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