Day 8: Obstetrics and Pediatrics Anaesthesia

Question 1

How does the anaesthetic risk differ between a patient at term and a patient in the first trimester of pregnancy?

Answer 1

The anaesthetic risk in pregnancy varies significantly depending on the gestational age. A patient at term is typically at a higher risk due to physiological changes, increased blood volume, potential airway difficulties, and the presence of comorbidities related to late pregnancy. Conversely, a patient in the first trimester may face lower risks as they are generally healthier and have fewer physiological changes associated with pregnancy.

Question 2

respiratory changes that occur during gestation

Answer 2

• FRC decreased 20%
• Ventilation increased (progesterone)
  -At term minute ventilation increased 50%
  -O2 consumption increases 40-60% and 1000% in labour
  -Blood gas: compensated alkalosis
  -O2 dissociation curve shifted to right

Question 3

consequences of pregnancy

Answer 3

• greater risk of hypoxaemia
• airway difficulties

Question 4

how is a pregnant patient at greater risk of hypoxaemia

Answer 4

-decreased 02 stores
-increased O2 demand

Question 5

how does a pregnant patient have airway difficulties

Answer 5

airway oedema
worse mallampati score

Question 6

Why may a pregnant patient desaturate rapidly after induction of general anesthesia?

Answer 6

A pregnant patient may desaturate rapidly after induction of general anesthesia due to her reduced Functional Residual Capacity (FRC) and high metabolism. Despite adequate preoxygenation, the reduced FRC leads to decreased oxygen reserves, while the increased metabolism results in a rapid consumption of oxygen, contributing to rapid desaturation.

Question 7

What additional risk does a pregnant patient face under general anesthesia?

Answer 7

Pregnant patients are at high risk for aspiration under general anesthesia due to several factors including decreased lower esophageal sphincter tone, delayed gastric emptying, and increased intra-abdominal pressure caused by the gravid uterus.

Question 8

cardiovascular changes that occur during pregnancy

Answer 8

-cardiac output increased up to 50%
-systemic vascular resistance decreased by 20%
-during labour cardiac output increases a further 40% (especially due to pain)
-aortacaval compression (supine hypotensive syndrome) when lying down
-delivery: : autotransfusion of up to 500ml (does not happen in C section)

Question 9

haematological changes that occur during pregnancy

Answer 9

-blood volume increases 30-40%
-plasma protein concentration decreases
-hypercoagulable state

Question 10

What physiological change occurs in the hemoglobin level during pregnancy?

Answer 10

During pregnancy, the hemoglobin level typically drops, resulting in what is known as dilutional anemia.

Question 11

GIT changes that occurs during pregnancy

Answer 11

• increased gastric acid production
  -delayed gastric emptying from 12 weeks and increased even further during labour
  -decreased lower oesophageal sphincter tone
  -increased risk of gastro- oesophageal reflux (return to normal> 48 hours after delivery)
  -increased aspiration risk: prophylactic measure NB

Question 12

What precaution is taken for patients scheduled for Caesarean section under regional anesthesia?

Answer 12

Patients scheduled for Caesarean section under regional anesthesia receive sodium citrate orally to neutralize gastric secretions in case an emergency general anesthetic is required.

Question 13

How is general anesthesia managed for patients undergoing Caesarean section?

Answer 13

General anesthesia for Caesarean section is always performed as a rapid sequence induction to minimize the risk of aspiration.

Question 14

Describe the nature of the placenta in terms of its function.

Answer 14

The placenta is a temporary organ that serves as a bridge between the maternal and fetal circulations, allowing for nutrient and gas exchange between the mother and fetus.

Question 15

Is the blood supply to the placenta autoregulated?

Answer 15

No, the blood supply to the placenta is not autoregulated.

Question 16

What is the significance of maternal blood pressure on uteroplacental flow?

Answer 16

Maternal blood pressure significantly influences uteroplacental flow. Hypotension can compromise uteroplacental perfusion and lead to fetal distress.

Question 17

What are the consequences of hypotension on uteroplacental flow?

Answer 17

Hypotension can lead to severe uteroplacental insufficiency, compromising oxygen and nutrient delivery to the fetus, potentially resulting in fetal distress.

Question 18

Which anesthesia method often leads to hypotension and why is this significant in the context of placental function?

Answer 18

Spinal anesthesia frequently results in hypotension due to sympathetic blockade, which can significantly affect maternal blood pressure and, consequently, uteroplacental flow, posing a risk to fetal well-being.

Question 19

The challenges of providing anaesthesia in obstetrics

Answer 19

1. airway at risk of both aspiration and difficult intubation
2. respiratory capacity deceased: rapid desaturation
3. increased metabolic demand
4. two patients to bear in mind
5. C section is major surgery with potentially major blood loss

Question 20

options for analgesia for labour

Answer 20

-entonox (50/50 mixture of oxygen and nitrous oxide- self administered)
-opiods
- epidural anaesthesia

Question 21

effects of opioids during labour

Answer 21

pethidine, morphine
-can result in respiratory depression

Question 22

options for anaesthesia in C section

Answer 22

regional (spinal)
general

Question 23

What is considered the standard anesthesia technique for Cesarean section?

Answer 23

Spinal anesthesia is considered the standard anesthesia technique for Cesarean section.

Question 24

What are the primary benefits of using spinal anesthesia for Cesarean section?

Answer 24

Spinal anesthesia provides the best outcomes in terms of safety when no contraindications exist. It avoids potential problems associated with general anesthesia such as hypoxia, aspiration, and difficult airway management.

Question 25

How does spinal anesthesia compare to general anesthesia in terms of maternal consciousness during childbirth?

Answer 25

Spinal anesthesia allows the mother to remain awake and conscious during childbirth, facilitating her presence at the birth and early bonding with the newborn.

Question 26

Are mortality and morbidity rates different between general anesthesia and regional anesthesia for Cesarean section?

Answer 26

Both general anesthesia and regional anesthesia (such as spinal anesthesia) for Cesarean section carry risks of mortality and morbidity, although the specific rates may vary depending on individual patient factors and clinical circumstances.

Question 27

contraindications of neuraxial blockade

Answer 27

-Haemorrhage and hypovolaemia
-Major placenta praevia (even if a planned C/S)
-Thrombocytopaenia in pre-eclampsia (<75%)
-CVS comorbidities (stenotic lesions, cardiomyopathy)

Question 28

What are the initial preparatory steps for administering obstetric spinal anesthesia?

Answer 28

The initial steps involve conducting a regular history and examination, obtaining consent, and ensuring antacid prophylaxis with sodium citrate solution.

Question 29

What is the recommended prophylactic treatment prior to obstetric spinal anesthesia?

Answer 29

Antacid prophylaxis with sodium citrate solution is recommended to reduce the risk of aspiration during spinal anesthesia.

Question 30

What is essential for successful obstetric spinal anesthesia?

Answer 30

Good intravenous access and co-loading with isotonic crystalloids at the time of block are essential for successful obstetric spinal anesthesia.

Question 31

What is the typical location for administering the spinal anesthesia?

Answer 31

The typical location for administering the spinal anesthesia is at the L3/L4 level using a pencil-point needle.

Question 32

What is the standard dose and composition of the spinal anesthesia mixture?

Answer 32

The typical dose for obstetric spinal anesthesia is 2 mL of 0.5% bupivacaine with dextrose, often supplemented with an opioid such as 10 µg of Fentanyl, resulting in a total dose of 2.2 mL.

Question 33

How is patient positioning managed during obstetric spinal anesthesia?

Answer 33

Patients are positioned supine with a 15º left lateral tilt or wedge to prevent aortocaval compression and optimize maternal and fetal hemodynamics during the procedure

Question 34

What are the standard monitoring parameters during obstetric spinal anesthesia?

Answer 34

Standard monitoring during obstetric spinal anesthesia includes non-invasive blood pressure monitoring, pulse oximetry, and electrocardiography (ECG).

Question 35

When is supplemental oxygen administered intraoperatively?

Answer 35

Supplemental oxygen is administered intraoperatively if needed to maintain adequate oxygenation.

Question 36

What is an important consideration regarding blood pressure during obstetric spinal anesthesia?

Answer 36

: Hypotension should be anticipated during obstetric spinal anesthesia due to sympathetic blockade, and proactive management is crucial.

Question 37

How is hypotension managed intraoperatively?

Answer 37

Hypotension during obstetric spinal anesthesia is managed with a fluid bolus and administration of vasopressors.

Question 38

What is the vasopressor of choice for managing hypotension during obstetric spinal anesthesia?

Answer 38

Phenylephrine is the vasopressor of choice for managing hypotension during obstetric spinal anesthesia, typically administered at doses of 50-100 µg.

Question 39

What medication is commonly administered at delivery to prevent postpartum hemorrhage?

Answer 39

Oxytocin is commonly administered at delivery to prevent postpartum hemorrhage, with an initial intravenous bolus of 2-3 U over 30 seconds, followed by an infusion of 10-20 U in 1000 mL crystalloid. However, oxytocin administration should be carefully monitored as it can cause hypotension.

Question 40

What interventions can be considered if there is inadequate blockade during obstetric anesthesia?

Answer 40

If there is inadequate blockade during obstetric anesthesia, interventions may include inhaled nitrous oxide, administration of alfentanil (250 μg) or fentanyl (50 μg) post-delivery, small doses of benzodiazepines (e.g., midazolam 1-2 mg), local anesthetic (LA) infiltration, or conversion to general anesthesia.

Question 41

What medications are commonly used for post-delivery pain management in obstetric anesthesia?

Answer 41

Post-delivery pain management in obstetric anesthesia may involve the use of medications such as alfentanil or fentanyl.

Question 42

When might benzodiazepines be administered in this context?

Answer 42

Benzodiazepines may be administered in small doses for anxiolysis and sedation if needed.

Question 43

What are important considerations regarding the administration of benzodiazepines?

Answer 43

It is important to consider the potential side effects of benzodiazepine administration, including amnesia and respiratory depression, which should be monitored closely.

Question 44

How is local anesthetic infiltration utilized in managing inadequate blockade?

Answer 44

Local anesthetic infiltration can be utilized to enhance blockade and provide targeted pain relief to the surgical site.

Question 45

What is an alternative option if the blockade remains inadequate despite intervention?

Answer 45

If the blockade remains inadequate despite intervention, conversion to general anesthesia may be considered for better pain control and patient comfort.

Question 46

What are the two options for anesthesia in patients with an epidural requiring Cesarean section?

Answer 46

The two options for anesthesia in patients with an epidural requiring Cesarean section are:
a) Convert the epidural into a spinal-like block by administering a high dose and volume of local anesthetic as a top-up.
b) Remove the epidural and perform a spinal anesthesia.

Question 47

What is an additional consideration for anesthesia management if the decision is to remove the epidural and perform a spinal anesthesia?

Answer 47

If the decision is to remove the epidural and perform a spinal anesthesia, it is possible to keep the epidural catheter in place for post-operative analgesia and perform the spinal one level lower to avoid overlap of sensory blockade.

Question 48

general anaesthesia for C/S indications

Answer 48

*Maternal request (rare)
*Any contraindication for neuraxial blockade
*Failed blockade

*Obstetric indications
-Severe fetal distress (fetal bradycardia)
-Obstetric haemorrhage (placenta praevia, abruptio placentae)
-HELLP syndrome / sever pre-eclampsia

Question 49

Why is oxygenation considered paramount in obstetric anesthesia?

Answer 49

Oxygenation is paramount in obstetric anesthesia because while aspiration can be survived, lack of oxygen is fatal.

Question 50

What is the approach to induction of general anesthesia (GA) in obstetrics?

Answer 50

Obstetric general anesthesia always follows a rapid sequence induction protocol to minimize the risk of aspiration.

Question 51

What action is essential if difficulty is encountered during induction and patients become hypoxic?

Answer 51

If difficulty is encountered during induction and patients become hypoxic, it is essential to provide oxygen immediately.

Question 52

What measures should be taken if bag-mask ventilation (BMV) is necessary during induction?

Answer 52

If bag-mask ventilation (BMV) is necessary during induction, it must be performed promptly to ensure adequate oxygenation. Additionally, a temporary airway such as a supraglottic airway (SGA) or laryngeal mask airway (LMA) may be placed to maintain airway patency and oxygenation. It is preferable to risk aspiration than to deprive the patient of oxygen.

Question 53

What are the initial steps in preparing for general anesthesia (GA) in obstetrics?

Answer 53

The initial steps in preparing for GA in obstetrics include administering antacid prophylaxis and ensuring good intravenous (IV) access.

Question 54

What is the goal of preoxygenation before induction of GA?

Answer 54

The goal of preoxygenation before induction of GA is to maximize oxygen reserves in the lungs, aiming for an end-tidal oxygen concentration of greater than 80%.

Question 55

What is the preferred induction technique in obstetric GA?

Answer 55

Rapid sequence induction is the preferred technique for induction of GA in obstetrics.

Question 56

Which medications are commonly used for rapid sequence induction?

Answer 56

Classically, thiopentone and suxamethonium are used for rapid sequence induction in obstetric GA. Propofol is also suitable if there is no hemodynamic instability.

Question 57

What is the approach to opioid administration during obstetric GA?

Answer 57

Opioids are typically avoided until the delivery of the baby during obstetric GA to minimize the risk of neonatal respiratory depression.

Question 58

What is the standard approach to pre-delivery analgesia in obstetric anesthesia?

Answer 58

Pre-delivery analgesia in obstetric anesthesia commonly involves the use of a nitrous oxide/oxygen mixture (50/50 or 60/40) along with volatile anesthetics.

Question 59

What is the composition of the nitrous oxide/oxygen mixture commonly used during obstetric anesthesia?

Answer 59

The nitrous oxide/oxygen mixture used during obstetric anesthesia typically consists of 50% nitrous oxide and 50% oxygen, or 60% nitrous oxide and 40% oxygen.

Question 60

What are the preferred volatile anesthetics for intraoperative maintenance during obstetric anesthesia?

Answer 60

Isoflurane or sevoflurane are commonly used volatile anesthetics for intraoperative maintenance during obstetric anesthesia.

Question 61

What medications are administered at delivery, after clamping of the umbilical cord?

Answer 61

At delivery, after clamping of the umbilical cord, the following medications are commonly administered:
*Oxytocin as per spinal anesthesia protocol, including a bolus and infusion.
*Opioids such as fentanyl or morphine for additional pain relief.
*Intravenous paracetamol to manage postoperative pain.
*Nitrous oxide is continued, and volatile anesthetic levels are carefully titrated to prevent uterine hypotonia.

Question 62

What is the recommended approach for extubation following obstetric anesthesia?

Answer 62

Following obstetric anesthesia, extubation should be performed while the patient is awake to minimize the risk of airway complications.

Question 63

What is the preferred position for the patient during extubation?

Answer 63

It is preferable for the patient to be positioned on their side during extubation to reduce the risk of aspiration.

Question 64

What steps should be taken to ensure proper monitoring in the recovery room?

Answer 64

In the recovery room, the patient should be closely monitored to ensure stable vital signs and adequate recovery from anesthesia.

Question 65

What is the goal of post-delivery management regarding pain control?

Answer 65

The goal of post-delivery management is to establish appropriate analgesia to manage postoperative pain effectively.

Question 66

Are opioids contraindicated if the patient is breastfeeding?

Answer 66

Opioids are not contraindicated if the patient is breastfeeding; however, caution should be exercised with dosing to avoid adverse effects on the infant.

Question 67

What are the clinical features of severe pre-eclampsia?

Answer 67

Severe pre-eclampsia is characterized by hypertension, proteinuria, and oliguria. It may also present with complications such as pulmonary edema.

Question 68

What is the characteristic triad of symptoms associated with HELLP syndrome?

Answer 68

The characteristic triad of symptoms associated with HELLP syndrome includes hemolysis, elevated liver enzymes, and low platelets.

Question 69

What is the primary treatment approach for severe pre-eclampsia?

Answer 69

The primary treatment for severe pre-eclampsia is urgent delivery of the baby.

Question 70

What anesthesia technique is preferred for urgent delivery in cases of severe pre-eclampsia?

Answer 70

Despite the urgency, spinal anesthesia remains the method of choice for delivery in severe pre-eclampsia, provided the platelet count is acceptable (>75) and there is no fetal bradycardia.

Question 71

What are the considerations for general anesthesia in severe pre-eclampsia?

Answer 71

In cases where general anesthesia is required, the intubation response must be dampened to prevent exacerbation of hypertension. This may involve the administration of magnesium sulfate bolus, lignocaine, and alfentanil.