What are the step‑by‑step drug doses for a typical adult (ASA I‑II, 18‑65 years, 70 kg, no organ dysfunction) undergoing general anesthesia?

General Anesthesia Drug Dosing Protocol for Standard Adult Patient

For a typical adult patient (70 kg, ASA I-II, no organ dysfunction) undergoing general anesthesia, use propofol 1.5-2.5 mg/kg IV for induction, fentanyl 1-2 mcg/kg IV for analgesia, and rocuronium 0.6 mg/kg IV for neuromuscular blockade, followed by maintenance with either propofol infusion or volatile anesthetic with supplemental opioids titrated to surgical stimulus. 1

Pre-Induction Phase

Antisialogogue (Optional, 30-60 minutes pre-procedure)

• Glycopyrronium bromide 0.2-0.4 mg IM or 0.1-0.2 mg IV if administered immediately before induction 2
• Note: May produce significant tachycardia; less commonly, atropine 0.3-0.6 mg IM or 0.2-0.3 mg IV can be used but causes more tachycardia 2

Anxiolysis/Amnesia (Optional)

• Midazolam 0.02 mg/kg IV or 1-2 mg IV titrated to effect 1
• Peak effect occurs at 5-10 minutes, so exercise caution with multiple doses 2
• Reduce dose by at least 20% in elderly patients (>60 years) or ASA III-IV 1

Induction Phase

Step 1: Pre-oxygenation

• Administer 100% oxygen for 3-5 minutes via face mask 2

Step 2: Opioid Administration

• Fentanyl 1-2 mcg/kg IV (for 70 kg patient: 70-140 mcg) 1
  • Use 1 mcg/kg for minor/ambulatory procedures 1
  • Use 2 mcg/kg for major/invasive procedures 1
• Alternative: Remifentanil 0.5-1 mcg/kg/min infusion with initial 1 mcg/kg bolus over 30-60 seconds if intubation planned within 8 minutes 3

Step 3: Hypnotic Induction Agent

• Propofol 1.5-2.5 mg/kg IV (for 70 kg patient: 105-175 mg) 1
  • Reduce by 50% in elderly patients (>60 years) 1
  • Administer as smooth bolus over 30-60 seconds 1
• Alternative for hemodynamically unstable patients: Etomidate 10-20 mg IV 1
• Alternative with analgesic properties: Ketamine 1-2 mg/kg IV 1

Step 4: Neuromuscular Blockade (if intubation required)

• Rocuronium 0.6 mg/kg IV (for 70 kg patient: 42 mg) for standard intubation 2
• Succinylcholine 1 mg/kg IV (for 70 kg patient: 70 mg) for rapid sequence induction only 2
  • Caution: Succinylcholine is a malignant hyperthermia trigger agent 2
• Wait 60-90 seconds for rocuronium or 45-60 seconds for succinylcholine before laryngoscopy 2

Step 5: Laryngoscopy and Intubation

• Perform laryngoscopy and endotracheal intubation 2
• Confirm tube placement with two-point check: (1) visualization of tube through vocal cords, and (2) capnography to exclude esophageal intubation 2

Maintenance Phase

Option A: Total Intravenous Anesthesia (TIVA)

• Propofol infusion: 100-200 mcg/kg/min (for 70 kg patient: 7-14 mg/min or 420-840 mg/hr) 1
• Remifentanil infusion: 0.05-2 mcg/kg/min depending on surgical stimulus 3
  • With nitrous oxide 66%: 0.4 mcg/kg/min baseline 3
  • With propofol alone: 0.25 mcg/kg/min baseline 3
  • Titrate upward in 25-100% increments or downward in 25-50% decrements every 2-5 minutes 3
  • Supplemental boluses of 1 mcg/kg every 2-5 minutes for transient intense surgical stress 3

Option B: Volatile Anesthetic Maintenance

• Desflurane 2.6-8.4% with nitrous oxide 60% or 3.1-8.9% in oxygen alone 4
• Isoflurane 0.7-1.4% with nitrous oxide 60% 4
• Sevoflurane 0.3-1.5 MAC 1
• Supplemental fentanyl boluses 0.5-1 mcg/kg as needed every 30-60 minutes 2
• Caution: All volatile anesthetics are malignant hyperthermia trigger agents 2

Multimodal Analgesia (Opioid-Sparing Strategy)

• Acetaminophen 15-20 mg/kg IV loading dose (for 70 kg patient: 1050-1400 mg), then 10-15 mg/kg every 6-8 hours (maximum 60 mg/kg/day) 1
• Ketorolac 15-30 mg IV (if not contraindicated) 1
• Ketamine 0.5 mg/kg IV bolus followed by 0.25-0.5 mg/kg/hr infusion for additional analgesia 1
• Lidocaine 1.5 mg/kg IV bolus followed by 1.5 mg/kg/hr infusion 1

Adjunctive Sedation (if needed)

• Dexmedetomidine 0.5-1 mcg/kg IV loading dose over 5 minutes, followed by 0.2-0.7 mcg/kg/hr infusion 1
• Caution: Bolus dosing associated with hypertension and bradycardia 2

Antiemetic Prophylaxis

• Dexamethasone 0.15-0.25 mg/kg IV (for 70 kg patient: 10.5-17.5 mg, typically give 4-8 mg) at induction 1
• Ondansetron 4 mg IV near end of surgery 5

Emergence and Recovery Phase

Reversal of Neuromuscular Blockade

• Monitor Train-of-Four (TOF) ratio; must be >90% before extubation 2
• Neostigmine 0.04-0.07 mg/kg IV with glycopyrrolate 0.01 mg/kg IV if TOF <90% 2
• Alternative: Sugammadex 2-4 mg/kg IV for rapid rocuronium reversal 2

Discontinuation of Anesthetics

• Stop volatile anesthetics 5-10 minutes before anticipated end of surgery 4
• Reduce propofol infusion rate by 50% in final 10 minutes 1
• Continue remifentanil until end of procedure, then discontinue (rapid offset within 3-5 minutes) 3

Extubation Criteria

• TOF ratio >90% 2
• Regular spontaneous breathing with adequate gas exchange 2
• Satisfactory hemodynamic conditions 2
• Awake patient (eye opening/response to commands) 2

Critical Monitoring Requirements

• Continuous pulse oximetry, capnography, blood pressure, heart rate, and respiratory rate throughout entire anesthetic 1
• Capnography monitoring every 5-15 minutes until discharge criteria met 1
• Neuromuscular blockade monitoring when muscle relaxants used 2

Emergency Reversal Agents (Must Be Immediately Available)

• Naloxone for opioid reversal: 0.04-0.4 mg IV, repeat every 2-3 minutes as needed 1
• Flumazenil for benzodiazepine reversal: 0.2 mg IV over 15 seconds, then 0.1 mg every 60 seconds (maximum 1 mg) 1
• Dantrolene for malignant hyperthermia: 2 mg/kg IV initial dose, repeat until symptoms resolve (may need 36-50 ampoules for adult; maximum may exceed 10 mg/kg) 2

Common Pitfalls to Avoid

Respiratory Depression

• Avoid excessive opioid dosing, especially when combining with propofol or benzodiazepines 1
• Use capnography for early detection of hypoventilation 1
• With propofol TCI, avoid effect-site concentrations >1.5 mcg/ml when using concomitant opioids 2

Inadequate Analgesia

• Do not rely on single-agent analgesia; employ multimodal approach combining acetaminophen, NSAIDs, ketamine, and regional techniques 1
• Anticipate surgical stimulus and provide supplemental boluses before intense stimulation 3

Malignant Hyperthermia Risk

• Avoid volatile anesthetics and succinylcholine in susceptible patients 2
• If MH suspected: immediately stop trigger agents, hyperventilate with 100% oxygen, give dantrolene 2 mg/kg IV, and call for help 2

Hemodynamic Instability

• Reduce induction doses by 50% in elderly patients (>65 years) to prevent hypotension 1
• Consider etomidate or ketamine for hemodynamically unstable patients instead of propofol 1
• Ketamine 0.5 mg/kg may protect against post-induction hypotension better than fentanyl alone 6

Inadequate Neuromuscular Reversal

• Always monitor TOF quantitatively; clinical assessment alone is unreliable 2
• Do not extubate until TOF ratio >90% 2
• Have reversal agents immediately available 2