Cesarean Section

Question 1

What does anesthesia for patients undergoing cesarean section focus on?

Answer 1

1) Providing adequate analgesia for the mother with the least amount of cardiovascular depression
2) delivering viable neonates while minimizing negative effects of the drug

Question 2

What physiological changes are seen in the mother that we have to take note of when choosing anesthetic drugs?

Answer 2

• Increase in blood vol. to meet increase metabolic demands
• Relative anemia from larger increase in plasma volume compared to red cell mass
• Increased heart rate and stroke volume to meet oxygen demands
• More susceptible to hypotension due to blunted response as a result of decreased baroreceptor activity
• Displacement of diaphragm due to pregnant uterus decreases tidal volume and functional residual capacity (FRC)
• More prone to hypoxemia

Question 3

What drugs are considered safe in a patient having a C-section?

Answer 3

• Opioids - reversible if newborns require it
• Benzodiazepines - do not cause significant cardiovascular depression
• Premedication with an anticholinergic - to counter related bradycardia or vagal stimulation

Question 4

What anesthetic drug would you not use in a C-section patient?

Answer 4

Alpha-2 agonist

• reduces cardiac output affecting placenta perfusion
• has been observed to reduce survivability of newborns

Question 5

Why is rapid induction and intubation favored in a c-section patient?

Answer 5

• Pregnancy increases gastric acid secretion and prolonged gastric emptying
• Higher chance of regurgitation and subsequent aspiration due to increased intragastric pressure from uterus and decreased lower oesophagus sphincter tone

Question 6

Why is propofol often used in C-sections?

Answer 6

• Rapid onset, short duration of action, minimal hepatic metabolism, rapid elimination, very little residual effect on neonates
• Must be titrated carefully to avoid significant respiratory depression and hypoxemia

Question 7

Etomidate

Answer 7

Good option for cardiovascular function, but should be given with benzodiazepine which may cause prolonged depression in the neonate

Question 8

Ketamine

Answer 8

• given as a combination with benzo or opioids
• prolonged depression in neonates
• reversible by flumazenil
• doens’t affect neonatal survival

Question 9

Inhalants

Answer 9

• pregnancy lowers MAC by 25-40% = increases sensitive to inhalant
• increased respiratory drive due to increased sensitivity to PaCO2 = higher minute volume
• therefore requires less inhalant

Question 10

What ventilator settings are recommended?

Answer 10

PEEP and IPPV

-reduction in lung expansion results in a larger degree of actelectasis

Question 11

Why should you prevent hypocapnia to occur from hyperventilation?

Answer 11

Alkalosis reduces fetal oxygen delivery by reducing oxygen offloading (left shift in oxygen-hemoglobin dissociation curve) and reduces uterine blood flow