Introduction: Intrathecal fentanyl is routinely mixed with hyperbaric bupivacaine
during spinal block, but this may alter the baricity of both drugs and
hence
affect their spread and action.
Aim:
This study aimed to compare the sequential administration of intrathecal
fentanyl and bupivacaine to the routine mixing of the two drugs as regard
the block characteristics, the postoperative analgesia duration, and the
adverse
effects.
Methods:
Current prospective, controlled, randomized trial was carried out
on
100 adult participants subjected to lower limb orthopedic surgeries under
spinal
anesthesia. Subjects were allocated randomly into two equal groups
(50
each). Group P: received premixed solution of hyperbaric bupivacaine
(HB)
0.5 % (12.5 mg) plus 25 µg
of fentanyl in the same syringe and group < br />S:
received 25 µg
of fentanyl followed by 12.5 mg of HB in sequential manner.
Block characteristics, time to the first rescue pethidine request, number
of
participants who requested for pethidine within the first 6 postoperative
hours,
and adverse effects were assessed.
Results:
Group S patients had statistically significantly faster onset of both
sensory
(4.58 ±
1.5 vs 5. 40 ±
1.8 min, p = 0.02) and motor block (5.79 ±
1.5
min versus 6.64 ±
1.9 min, p = 0.01), shorter time to achieve the highest
sensory
level (6.12 ±
1.96 min vs 8.77 ±
2.5min, p = 0.00), and a longer
time
till the first postoperative rescue analgesic need (252.26 ±
39.3 min
versus
234.70 ±
40.2 min, p = 0.03) . Group P patients achieved statistically
significantly
higher level of sensory blockade and showed longer sensory
block
duration (216.30 ±30.8
vs 199.44±
23.8, p = 0.003). Adverse effects
were
comparable in both groups.
Conclusions:
The sequential administration of fentanyl and hyperbaric bupivacaine
improves the spinal block characters in patients subjected to lower
limb orthopedic surgeries with comparable adverse effects profile in comparison
to mixing both drugs.