Obstetric and Bronchial Asthma Case Discussions

Normal Pregnancy Case Presentation
What is the patient profile and obstetric history in this normal pregnancy case?
A 29-year-old primigravida female at 39+2 weeks of gestation presented for elective cesarean section due to breech presentation.
She is a booked and immunized case with last menstrual period on 19th April 2022.
Her conception was spontaneous, pregnancy confirmed after 45 days of amenorrhea.
She had no history of drug or alcohol intake, rash, fever, or bleeding per vagina.
She took folic acid in the first trimester, received tetanus toxoid at 6 weeks, and consumed iron and calcium supplements regularly.
What history was obtained to rule out preeclampsia?
The patient denied excessive weight gain, decreased urine output, headache, blurring of vision, or epigastric pain in both second and third trimesters.
These questions help rule out preeclampsia and hypertensive disorders of pregnancy, which can arise after 20 weeks of gestation (typically around 24 weeks).
What are the key cardiovascular changes in pregnancy and why are they important to an anesthesiologist?
Cardiac output increases due to increased stroke volume and heart rate (20-30% increase).
Heart rate increases by 15-20 bpm (95 bpm may be acceptable in pregnancy).
Systemic vascular resistance reduces by 10-15%.
The apical impulse shifts cephalad and laterally.
Ejection systolic murmurs and wide splitting of heart sounds may be heard.
ECG may show left axis deviation and T wave changes.
These changes are important because there is increased metabolic demand and oxygen consumption in pregnancy.
The anesthesiologist must maintain zero tolerance for hypotension as fetal circulation depends on maternal hemodynamic stability.
The patient must maintain blood pressure throughout cesarean section, whether under general or regional anesthesia.
What are the hematological changes in pregnancy that protect mother and baby?
Plasma volume increases by 40-50% while RBC mass increases by approximately 30%, causing physiological anemia and reduced hematocrit.
All clotting factors increase except factors XI and XIII, with fibrinogen levels almost doubling.
Platelet count may reduce due to hemodilution.
Oxygen-carrying capacity may be reduced due to hemodilutional anemia.
What is supine hypotension syndrome and how is it managed?
Supine hypotension syndrome occurs when the gravid uterus compresses the inferior vena cava (and later the aorta) after the uterus becomes abdominal (from late second trimester).
About 10% of patients develop this syndrome.
Patients may experience faintness, dizziness, and blood pressure fall in the supine position.
Management includes:
What are the airway considerations in a pregnant patient?
Capillary dilation causes friable mucosal edema in the airway.
Mallampati grade can change from grade II to even grade IV between 14 weeks and 38 weeks in over 30-40% of patients.
Airway changes worsen during labor due to engorged vessels, hyperemia, and bearing down.
Extubation can be more difficult than intubation as airway changes persist and may worsen.
Pre-anesthetic evaluation when not in labor may not predict difficult intubation during emergency cesarean section.
What investigations are needed for this elective cesarean section?
For a normal pregnancy without comorbidities, only a complete blood count (CBC) with platelet count is essential.
PT/INR is not routinely needed unless there is suspicion of hypertensive disorders or HELLP syndrome.
Obstetric ultrasound should be reviewed for placental position.
ECG and echo are not routinely required as cardiovascular changes in pregnancy are physiological and do not need proof.
Review of antenatal investigation charts helps identify any deterioration.
How would you manage an unresponsive pregnant patient during pre-anesthetic evaluation?
  1. Check responsiveness by shaking shoulders
  2. Simultaneously ask nurse to check blood sugar (though hypoglycemia is unlikely)
  3. Check carotid pulse
  4. Call for help immediately
  5. If no pulse, initiate CPR with chest compressions

Resuscitation differs in pregnancy:

Commonest cause in an otherwise normal lady is supine hypotension syndrome.
Perimortem cesarean section decompresses the gravid uterus, making resuscitative efforts more effective.
Classical vertical incision is used for perimortem C-section.
Maternal mortality is a notifiable issue - saving the mother is paramount.
Why is regional anesthesia preferred over general anesthesia for elective cesarean section?
Regional anesthesia is preferred due to inherent risks of airway management in pregnancy.
Advantages include:

The pregnant patient is never considered to have an empty stomach due to:

Classic Mendelson's syndrome (chemical pneumonitis) occurs when gastric contents with pH <2.5 and volume >25 mL are aspirated.
Mendelson described this in 1946.
How do you prepare a patient for elective cesarean section under general anesthesia?
  1. Take informed consent including discussion about awareness risk
  2. Ensure fasting: 8 hours for solids, 6 hours for soft diet, 2 hours for clear liquids
  3. Administer aspiration prophylaxis: H2 blockers (ranitidine 150 mg night and morning) or PPI with metoclopramide in morning
  4. Preoxygenate adequately - pregnant patients desaturate faster due to respiratory changes
  5. Prepare difficult airway trolley
  6. Ensure qualified assistant is present
  7. Plan for rapid sequence induction (RSI) or modified RSI (gentle ventilation allowed) with cricoid pressure
What are the drug choices for general anesthesia in cesarean section?
Induction agents:

Muscle relaxant:

Maintenance:

Awareness is more common during cesarean section than any other surgery - consent must include this discussion.
Other high-awareness situations include polytrauma with hemodynamic instability.
What are the options for labor analgesia?
Options include:

In low-resource settings, intrathecal opiates or small-volume local anesthetics may be used.
How do you convert labor epidural analgesia to epidural anesthesia for cesarean section?
  1. Stop the dilute local anesthetic infusion
  2. Use lidocaine with adrenaline or bupivacaine
  3. Alternative: add 3 mL of sodium bicarbonate to 30 mL of lidocaine with adrenaline to alkalinize and speed onset
  4. Give adequate volume (8-10 mL) and turn patient side to side for equal spread
  5. Dense blockade usually achieves surgical anesthesia quickly
What are the contraindications to spinal anesthesia in pregnancy?
Contraindications include:

Otherwise, regional anesthesia (subarachnoid block) is preferred.

Bronchial Asthma Case Presentation
What is the patient profile in this bronchial asthma case?
A 28-year-old female, known case of bronchial asthma since 3 years of age,
presented with discharge from right ear and impaired hearing for 4 months,
posted for right tympanoplasty under anesthesia.
She has occasional episodes of wheezing relieved by medication,
last episode 2 years ago, controlled on medication with no hospital admissions.
Height 152 cm, weight 55 kg, BMI 23.8 kg/m².
Current medications: Formoterol + budesonide inhaler twice daily for 5 years, salbutamol inhaler 2 puffs SOS.
What are the positive findings on respiratory examination?
Inspection: Respiratory rate 18/min, chest shape normal, bilateral chest movements equal and decreased, no accessory muscle use
Palpation: Chest expansion 2 cm, AP diameter 28.5 cm, transverse diameter 29.5 cm, movements normal bilaterally, tactile vocal fremitus normal
Percussion: Resonant note all over in sitting position
Auscultation: Vesicular breath sounds heard, vocal resonance normal, no added sounds
Bedside tests: Breath holding time 26 seconds, laryngeal height 6 cm, forced expiratory time 4 seconds
What investigations are needed for this patient?
  1. CBC: Look for WBC count (elevated in infection), absolute eosinophil count (acceptable levels?)
  2. Serum IgE: Elevated in type 1 hypersensitivity reactions (target >1000 units/mL)
  3. Chest X-ray: May show hyperinflated lung fields, flattened diaphragm, tubular heart in chronic asthma/COPD
  4. ECG: To rule out right ventricular strain
  5. Pulmonary Function Tests (PFT): Bedside and formal spirometry
  6. Arterial Blood Gas (ABG) if patient is poorly controlled

PFT findings in obstructive disease:

PFT should be repeated after bronchodilator to assess reversibility and disease control.
Why is it important to assess effort tolerance?
Effort tolerance indicates disease severity and has implications for anesthetic planning.
Classification:

This patient had grade 0 (no exertion intolerance on rest or normal exercise).
What are the anesthetic concerns in a patient with bronchial asthma?
Airway hyperresponsiveness: Airway manipulation during anesthesia may trigger bronchospasm
Pathophysiology of airway narrowing in asthma:

Key concerns:
What are the drugs used to treat bronchial asthma?
Short-acting beta-2 agonists (SABA): Salbutamol

Anticholinergic agents: Ipratropium bromide

Corticosteroids:

Mast cell stabilizers: Sodium cromoglycate - prophylactic only, not for acute attacks

Methylxanthines: Theophylline, Aminophylline
When should steroids be supplemented in asthmatic patients undergoing surgery?
Steroid supplementation is needed when:

Stress factors requiring supplementation: surgical incision, anesthesia itself, sepsis, any stressful situation
Topical steroids (ointments) may not require supplementation depending on area and potency
If patient had an asthmatic attack 2 weeks ago but is now clear, continue the same bronchodilators the patient responds to - do not try new drugs on table
How do you manage intraoperative bronchospasm?
  1. Increase FiO₂ to 100%
  2. Check differential diagnosis for tight bag:
    • Endobronchial intubation
    • Kinked/tube obstruction
    • Mucus plug/secretions
    • Pneumothorax
    • Patient biting tube
    • Bronchospasm
  3. Manual ventilation to check compliance, auscultate chest
  4. Deepen anesthesia - give additional propofol or increase inhalational agents (higher MAC)
  5. Nebulize short-acting beta-2 agonists via ETT (8-10 puffs MDI as much is lost in circuit)
  6. Suction if mucus plug suspected
  7. Give intravenous corticosteroids (hydrocortisone) - takes 4-6 hours but worth giving
  8. Check ABG - acidosis (low pH) makes beta-2 agonists ineffective, correct acidosis
  9. Consider magnesium sulfate: 50 mg/kg over 20 minutes
  10. Consider ketamine - has bronchodilator properties
  11. Inhalational agents: Sevoflurane is bronchodilator (but less effective than halothane); desflurane is contraindicated
  12. Last resort: Intravenous epinephrine 2-5 mcg (not per kg) or use anesthetic machine to deliver inhalational agent in ICU/emergency
How do you manage pneumothorax if suspected during bronchospasm?
If auscultation reveals no air entry on one side with tight bag and poor compliance:
  1. Insert needle in 2nd intercostal space, midclavicular line (classic approach)
  2. Follow with intercostal drainage (ICD)
What are the strategies to prevent bronchospasm during anesthesia?
What are extubation considerations in asthmatic patients?
Options:

Extubation can be more difficult than intubation as airway changes persist.
Postoperative mechanical ventilation strategy should be planned if patient is not stable.