Abstract
Objective: To evaluate the efficacy of combined incisional
infiltration with Bupivacaine and Paracetamol suppositories with Paracetamol
suppositories alone in relieving the postoperative pain associated with surgery
of inguinal pathologies.
Methods: Prospectively,
one hundred and ten children whom underwent groin surgery at Prince Rashed Ben
Al-Hassan hospital from April
1, 2008 to December
1, 2008 were included in the study. Their ages ranged from six
months to 13 years. Surgery was performed under general anesthesia. Patients were randomized into two groups; group A (55patients) received Paracetamol
rectally 30 mg/kg immediately preoperatively, while group B (55 patients) had
Paracetamol rectally 30 mg/kg and incisional wound infiltration with Bupivacaine
1mg/kg. Postoperative pain was managed by giving Paracetamol. The duration of
the postoperative analgesia was estimated based on the time when rescue
analgesia was first given. Assessment of the quality of postoperative analgesia
was based on the children’s behavior.
Results: In our
study, both parents and older children were willing to cooperate. None of the
children in the study groups suffered from local anesthetic toxicity such as arrhythmias,
seizures, allergy and hematoma or tissue edema. In group A, 15 children
suffered pain in the recovery room and received further analgesia in the form
of Paracetamol suppositories, 18 had pain and received analgesia at home within
four to six hours after discharge. The remaining 22 suffered pain during the
next five days after surgery. In group
B, two patients had pain in the recovery room, eight had pain with early
mobilization at home and had their first analgesic dose after five to eight
hours. The other 45 children had no significant post-operative pain. Group B
showed an increased duration of postoperative analgesia with early
mobilization. Rescue mean time at which children had their first post-operative
dose of analgesia was two to four hours in group A and it was five to eight
hours in group B. No patient in group B needed analgesia after day three
post-operatively.
Conclusion: Wound
infiltration with Bupivacaine 1mg/kg combined with rectal Paracetamol 30 mg/kg
has a better and valuable efficacy compared to the rectal Paracetamol 30 mg/kg
alone with respect to providing pain relief following inguinal herniotomy,
hydrocelectomy and orchidopexy in children, with a longer duration of pain
relief and earlier mobilization.
Key words: Analgesic, Bupivacaine, Groin pathologies, Local
anesthetic, Paracetamol
JRMS
March 2010; 17(1): 52-56
Introduction
Surgery for groin pathologies such as inguinal
herniotomy, hydrocelectomy and orchidopexy in children is usually a day case
procedure frequently associated with considerable postoperative pain and it
remains a challenge to provide adequate analgesia with minimal side effects.(1)
Opioids administration is among the oldest and most commonly used medication for
postoperative analgesia. Unfortunately, pain relief with opioids is often
unsatisfactory and can lead to a delay in recovery and hospital discharge due
to associated adverse events.(2-5) Paracetamol is widely
accepted as a standard pain treatment for postoperative children in many
countries and commonly used for outpatient management of pain in pediatrics.(4,6,7)
Various regional anesthetic techniques are widely used to provide postoperative
analgesia in infants and children following inguinal hernia repair,
circumcision, hypospadias repair, orchidopexy, lower limb, perineal or lower
abdominal surgery.(8-12) Based on the fact that multimodal
analgesia decreases postoperative pain and improves patient comfort,(11)
we hypothesized that the addition of pre- and
post-surgical Bupivacaine wound infiltration would enhance Paracetamol suppositories’ induced postoperative
analgesia. Therefore, to verify this hypothesis, we performed a
prospective, double blind, placebo controlled study designed to assess the
analgesic effect of
pre- and post-surgical Bupivacaine wound
infiltration when administered as an adjuvant to using preoperative Paracetamol suppositories.
Methods
After human research ethics committee approval and obtaining informed consent from the parents, 110 children underwent surgery for different groin
pathologies with ages ranging from six months to 13 years and body weight
ranges from 5kg to 49kg were enrolled in this study. Anesthesia was
induced via a facemask with 8% sevoflurane in a mixture of 50% nitrous oxide in
oxygen. After induction and establishment of intravenous access, Fentanyl
(2μg/kg) and Atracurium (0.5mg/kg) was administered intravenously to facilitate
laryngeal mask airway insertion. Anesthesia for both groups was maintained with
1–3% sevoflurane in a mixture of 50% nitrous oxide in oxygen. Mechanical
ventilation was adjusted to maintain the end-tidal carbon dioxide between 35–45
mmHg. Monitoring during anesthesia included electrocardiogram, pulse oximeter
and noninvasive blood pressure. Patients were randomized by means of sealed envelopes into two groups (55 each). The anesthetist was aware of the
randomization and ensured that the correct drugs and doses were administered. The
anesthetist was not part of the assessment of patients.
Group A (55 children) after anesthesia and before
scrubbing the patient, Paracetamol 30mg/kg given rectally. As a control group, half the dose of normal saline 0.4ml/kg (0.2ml/kg for those above 20kg) was infiltrated after patient’s
preparation immediately prior to wound incision, surgery then carried out
according to the specific groin pathology which was inguinal hernia, hydrocele
or orchidopexy. Before skin closure the remaining half of the normal saline was infiltrated through the wound. At the completion
of the surgery, muscle relaxation was reversed by a combination of 0.02 mg/kg Atropine
Sulphate and 0.05 mg/kg Neostigmine. The laryngeal mask airway was removed when
the patient was awake; patients were sent to the recovery room and observed for
two hours.
Group B (55 children) after anesthesia and before
scrubbing the patient, received Paracetamol 30mg/kg rectally. As a study group, half the dose of the local anesthetic drug Bupivacaine
1mg/kg of the 0.25% solution (0.5% solution for those above 20kg) was infiltrated
after patient’s preparation immediately prior to wound incision, then carried
out according to the specific groin pathology. Before skin closure the
remaining half of the local anesthetic drug was infiltrated through the wound,
with 1-2ml infiltrated in the scrotal wound in cases of orchidopexy.
The
analgesic status of the patient was evaluated by an attending nurse in the
recovery room for two hours and by the parents at home using an objective pain
score as described by Wolf et al.(13) (Table I). This
involved assessing pain by five criteria; crying, movement, agitation, posture
and localization to pain. The minimum score is zero and the maximum score is 10
(maximum score if too young to complain of pain is 8). A pain score of four or
more signified pain. Parents were taught the use of this pain scale and were
advised that if the child scored four or more, Paracetamol 30 mg/kg should be given but they should not exceed four
doses in a day for the next five days.
A follow-up appointment was scheduled within two weeks
after surgery. Statistical analysis of the results was performed using SPSS for
window program, Mann Whitney U and T-tests. P-value <0.05 was considered
statistically significant.
Table I. Wolf objective pain scale
|
Points
|
Findings
|
Parameter
|
No
|
|
0
|
no
crying
|
Crying
|
1
|
|
1
|
crying respond to tender loving care
|
|
|
|
2
|
crying not
responding to tender loving care
|
|
|
|
0
|
no
movements
|
Movements
|
2
|
|
1
|
restless moving about in bed
constantly
|
|
|
|
2
|
thrashing
(moving wildly)
|
|
|
|
0
|
asleep or calm
|
Agitation
|
3
|
|
1
|
can be
comforted to lessen the agitation (mild)
|
|
|
|
2
|
cannot
be comforted (hysterical)
|
|
|
|
0
|
normal
|
Posture
|
4
|
|
1
|
flexing legs and
thighs
|
|
|
|
2
|
holding groin
|
|
|
|
0
|
asleep or states no
pain
|
Complains of pain
|
5
|
|
1
|
cannot localized
|
|
|
|
2
|
can localizes pain
|
|
|
Table II. Demographic data, duration of operation and time of
rescue analgesia
|
|
Group A (control)
N = 55
|
Group B (Study)
N = 55
|
P-value
|
|
M/F
|
41/14
|
48/7
|
0.089*
|
|
Age (Years)
|
0.5-13 (4.91±2.11)
|
0.5-13 (5.39±2.48)
|
0.272*
|
|
Weight (Kg)
|
5-49 (19.21± 7.16)
|
5-49 (18.17± 5.59)
|
0.398*
|
|
Duration of operation
(Minutes)
|
20-45 (37.20±5.09)
|
25-50 (38.64±6.11)
|
o.183*
|
|
Rescue
analgesia (Hours)
|
2-4 (3.36±0.68)
|
5-8 (6.51±1.15)
|
<0.001**
|
*No
statistical significant differences were found between groups.
**Statistical
significant differences were found between groups.
Table III. Number of patients requiring postoperative analgesia
|
|
Group A (control)
N = 55
|
Group B (Study)
N = 55
|
P-value
|
|
1st day
|
33
|
10
|
<0.001
|
|
2nd day
|
22
|
8
|
0.002
|
|
3rd day
|
10
|
3
|
0.038
|
|
4th day
|
5
|
0
|
0.022
|
|
5th day
|
4
|
0
|
0.041
|
Statistically significant differences were found between groups.
Results
In our study, both
parents and older children were willing to cooperate and no patient dropped
out. No statistically significant difference was noticed between the two groups
with respect to age, weight or duration of the operation (Table II). None of
the children in the study group suffered from local anesthetic toxicity, arrhythmia,
seizure, allergy, hematoma or tissue edema. In group A, 15 children suffered
pain in the recovery room and received further analgesia in the form of Paracetamol
suppositories, 18 had pain and received analgesia at home within four to six
hours after discharge, 22 suffered pain during the few days after surgery and had
occasional analgesia.
In group B, two patients
had pain in the recovery room, eight had pain with early mobilization at home and
had their first analgesic dose after five to eight hours. The other 45 children
had no significant post-operative pain (Table III). Group B showed a
significant increase in the duration of postoperative analgesia with early
mobilization. The efficacy of postoperative analgesia tended to be more
adequate in group B. The mean duration and standard deviation of the
postoperative analgesia in group B was 6.51±1.15 hours, while in group A it was
3.36±0.68 hours. From the beginning of the observation period, group B tended
to have a better quality of postoperative analgesia. Nine children in group B
were mobilized earlier, during the first two hours postoperatively, compared to
only two children in group A who were mobilized, while the rest were mobilized
later
Discussion
Pediatric patients
with groin pathologies such as inguinal hernia, hydrocele and undescended
palpable testes are good candidates for day-case surgery. Effective
postoperative analgesia and early mobilization of children are considered
important in order to shorten the duration of the postoperative stay. Local and
regional techniques performed under general anesthesia are well-established in
postoperative pain control following inguinal surgery in children such as caudal
block, ilioinguinal/iliohypogastric nerve block, paravertebral block and wound
infiltration.(3,9,12,14)
Studies comparing
postoperative pain relief for inguinal surgery in children using wound
infiltration with that provided by other regional techniques have been reported,
only a few are comparing wound infiltration with Paracetamol, which is a
routine method for pain relief after herniotomy in children.(3)
In the present study, the efficacy, duration and quality of postoperative
analgesia provided by wound infiltration with 0.25% (0.5% for those above 20kg)
Bupivacaine 1mg/kg, combined with rectal Paracetamol 30mg/kg were compared to
that of Paracetamol 30mg/kg alone. Previous studies in children and infants
have shown that wound infiltration with Bupivacaine at the end of inguinal
herniotomy produces analgesia comparable to that rendered by caudal block or by
ilioinguinal/iliohypogastric nerve block.(9,12) Wound
infiltration is easy to perform and small doses of Bupivacaine are effective
for wound infiltration and are half the dose required for caudal or field
block. Mobley et al. measured serum
Bupivacaine concentrations in 12 children who underwent elective herniotomy or who
received analgesia in the form of wound infiltration with Bupivacaine
1.25mg/kg. They found that the peak serum concentrations were lower than those
associated with other local anesthetic blocks and well below potentially toxic levels.(15)
In our study, none of the children in
the wound infiltration group suffered from local anesthetic toxicity, Bupivacaine
was injected just before wound incision and before wound closure. Although most
patients in group B had adequate postoperative analgesia, six children in group
A and two in group B suffered severe pain. In our study, the presence of 15 children
in group A who complained of pain in the
recovery room indicates that in 27% of children who received rectal Paracetamol,
the analgesia was inadequate. Matsota et al., they compared the efficacy
of post-incisional wound infiltration with levobupivacaine 1.25mg/kg with Paracetamol
30mg/kg administered rectally and found that post-incisional wound infiltration
with levobupivacaine 1.25mg/kg has a similar efficacy to rectal Paracetamol 30mg/kg
with respect to providing pain relief following inguinal hernia repair in
children, but with a longer duration and earlier mobilization of the children.(3)
Prevention of pain whenever possible, using multi-modal analgesia, has
been shown to work well for nearly all cases and can be adapted for day cases,
major cases, the critically ill child, or the very young.(11)
In the present study, group B had
prolonged analgesia with a better quality. The mean duration of postoperative analgesia
in the post-incisional wound infiltration group was 6.51 ± 1.15 hours, while in
group A it was 3.36 ± 0.68 hours, respectively.
The statistical
analysis showed a significant difference between the two groups, taking into
account that even a short lasting pain is important for children’s
postoperative discomfort and that these children may develop increased anxiety
about any future medical intervention. Early mobilization is another important
factor that affects both the quality of postoperative analgesia and the
discharge from hospital after day-case surgery. In our study, the assessment of
the quality of postoperative analgesia based on children’s mobilization
revealed a significant difference between the two groups during the early
postoperative period.
Conclusion
Wound infiltration
with Bupivacaine 1mg/kg combined with rectal Paracetamol 30mg/kg has better and
more valuable efficacy compared to rectal Paracetamol 30mg/kg alone with
respect to providing pain relief following inguinal herniotomy, hydrocelectomy
and orchidopexy in children. Furthermore
it is associated with a longer duration of pain relief and earlier mobilization.
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