2. Definition and History
Anesthesia is defined as the total loss of sensation (touch, pain,
temperature) and may include loss of consciousness in case of general
anesthesia
History:
Oliver Wendell Holmes- coined the term anesthesia
John snow- Father of Anesthesia – popularized the concept of
obstetric anesthesia after administering chloroform to Queen
Victoria on her 8th delivery
August Bier- 1st spinal anesthesia
Carl koller- 1st local anesthesia – used in ophthalmic surgeries
3. Types of anesthesia used in obstetrics
Spinal anesthesia
Epidural anesthesia
Continuous spinal anesthesia
General Anesthesia
Paracervical block
Pudendal nerve block
4. Spinal anesthesia
It is the most preferred method of anesthesia
Advantages:
Has a very rapid onset and dense neural block
Less neonatal exposure to potentially
depressant drugs
Decreased risk of regurgitation and
maternal pulmonary aspiration
Awake patient at the time of child birth
Quicker and easier to perform
5. Technique:
Hyperbaric 0.5% bupivacaine (10-12 mg) is the most commonly used
agent gravid uterus compressing the subarachnoid space cause faster
spread of drug and progesterone will allow increased sensivity to local
anesthetic drugs
With patient in sitting position the drug is Injected in subarachnoid space
at L3-L4 level using Quinckes 25G needle
Block level is T4-T6
Its duration of action is around 1.5- 2 hours
Addition of 12.5-25 mcg of fentanyl to Bupivacaine enhances the intensity
of block and also prolongs the duration of anesthesia
Addition of preservative free morphine 0.1-0.2mg can prolong
postoperative analgesia upto 24hrs but requires special monitoring of vitals
for respiratory depression
6. After spinal anesthesia, the patient is placed in supine with left
uterine displacement to avoid compression of inferior vena cava
Supplemental oxygen id provided
Blood pressure monitored for hypotension
Intravenous injection Ephedrine( E6) can be used to maintain the
blood pressure > 100/60mmHg
Bradycardia may occur due to higher level of spinal block or due to
vagal stimulation due to traction of peritoneum
Monitoring is important due to risk of amniotic fluid embolism
Postoperatively cares should continue till the effects of spinal
anesthesia are receded. Monitirng for PDPH is required and should be
managed adequately.
7. Contraindiactions:
Coagulation disorders due to pre eclampsia or HELLP syndrome
clot can lead to compression of spinal cord that can cause permanent
paraplegia
Infection at the site of injection meningitis
severe hypertension sudden drop in BP after spinal can cause
hypoperfusion of vital organs
Septicemia
Cardiac disorders ( Mitral stenosis/ Aortic stenosis)
Raised ICT
Severe thrombocytopenia
8. Complications:
Post dural puncture headache
Hypotension
Urinary retention
Respiratory depression due to high level of block
Neuropathy – temporary or permanent
Meningitis
Cauda equina syndrome
9. Epidural anesthesia
Epidural is the most common type of anesthesia use during labour(
main goal is analgesia rather than anesthesia)
Bupivacaine is the drug of choice
Block at T10 level (sensory and sympathetic block) T4 in C-section
can be used during 1st and 2nd stage of labour
Effect of epidural:
Shortening of 1st stage of labour
Prolongation of 2nd stage of labour
Sympathetic block Vasodilation decreased placental perfusion
transient fetal bradycardia
Managed by IVF and placing mother in left lateral position
10. Technique:
L3- L4 space is injected with a local anesthetic to provide numbness
and epidural needle is inserted
A catheter is threaded through the needle into the epidural space
and needle is removed. The catheter is palced in situ to provide
medications
Advantages, contraindications and complications are same as that of
spinal anesthesia
11. Continuous spinal anesthesia
The dura is pierced with an epidural needle and the threads the
epidural catheter within the intrathecal space
Smaller doses of anesthetic agent (bupivacaine) can be given in an
incremental pattern
Advantage in high risk parturients such as cardiac disorders,
morbidly obese patients and those with neuromuscular disease
12. General anesthesia
Advised only in patients where spinal anesthesia is contraindicated
Disadvantage:
-Mother is unconscious hence cannot participate in child birth
-anesthesia might wear off quickly and result in postop pain
Technique:
- Inj metoclopramide or H2 blockers should be given in patients
with high risk of aspiration
- patient is placed in supin eposition with left uterine
dispalcment
- premedication with glycopyrrolate+ fentanyl+ xylocard
- preoxygenation with 100% O2 for 3-5 mins
13. Induction with inj Propofol and inj Atracurium
In hypotensive crisis, Inj ketamine 1-1.5mg/kg is substituted for
propofol
ET tube is inserted and secured in place
N2O:O2= 50:50 with isoflurane 1 volume%
After delivery, N2O is increased to 70% isoflurane is decreased
or discontinued and opioid is administered
Inj oxytocin 10mg is injected into IVF
Once procedure is completed, reversal with Inj Neostigmine and
Glycopyrolate
Patient is extubated
14. Paracervical block
It is a regional block
Needle used is 22G Quinckes needle
1% of 5-10ml lignocaine on both lateral fornices of vagina 2/4
and 10/8’o clock position( maximum dose upto 25ml)
Not to be given at 3 and 9’o clock position due to
descending cervical artery
Block: Pelvic plexus carrying pain from cervix to spinal cord
Used in pain relief during 1st stage of labour pair and to repair
cervical tears
Disadvantage: short acting and blocks pain from cervix alone hence
cannot be used for 2nd stage
15. Pudendal nerve block
It is a regional block
Needle used is 22G Quinckes needle
1% of 5-10ml lignocaine( maximum dose upto 25ml)
Site: Ischial spine by piercing sacrospinous ligament
Blocks pudendal nerve
Used in 2nd stage of labour, instrumental delivery, perineal and
vaginal tear repairs
cannot be used in 1st stage of labour and cervical tear repairs
