Obstetric Analgesia & Anesthesia

Question 1

To what do the degrees of pain experienced during labor depend on?

Answer 1

Parity, duration of labor, pelvic anatomy
Fetal size and presentation
Use of oxytocin (augment labor)
Psychological preparation
Emotional support
Past experiences

Question 2

What happens physiologically during labor?

Answer 2

INC O2 consumption
Hyperventilation (hypocarbia)
INC catecholamines, cortisol, B-endorphin

Question 3

What are the maternal factors that may prompt anesthetic consultation?

Answer 3

BMI >30kg/m2
short or thick neck or skeletal neck abnormality
Obstructive lesions: edema, anatomical abn, trauma
Decreased range of motion in opening the mouth or small mandible

Thyromegaly or other neck tumor
Severe preeclampsia syndrome
Bleeding disorders
Obstetrical complications with high risk of operative delivery
Maternal medical complications such as cardiopulmonary disease
Previous anesthetic complications

Question 4

Wht are the ASA physical status and classification in obstetric patients?

Answer 4

ASA II = normal pregnancy, well-controlled gestational HTN, contrlled preeclampsia w/o severe features, diet-controled DM

ASA III = preeclampsia with severe features, gestational DM w complicatoins or high insulin requirements, thrombophilic disease requiring anticoagulation

ASA IV = preeclampsia with severe features complicated by HELLP

ASA V = uterine rupture

Question 5

What are the relevant dermatomes in labor and delivery?

Answer 5

Uterus and cervix = T10 to L1
Fallopian tube = T11 to L1
Vagina & Pelvic outlet = S2-S4
Peritoneum = T4

Question 6

What type of pain occurs in the stages of labor?

Answer 6

1st stage = visceral pain (uterine contractions, cervical dilaltion, distention of lower uterine segment)

2nd stage = Somatic pain (stretching, distention, ishcemia of vagina)

Question 7

What are the different analgesic & anesthetic techniques for labor & delivery?

Answer 7

Parenteral agents/Systemic Analgesia
Inhalational agents
Regional Anesthesia
Local infiltration/Field block
General anesthesia

Question 8

What is an anatomic and physiologic consideration to happen in a pregnant patient’s airway?

Answer 8

Airway edema = starts during 1st trim & progresses

Question 9

What is test is used to evaluate the airways before the patient goes into labor and during labor?

Answer 9

Progression of Mallampati score

Question 10

What are the diff airway changes during labor & delivery?

Answer 10

Incerased airway friability
- epistaxis is more common

Question 11

When does CO incerase during pregnancy?

Answer 11

Begins @ 25th week and peaks during early 3rd trimester

Question 12

What happens when the pregnant women is in a supine position?

Answer 12

Aortocaval compression = dizziness, lightheadedness, nausea, or syncope

Question 13

What are the 3 symptoms characterizing Supine hypotension syndrome?

Answer 13

Diaphoresis
Nausea & vomiting
Hypotension

Question 14

What can cause fetal acidosis?

Answer 14

Prolonged maternal hypotension (<10-15 mins)

Question 15

How does the body compensate when under anesthesia & has aortocaval compression?

Answer 15

Increased SVR

Question 16

What are the managements of aortocaval compression?

Answer 16

Avoidance of supine position
Left lateral tilt during labor & CS

Question 17

What are the impliations to anesthesia practiece?

Answer 17

INC risk of aspiration, gastric reflux

Question 18

What re the fasting recommendations before anesthesia?

Answer 18

2h = clear liquid
4h = breast milk = 4h
Infant formula = 6h
Nonhuman milk = 6h
Fried foods, fatty foods, or meat = >8hrs

Question 19

What is aka as twilight anesthesia?

Answer 19

Pareteral agents/systemic analgesia
- uses narcotic & a tranquilizer-antiemetic

Question 20

What is the indication for high and low doses of Nitrous oxide?

Answer 20

Low dose = analgesic & anxiolytic
High dose = anesthetic

Question 21

What are volatile agents used for vaginal delivery?

Answer 21

Isoflurane, sevoflurane, desflurane with O2 & air

Question 22

When is Paracervical nerve block given?

Answer 22

1st stage of labor = gives pain relief
Lidocaine & Chloroprocaine
Short duration (45-60mins)

Question 23

What are dangers of Paracervical nerve block?

Answer 23

Fetal bradycardia
Local anesthetic systemic toxicity
Direct fetal trauma/injection

Question 24

What regional anesthesia can be used in the 2nd stage of labor?

Answer 24

Pudendal nerve block

Question 25

What are the landmarks of pudendal nerve block?

Answer 25

Ischial spines & sacrospinous ligament

Question 26

What are the location of Neuraxial anesthesia?

Answer 26

Subarachnoid space or epidural space

Question 27

What is the diff betw onset of action of spinal & epidural anesthesia?

Answer 27

Spinal = rapid
Epidural = slower

Question 28

What are pregnant patient risks under general anesthesia?

Answer 28

Aspiration risk
Difficult airway
Uterine relaxation

Question 29

What aer the preparatory needs of pregnnat px undergoing general anesthesia?

Answer 29

Pre-oxygentation
Left uterine displacement
Aspiration prophylaxis

Question 30

What is the recommended induction & intubation procedure in preg px undergoing general anesthesia?

Answer 30

Rapid-sequence intubation

Question 31

What are the risk of local anesthetic systemic toxicity?

Answer 31

Symptoms initially excitatory/stimulation -> depression with increasing serum levels

Question 32

Whta volatile agent for general anesthesia is used to relax the uterine in high concentrations?

Answer 32

Propofol

Question 33

What re indications for uterine relaxation in general anesthesia?

Answer 33

Internal podalic version
Replacement of inverted uterus
Deliveryof retained placenta

Question 34

When should neuraxial anesthesia be started?

Answer 34

During active stage of labor