICAL IMPLICATIONSREMARKSTHIOPENTONE0.4 to 1.1Freely diffusible. Prompt and reliable induction.Fetal brain levels < levels enough to cause depressionPopular agent of choiceNo analgesic and amnesic effects.PROPOFOL0.65 to 0.85(bolus 2 to 2.5 mg/kg)0.50 to mg/kg/hr)FDA – category B drugmay attenuate the response to laryngoscopy and intubationUBF no changeSedative effect on neonateLower 1 and 5 min apgar scores (2.8 mg/kg)KETAMINEETOMIDATE1.26( in 1.5 min)Used in hypotension and asthmaRapidly crosses placentaUsed in hemodynamic instability0.5
69 Conduct of Anaesthesia - General Anaesthesia Maintenance of Anaesthesia:GOALS:Adequate maternal and fetal oxygenationMaintain maternal normocapnia (avoid hyperventilation as it may lead to uteroplacental vasoconstriction)Appropriate depth to avoid awareness , promote maternal comfortMinimal effect on uterine tone.Minimal adverse effect on neonate.MONITORING - ASA recommended minimal mandatory monitors
70 Post-delivery: Pre-delivery: O2:N20 50:50 + 1 MAC Inhalational agent O2:N2O :: 30:70Reduction of Inhalation agent( MAC)Morphine 0.1 mg/kg or Fentanyl 1-2 µg/kg.Extubation done when neuromuscular blockade fully reversed and patient is awake and responds to command.
71 I-D TIME AND U-D TIMEInduction –delivery(I-D) time - less than 15 minutesUterine-delivery (U-D) interval- less than 90 secondsImplication – Abdomen preparation and draping should be done before induction of anaesthesia
72 UTEROTONIC AGENTS 1.Oxytocin infusion Route : i.v. Side effects :hypotension ,tachycardia, water intoxicationBolus injection Maternal tachycardia & HypotensionDose : 200 Mu/min2.MethylergometrinRoute :i.m /i.v.Side effect: Severe Hypertension, bradycardiaDose : 0.2 mg20U to 500mL makes 40U/mL. Ideally, it should run at 1-2 mL/Min
74 EXTERIORISATION OF UTERUS Increase the incidence of nausea and vomitingCause a tugging sensationRequire a higher level of dermatomal block
75 Complication of general anaesthesia AWARENESS AND RECALL Causes: 1.Avoidance of sedative premedication 2.Deliberate use of low concentration of volatile anaesthetic agent 3.Use of muscle relaxant 4.Reduction in dose of anesthetic agent during hypotension 5.The mistaken assumption that high baseline sympathetic tone is responsible for intraoperative tachycardia.
76 Role of Depth of Anaesthesia monitoring i.e. BIS BIS is an empirically derived EEG parametersVALIDATED to greater extentDesired value less than 60Reduces but can not prevent awareness episodes
77 For RA: How to avoid: Lyons and Macdonald* recommend- Larger induction dose of barbiturate(thiopental 5-7 mg/kg)Isoflurane 1% prior to deliveryAfter delivery: administration of opioid and decrease conc .of isofluraneFor RA:Midazolam mg/kg provide min of anterograde amnesia in RA(* Lyons G ,Macdonald R. Awareness during caesarean section. Anaesthesia 1991)
78 Complications of general anaesthesia ASPIRATION PNEUMONITISFirst Described by Mendelson in 1946.Chemical injury to tracheobronchial tree and alveoli caused by inhalation of sterile acidic gastric contents.RISK FACTORS:Gastric Volume > 25mLGastric pH < 2.5Predisposing Factors:Impaired LES toneImpaired laryngeal reflexesAltered gastric motilityAbsence of pre-operative fasting
80 Aspiration Pneumonitis DiagnosisTime of presentation variable First 24 HoursHistory of predisposing factorsWheeze & laboured breathingProgresses to ARDS and Pulmonary OedemaCXR Changes with Hypoxemia: Suspect Silent AspirationCXR: B/L fluffy interstitial shadows
81 Aspiration Pneumonitis Treatment:Mild Nebulisation, Oxygen InhalationSevere Prompt intubation &Tracheal Suctioning before Positive pressure ventilationPEEP, CPAP To maintain oxygenationMech. Ventilation Low tidal volume (6mL/kg) and Plateau Pressure <30 cm H20Fluids : CVP guidedAntibiotics- not efficaceous, can lead to infection by resistant organisms.Steroids- not recommendedNo role for prophylactic antibioticsIf used, should be either guided by culture reports of tracheobronchial aspirate, or broad spectrum empirical antibiotics with gram negative coverageNo role for steroid, though they are used81
82 Prevention - Antiaspiration Prophylaxis: Planned CS: Ranitidine 150 mg and Metoclopramide 10 mg PO night before and minutes before surgeryEmergency CS :0.3M Sodium Citrate, 30mL PO 30 Min before Surgery.Ranitidine 50 mg IV + Metoclopramide, 10 mg IV prior to surgery.Na citrate does not dercrease the volume and dose need to be repeated if the surgery is prolonged .
83 Fasting guidelines (ASA recommendations) Clear liquids : uncomplicated patients for c.s. can have clear liquid upto 2 hours before induction of anaesthesiaSolids :- solid food to be avoided in labouring patients- In elective surgery fasting should be 6-8 hours depending on the fat content
84 Complications of general anaesthesia HYPOTENSION –most important cause-Induction agents-intravenous-inhalationalUse of oxytocinMajor Blood loss /PPHTreatment –using the induction agent in appropriate dosesuse of vasopressors as previously discussedactive management of PPH
85 Complications of general anaesthesia UTERINE ATONYCauses:High parityOverdistended uterusProlonged labourAbnormal placentation hypotensionTreatment :Oxytocin(200mU/ min)Methylergometrine(0.2 mg i.m.)Prostaglandin F2α (250 µg i.m.)
86 Complications of general anaesthesia POST OP NAUSEA AND VOMITINGRisk factorsFemale genderHistory of motion sicknessUse of perioperative steroidsNon smoking status
87 Drugs used for prevention DoseTimeMetoclopramide10 mg i.v.Prior to surgery or after cord clampingOndansetron4 mg i.v.After cord clampingGranisetron40mcg/kg i.v.
88 CASE 222 yr primigravidae, ASA grade I, planned for emergency LSCS in view of cord prolapse with fetal distressObstetric history -WNLGPE : WNLAirway assessment- Mouth opening adequate-MPG 2-Neck movements-normal-TMD - WNL
89 Informed consent taken Inj ranitidine(50 mg i.v.), inj .metoclopramide (10 mg i.v.)Necessary equipment prepared, monitors attachedpreoxygenation with 100% oxygenAbdomen cleaned and draped side by sideRSI with cricoid pressure,4mg/kg thiopentone,confirm ventilationSuccinylcholine 1.5 mg/kg,Laryngocopic view of glottis (Cormack & Lehane GRADE III)Failed tracheal intubation(2 attempts with change of blade, use of styletted ET tube and change of hand)
90 Ventilate with 100% Oxygen Facemask with cricoid pressure OR Management of FailedIntubation in PregnantPatientsFailed IntubationCall for helpVentilate with 100% OxygenFacemask with cricoid pressure ORLMA and cricoid pressureAssess Ventilation and OxygenationAdequate
92 Rosen’s Modification of Tunstall Drill (Failed Intubation Drill) 1.Maintain Cricoid PressurePlace the patient Left lateral, Head Down.2.Maintain oxygenation by IPPV with 100% oxygenIf difficult- Try change in position, oropharyngeal airwayor 2 person mask ventilation3.If airway obstruction persists, Release cricoid pressure.4. If ventilation & oxygenation easy, ventilate with oxygen, nitrous oxideAnd halogenated agent.Proceed with surgery with face mask ventilationAllow resumption of spontaneous ventilation5.Aspirate gastric contents & instil nonparticulate antacid with Orogastrictube. Withdraw tube while suctioning oropharynx.6.Level table. Place patient supine. Allow surgery to continue withInhalational anaesthesia. Expert paediatrician must be present.
93 CVCI Management of Failed Intubation in Pregnant Patients Call for helpVentilate with 100% OxygenFacemask with cricoid pressure ORLMA and cricoid pressureAssess Ventilation and OxygenationInadequateCVCIConsider Non surgical AirwayLMA with Cricoid Pressure ORCombitube ORTTJVSurgical Airway:Cricothyrotomy ORTracheostomyDeliver Baby
94 “ Parturients die of desaturation rather than not being able to intubate”
95 Use of PLMA in obstetrics As a rescue device in cases where conventional mask ventilation is difficult/ impossible.As a conduit for intubation in case of difficult intubation.To facilitate fibreoptic intubation with bronchoscope.Role in Elective casesarean delivery - yet to be established
96 Han TH, Briamacombe J et al Han TH, Briamacombe J et al. The Classic laryngeal mask airway is effective and probably safe in selected healthy parturients for elective caesarean delivery: A prospective study of 1067 cases. Can J Anesth 2001.Conclusion – LMA is effective and probably safe for Casearean section in healthy selected parturients when managed by experienced LMA user
97 Halaseh RK, et al. The use of PLMA in casearean section experience in 3000 cases. Anesth Intensive Care 2010Conclusion –PLMASelected patientsMETHOD OF INSERTIONNo aspirationGood alternative to TT
98 Disadvantages :Placement can induce vomiting, laryngospasmAspiration of gastric contents is not prevented.Improper positioning can lead to gastric insufflationUse of PPV may be limited.Multiple insertion attempts may lead to airway trauma.However, use of PLMA avoid these disadvantages to an extent
99 Intrauterine fetal resuscitation 1. Optimise maternal positionRelieve aortocaval compressionRelieve umbilical cord compression2. Administer supplemental oxygen3. Maintain maternal circulationRapid administratiom of i.v. fluidsUse of vasopressors to treat hypotension. In case of uterine tachysystole or hypertonusAdministration of tocolyticUse of nitroglycerin ( µg i.v.) provide uterine relaxation in seconds .
100 KEY POINTSDuring pregnancy LES tone is ↓, gastric motility ↓ - Increased risk of aspirationThe gastrointestinal changes persist 36 hours post deliveryRole of supplemental oxygen during RA -in non compromised fetus – questionableLeft uterine displacement essential , irrespective of technique usedUmbilical cord prolapse without fetal distress- not an absolute indication of GA
101 The combination of aspiration, test dose and fractionation of dose increases the safety Cricoid pressure can increase the C/ L grading by 1End tidal MAC requirement of IAA to be maintained to 1 to prevent maternal awareness and uterine relaxationWhile choosing IAA, must consider reduced MAC in obstetric patients as well as the potential for maternal awareness and uterine relaxation
102 REFERENCESObstetric Anaesthesia, Principles and Practice, David H Chestnut, 4th EdMiller’s Anesthesia, 7th EdWylie and Churchill Davidson’s A Practice of Anaesthesia, 7th EdBarash & Stolting AnaesthesiaMorgan’s Anaesthesia.
105 Conduct of Anaesthesia - General Anaesthesia Inducing Agents: Thiopentone Sodium, Ketamine, Propofol.Thiopentone Sodium:Most popular. SafePrompt and reliable inductionNo airway irritability.Dose: 4-5mg/kgCrosses placenta.Peak UV conc. In 1 minuteUA:UV ratio 0.87 at I-D interval 8-22 minFetal brain levels < levels enough to cause depressionDisadvantage:No analgesic and amnesic effects.
106 Propofol: Controversial Rapid smooth induction, rapid awakening. Dose: 2-2.5mg/kgF:M ratio at Delivery: 0.7Neonatal Apgar scores and neurobehavioral scores lower in propofol group compared to Thiopentone(Celleno et al)Greater incidence of maternal hypotension –may attenuate the response to laryngoscopy and intubationMore expensive, provide vehicle for bacterial growth
107 Ketamine: Rapid onset. Has sympathomimetic action. Better in Asthma and hypovolemiaProvides analgesia, amnesia and hypnosisDose 1mg/kg.100% oxygen can be administeredDisadvantagesIncreases laryngoscopy and intubation response,myocardial depression
108 Vecuronium: Rocuronium: Muscle Relaxants: Succinyl Choline: Dose-1-1.5mg/KgOptimal intubation time of 45 SecMinimal placental transferRocuronium:Dose: 0.6mg/kg (Intubation time 98 sec)mg/kg (48 sec)Duration of action prolonged: Anticipated difficult airwayVecuronium:Dose:0.1 mg/kg(onset time -144 sec)Used when scholine is contraindicatedDose reduction not needed because the decrease in pseudocholinestrase activity in pregnancy is offset by increase in total body water.