Anesthesia for Cholecystectomy

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Pre-medication Administered to reduce anxiety, provide analgesia, and prevent nausea/vomiting. Midazolam: $0.02 - 0.04 \text{ mg/kg IV}$ (e.g., $1.5 - 3 \text{ mg}$ for $70 \text{ kg}$ patient). Anxiolytic, sedative. Fentanyl: $1 - 2 \text{ mcg/kg IV}$ (e.g., $70 - 140 \text{ mcg}$ for $70 \text{ kg}$ patient). Opioid analgesic. Ondansetron: $4 \text{ mg IV}$. Anti-emetic. Ranitidine or Famotidine: $50 \text{ mg IV}$ (Ranitidine) or $20 \text{ mg IV}$ (Famotidine). H2 blocker to reduce gastric acid. Induction of Anesthesia Achieve rapid unconsciousness and facilitate intubation. Pre-oxygenation: $100\%$ oxygen via face mask for $3-5$ minutes. Propofol: $1.5 - 2.5 \text{ mg/kg IV}$ (e.g., $105 - 175 \text{ mg}$ for $70 \text{ kg}$ patient). Hypnotic agent, rapid onset, short duration. Fentanyl: $1 - 2 \text{ mcg/kg IV}$ (e.g., $70 - 140 \text{ mcg}$ for $70 \text{ kg}$ patient). For analgesia and blunting sympathetic response to intubation. Rocuronium: $0.6 - 1.2 \text{ mg/kg IV}$ (e.g., $42 - 84 \text{ mg}$ for $70 \text{ kg}$ patient). Non-depolarizing neuromuscular blocker for muscle relaxation to facilitate intubation. Lidocaine (optional): $0.5 - 1.0 \text{ mg/kg IV}$ to blunt cough reflex and pain on propofol injection. Intubation: Once adequate muscle relaxation is achieved, perform laryngoscopy and endotracheal intubation. Confirm tube placement. Maintenance of Anesthesia Maintain unconsciousness, analgesia, and muscle relaxation throughout the procedure. Inhalational Agent: Sevoflurane: $0.8 - 2.5\%$ end-tidal concentration. Desflurane: $4 - 10\%$ end-tidal concentration. Isoflurane: $0.5 - 1.5\%$ end-tidal concentration. Administered with oxygen and air mixture to maintain MAC (Minimum Alveolar Concentration) for surgical depth. Analgesia: Fentanyl: $0.5 - 1 \text{ mcg/kg IV}$ boluses as needed (e.g., $35 - 70 \text{ mcg}$ boluses). Remifentanil (infusion): $0.05 - 0.2 \text{ mcg/kg/min IV}$. Titrate to effect. Muscle Relaxation: Rocuronium: $0.1 - 0.2 \text{ mg/kg IV}$ boluses as needed (e.g., $7 - 14 \text{ mg}$ boluses) based on neuromuscular monitoring (TOF). Cisatracurium: $0.03 \text{ mg/kg IV}$ boluses as needed. Ventilation: Mechanical ventilation to maintain normocapnia ($ \text{EtCO}_2 \approx 35-45 \text{ mmHg}$). Fluid Management: Crystalloids (e.g., Lactated Ringer's) at $3-5 \text{ mL/kg/hr}$. Reversal of Neuromuscular Blockade Restore full muscle function at the end of surgery. Sugammadex (for Rocuronium or Vecuronium): If TOF count $\ge 2$: $2 \text{ mg/kg IV}$ (e.g., $140 \text{ mg}$ for $70 \text{ kg}$ patient). If TOF count $0$ with $1-2$ post-tetanic counts: $4 \text{ mg/kg IV}$. Immediate reversal (e.g., cannot intubate, cannot ventilate): $16 \text{ mg/kg IV}$. Rapid onset, directly encapsulates the neuromuscular blocker. Neostigmine & Glycopyrrolate (for non-depolarizing NMBs like Rocuronium, Cisatracurium): Neostigmine: $0.03 - 0.07 \text{ mg/kg IV}$ (max $5 \text{ mg}$). Acetylcholinesterase inhibitor. Glycopyrrolate: $0.01 \text{ mg/kg IV}$ (typically $0.2 \text{ mg}$ for every $1 \text{ mg}$ Neostigmine). Anticholinergic to counteract muscarinic side effects of Neostigmine (bradycardia, salivation). Administer when TOF count $\ge 2$. Slower onset; monitor for full recovery. Monitoring: Use neuromuscular stimulator (e.g., Train-of-Four, TOF) to confirm full recovery (TOF ratio $> 0.9$). Post-operative Analgesia and Nausea Prevention Multimodal approach: Paracetamol: $1000 \text{ mg IV}$. Ketorolac: $15 - 30 \text{ mg IV}$ (if no contraindications). Long-acting Opioid: e.g., Morphine $2 - 5 \text{ mg IV}$ or Hydromorphone $0.5 - 1 \text{ mg IV}$ titrated to effect. Local anesthetic infiltration at incision site by surgeon. PONV Prophylaxis: Dexamethasone: $4 - 8 \text{ mg IV}$. Ondansetron: $4 \text{ mg IV}$ (if not given pre-op or if symptoms persist). Patient-Specific Considerations (37-year-old woman, $70 \text{ kg}$ assumed) Dosages provided are for a $70 \text{ kg}$ patient. Adjust based on actual body weight and clinical response. Consider potential for pregnancy if not ruled out, and adjust drug choices accordingly.