ANAESTHESIA FOR CAESAREAN SECTION

ROLE OF INTRAUTERINE RESUSCITATION

Presenter: Dr Neha GuptaModerator: Dr Geetanjali

University College of Medical Sciences & GTB Hospital, Delhi

www.anaesthesia.co.in email: anaesthesia.co.in@gmail.com

James Young Simpson (1811-1870)

HISTORY1847 : Introduction of inhalational agentsJames 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 (1900-1930): Refinement of regional anaesthesia

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 pelvis

In India the caesarean rates have increased from 21.8% in 1988-89 to 25.4% in 1993-94*

(* Bhasin SK, Rajoura OP, Sharma AK,et al. A high prevalence of caesarean section rate in East Delhi. Indian J Community Med 2007;32:222-4) 

CAESAREAN SECTION

It 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)

INDICATIONS FOR CAESAREAN SECTIONAbsoluteAbsoluteMaternalCephalo-pelvic DisproportionNon progression of labourFetal:Fetal DistressNon-cephalic presentationsMultiple gestationsPregnancy RelatedAbruptio PlacentaGrade 3 or 4 Placenta PreviaCervical obstructive lesionsLarge vulvar condylomata

RelativeRelativeMaternalRelative CPDMaternal preferenceFetal:Twins with first in non

cephalic presentation

Pregnancy RelatedLesser degrees APHPrevious Caesarean

COMPLICATIONS OF CSHemorrhage• Uterine atony• Uterine laceration• Broad ligament hematomaInfection• Endometritis• Wound infectionPost op complications• Cardiovascular: venous thromboembolism• Gastrointestinal: ileus, adhesions, injury• Genitourinary: bladder or ureter injury• Respiratory: atelectasis , aspirationChronic painFuture risk• Placenta previa,placenta accreta, uterine rupture

PAIN PATHWAYSDuring 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 levels

Implications: Aim is to achieve T4 dermatomal level

ANAESTHESIA FOR CASEAREAN SECTION

Techniques of Anaesthesia:1. Regional Anaesthesia• Subarachnoid Block• Epidural Anaesthesia• Combined Spinal-Epidural Anaesthesia

2. General anaesthesia3. Local anaesthesia

Anaesthesia for Caesarean SectionDepends on:• Indication for CS• Urgency of the procedure• Maternal and fetal health• Maternal desiresIf time not a factor RA preferredEpidural for Labour Analgesia in-situ

Extension of BlockRA contraindicated, or Emergency procedure

GA

Classification of caesarean section according to urgencyCategory 1- requiring IMMEDIATE delivery -a threat to maternal or fetal lifeCategory 2- requiring URGENT delivery -maternal or fetal compromise that is not

immediately life threatening

Category 3- requiring EARLY delivery -no maternal or fetal compromiseCategory 4-ELECTIVE delivery -at time suited to the woman and maternity

staff

Category 1 sections should be delivered within 15 minutes

Examples of category 1 include-1.Major haemorrhage2.Profound and persistent fetal

bradycardia3.Prolapsed cord4.Shoulder dystocia5.Uterine rupture

REGIONAL ANAESTHESIADefinitive 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

SPINAL ANAESTHESIASAB most common and preferred technique for CS.

Advantages of SABDisadvantages

• Simplicity of technique Limited Duration• Reliability• Rapid onset Hypotension• Dense neural block• Less shivering Prolonged Motor block • Minimal fetal exposure to drugs Nausea &

Vomiting

EPIDURAL ANAESTHESIAAdvantages

Level TitrableSlower onset of

sympathetic blockBlock height and

Duration Extendable Less intense motor

blockPost operative

analgesiaLess Chances of DVT

DisadvantagesSlow onset of

anaesthesiaIncreased failure ratesAccidental IV injectionCatheter migration Increased chances of

total / high spinalTechnically difficult

COMBINED SPINAL EPIDURAL ANAESTHESIA Rapid and predictable onset of SABAbility to augment anaesthesia

CSE TECHNIQUES1.Use of conventional doses of hyperbaric

drugs2.Sequential CSE technique3.Extradural volume extension (EVE) technique

COMBINED SPINAL EPIDURAL ANAESTHESIA Benefits:Lower intrathecal dose of LAIncreased success rates for correct epidural

placementMore intense block, less intra operative pain

compared to epidural

Disadvantages:Untested epidural catheterHypotension

GENERAL ANAESTHESIAIndications:

• Maternal refusal• Local site infection• Raised intracranial

tension • Severe Fetal Distress • Acute maternal

hypovolemia• Significant

coagulopathy• Inadequate RA/failed RA

Relative Contraindications:

• Anticipated difficult airway

• Malignant hyperthermia

• Severe asthma

CONSIDERATIONS IN REGIONAL ANAESTHESIAPreloading/ co-loadingAnti aspiration prophylaxisPositioning in RAChoice of LAChoice of vasopressorsEpidural test dose Complications of RA i.e. Nausea and

vomiting, Hypotension, Accidental intravascular injection or dural tap under Epidural anaesthesia, PDPH, LA toxicity

PRELOADING /CO-LOADINGPreloading- 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/ colloids

Implication – Initiation of anaesthesia should not be delayed in order to administer a fixed volume of fluid.

Anti aspiration prophylaxis Increased risk of

Gastric Aspiration in pregnancy

- ↓ gastric motility- ↓ LES tone - ↑ gastric emptying

time.- ↑ Intragastric

pressure

Antiaspiration Prophylaxis:Planned CS: Ranitidine 150 mg and Metoclopramide 10 mg

PO night before and 60-90 minutes before surgery

Emergency CS :• 0.3M Sodium Citrate, 30mL PO 30 Min before

Surgery.• Ranitidine 50 mg IV + Metoclopramide, 10

mg IV prior to surgery.

POSITIONING IN RAMinimum left lateral tilt of 25ºleft lateral displacement to be maintained

with a wedge under the right buttock .

1o cm

34 cm 2.5

cm

POSITIONS FOR RA Lateral position • better

uteroplacental blood flow

• more comfortable• minimises patient

movement during needle insertion

Sitting position• Distance from skin

to epidural space is shorter

• Interspinous spaces difficult to appreciate

• Restricted use : i.e. umbilical cord prolapse, footling presentation.

CHOICE OF LOCAL ANAESTHETIC FOR SABDrug Dosage (mg) Range (ml) Duration

(min)

Bupivacaine(H)(0.5%)

7.5-15 1.5-3 60-120

Ropivacaine 15-25 60-120

Lidocaine(H) (5% )

60-80 1.2-1.5 45-75

chestnut’s obstetric anaesthesia (4th edition)

Local anaesthetics for epidural anaesthesia Drug Dose range Duration(min)

Bupivacaine 0.5% 75-125 mg 120-180

Ropivacaine 0.5% 75-125 mg 120-180

Lignocaine 2% with epinephrine 5µg/ml

300-500 mg 75-100

chestnut’s obstetric anaesthesia (4th edition)

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 higher 5.Pelvic widening & resultant head down tilt in lateral

position

Pelvic widening & resultant head down tilt

Adjuvant agents

ADVANTAGES

Improves the quality of intraoperative anaesthesia

Prolongs the postoperative analgesiaReduce the dose of LA and thus the side

effects

ADJUVANTS DRUG DOSAGE Range(ml) Duration(min)

Fentanyl(5o µg/ml)

10-25 µg 0.2-0.5 180-240

morphine 0.1-0.25 mg 720-1440

Sufentanyl 2.5-5µg 180-240

Midazolam 1-2 mg

Side effects OF OPIOID ADJUVANTSPruritisDelayed respiratory depressionNausea and vomitingUrinary retentionReactivation of varicella zoster

Spinal NeedlesQuincke type Spinal NeedlesQuincke type Spinal Needles

Whitacre type Spinal NeedlesWhitacre type Spinal Needles

CHOICE OF VASOPRESSORSEphedrine:• mixed alpha and beta adrenergic receptor agonist• Increase blood pressure without a decrease in uterine

blood flow

DOSE – 10 mg prophylaxis 5- 10 mg therapeuticS/E• Tachyphylaxis • Can lower umbilical cord pH by1.Readily cross placenta cause fetal tachycardia2. Stimulate fetal metabolism by direct b-adrenergic effect• maternal tachycardia

Phenylephrine: (first line agent)• alpha-receptor agonist • Equally effective as ephedrine• better umbilical cord pH • better preserves uterine blood flow

Dose : 50- 100 µg

S/E - maternal bradycardia

Why phenylephrine?Does not have beta adrenergic agonist action

thusNo beta adrenergic action in fetus and thus

better maintain fetal metabolism Least chances of fetal acidosis or hypoxia, as

reflected by better maintained umbilical cord pH.

EPIDURAL TEST DOSERole – To check the intrathecal and intravascular

placement of epidural catheter 3 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.

RECOMMENDED SAFETY PROCEDURE BEFORE INJECTION OF TEST DOSE

Perform aspiration testIn labour- 2 ml of 1.5- 2% LA with out ADRFor C.S – 3 ml of 1.5- 2% 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

promptly

Prince G et al: Obstetric epidural test dose. A reappraisal. Anaesthesia 1986.

Regional Anaesthesia – ComplicationsHYPOTENSION :

Def: ↓ in SBP of more than 20%-30% from baseline

OR a SBP lower than 100 mm hg.Prevention : Left uterine displacementPrehydrationProphylaxis with vasopressorLeg elevation or wrappingTreatment : i.v fluids vasopressors

Regional Anaesthesia – Complications NAUSEA AND VOMITINGCAUSES –1.Hypotension hypotension

Gut ischemia brain stem hypoperfusion

Release of emetogenic Stimulation of vomitingSubstance Centre

Vomiting

2. Increased vagal activity3. Surgical stimuli- exteriorisation of uterus4. Bleeding 5. Drugs : ureterotonic agents

Treatment• Prevention of hypotension• Metoclopramide• Ondansetron

Regional Anaesthesia – ComplicationsPost Dural Puncture HeadacheRisk factors: • Age<40• Women • Pregnancy• Use of wider guage and dura cutting spinl needle.

Symptoms:• Frontal / Occipital headache• Positional• Varying severity• Neck Stiffness• Ocular or Auditory symptoms• Onset within 48 hours

Regional Anaesthesia – ComplicationsPathophysiology

Treatment:Early: Psychological support

prevent dehydrationDrugs: NSAIDs, Caffeine, SumatriptanEpidural Saline PatchEpidural Blood Patch-15-20 mL autologous blood

used.

Leakage of CSF Traction on pain sensitive structures

Regional Anaesthesia – ComplicationsHigh 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 arrest

Treatment: Prompt tracheal intubation and ventilation with 100% oxygen, maintenance of maternal circulation

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 12-

20 hours*Kuczkowski K M et.al. Acta Anaesthesiol scand :2003

Regional Anaesthesia – ComplicationsLA toxicity: IV injection of LA.

Bupivacaine most cardiotoxic, Toxicity enhanced in pregnancy.

Clinical Features: Convulsions, Arrhythmias Cardiovascular collapseTreatment – for CNS Symptoms-symptomatic oxygen supplementation ,tracheal

intubation Prevention – Epidural test dose with adrenalin 15µg.

ROLE OF INTRALIPIDRole - local anesthetic-induced cardiac arrest that is

unresponsive to standard therapy, in addition to standard cardio-pulmonary resuscitation

Mechanism: . 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 restored Maximum dose - 8 mL/kg

Case 1 24 yr old, primigravidae, ASA grade I, with

complaints of• Amenorrhea for 9 months• Leaking per vaginum for 2 hours• Pain abdomen for 2 hoursObstetric history- WNLGPE – WNLPlan - Emergency LSCS in view of

cephalopelvic dispropotion in labour.

Single shot spinal anaesthesia

PATIENT PREPARATION• Preanaesthetic evaluation –history -clinical examinationFasting was 8 hours.• Informed consent taken• Inj Ranitidine (50 mg i.v.), Inj metoclopramide(10

mg i.v.) 30 min prior to surgery

• Monitoring i.e.ECG, NIBP ,Pulse oximetry. • Coloading : 1.5 l ringer lactate• Positioning : Left lateral Displacement maintained

with a Wedge under right buttock.

• Sitting position• 25 G quincke needle; in L3-L-4 space ; • 10 mg(2 ml) of 0.5%bupivcaine H• T4 level achieved .• Oxygen by face mask to provide an Fio2 0.5 -0.6• No 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

ANAESTHESIA FOR CAESAREAN SECTION

ROLE OF INTRAUTERINE RESUSCITATION

MODERATOR: DR GEETANJALI

GENERAL ANAESTHESIA

GA associated mortality

Pulmonary aspiration- 1: 400-500 versus 1: 2000

Failed tracheal intubation – 1: 300 versus 1: 2000

CONSIDERATIONS IN GAAirway assesmentPositioningAnti-aspiration prophylaxisPreoxygenationRSI Skin incision – uterine incision time, Uterine incision –

baby delivery timeUterotonic agentsExterioratization of uterusComplications i.e. Awareness,Aspiration,Difficult airway,

altered neonatal outcome, hypotension and others

WHY DIFFICULT AIRWAY?

WHY DIFFICULT AIRWAY? Risk factor for airway complication in pregnancy1.Airway edema2.Weight gain3.Enlarged breast4. Full dentition5. Decreased LES tone6.Reduced gastric emptying during labour

Rapid desaturation due to Increased oxygen consumption and reduced FRC.

AIRWAY ASSESSMENT1.Mallampatti classification2.Atlanto occipital joint extension3.Thyromental distance4. Mandibular protrusion test

Benumof’s 11 point sytem for evaluation of airway

AIRWAY ASSESSMENT1.Mallampatti classification2.Atlanto occipital joint extension3.Thyromental distance4. Mandibular protrusion test

Benumof’s 11 point sytem for evaluation of airway

CONSIDERATIONS IN GAAirway assesmentPositioningAnti-aspiration prophylaxisPreoxygenationRSI Skin incision – uterine incision time, Uterine incision –

baby delivery timeUterotonic agentsExterioratization of uterusComplications i.e. Awareness, hypotension, Uterine

atony, Blood loss, PONV, Difficult airway.

POSITIONING

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 devices

Commercially available RAMP

CONSIDERATIONS IN GA Airway assessmentPositioningAnti-aspiration prophylaxisPreoxygenationRSI Skin 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,

Conduct of general anaesthesiaPreparation in OT: Machine check

Difficult Airway cart with short handle laryngoscopesOropharyngeal airwayOne extra styletted endotracheal tubeMagill forcepLaryngeal mask airwayIntubating Laryngeal mask airwayTrained assistant to be availableFiberoptic bronchoscope

Verify that surgeons are ready to begin the surgery

Conduct of General anaesthesiaPreoxygenationAim : increase in oxygen content and maximise the time to

desaturation.1. conventional method : normal tidal volume for 3 minutes

2. 4 vital capacity breaths over 30 seconds(In emergency)

3. 8 vital capacity breaths over one minute.Rapid Sequence Induction• Thiopental 4-5 mg/kg• Continued application of Cricoid Pressure (10 N when

awake,increase to 30N after loss of consciousness.)• Succinylcholine 1-1.5 mg/kg; wait for 30-40 seconds.

Why Rapid Sequence Induction?

Recommended technique for General Anaesthesia

Problem- Difficult laryngoscopy and failed

intubation in group of patients who are already at risk of rapidly developing hypoxemia

Conduct of Anaesthesia - General AnaesthesiaSellick’s Manoeuvre:Dedicated Assistant20-30 N (2-3 Kg)

ForceDirected backwardsContinued till airway

secured and cuff is inflated

INTRAVENOUS AGENTSAGENT F:M CLINICAL

IMPLICATIONSREMARKS

THIOPENTONE

0.4 to 1.1 Freely diffusible. Prompt and reliable induction. Fetal brain levels < levels enough to cause depressionPopular agent of choice

No analgesic and amnesic effects.

PROPOFOL 0.65 to 0.85(bolus

2 to 2.5 mg/kg)0.50 to

0.54 (inf @ 6-9

mg/kg/hr)

FDA – category B drugmay attenuate the response to laryngoscopy and intubation UBF no change

Sedative effect on neonateLower 1 and 5 min apgar scores (2.8 mg/kg)

KETAMINE

ETOMIDATE

1.26( in 1.5 min)

Used in hypotension and asthma

Rapidly crosses placenta 0.5

Used in hemodynamic instability

Conduct of Anaesthesia - General Anaesthesia Maintenance of Anaesthesia:• GOALS:1.Adequate maternal and fetal oxygenation2.Maintain maternal normocapnia (avoid

hyperventilation as it may lead to uteroplacental vasoconstriction)

3.Appropriate depth to avoid awareness , promote maternal comfort

4.Minimal effect on uterine tone.5.Minimal adverse effect on neonate.

MONITORING - ASA recommended minimal mandatory monitors

• Pre-delivery: O2:N20 50:50 + 1 MAC Inhalational agent

• Post-delivery: • O2:N2O :: 30:70

• Reduction of Inhalation agent(0.5-0.75 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.

I-D TIME AND U-D TIME• Induction –delivery(I-D) time - less than 15

minutes • Uterine-delivery (U-D) interval- less than

90 seconds

Implication – Abdomen preparation and draping should be done before induction of anaesthesia

UTEROTONIC AGENTS1.Oxytocin infusion• Route : i.v.• Side effects :hypotension ,tachycardia, water

intoxication• Bolus injection Maternal tachycardia &

Hypotension• Dose : 200 Mu/min

2.Methylergometrin• Route :i.m /i.v. • Side effect: Severe Hypertension, bradycardia• Dose : 0.2 mg

3.PGF2 alpha (carboprost)• Route : i.m. /intramyometrial• Side Effects: Nausea, Vomiting, diarrhoea,

Fever, Tachycardia, Hypertension, Bronchoconstriction

• Contraindication: Bronchial Asthma• Dose - 250 µg• Max Dose – 2gm

EXTERIORISATION OF UTERUS Increase the incidence of nausea and

vomitingCause a tugging sensationRequire a higher level of dermatomal block

Complication of general anaesthesiaAWARENESS AND RECALLCauses:1.Avoidance of sedative premedication2.Deliberate use of low concentration of volatile

anaesthetic agent3.Use of muscle relaxant4.Reduction in dose of anesthetic agent during

hypotension5.The mistaken assumption that high baseline

sympathetic tone is responsible for intraoperative tachycardia.

Role of Depth of Anaesthesia monitoring i.e. BIS

BIS is an empirically derived EEG parametersVALIDATED to greater extentDesired value less than 60 Reduces but can not prevent awareness

episodes

How to avoid:Lyons and Macdonald* recommend-• Larger induction dose of barbiturate(thiopental 5-7

mg/kg)• Isoflurane 1% prior to delivery• After delivery: administration of opioid and decrease

conc .of isoflurane

For RA:Midazolam 0.075 mg/kg provide 30-60 min of

anterograde amnesia in RA

(* Lyons G ,Macdonald R. Awareness during caesarean section. Anaesthesia 1991)

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 > 25mL Gastric pH < 2.5Predisposing Factors:

Impaired LES toneImpaired laryngeal reflexesAltered gastric motilityAbsence of pre-operative fasting

Aspiration PneumonitisPathophysiology:

Epithelial DegenerationEpithelial DegenerationInterstitial & Alveolar OedemaInterstitial & Alveolar OedemaHaemorrhage into alveoliHaemorrhage into alveoli

ARDS & Pulmonary oedemaARDS & Pulmonary oedema

Destruction of Destruction of PneumocytesPneumocytes

Decreased Decreased SurfactantSurfactant

Hyaline membraneHyaline membraneFormationFormation

V/Q mismatchV/Q mismatch

Destruction ofDestruction ofMicrovasculatureMicrovasculature

Increased PulmonaryIncreased PulmonaryVascular ResistanceVascular Resistance

Increased Vd/VtIncreased Vd/Vt

Aspiration of A

cidic A

spiration of Acidic

Contents

Contents

Aspiration PneumonitisDiagnosisTime of presentation variable First 24 HoursHistory of predisposing factorsWheeze & laboured breathing Progresses to ARDS and Pulmonary OedemaCXR Changes with Hypoxemia: Suspect Silent

AspirationCXR: B/L fluffy interstitial shadows

Aspiration PneumonitisTreatment:Mild Nebulisation, Oxygen Inhalation

Severe Prompt intubation &Tracheal Suctioning before Positive pressure ventilation

PEEP, CPAP To maintain oxygenationMech. Ventilation Low tidal volume (6mL/kg)

and Plateau Pressure <30 cm H20Fluids : CVP guided Antibiotics- not efficaceous, can lead to infection

by resistant organisms. Steroids- not recommended

Prevention - Antiaspiration Prophylaxis:Planned CS: Ranitidine 150 mg and Metoclopramide 10 mg

PO night before and 60-90 minutes before surgery

Emergency CS :• 0.3M Sodium Citrate, 30mL PO 30 Min before

Surgery.• Ranitidine 50 mg IV + Metoclopramide, 10

mg IV prior to surgery.

Fasting guidelines (ASA recommendations)Clear liquids : uncomplicated patients for c.s.

can have clear liquid upto 2 hours before induction of anaesthesia

Solids :- solid food to be avoided in labouring patients

- In elective surgery fasting should be 6-8 hours depending on the fat content

Complications of general anaesthesia HYPOTENSION –most important cause-• Induction agents-intravenous -inhalational• Use of oxytocin• Major Blood loss /PPHTreatment –• using the induction agent in appropriate doses • use of vasopressors as previously discussed • active management of PPH

Complications of general anaesthesia UTERINE ATONYCauses:• High parity • Overdistended uterus• Prolonged labour• Abnormal placentation hypotension

Treatment :• Oxytocin(200mU/ min)• Methylergometrine(0.2 mg i.m.)• Prostaglandin F2α (250 µg i.m.)

Complications of general anaesthesia

POST OP NAUSEA AND VOMITINGRisk factors• Female gender• History of motion sickness• Use of perioperative steroids• Non smoking status

Drug Dose Time

Metoclopramide 10 mg i.v. Prior to surgery or after cord clamping

Ondansetron 4 mg i.v. After cord clamping

Granisetron 40mcg/kg i.v. After cord clamping

Drugs used for prevention

CASE 222 yr primigravidae, ASA grade I, planned for

emergency LSCS in view of cord prolapse with fetal distress

• Obstetric history -WNL• GPE : WNL

• Airway assessment- Mouth opening adequate -MPG 2 -Neck movements-normal -TMD - WNL

• Informed consent taken • Inj ranitidine(50 mg i.v.), inj .metoclopramide (10 mg i.v.)• Necessary equipment prepared, monitors attached preoxygenation with 100% oxygen Abdomen cleaned and draped side by side RSI with cricoid pressure, 4mg/kg thiopentone, confirm ventilation Succinylcholine 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)

Failed Failed IntubationIntubation

Call for helpCall for helpVentilate with 100% OxygenVentilate with 100% Oxygen(1)(1)Facemask with cricoid pressure ORFacemask with cricoid pressure OR(2)(2)LMA and cricoid pressureLMA and cricoid pressure

Assess Ventilation and OxygenationAssess Ventilation and Oxygenation

AdequateAdequate

Management of Failed Management of Failed Intubation in PregnantIntubation in PregnantPatientsPatients

Assess Fetus Fetus

Fetal DistressFetal Distress

Surgical AirwaySurgical Airway

No Fetal Distress

Awaken PatientAwaken Patient

Intubate Regional

SucceedFailSucceed

Extubate overJet Stylet

Fail

Mask with cricoid pressure

Rosen’s Modification of Tunstall Drill(Failed Intubation Drill)

1.Maintain Cricoid Pressure Place the patient Left lateral, Head Down.

2.Maintain oxygenation by IPPV with 100% oxygen If difficult- Try change in position, oropharyngeal airway or 2 person mask ventilation

3.If airway obstruction persists, Release cricoid pressure.

4. If ventilation & oxygenation easy, ventilate with oxygen, nitrous oxide And halogenated agent. Proceed with surgery with face mask ventilation Allow resumption of spontaneous ventilation

5.Aspirate gastric contents & instil nonparticulate antacid with Orogastric tube. Withdraw tube while suctioning oropharynx.

6.Level table. Place patient supine. Allow surgery to continue with Inhalational anaesthesia. Expert paediatrician must be present.

Failed IntubationFailed Intubation

Call for helpCall for helpVentilate with 100% OxygenVentilate with 100% Oxygen(1)(1) Facemask with cricoid pressure ORFacemask with cricoid pressure OR(2)(2) LMA and cricoid pressureLMA and cricoid pressure

Assess Ventilation and OxygenationAssess Ventilation and Oxygenation

InadequateInadequate

Consider Non surgical AirwayConsider Non surgical Airway(1)(1) LMA with Cricoid Pressure ORLMA with Cricoid Pressure OR(2)(2) Combitube ORCombitube OR(3)(3) TTJVTTJV

Surgical Airway:Surgical Airway:(1)(1) Cricothyrotomy ORCricothyrotomy OR(2)(2) TracheostomyTracheostomy

Deliver BabyDeliver Baby

Management of Failed Management of Failed Intubation in PregnantIntubation in PregnantPatientsPatients

CVCI

“ Parturients die of desaturation rather than not being able to intubate”

1. As a rescue device in cases where conventional mask ventilation is difficult/ impossible.

2. As a conduit for intubation in case of difficult intubation.

3. To facilitate fibreoptic intubation with bronchoscope.

4. Role in Elective casesarean delivery - yet to be established

Use of PLMA in obstetrics

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

Halaseh RK, et al. The use of PLMA in casearean section experience in 3000 cases. Anesth Intensive Care 2010

Conclusion – PLMASelected patientsMETHOD OF INSERTION No aspiration Good alternative to TT

Disadvantages :

1.Placement can induce vomiting, laryngospasm

2.Aspiration of gastric contents is not prevented.

3.Improper positioning can lead to gastric insufflation

4.Use of PPV may be limited.

5.Multiple insertion attempts may lead to airway trauma.

However, use of PLMA avoid these disadvantages to an extent

Intrauterine fetal resuscitation1. Optimise maternal position• Relieve aortocaval compression• Relieve umbilical cord compression2. Administer supplemental oxygen3. Maintain maternal circulation• Rapid administratiom of i.v. fluids• Use of vasopressors to treat hypotension . In case of uterine tachysystole or hypertonus• Administration of tocolytic• Use of nitroglycerin (50-100 µg i.v.) provide uterine

relaxation in 40-45 seconds .

KEY POINTS During pregnancy LES tone is ↓, gastric motility

↓ - Increased risk of aspiration The gastrointestinal changes persist 36 hours

post delivery Role of supplemental oxygen during RA -in non

compromised fetus – questionable Left uterine displacement essential ,

irrespective of technique used Umbilical cord prolapse without fetal distress-

not an absolute indication of GA

The combination of aspiration, test dose and fractionation of dose increases the safety

Cricoid pressure can increase the C/ L grading by 1

End tidal MAC requirement of IAA to be maintained to 1 to prevent maternal awareness and uterine relaxation

While choosing IAA, must consider reduced MAC in obstetric patients as well as the potential for maternal awareness and uterine relaxation

REFERENCESObstetric Anaesthesia, Principles and

Practice, David H Chestnut, 4th Ed

Miller’s Anesthesia, 7th Ed

Wylie and Churchill Davidson’s A Practice of Anaesthesia, 7th Ed

Barash & Stolting Anaesthesia

Morgan’s Anaesthesia.

www.anaesthesia.co.in

anticipated difficult airway

avoid airway manipulation

Accept airway manipulation

labour Caesarean delivery airway preparation

elective

emergency

CSE

LEA

CSA

Awake laryngoscopy

Awake fob intubation

Awake tracheostomy

SPINA

L

LEA

CSE

CSA

SPINA

L

CSE

CSA

vv

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 min Fetal brain levels < levels enough to cause

depressionDisadvantage:

No analgesic and amnesic effects.

Propofol: ControversialRapid smooth induction, rapid awakening.Dose: 2-2.5mg/kgF:M ratio at Delivery: 0.7 Neonatal 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 intubation

More expensive, provide vehicle for bacterial growth

Ketamine:Rapid onset. Has sympathomimetic action. Better in Asthma and hypovolemiaProvides analgesia, amnesia and hypnosisDose 1mg/kg. 100% oxygen can be administered Disadvantages

Increases laryngoscopy and intubation response, myocardial depression

Muscle Relaxants: Succinyl Choline:

Dose-1-1.5mg/Kg Optimal intubation time of 45 SecMinimal placental transfer

Rocuronium:Dose: 0.6mg/kg (Intubation time 98 sec)

0.9-1.2 mg/kg (48 sec)Duration of action prolonged: Anticipated

difficult airway

Vecuronium:• Dose:0.1 mg/kg(onset time -144 sec)• Used when scholine is contraindicated