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Labour Analgesia
Dr. Ramilaben Chaudhary
2nd year resident
History
Pain during pregnancy is a physiological phenomenon but one must know that once it exceeds a certain intensity and duration does produce harmful effects both on mother and fetus and thence some form of analgesia must be offered to all parturient.
Cont….
In1853, Dr John gave first obstetric analgesia to Queen Victoria who delivered Prince Leopold under the effect of chloroform.
Nerve Supply
Uterus and cervix
-Sensory pathway ran by way :
Uterus and cervical ganglia (Frankenhauser) ,inferior and superior hypogastric plexus.
Posterior roots of 11th and 12th thoracic
nerves (T11 & T12) and sometimes T10 and L1.
Motor pathway run by
Starts in 10,11 and 12th thoracic vertebra
Aortic,hypogestric & uterine plexuses
Terminate in uterus
Vulva, Vagina and perineum
Afferent fibers carrying sensations from birth canal,perineum and vulva.
Afferent fibers of posterior roots of S2, S3 and S4.
Main motor supply via Pudendal nerve
Cause of pain
First stage:
Due to - uterine contractions
-thinning of lower uterine segment
- dilatation of cervix
Second stage
Due to
-Uterine contractions
- Stretching of vulva, vagina and perineum.
Third stage
Due to
-Passage of placenta through cervix
- Uterine contraction
Causes of pain
Myometrial hypoxia Stretching of cervix Pressure on nerve ganglia adjacent to cervix Pressure on bladder, urethra and rectum Traction on tubes, ovaries and peritoneum Traction on supporting ligament Distension of muscles of pelvic floor
Ideal prerequisites
For the mother:
- Relief of pain
- Freedom from fear of vaginal delivery
- Safe and painless delivery
-Efficiency of contractions not decreased
-Pt cooperation is maintained
- Health of mother is not in danger
For the infant:
-Should not cause neonatal depression
-Should not cause fetal bradycardia For the obstetrician:
-Deliberal management of labour
-Optimum condition at delivery
Methods of pain relief
Non pharmacological
Pharmacological
Non pharmacological
Natural child birth
-Emotional support
-Hot and cold compresses
-Vertical position
Conti….
Acupuncture
-Transcutaneous electrical nerve stimulation
-Psycho prophylaxis
TENS
Intermittently pulsed electrical current to the back over the lower thoracic and upper spine.
sensory fibres are stimulated & synapse with interneurons in substantia gelatinosa.
So inhibit the release of neurotransmitter it shortens the overall duration of labour &
give great satisfaction to mother.
Cont...
Touch and massage
-Hydrotherapy
-Biofeedback
-Hypnosis
Pharmacological methods
Systemic drugs:
-Opiates
-Benzodiazepines
-Barbiturates
-Ketamine
-Phenothiazines
-NSAIDS
Cont…...
Peripheral nerve blockade
-Paracervical
-Local infiltration
-Pudendal
Cont….
Central nervous blockade
-Spinal
-Lumber epidural
-caudal epidural
-combined spinal and epidural
Inhalational agents
Nitrous oxide
Halothane
Isoflurane
During first stage of labour
Objectives:
-Pain relief
-Maintaining mother’s cooperation
-No or with interference in progress of labour
Systemic medications
Paracervical block
Epidural block
Systemic medications
They cross the placenta They may be
-Narcotic medications
-Amnesics
-Sedative tranquilizers
Narcotic medications
Used to alleviate pain Pethidine can be used.
Dose:50-100mg IM
25-50MG IV
Peak analgesia:IM 40-50 mins
IV 5-10 mins
Duration: 3-4 hrs
Side effects
Dose dependant neonatal depression Decreased beat to beat variability in FHS Decreased Apgar score Poor neonatal neurobehavioral score
Narcotics effects in fetus can be antagonized with Naloxane 5-10 mg/kg
Amnesics
Hyoscine is used 0.2 to 0.6mg intramuscularly with analgesia Effect on maternal behavior is unpredictable
e.g. Excitement to Delirium S/E include dry mouth,fetal Tachycardia
Sedative Tranquilizers
Barbiturates:Phenobarbital & secobarbital have been tried but causes fetal respiratory depression with repeated doses.
Phenothiazines:Chlorpromazine,prochlorperazine and promethazine.Desirable effects are Sedation,antiemesis & lack of fetal resp depression.
Benzodiazepam
Used as sedatives. Reduce anxiety,promote sleep in early labour
& decreased narcotic requirements without prolonging labour.
Diazepam:Crosses placenta immediately
Dose:<30mg
S/E Hypotonia,hypothermia,lethargy and resp.depression in baby
Paracervical block
Effective method
Easily performed
Can be given by Obstetrician
Technique
Transvaginaly During active phase 20 gauge needle 13-18 cm long Into posterolateral Fornices at 3& 9 o’clock
position Effectiveness for 1 hour.
Complications
Maternal: -Paraesthesia in limbs
- IV injection
-Hypotension
-Hematoma Fetal: -24% bradycardia
-4%Tachycardia
-2% mixed pattern
Pain relief during 2nd stage
Inhalational analgesia Inhalational anesthesia Intravenous anesthesia Regional anesthesia: -epidural
- spinal
-caudal
-Pudendal
Inhalational analgesia & anesthesia
Generally reserved for situations where rapid deliveries are required like fetal distress, intrauterine manipulations
Nitrous oxide
Relatively insoluble in blood Induction & recovery is fast effective analgesia during contractions generally nontoxic given as Entonox :50:50 mixture in oxygen
so decreased chances of maternal hypoxemia
Halothane & Isoflurane
Initial analgesia Anesthesia follows with higher dosage BP decreased in a dose dependent fashion decreased intensity of uterine contraction
Intravenous anesthesia
For rapid induction of GA Agents are Thiopentone,
Ketamine & Propofol used as inducing agents followed by
Inhalational anesthesia for maintenance.
Cont…..
Thiopentone: <4mg/kg Ketamine: 0.25mg/kg and infusion rate of
0.5 to 1 microgram/kg/min
-lower doses it is safe and effective
-Higher doses:-maternal apnea
-Laryngospasm
-hypertension & ut tone.
Cont….
Contraindications of Katamine
-Pre eclampsia
-Eclampsia
-Hypertension
-Psychiatric disease
-Epilepsy
Regional Anesthesia
Epidural block Spinal block Caudal block Pudendal block Local infiltration
Advantages of regional anesthesia
Complete relief of pain is possible so decreased degree of hyperventilation and improve Utero placental perfusion.
Nearly eliminate psychological and emotional reaction to severe pain.
Effective pain relief changes incoordinate uterine contraction to co ordinate one and improve the placental circulation.
Allow parturient to be awake and participate in in labor.
Disadvantages
Increased incidence of Occiput posterior or Occiput transverse position if premature perineal relaxation is produced.
Complications like maternal Hypotension,total spinal & local anesthetic toxicity is possible.
Urge to bear down is decreased.
Epidural Anesthesia
Technique: During active phase of labour
-pt on side or sits up
-Needle in 2nd & 3rd lumbar interspace
-Catheter is inserted
-Drug is injected
-Relief of pain in 5-10mins & max. effect in 15-20 mins.
Contraindications
Allergy to the drug Coagulopathy Skin infection at site Significant hemorrhage Supine Hypotension syndrome Significant cardiopulmonary ds. Ds of CNS or PNS
Limitations
Autonomic blockade Hypotension Post dural puncture headache. Missed segment High or total spinal blockade.
Commonly used drugs
Bupivacaine:Most commonly used.
-Concentration ranging from0.05% to 0.5% .
-Maximum dose:2mg/kg every 4hrly
-Duration of action:2-3 hrs
-S/E: cardiotoxicity if given IV.
Cont...
Lignocaine:Used as 1-2% solutions
-Toxic dose is 3mg/kg without adrenaline & 6-7mg/kg with
adrenaline
-Effective concentration are 0.75-1% for labour and vaginal delivery
S/E: At higher conce. Compromised neonatal neurobehavioral function
Caudal block
Performed by injecting into caudal space through sacral hiatus .
Only after active phase. For block below T10
Damage may occur to fetal head. May paralyse perineal muscles
Spinal block
Advantages:
-Excellent anesthesia
-Easier to administer than epidural
-Useful for difficult deliveries
Disadvantages
Post spinal dural headache Bladder dysfunction Parasthesia in lower limb Can not be used in early labour Increased incidence of operative deliveries
Double catheter
One catheter in lumbar epidural space and another in caudal space.
Combine epidural & extradural analgesia is more popular
Now a days very popular
Pudendal Block
Time of administration;
Primi: Full dilatation
Multi: 7-8cm dilatation Gives perineal analgesia & relaxation
Indications
Spontaneous vaginal delivery Low forceps Breech deliveries Episiotomies Repair of lacerations
Types
Percutaneous Trans perineal
Trans vaginal
Advantages: -Simple -No systemic or fetal effects -Mother awake -No effects on ut contraction Disadvantages:-Does not relieve pain but
gives perineal analgesia & relaxation -Perineal & Vulval infiltration needed. -Needle breaks & inj. Into vessel
Local Anesthesia
For incision and repairs of episiotomy
Agent used is Xylocaine 1%
S/E:Trauma and inj of LA into fetal scalp .
Anesthesia for LSCS
Local
General
Spinal
Depends on
Indication of CS Prevalence of maternal condition Presence of complicating obstetric factors Fetal status Wishes of patients
Multiple pregnancy
Epidural for labour ,vaginal delivery and CS
GA may preferred
Anteparterm hemorrhage General Anesthesia
Preeclampsia & eclampsia
Epidural analgesia if no contraindications of that.
GA may be used
Diabetes malitus Epidural blockage for labour and delivery GA or regional for CS
Cardiac disease
For Acynotic with mild MS epidural is preferred .
For pts on anticoagulant:sedatives + Paracervical block.
PROGRAMMED LABOURinclusion criteria*age-18-35yrs*maturity-37-41wks*clinically no CPD*no medical or obstetric risk factors*no fetal distressWith experience , high risk cases can be included
Entry criteria*Cx dilatation->3cm $ >50% effaced*fetal head should be engaged*show or amniotomy*Ut. Contraction ->3/10 min.& last for 35-45 sec.
Protocol
*Amniotomy
*FHS monitoring
*Optimizing pains by prostaglandins or oxytocins
*Optimizing pain relief facilitated by – 6.0 mg pentazocin & 2,0 mg diazepam diluted in 10 ml DW & give IV
*Tramadol -1.0mg/kg wt IM
*Inj. Drotin 1amp. Or Inj.Epidocin 1amp.
*at 7-8 cm , if required , inj. Ketamine 0.5mg/kg wt. & then SOS ½ of the initial dose at ½ hrly till delievary
Thank you