Background and goal of study: The aim w as to know the incidence of breakthrough pain (BP)
comparing tw o analgesic regimes. We also evaluated the BP incidence betw een epidural (EA) and
combined spinal epidural (CSE) analgesia.
Materials and methods: We performed a randomized double blind clinical trial on nulliparous
w omen (18-40 yrs old), w ith a cervical dilatation < 4cm at singleton term pregnancy. Exclusion
criteria w ere contraindication for EA and the presence of systemic disease. Patients w ere
randomized to receive EA w ith PCEA (group 1), EA plus PIEB (group 2), CSE w ith PCEA (group 3), or
CSE plus PIEB (group 4). The anaesthesiologist w ho performed the epidural block w as blinded for
the analgesic regime, and pain w as assessed by a third anaesthesiologist blinded for the technique
or analgesic regime. All patients had a background epidural infusion (0.125% levo-bupivacaine w ith
1.45 mcg/ml fentanyl, 5 ml/h.). PCEA groups w ere set w ith 10 ml boluses (20 min lockout interval).
PIEB groups received 10ml bolus per hour (20 min lock time w ith PCEA). BP w as defined as the need
for analgesia due to pain ≥4 in visual analog scale (VAS) and treated w ith 10ml bolus of epidural
infusion. Failed block w as considered w hen VAS w as >3 sixty minutes after epidural catheter
insertion and patients w ere excluded from the analysis. We recorded BP episodes, PCEA boluses,
total volume of infusion, VAS pain scores, delivery outcomes, and maternal satisfaction.
Results: 60 patients w ere included. Groups w ere homogeneous. 93% of PIEB groups patients had
0 episodes of BP, and 95% of PCEA patients had at least 1 episode of BP. (p=0,002). There w as
less BP episodes in PIEB groups (mean 0.5 ± 0.9 in group 2; 1.2 ± 1.8 in group 4) compared w ith
control groups (2.4 ± 1.7 in group 1; 2.9 ± 1.7 in group 3) (P < 0.05). Total local anaesthetic in
demand for BP w as significantly low er in PIEB (mean 4.1 ± 7.2 ml in group 2; 95%; 9.4 ± 17.7 ml in
group 4) compared w ith PCEA groups (28.8 ± 16.8 ml in group 1; 28.0 ± 16.0 ml in group 3) (P <
0.05). There w ere no difference betw een CSE versus EA groups regarding number of BP episodes
and PCEA boluses (P >0.05). VAS w ere low er in CSE compared w ith epidural groups at 30 min (P <
0.001), but they w ere comparable during labour. The incidence of failed block w as 11.7%.
Conclusion: PIEB reduced the incidence of BP during labour compared to PCEA. CSE technique
could not reduce the number of episodes of BP after the first 30 minutes.

Breakthrough pain in labour. A randomized double blind clinical trial comparing programed intermitent epidural boluses (PIEB) versus patient controlled epidural analgesia (PCEA) with epidural or combined spinal epidural technique: preliminary results