What is the recommended anesthesia plan for a 43-year-old female (F), weighing 61.2kg, with a history of occasional (occ) migraines, classified as American Society of Anesthesiologists (ASA) 1, undergoing a vaginal hysterectomy using spinal anesthesia with sedation?

Anesthesia Plan for Vaginal Hysterectomy with Spinal and Sedation

For this 43-year-old, 61.2kg, ASA 1 patient undergoing vaginal hysterectomy, administer 12 mg (1.6 mL) of 0.5% hyperbaric bupivacaine intrathecally using a pencil-point spinal needle, followed by propofol sedation at 0.4 mg/kg loading dose then 1.5-2 mg/kg/hr infusion to maintain conscious sedation. 1

Preoperative Preparation

• NPO Status: Clear liquids permitted up to 2 hours before procedure; solid foods avoided for 6-8 hours 2
• Aspiration Prophylaxis: Administer nonparticulate antacid (e.g., sodium citrate 30 mL), consider adding ranitidine 50 mg IV and/or metoclopramide 10 mg IV within 60 minutes of procedure start 2
• Antibiotic Prophylaxis: Cefazolin 2g IV (or 3g if >120kg) within 60 minutes before incision 3
• IV Access: Establish 18-gauge or larger IV catheter before initiating spinal anesthesia 1
• Preemptive Analgesia: Consider acetaminophen 1000 mg PO and/or celecoxib 200-400 mg PO 1-2 hours preoperatively 2, 3

Spinal Anesthesia Technique

Dosing: Use 12 mg (1.6 mL) of 0.5% hyperbaric bupivacaine in dextrose for lower abdominal procedures including vaginal hysterectomy 1. This dose provides adequate sensory level (T10) and duration (2-3 hours) for the procedure 4, 5.

Needle Selection: Use pencil-point spinal needle (Whitacre or Sprotte, 25-27 gauge) instead of cutting-bevel needle to minimize post-dural puncture headache risk 2

Positioning: Perform spinal in sitting position for optimal distribution of hyperbaric solution 4

Technique:

• Position patient sitting with back flexed
• Identify L3-4 or L4-5 interspace
• Aspirate to confirm CSF flow and observe characteristic "swirl" when bupivacaine mixes with CSF 1
• Inject slowly over 15-30 seconds
• Position patient supine immediately after injection

Sedation Protocol

Propofol Conscious Sedation: This is the preferred sedation technique for vaginal hysterectomy under spinal anesthesia 6

• Loading Dose: 0.2-0.4 mg/kg (12-24 mg for this 61.2kg patient) administered in 0.2 mg/kg increments every minute until spontaneous eye closure or nystagmus appears 6
• Maintenance Infusion: 1.5-2 mg/kg/hr (92-122 mg/hr or approximately 25-35 mcg/kg/min) adjusted to maintain conscious sedation with spontaneous ventilation 6
• Titration Goal: Patient should respond to verbal stimulation but remain comfortable and amnestic 2, 6

Alternative Sedation: If propofol unavailable, use midazolam 1-2 mg IV boluses titrated to effect, though propofol provides superior respiratory profile 6

Intraoperative Monitoring and Management

Standard Monitoring: Continuous pulse oximetry, ECG, non-invasive blood pressure every 3-5 minutes initially then every 5-15 minutes, capnography if sedation depth increases 2

Hypotension Management:

• Expect sympathetic blockade causing vasodilation 1
• Treat MAP <65 mmHg lasting >5 minutes with phenylephrine 50-100 mcg IV boluses or ephedrine 5-10 mg IV 5
• Maintain IV crystalloid at 500-1000 mL during procedure for euvolemic state 3

Respiratory Monitoring: Propofol sedation at these doses actually improves respiratory parameters compared to no sedation during spinal anesthesia 6. Monitor respiratory rate, SpO2 >95%, and nasal ETCO2 <50 mmHg 2, 6

Supplemental Oxygen: Provide 2-4 L/min via nasal cannula 2

Postoperative Analgesia

Multimodal Approach:

• Scheduled acetaminophen 1000 mg PO/IV every 6 hours 2, 3
• Scheduled NSAID: ketorolac 15-30 mg IV every 6 hours (maximum 5 days) or ibuprofen 600 mg PO every 6 hours 2
• Opioid rescue only: oxycodone 5 mg PO every 4 hours PRN for breakthrough pain (NRS >4) 2, 5

Expected Pain Control: Spinal bupivacaine provides excellent analgesia for 4-8 hours postoperatively, with significantly lower pain scores and reduced opioid requirements compared to general anesthesia alone 5, 7

Critical Safety Considerations

Avoid These Pitfalls:

• Do NOT inject spinal during uterine contractions if patient in labor (not applicable here but critical safety point) 1
• Do NOT use cutting-bevel spinal needles due to increased PDPH risk 2
• Do NOT allow propofol sedation to progress to deep sedation/general anesthesia—maintain verbal responsiveness 2
• Do NOT administer additional local anesthetic doses without considering cumulative toxicity risk 1

Emergency Preparedness: Have lipid emulsion 20% immediately available for local anesthetic systemic toxicity (LAST), though risk is minimal with proper spinal technique 1. Ensure resuscitation equipment and vasopressors at bedside 2, 1.

Migraine Consideration: Her history of occasional migraines is not a contraindication to spinal anesthesia. Ensure adequate hydration and consider ondansetron 4 mg IV for PONV prophylaxis, as nausea can trigger migraines 2.

Recovery and Discharge

Recovery Room Monitoring: Continue monitoring until sensory level regresses to L2-L3, motor function returns (Bromage score ≤2), and hemodynamics stable 5

Expected Recovery Time: Patients receiving spinal with propofol sedation meet discharge criteria approximately 90-100 minutes postoperatively, faster than general anesthesia alone 5

Mobilization: Ambulate once motor block resolved (typically 3-4 hours) and orthostatic vital signs stable 5