Total Local Anesthetic Dose Delivered by PIEB Versus Continuous Epidural Infusion
Programmed intermittent epidural bolus (PIEB) protocols generally deliver a lower total amount of epidural local anesthetic than continuous steady-rate epidural infusions in labor analgesia trials using comparable background regimens. [1][2][3]
The magnitude of total-dose reduction varies by drug concentration, bolus volume, lockout interval, and whether rescue dosing is used. [1][2][3]
Dose Comparison in Labor Analgesia Trials
In a randomized trial of low-dose ropivacaine (0.08%) without opioids for labor analgesia, median total local anesthetic volume was 59.9 mL (45–66) with PIEB versus 69.5 mL (44–92) with continuous infusion (p = 0.033). [1]
In a separate randomized trial using ropivacaine epidural anesthetics with a PIEB strategy, median hourly epidural anesthetic consumption was 9.4 mL/h with PIEB versus 14.3 mL/h with continuous infusion (p < 0.001). [2]
Dose Comparison in Postoperative Epidural Analgesia
In a randomized trial of postoperative thoracic/abdominal cancer surgery epidural analgesia using ropivacaine with PCEA support, total local anesthetic administered in the first 24 hours was similar between groups: 123 mg (IQR 114–136) with PIEB versus 126 mg (IQR 120–134) with continuous infusion. [4]
Quantitative Direction of Effect Across Studies
Labor studies that reported total dose found lower local anesthetic consumption with PIEB than with continuous infusion in at least some protocols. [1][2]
Postoperative evidence exists showing no difference in total local anesthetic consumption during defined time windows. [4]
Treatment Context That Alters Total Dose Delivered
Total-dose differences are protocol dependent due to programmed bolus delivery schedules that change the balance between background dosing and supplemental (rescue) epidural dosing behavior. [1][2][4]
Common Protocol-Driven Interpretation for “Total Local Anesthetic Dose”
When total local anesthetic is reported as total volume delivered, PIEB has been associated with smaller total volume than continuous infusion in labor trials. [1]
When total local anesthetic is reported as dose per hour or total mass over a defined interval, PIEB may reduce hourly consumption in labor trials but may show no measurable difference in postoperative total consumption depending on the study design. [2][4]
Key Evidence Supporting the Comparison
Lower total local anesthetic volume with PIEB versus continuous infusion has been demonstrated with ropivacaine 0.08% in labor (59.9 mL vs 69.5 mL, p = 0.033). [1]
Lower hourly consumption with PIEB versus continuous infusion has been demonstrated in labor analgesia (median 9.4 mL/h vs 14.3 mL/h, p < 0.001). [2]
No difference in first-24-hour total local anesthetic mass has been demonstrated in postoperative epidural analgesia (123 mg vs 126 mg). [4]