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Various surgeries such as inguinal hernioplasty and open appendectomy lead to mild to severe postoperative pain.
The addition
of dexmedetomidine to bupivacaine in Transversus Abdominis Plane (TAP) blockade reduced postoperative pain
scores and morphine consumption, in addition to increasing satisfaction in
patients undergoing lower abdominal surgery. Dexmedetomidine had no effect on
nausea and vomiting scores and the need for antiemetic.
Various surgeries such as inguinal hernioplasty and open
appendectomy lead to mild to severe postoperative pain. In many cases, this
postoperative pain can be chronic and may cause undesirable events. Among
patients who undergo the hernia repair, about 54% patients are known to suffer
from pain after the procedure. The transverse abdominis plane, one of the
peripheral nerve blocks is known to significantly control the pain after the
hernioplasty. However, coadministration of local anesthesia provides
synergistic effect and prolonged duration of blockade. Dexmedetomidine is a
selective α -2-adrenergic agonist with analgesic and sedative properties. When
administered as a perineural adjuvant, dexmedetomidine reduces the initial
blocking time while prolonging the duration of sensory-motor blockade.
Rationale behind the
research:
Postoperative pain is the chronic
condition causing discomfort and prolonged immobility in patients. None of the
published study provide the satisfactory results to patients.
Therefore, the present study by Aksu
R et. al., evaluated the effect of bupivacaine and dexmedetomidine added
to bupivacaine for TAP blockade in pain control and estimated the patient
satisfaction after the lower abdominal surgery.
Objective:
To evaluate the effect of
bupivacaine and dexmedetomidine added to bupivacaine used in TAP block on
postoperative pain and patient satisfaction in patients undergoing lower
abdominal surgery.
Study outcome measures:
During the postoperative period, HR continued to increase in the BD Group at zero and 24 h compared to Group C and at 120 h, 6 h and 12 h compared to groups C and B (p<0.05). Intergroup HR assessment showed a decrease from baseline HR at 10, 30, 45 and 60 minutes of operation in Group B and at each measurement period, excluding the postoperative period of 24 h in the BD group (p<0.05). However, 0.5 mg of atropine was required because the HR of two patients was <50 bpm. There was no difference in relation to the baseline values of Group C (p>0.05) (Figure 1).
Figure 1: Heart rate (HR)
Compared with Group C, there was a decrease in the normal clinical blood pressure level at the 10th minute of Group B operation; at the 30th, 45th and 60th postoperative hours and at the 6th postoperative hour in the BD Group and in the 12th hour in comparison to the Group B (p>0.05) (Figure 2).
Figure 2: Mean blood pressure (MAP) (mmHg)
Although a statistically significant reduction in VAS score was observed only in the BD group compared to the C group in the postoperative period (0 min), reduction in groups B and BD between 120min to 8 h in post-was statistically significant (p<0.05). The reduction in the BD group between 10 to 24 h postoperatively was statistically significant when compared with groups B and C (p<0.05) (Figure 3).
Figure 3: VAS scores in the postoperative period
The present study demonstrated that the administration of
TAP block after induction of anesthesia reduced the VAS score in comparison
with the control group, while minimizing postoperative morphine consumption.
To prolong the duration of pain
relief with TAP block, the blockade should be administered soon after the
induction of anesthesia and shortly before the surgical incision. Bharti et
al applied the TAP block at the end of the surgery and reported that the
blockade did not extend the time to the first need for analgesia compared to
the control group; however, the authors reported a reduction in total morphine
consumption in the second postoperative hour. Niraj et al administered a
unilateral TAP block with 20 mL of 0.5% bupivacaine in open appendectomy. In
the control group, the mean 24-hour morphine intake was 50mg, compared with
28mg in the group that received the TAP blockade. Cho et al reported
that administration of the TAP block with 20 mL of 0.5% bupivacaine for open
appendectomy reduces intraoperative fentanyl consumption as compared to the
control group. Besides, TAP blockade with 20 mL of 0.5% levobupivacaine
provided 12 h of postoperative analgesia, but the effect was not continuous till
24 h postoperatively. However, this result may be due to the limited number of
patients.
The number of studies reported
that the addition of dexmedetomidine to local anesthesia prolonged the local
anesthetic action time and reduced the need for anesthetics. According to
Agarwal et al., the analgesia lasted for up to 8 h with the addition of
100μg of dexmedetomidine to bupivacaine for the supraclavicular block.
Similarly, the study conducted by Almarakbi et al added dexmedetomidine
to TAP blockade and showed significantly longer analgesic action in the
dexmedetomidine group and lowered the morphine consumption. In our study, we
administered the TAP block with 20mL of 0.5% bupivacaine and 100μg of
dexmedetomidine + bupivacaine for the open appendectomy and inguinal hernia,
and 24 h morphine consumption in the control, bupivacaine, and bupivacaine +
dexmedetomidine groups was of 28.8mg, 17.5mg, and 8.2mg, respectively. The use
of morphine in the period of 2-24 h in both TAP groups was significantly lower
than in the control group, but lower consumption of morphine was observed in
the bupivacaine group + dexmedetomidine at all times measured at 24 h,
including the first 2 h, compared to the control and bupivacaine groups. In
general, VAS measurement is used for postoperative pain assessment.
The present study suggested that there was a significant decrease in the BD group at 0-24 h when compared to the control group and at 10-24 h when compared with the B group. In the BD group, there was a decrease in 2-8 h in comparison with the control group. While in the TAP block administration of bupivacaine alone provided a reduction of the VAS scores for 8 h, the addition of dexmedetomidine prolonged this effect up to 24 h. The VAS score was lower postoperatively (0 min) in the group with dexmedetomidine addition. Therefore, it can be considered that dexmedetomidine provides a faster onset of sensory block and increases the efficiency of the blockade.
The satisfaction scores in the group receiving the addition
of bupivacaine-dexmedetomidine were higher than in other two groups.
NA
Rev Bras Anestesiol. 2018 Jan - Feb;68(1):49-56.
Efficiency of bupivacaine and association with dexmedetomidine in transversus abdominis plane block ultrasound guided in postoperative pain of abdominal surgery
Recep Aksu et al.
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