The landmark-guided transversus abdominis plane (TAP) block is an effective method
of providing postoperative analgesia in patients undergoing lower abdominal surgery.
We evaluated the analgesic efficacy of the ultrasound (US)-guided TAP block in patients
undergoing Caesarean delivery.
A randomized, double-blind, placebo-controlled trial was performed at a tertiary maternity
hospital. Fifty women undergoing Caesarean delivery received bilateral US-guided TAP
blocks with either ropivacaine 0.5% or saline. All participants received a spinal
anaesthetic with bupivacaine and fentanyl, followed by postoperative acetaminophen,
non-steroidal anti-inflammatory drugs, and patient-controlled i.v. morphine without
long-acting intrathecal opioids. Each patient was assessed 24 h after delivery for
morphine usage, average pain score, nausea, vomiting, pruritus, drowsiness, and satisfaction
with pain relief.
Forty-seven participants completed the trial, 23 in the active group and 24 in the
placebo group. Total morphine use in 24 h was reduced in the active group (median
18.0 mg) compared with the placebo group (median 31.5 mg, P<0.05). The active group
reported improved satisfaction with their pain relief measured by visual analogue
scale compared with the placebo group (median 96 vs 77 mm, P=0.008). Fewer patients
required antiemetics in the active group (P=0.03). There were no local complications
attributable to the TAP block, but one participant had an anaphylactoid reaction after
ropivacaine injection.
The US-guided TAP block reduces morphine requirements after Caesarean delivery when
used as a component of a multimodal analgesic regimen. Registered with the Australia
New Zealand Clinical Trials Registry ACTRN12608000540314. URL: http://www.anzctr.org.au/trial_view.aspx?ID=83176.