Regional anaesthesia

1. ADDING NALBUPHINE TO TRANSVERSUS
ABDOMINIS PLANE BLOCK FOR POSTOPERATIVE
ANALGESIA AFTER INGUINAL HERNIA REPAIR

2. 1. INTRODUCTION
• Post-operative pain of inguinal hernia repair can be moderate to
severe and may be associated with prolonged hospital stay and
delayed return to normal daily activities. Inadequately treated
postoperative pain may be a risk factor for persistent pain after
hernia surgery. A review found that eleven percent of patients
suffered chronic pain after mesh inguinal hernia repair, and that
almost one-third of patients had limitations in daily leisure
activities as a consequence of chronic pain (Jeffrey et al, 2012).

3. • Current methods use for post-operative pain relief after inguinal
hernia repair consist of systemic tramadol or non-steroidal anti-
inflammatory drugs (NSAIDs), oral or suppository paracetamol or
diclofenac, regional nerve blocks such as ilioinguinal and
iliohypogastric nerve (IL/IHN) block, transversus abdominis plane
(TAP) block and surgical fields block with local wound infiltration.
NSAIDs has little effect on surgical stress responses and organ
dysfunction. The side effects of NSAIDs are not easily reversed; such
as gastrointestinal bleeding, platelet dysfunction and renal failure.
Moreover, as with any opioid use such as oral, systemic or intrathecal,
there is high incidence of itching, nausea, vomiting, sedation and
occasionally respiratory depression and urinary retention may occur

4. • Ilioinguinal and iliohypogastric nerve (IL/IHN) block, surgical fields
block and local infiltration methods are sometimes unsatisfactory for
surgeon due to infiltration of local anaesthetic agent near around the
surgical field. Transversus abdominis plane (TAP) block is one of the
regional block techniques that provide excellent analgesia over a
limited field with minimal systemic effects. These blocks are
generally easy to perform, inexpensive and safe. TAP block involves
deposition of local anaesthetic agent into the fascial plane superficial
to the transversus abdominis muscle. This technique is widely used for
intra and post-operative pain treatment in lower abdominal surgeries
(Hebbard et al 2007).
• .

5. • Nalbuphine, a mixed agonist-antagonist opioid, has a potential to
attenuate the mu-opioid effects and to enhance the kappa-opioid
effects. It was synthesized in an attempt to produce analgesia without
the undesirable side effects of a mu agonist. Also, its combination
with mu agonist opioids was tried by many researchers to decrease the
incidence and severity of the common mu agonist side effects
(respiratory depression, undesirable sedation, pruritus, nausea,
vomiting and urinary retention) (Eisenach, Carpenter & Curry, 2003).

6. • Nalbuphine was studied several times as an adjuvant to local
anesthetics in spinal, epidural and local, intravenous block, and the
result of all studies concludes that nalbuphine is effective when used
as an adjuvant to local anaesthetics in spinal, epidural, and local
intravenous block, as it significantly prolongs the block duration. The
analgesic effect of nalbuphine has been found to be equal to the
analgesic effect of morphine but unlike morphine, nalbuphine has a
ceiling effect on respiration. (Gunion, Marchionne & Anderson,
2004).

7. • Bhattacharjee et al 2014 reported duration of postoperative analgesia
to be 290 minutes following TAP block with bupivacaine. Inguinal
hernia repair is frequently associated with persistent postoperative
pain and the reduction of postoperative 24–48 hour is important.

8. • The main concern about using TAP block with local anaesthetic alone
is the duration of analgesia which hardly lasts for 6–8 hr. Several
adjuvants including opioids, clonidine, dexmedetomidine, ketamine,
midazolam, dexamethasone and adrenaline have been studied with
single-shot regional techniques, to increase the duration of local
anaesthetic action and to prolong post-operative pain relief.
• This study is aimed to find out whether nalbuphine added to
tranversus abdominis plane block might increase duration of local
anaesthetic action.

9. 1.2. Justification
• In Yangon General Hospital, over 300 cases of inguinal hernia repairs were done
from 2019 to 2022. Inguinal hernia repairs are performed under anaesthetic
techniques including spinal, regional or general anaesthesia. Spinal anaesthesia with
or without intrathecal opioid is most commonly used.

10. • Pain can extend to chronic persistent pain if acute post-operative pain
is insufficiently controlled. Postoperative pain following inguinal
hernia repair is controlled with drugs such as paracetamol or
diclofenac suppository, IV or IM ketorolac or tramadol, regional
blocks such as ultrasound guided ilio-inguinal and ilio-hypogastric
nerve block, unilateral TAP block or surgical fields infiltration with
local anaesthetic (LA) agent.

11. • In current practice, adjuvants such as tramadol, ketamine,
dexamethasone are being used to increase the analgesic effect of local
anaesthetic agent in regional nerve block.
• In this study, nalbuphine, an opioid agonist antagonist, will be added
to ultrasound-guided TAP block as an adjuvant. This study is aimed to
identify the analgesic effect of TAP block with bupivacaine for post-
operative pain relief after inguinal hernia repair by adding nalbuphine
(10 mg) as an adjuvant.

12. 3. AIM AND OBJECTIVES
• 3.1. Aim
• To study the effects of adding nalbuphine to transversus abdominis plane block for
postoperative analgesia after inguinal hernia repair.

13. 3.2. Objectives
1. To compare the intensity of post operative pain between bupivacaine
with nalbuphine added group (group A) and bupivacaine alone group
(group B) at 1, 2, 4, 6 and 12 hr after operation by using VAS pain
score.
2. To compare the duration of analgesia between the two groups in
inguinal hernia repair.
3. To compare the requirement of total rescue analgesia given after
operation between the two groups.

14. Patients undergoing hernia repair surgery
under spinal anaesthesia
Selected according to inclusion and exclusion
criteria
Block randomization
Spinal anaesthesia with usual doses of 0.5% heavy
bupivacaine
Group A (n=40)
TAP block with 0.25%
bupivacaine alone
•Note time of TAP block, first request of analgesic postoperatively
•Find out the duration of analgesia
•If VAS score >4 at the time of pain assessment or patient request
analgesic, IV Tramadol 50mg and determine total Tramadol requirement
for post-op 24 hours
•Observe severity of pain using VAS score at postop 1, 2, 4, 6 and 12
hours
Group B (n=40)
TAP block with nalbuphine
10mg added to 0.25%
bupivacaine
USG guided unilateral TAP
block with 0.25%
bupivacaine 20cc at the end
of surgical procedure
USG guided unilateral TAP block
with nalbuphine 10mg added to
0.25% bupivacaine 20cc at the
end of surgical procedure
Flow chart of the study

15. Table (3) Total doses of rescue analgesia (IV Tramadol 50mg/dose)
Total doses of rescue
analgesia (mg)
Group A
(n=40)
Group B
(n=40)
P value
Mean_+ SD

16. Table (4) VAS score (hours) in both groups after TAP block
Hours Group A
(n=40)
Group B
(n=40)
Statistics
Mean SD Mean SD P value
2
4
6
24

17. Table (5) Complications
Group A
(n=40)
Group B
(n=40)
Number Percent Number Percent
Epigastric pain
GI bleeding
Nausea
Vomiting