Bupivacaine Dosing Guidelines for Obstetric Regional Anesthesia

Labor Analgesia – Initial Dosing

Administer an initial bolus of 2.5 mg bupivacaine (or an equivalent dose) when starting intrathecal‑catheter labor analgesia, combined with up to 15 µg fentanyl (or 2.5 µg sufentanil equivalent) to enhance analgesia while limiting opioid‑related adverse effects. Evidence level: not specified. 1
Use bupivacaine concentrations of 0.1 %, 0.125 % or 0.25 % with a total volume of 1–2.5 mL for the initial dose. Evidence level: not specified. 1, 3
The ED95 for the bupivacaine‑fentanyl combination is approximately 1.75 mg bupivacaine + 15 µg fentanyl; doses up to 2.5 mg bupivacaine provide more reliable analgesia. Evidence level: not specified. 3

Continuous infusion: bupivacaine 0.1–0.125 % with 2–2.5 µg/mL fentanyl, infused at 1–4 mL/h. Evidence level: not specified. 5, 6, 4
Intermittent bolus: administer 1–5 mL of 0.1 % or 0.125 % bupivacaine containing 2 µg/mL fentanyl by the anesthesiologist. Evidence level: not specified. 5, 2, 4
For breakthrough pain during a continuous infusion, give a 1–2 mL bolus of the same solution. Evidence level: not specified. 5, 4

If intrathecal placement is recognized only after 10 mg bupivacaine has been administered through the catheter, first assess the sensory block level; only give additional incremental doses up to 2.5 mg once the block has receded to the T10 dermatome. Evidence level: not specified. 1, 2, 3

With epinephrine: maximum single dose 3.0 mg/kg (≈ 225 mg for an average adult). Evidence level: not specified. 7
Without epinephrine: maximum single dose 2.5 mg/kg (≈ 175 mg for an average adult). Evidence level: not specified. 7

Give incremental boluses limited to 2.5 mg bupivacaine (or equivalent) per increment. Evidence level: not specified. 9, 4
Wait at least 3 minutes between each incremental top‑up. Evidence level: not specified. 9
Assess and document the block response before administering additional top‑ups. Evidence level: not specified. 9
Add 300 µg diamorphine or 100 µg preservative‑free morphine for postoperative analgesia after conversion. Evidence level: not specified. 9
Perform all high‑dose intrathecal injections for cesarean conversion in the operating theatre, not in the delivery room. Evidence level: not specified. 9

Continuously monitor blood pressure, ECG, and oxygen saturation.
Assess block height at least every 5 minutes until no further extension is observed.
Maintain fetal heart‑rate monitoring while the patient is in the operating theatre.
Remain vigilant for signs of high spinal block, especially after intrathecal catheter top‑ups. Evidence level: not specified. 9

Do not compensate low volume with high concentration; volume primarily determines spread of the block, while concentration determines its intensity. Evidence level: not specified. 10