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Carbetocin (Carbotocin) in LSCS (Lower Segment Caesarean Section)

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Standard Dosing and Administration

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Why Carbetocin in LSCS?

• Duration of action is 4-7x longer than oxytocin (half-life ~40 min vs ~4-10 min for oxytocin)
• Single dose replaces the need for an oxytocin infusion post-LSCS
• Reduces need for additional uterotonic agents
• Particularly preferred when uterotonic infusion setup is inconvenient

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Heat-Stable Formulation (WHO 2018 Recommendation)

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Contraindications

• Hypersensitivity to carbetocin or oxytocin
• Before delivery of the baby (risk of fetal asphyxia)
• Hepatic or renal disease (use with caution)
• Cardiovascular disease (causes transient hypotension and tachycardia)
• Pre-eclampsia / eclampsia (use cautiously - oxytocin analogues can lower BP)

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Side Effects

• Transient hypotension and tachycardia (most common, especially with rapid IV push)
• Flushing, nausea, abdominal pain
• Headache
• Tremor

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Comparison with Oxytocin in LSCS

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Management of Allergic Reaction After Pantoprazole

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Step 1 - Assess Severity

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Step 2 - Immediate Actions (ALL grades)

1. STOP pantoprazole immediately - disconnect infusion / stop IV
2. Call for help - activate emergency response
3. Position: Lay patient flat (recumbent); if breathing difficulty, slight head elevation
4. Establish IV access (if not already present)
5. Monitor: BP, pulse, SpO2, ECG

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Step 3 - Drug Treatment by Severity

MILD (Urticaria / Pruritus only)

MODERATE (Angioedema, no airway compromise)

SEVERE / ANAPHYLAXIS

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Step 4 - Refractory / Cardiovascular Collapse

• IV Epinephrine bolus: 100 mcg (0.1 mg) diluted in 10 mL NS, over 5-10 min
• IV Epinephrine infusion: Start 1 mcg/min, titrate up
• Patient on beta-blockers? Use Glucagon 1-5 mg IV slowly over 5 min, then infusion 5-15 mcg/min (bypasses beta-blockade)
• Airway threatened (stridor, laryngeal edema): Early intubation - do NOT delay; if unable to intubate, cricothyroidotomy

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Step 5 - Observation and Biphasic Reactions

• Observe for minimum 4-6 hours after resolution (risk of biphasic anaphylaxis - recurrence without re-exposure)
• Admit if: severe reaction, IV epinephrine used, unknown trigger, poor social support
• Serum tryptase: Draw at 1 hour (peaks at 1 hour, remains elevated up to 4 hours) to confirm anaphylaxis

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Step 6 - Discharge / After Care

• Prescribe epinephrine autoinjector (EpiPen) for all patients who had anaphylaxis
• Oral antihistamine for 3-5 days
• Oral prednisolone 40-60 mg for 3-5 days (to prevent late phase/biphasic reaction)
• Document allergy clearly: pantoprazole, and warn about cross-reactivity with other PPIs (lansoprazole, omeprazole, rabeprazole, esomeprazole - all share the benzimidazole ring structure)
• Refer to allergist for formal allergy testing

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Key Points to Remember

• Epinephrine IM is ALWAYS first-line in anaphylaxis - antihistamines and steroids are only second/third-line and must NOT replace or delay epinephrine
• IM into the lateral thigh gives faster and higher peak levels than deltoid or SC route
• No absolute contraindications to epinephrine in anaphylaxis
• All PPIs can cross-react - avoid the entire class if true allergy confirmed; use H2 blockers (ranitidine/famotidine) or sucralfate as alternatives

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Next Step Protocol (Reaction Not Relieved by Avil + Hydrocortisone)

STEP 1 - Epinephrine IM (FIRST AND MOST URGENT)

Adrenaline 1:1000 → 0.5 mL (0.5 mg) IM into the outer lateral thigh

• Do NOT give IV epinephrine as first dose (risk of cardiac arrhythmia)
• Can repeat every 5-10 minutes up to 3 doses if no improvement
• Thigh is preferred over deltoid (faster absorption, higher peak levels)

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STEP 2 - Simultaneously

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STEP 3 - Add H2 Blocker (if not already given)

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STEP 4 - If Still Not Responding (Refractory Anaphylaxis)

A. Escalate Corticosteroid Dose

• Hydrocortisone 250-500 mg IV (your initial 100 mg was inadequate for severe reaction)
• OR Methylprednisolone 80-125 mg IV

B. IV Epinephrine (if IM not working or cardiovascular collapse)

• Bolus: 100 mcg (0.1 mg) diluted in 10 mL NS - give over 5-10 min
• Infusion: 1-10 mcg/min, titrate to BP response

C. If patient is on Beta-blockers (epinephrine not working well)

• Glucagon 1-5 mg IV slow bolus over 5 min
• Then infusion 5-15 mcg/min
• Glucagon bypasses the blocked beta receptors directly

D. Bronchospasm not relieving

• Salbutamol (Ventolin) nebulization - 2.5-5 mg every 20 min
• IV Aminophylline if still refractory

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STEP 5 - Airway Threat (Stridor / Laryngeal Edema)

• Intubate early - do not wait for complete obstruction
• If unable to intubate → Cricothyroidotomy (emergency surgical airway)

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Quick Decision Tree

Avil + Hydrocortisone 100mg given → No relief
            ↓
ANAPHYLAXIS - Give Adrenaline 0.5 mg IM (lateral thigh) IMMEDIATELY
            ↓
Oxygen + IV NS bolus + Lay flat
            ↓
Add H2 blocker (Ranitidine IV)
            ↓
Still no relief → Escalate steroid dose + IV Adrenaline infusion
            ↓
Beta-blocker patient → Glucagon IV
            ↓
Airway compromised → INTUBATE NOW

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Key Message

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Anaphylaxis Not Relieved by Avil + Hydrocortisone - Patient is PREGNANT

The Golden Rule

Epinephrine is still the NEXT and MANDATORY step - pregnancy is NOT a contraindication. Treating the mother effectively IS treating the fetus. Untreated anaphylaxis kills both mother and baby. A hypoxic, hypotensive mother is far more dangerous to the fetus than epinephrine.

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What Changes in Pregnancy vs Non-Pregnant

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Step-by-Step Management

STEP 1 - Epinephrine IM (GIVE NOW)

Adrenaline 1:1000 → 0.5 mg (0.5 mL) IM into the OUTER LATERAL THIGH

• Repeat every 5-10 min if no response (up to 3 doses)
• Category C - teratogenic only at very large doses in animals; benefits far outweigh risk in anaphylaxis
• There are NO absolute contraindications to epinephrine in anaphylaxis, including pregnancy

STEP 2 - Position

• Left lateral decubitus tilt (left side down, 15-30°)
• Prevents the gravid uterus compressing the inferior vena cava and aorta (aortocaval compression)
• If supine, venous return drops sharply → worsens hypotension → worsens fetal distress

STEP 3 - Simultaneously

STEP 4 - Escalate Corticosteroid Dose

• Your initial hydrocortisone 100 mg was not enough for a severe reaction
• Hydrocortisone 200-500 mg IV or Methylprednisolone 80-125 mg IV
• Safe in pregnancy

STEP 5 - If Still Refractory

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What to AVOID or Use Cautiously

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Fetal Considerations

• Fetal bradycardia or late decelerations on CTG may indicate fetal distress from maternal hypotension - the answer is to fix the mother, not deliver immediately
• Emergency caesarean is considered if maternal condition is refractory and fetal compromise is severe - decision made jointly with obstetrician
• Epinephrine can cause dose-dependent fetal tachycardia and transient fetal acidosis - this is acceptable and reversible; far better than fetal anoxia from maternal collapse

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Quick Summary

Avil + Hydrocortisone 100mg → No relief → Patient PREGNANT
              ↓
Adrenaline 0.5 mg IM (lateral thigh) - NO contraindication in pregnancy
              ↓
LEFT LATERAL TILT (not flat supine)
              ↓
High-flow O2 + Aggressive IV NS bolus
              ↓
Escalate hydrocortisone dose + Add H2 blocker
              ↓
Call Obstetrician + Start fetal monitoring
              ↓
Refractory → IV Adrenaline infusion + Phenylephrine for BP
              ↓
Consider emergency LSCS if maternal/fetal collapse

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Phenylephrine Dose in Pregnant Patient with Refractory Hypotension (Anaphylaxis)

Context Note

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Dosing

IV Bolus (for acute hypotension)

100-150 mcg IV bolus - repeat every 2-3 minutes as needed, titrating to blood pressure

• Standard bolus: 100 mcg IV
• Can go up to 150-200 mcg per bolus if response inadequate
• Onset: rapid (within 1-2 minutes)

IV Infusion (for sustained hypotension)

25-100 mcg/min infusion, titrated to target BP

How to prepare infusion

• Add 10 mg phenylephrine (10 mL of 1 mg/mL) to 250 mL NS = 40 mcg/mL
• Run at 37.5 mL/hr = ~25 mcg/min starting rate

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Why Phenylephrine Over Other Vasopressors in Pregnancy?

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Important Caveat - Reflex Bradycardia

• Raises BP by vasoconstriction
• Can cause reflex bradycardia (baroreceptor-mediated) as a side effect
• If heart rate drops below 50-55 bpm → reduce or stop infusion
• May need atropine 0.6 mg IV for symptomatic bradycardia

In anaphylaxis (where tachycardia is usually already present), reflex bradycardia is less of a concern compared to elective LSCS - the alpha vasoconstriction is what you want.

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Quick Reference Card

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Dose of Phenylephrine in Allergic Reaction / Anaphylaxis

Important Framing First

• Epinephrine has been given but hypotension persists, OR
• Patient has refractory distributive shock despite epinephrine + IV fluids
• Particularly useful in pregnancy (as discussed) - less fetal acidosis than ephedrine

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Doses (from Tintinalli's Emergency Medicine)

IV Bolus - for acute hypotension

40-100 mcg IV bolus over 20-30 seconds, every 2-5 minutes as needed

• Start with 50-100 mcg
• Repeat every 2-5 min, titrating to blood pressure response
• Onset within 1-2 minutes

IV Infusion - for sustained/refractory hypotension

100-180 mcg/min initially (or 0.5 mcg/kg/min) Titrate to desired blood pressure response

How to prepare infusion (practical)

• Add 10 mg (10 mL of 1 mg/mL) phenylephrine to 100 mL NS = 100 mcg/mL
• Run at 60 mL/hr = 100 mcg/min starting rate
• Titrate up or down every 5-10 min based on BP

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Phenylephrine vs Other Vasopressors in Anaphylaxis

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Why Phenylephrine Works in Anaphylaxis Hypotension

Key Watchpoint - Reflex Bradycardia

• Phenylephrine raises BP → baroreceptors trigger reflex slowing of heart rate
• Watch HR closely during infusion
• If bradycardia develops (HR <50 bpm): reduce rate or give Atropine 0.6 mg IV

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Summary Box

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Preoxygenation of Obese Patient Planned for Laparoscopic Cholecystectomy

Why Obese Patients are Different - The Physiology

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The Four Pillars of Preoxygenation in the Obese

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PILLAR 1 - POSITION: Head-Up / Ramped (Most Important)

25-30° head-up (reverse Trendelenburg) OR ramped position

• Supine position is the enemy in obese patients - the abdominal mass pushes the diaphragm up, compresses lung bases, reduces FRC maximally
• Head-up position increases FRC by allowing diaphragm to descend
• 25° head-up significantly increases PaO2 after preoxygenation and prolongs time to desaturation to SpO2 92%
• 30° reverse Trendelenburg gives even more benefit - prolongs apnoea tolerance by ~1 minute vs supine
• Also improves laryngoscopic view during intubation

• Ear aligned horizontally with the sternal notch
• Achieved using towels/blankets under shoulders and head, OR commercial ramping device (e.g., HELP - Head Elevated Laryngoscopy Position)
• Compensates for posterior cervical fat pad which causes excess neck flexion

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PILLAR 2 - OXYGEN DELIVERY: 100% O2 via Tight-Fitting Face Mask

100% O2 for minimum 3-5 minutes of tidal volume breathing

• Use a well-fitting face mask with a fresh gas flow of 10-15 L/min
• Aim for EtO2 (end-tidal O2) ≥90% as the endpoint of adequate preoxygenation (more reliable than time alone)
• 3-5 min of tidal volume breathing is standard; in urgent cases, 4 vital capacity breaths can also be used (though less effective in obese patients than in normal weight)

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PILLAR 3 - CPAP / NIV DURING PREOXYGENATION

CPAP 10 cm H2O during preoxygenation significantly improves oxygenation

• CPAP recruits collapsed alveoli, increases FRC, reduces atelectasis
• 10 cm H2O CPAP during preoxygenation resulted in:
  • Higher PaO2 after intubation
  • Less atelectasis formation
  • Prolonged nonhypoxic apnoea duration (2 min → 3 min)
• Can use via tight-fitting CPAP mask or NIV/BiPAP mask
• NIPPV (non-invasive positive pressure ventilation) is superior to face mask alone for preoxygenation in morbidly obese

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PILLAR 4 - APNOEIC OXYGENATION (during intubation attempt)

High-Flow Nasal Cannula (HFNC) at 15-70 L/min during laryngoscopy

• Continue O2 delivery even during the apnoeic period of intubation
• HFNC provides passive apnoeic oxygenation via mass flow of O2 into alveoli
• Even simple nasal cannula at 5 L/min under the face mask provides some benefit
• Extends safe apnoea time during laryngoscopy

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Specific Considerations for Laparoscopic Cholecystectomy

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Practical Step-by-Step Protocol

1. Position: Ramped / 25-30° head-up BEFORE preoxygenation starts
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2. Apply tight-fitting face mask → 100% O2 at 15 L/min fresh gas flow
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3. Add CPAP 10 cm H2O via mask (if available / if morbidly obese)
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4. Preoxygenate for minimum 3-5 minutes tidal breathing
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5. Endpoint: EtO2 ≥ 90% (or FiO2 ≥ 0.9 at expiration)
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6. Place nasal cannula at 15 L/min UNDER the face mask for apnoeic oxygenation
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7. Induce anesthesia - keep HFNC running during laryngoscopy
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8. Intubate rapidly - have video laryngoscope ready (higher difficult airway risk)

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Quick Summary Table

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Anesthetic Considerations for Laparoscopic Cholecystectomy

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1. PREOPERATIVE ASSESSMENT

Patient factors to evaluate

Fasting

• Standard 6 hours solids / 2 hours clear fluids
• In acute cholecystitis or known GERD: treat as full stomach → RSI

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2. CHOICE OF ANESTHESIA

General Anesthesia with Endotracheal Intubation (ETT) - STANDARD

• ETT with controlled mechanical ventilation is mandatory for laparoscopic cholecystectomy
• LMA is generally avoided (high IAP from pneumoperitoneum risks aspiration around LMA)
• Reasons for ETT:
  • Protects airway from regurgitation (head-down position + raised IAP)
  • Allows controlled IPPV to manage hypercapnia from CO2 absorption
  • Secures airway against loss due to position changes

Can regional anesthesia be used?

• Not practical for standard laparoscopic cholecystectomy
• High spinal/epidural needed (T4 level) - uncomfortable with pneumoperitoneum
• General anesthesia is the standard of care

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3. PHYSIOLOGICAL EFFECTS OF CO2 PNEUMOPERITONEUM

A. Cardiovascular Effects

IAP should be kept ≤12-15 mmHg to minimize cardiovascular compromise

B. Respiratory Effects

Management: Increase minute ventilation (increase RR or TV) to maintain EtCO2 35-40 mmHg. Reduce IAP if EtCO2 uncontrollable.

C. Renal Effects

• ↓ Renal blood flow from IAP
• ↓ GFR - transient oliguria intraoperatively
• Usually reverses on deflation of pneumoperitoneum

D. Neurological

• Raised IAP → raised ICP (via raised intrathoracic pressure → impaired cerebral venous drainage)
• Relevant in patients with intracranial pathology

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4. POSITION: REVERSE TRENDELENBURG + LEFT TILT

• Cholecystectomy uses reverse Trendelenburg (head up, feet down) + left lateral tilt
• This shifts liver/gallbladder upward into operative field
• Beneficial respiratory effect: Reduces diaphragmatic compression slightly compared to flat supine with pneumoperitoneum
• Risk: Venous pooling in legs → ↓ venous return → ↓ CO
  • Counteracted with adequate IV fluids before tilting
  • DVT risk - use pneumatic compression devices (TED stockings or calf compressors)

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5. INDUCTION

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6. MAINTENANCE

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7. MONITORING

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8. COMPLICATIONS AND THEIR ANESTHETIC MANAGEMENT

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9. PONV (Post-Operative Nausea and Vomiting) - HIGH RISK

1. Ondansetron 4 mg IV (at induction or end of surgery)
2. Dexamethasone 4-8 mg IV (at induction)
3. Avoid N2O + use propofol TIVA if high risk (TIVA reduces PONV vs volatiles)
4. Consider droperidol or cyclizine as additional agent

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10. REVERSAL AND EXTUBATION

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11. POSTOPERATIVE ANALGESIA (Multimodal)

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12. SPECIAL CONSIDERATIONS IN OBESE PATIENT

• Ramped position, CPAP preoxygenation, video laryngoscopy
• Higher PEEP intraoperatively (10 cmH2O)
• Lung recruitment manoeuvres after pneumoperitoneum insufflation
• Sugammadex preferred over neostigmine for reversal (faster, more complete)
• Consider post-op HDU monitoring if BMI >45 or OSA

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Quick Summary

Preop → Assess CVS/RS/Airway/GERD risk
Induction → RSI if needed, ETT mandatory, Propofol + Fentanyl + Muscle relaxant
Maintenance → Volatile/TIVA, NO nitrous, ↑MV for CO2, PEEP, full paralysis
Monitor → EtCO2 most critical, airway pressures, TOF
Complications → Vagal Brady, CO2 embolism, Pneumothorax, Endobronchial ETT
PONV → Triple prophylaxis (Ondansetron + Dexamethasone + TIVA)
Reversal → Awake extubation, Sugammadex preferred
Postop → Multimodal analgesia, warn about shoulder tip pain