Anesthesia for Cesarean Section

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Questions and Answers

What position is the patient placed in on the operating table for cesarean section?

Supine with pelvic wedge (usually with lateral tilt)

Why is the abdomen prepared and draped before induction in some centers?

To minimize induction-delivery interval and drug accumulation in the fetus, especially for emergencies.

What is the purpose of preoxygenation before induction?

To increase FRC (functional residual capacity)

What medication is used to facilitate uterine contractions after delivery of the fetus?

Syntocinon Signup and view all the answers

What is the purpose of cricoid pressure during rapid sequence induction?

To prevent aspiration of stomach contents Signup and view all the answers

What type of ventilation is used during maintenance of anesthesia before delivery of the fetus?

IPPV (intermittent positive pressure ventilation) Signup and view all the answers

What is a potential intraoperative problem during cesarean section?

Aortocaval compression (hypotension) Signup and view all the answers

What is the final step in the emergence and recovery phase after cesarean section?

Transfer the patient to postnatal ward Signup and view all the answers

What is the recommended position to avoid aortocaval compression in a pregnant patient?

Lateral position Signup and view all the answers

What is an indication for general anesthesia instead of regional anesthesia in a pregnant patient?

Extreme urgency Signup and view all the answers

Why should sedatives be avoided in premedication for pregnant patients?

They will affect the neonate Signup and view all the answers

What is the purpose of giving an H2 antagonist in premedication for pregnant patients?

Acid aspiration prophylaxis Signup and view all the answers

What should be available in the theatre preparation for pregnant patients?

Donor blood and facilities for neonatal resuscitation Signup and view all the answers

What is an important aspect of the preoperative assessment for pregnant patients?

Standard history and examination Signup and view all the answers

What is the purpose of giving metoclopramide in premedication for pregnant patients?

To raise gastric pH Signup and view all the answers

What should be avoided during positioning of pregnant patients?

Full supine position Signup and view all the answers

How is cesarean delivery defined?

The surgical delivery of a fetus through surgical incisions made through the abdominal wall and the uterine wall. Signup and view all the answers

What type of incision is commonly used in cesarean section?

Lower uterine segment incision, also known as a horizontal or transverse cut. Signup and view all the answers

What is the characteristic of the majority of patients undergoing cesarean section?

Fit females with an obstetric problem. Signup and view all the answers

What is the reduced volume in late pregnancy that increases the risk of hypoxia with apnea?

Respiratory reserve volume (RV) and functional residual capacity (FRC). Signup and view all the answers

What is the formula to calculate residual volume (RV) in late pregnancy?

RV = FRC - ERV. Signup and view all the answers

What is the risk associated with decreased lower esophageal sphincter tone in late pregnancy?

Gastric acid aspiration. Signup and view all the answers

What is the effect of aortocaval compression on cardiac output and uteroplacental perfusion?

Decreased cardiac output and uteroplacental perfusion. Signup and view all the answers

What is the term for the compression of the maternal abdominal aorta and inferior vena cava by the gravid uterus?

Aortocaval compression. Signup and view all the answers

Study Notes

Cesarean Section

Defined as the surgical delivery of a fetus through surgical incisions made through the abdominal wall and the uterine wall
Usually performed by lower uterine segment incision (horizontal cut through the abdomen and uterus)
Another incision type is vertical incision or cut on the uterus

Patient Characteristics

Majority are fit females with an obstetric problem (pregnancy)
Minority have significant systemic diseases (hypertension or DM)

Physiology of Late Pregnancy

Reduced respiratory reserve volume (RV) and functional residual capacity (FRC) due to high risk of hypoxia with apnea
Venous engorgement and edema of airway mucosa (difficult intubation)
Susceptibility to gastric acid aspiration (high risk) due to decreased lower esophageal sphincter tone
Presence of aortocaval compression (compression of maternal abdominal aorta and inferior vena cava)

Indications for General Anesthesia

Extreme urgency (no time for spinal or epidural block)
Patient preference
Existing or expected hypovolemia (hypotension)
Sepsis, infection
Clotting abnormality
Neurological disease
Failed regional technique

Preoperative Assessment

Majority of women have been screened in the antenatal clinic
Elective patients have a routine preoperative visit
Emergencies may only have a rapid assessment
Standard history and examination is important, with particular attention to pre-eclampsia, diabetes, anemia, or other significant disease

Premedication

Avoid sedatives as they will affect the neonate
Acid aspiration prophylaxis:
- H2 antagonist (oral Ranitidine tab. 150 mg previous night and 2-4 hours preoperatively, and I.V. Ranitidine 50 mg as soon as operative delivery is decided)
- Antiacid (Sodium citrate 30 ml orally 30-45 min before induction, and Metoclopramide ampoule 10 mg I.V.)

Theatre Preparation

Experienced anesthetist and trained anesthetic assistant
Full range of equipment and drugs for general anesthesia and difficult intubation aids
Facilities and personnel for resuscitation of the neonate
Donor blood should be available

Perioperative Management

Monitoring: ECG, noninvasive blood pressure, end-tidal CO2, pulse oximeter, and temp. probe
Positioning: avoid full supine position, use pelvic wedge (lateral tilt) on operating table
Induction: rapid sequence induction with Thiopentone (3-4 mg/kg) and Suxamethonium (1-1.5 mg/kg)
Maintenance before delivery of the fetus:
- Nitrous oxide in oxygen
- Supplement with volatile agent
- Maintain neuromuscular block with Vecuronium or Atracurium
- IPPV (intermittent positive pressure ventilation)
Maintenance after delivery of the fetus:
- Syntocinon (5 units I.V. bolus, plus infusion of 15 units in 500 ml fluid over 3 hours)
- Methergine (0.2 mg I.M.) if hypotonia persists and bleeding continues
- I.V. opioids in adequate dose
- Midazolam can be given
- Nitrous oxide can continue
- Adequate concentration of volatile agent
- Antibiotic can be given

Intraoperative Problems in Cesarean Section

Aortocaval compression (hypotension)
Failed intubation (difficulty)
Massive bleeding
Drug reaction (allergy)
Amniotic fluid embolus

Emergence and Recovery

Neuromuscular block is reversed
Tracheal tube no longer tolerated
Fully recovered
Extubation
Transfer the patient to postnatal ward

Postoperative Period

Adequate opioid or NSAID analgesia
Early mobilization to reduce the risk of thromboembolism

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Description

This quiz covers the anesthesia theory for cesarean sections, including definition, indications, and procedure. It's designed for 2nd-semester anesthesia students.