|Year : 2012 | Volume
| Issue : 1 | Page : 17-20
A comparative study of caudal bupivacaine and midazolam for post operative analgesia in pediatric patients
K Himabindu, T Venugopalarao, PK Subramanyam
Department of Anaesthesiology, Guntur Medical College, Guntur, Andhra Pradesh, India
|Date of Web Publication||21-Mar-2012|
4-19-117, 5th Line, Vikasnagar, Guntur - 522 007
Source of Support: None, Conflict of Interest: None
Background: Postoperative discomfort that arises from pain is annoying for the child and parents. Genital and perineal surgical procedures are followed by moderate to severe pain resulting in postoperative complications like infection and also long term psychological effects on children. Under treatment of children for pain in post operative period has been reported in several centers. Intramuscular or intravenous analgesics have unpredictable effects and not accepted by children. Caudal bupivacaine with midazolam prolongs post operative pain relief.
Aim: To evaluate the relative efficacy and duration of caudal extradural bupivacaine 0.25% and a combination of bupivacaine and midazolam for intra and post operative analgesia.
Materials and Methods: This study was conducted in 50 ASA I children from pediatric surgery department requiring general anaesthesia for infra umbilical surgeries. After induction of general anaesthesia the children were given caudal extradural 1 ml/kg bupivacaine (0.25%) or bupivacaine with midazolam (0.50 micromg/kg) intra operative vitals, response to surgical stimulus measured. Post operatively assessment of pain was done by using objective pain score up to 24 hrs in the ward.
Results: The mean basal values of systolic blood pressure in both the group were comparable intraoperatively and didn't show any statistical significance indicating adequate analgesia intra operatively. Postoperatively 68% children in the bupivacaine group were pain free until 3 hours as compared to 80% children in bupivacaine with midazolam. Only 4% children in bupivacaine group were pain free until 6 hours post operatively, compared to 72% children in bupivacaine with midazolam indicating prolonged analgesia in this group. There was no significant changes hemo- dynamically in both groups post operatively. Conclusion: Caudal extradural analgesia with bupivacaine and midazolam gives prolonged analgesia postoperatively and can be used safely in children. It will also reduce the use of parenteral analgesics significantly with minimum side effects.
Keywords: Caudal analgesia, pediatric, bupivacaine, midazolam, post operative analgesia
|How to cite this article:|
Himabindu K, Venugopalarao T, Subramanyam P K. A comparative study of caudal bupivacaine and midazolam for post operative analgesia in pediatric patients. J NTR Univ Health Sci 2012;1:17-20
|How to cite this URL:|
Himabindu K, Venugopalarao T, Subramanyam P K. A comparative study of caudal bupivacaine and midazolam for post operative analgesia in pediatric patients. J NTR Univ Health Sci [serial online] 2012 [cited 2020 Apr 2];1:17-20. Available from: http://www.jdrntruhs.org/text.asp?2012/1/1/17/94170
| Introduction|| |
Pain is the commonest and most distressing effect of disease and surgery. It has been a great challenge and concern to researchers, strictly speaking pain is an unmeasurable entity and any scheme for its assessment in man must be open to both subjects and observers error. Studies over the past 15 years found that inadequate pain management is common in children.  Analgesic usage between adults and children consistently showed that children receive fewer, less frequent and smaller doses of potent opioids.  Reasons for withholding analgesia are numerous and include an overriding concern regarding respiratory depression and a notion that children don't respond to pain to the same degree as do adults. The drugs used as postoperative analgesics should be potent and should not produce after side effects such as emesis, respiratory depression or addiction Intramuscular and intravenous routes have the disadvantages of regional blood flow effects, peaks and valleys of concentrations in blood levels and sleep fluctuations apart from distress of pain by intramuscular route. PCAs are advocated in older children and continuous IV infusion has been tried in smaller infants.
Epidural analgesia in children is probably the most versatile regional analgesic technique ,, Epidural analgesia also maintains with good respiratory function after thoracotomy and upper abdominal procedures. , Caudal analgesia is the most useful and effective pediatric regional block in pediatric pain management post operatively. Extensive clinical experiences attest to the ease of performance, reliability and safety. A caudal block can easily provide anaesthesia or analgesia for infra-umbilical surgery and this technique reduces the intra operative requirements for potent inhaled agents and ensures excellent post operative pain relief.  Epidural opioids should be reserved for inpatients because of the risk of respiratory depressions and high incidence of urinary retention. There is a high incidence of pruritis with epidural opioids.
This study is aimed at evaluating the relative efficacy and duration of caudal bupivacaine 0.25% and a combination of bupivacaine and midazolam for intra and post operative analgesia in children and the incidence of side effects.
| Materials and Methods|| |
After obtaining institutional ethical committee approval, 50 patients in the age group of 2 months to 11 years of either sex, under going elective surgeries below umbilical area were included in the study. Study was double blinded and randomized.
Children were not pre-medicated with analgesic drugs and were fasting minimum for 4 hours. Pre-anaesthetic blood pressure, pulse rate and respiratory rate were recorded.
All children after pre-oxygenation were anaesthetized with standard induction procedure with thiopentone intravenously. Intubations were performed with suxamethonium 1.5 mg/kg. General anaesthesia was maintained by inhalation method using nitrous oxide, oxygen and halothane 0.5% to 2% using Rees modification of Ayres T-piece and on spontaneous ventilation. After anaesthesia all children were turned to left lateral position, inj bupivacaine 1 ml/kg preservative free (0.25%) or inj bupivacaine with in midazolam 50 mg/kg preservative free was injected into caudal epidural space under strict aseptic conditions and patients were turned and allowed for surgery. Blood pressure and heart rate were recorded during the intra operative period. Pain and other side effects were assessed postoperatively at 15 mt, 30 mt, 45 mt. 1 hr, 1 ½ hr, 2 hrs, 3 hrs, 6 hrs and 24 hrs.
Assessment of pain was recorded using the objective pain score [Table 1], the variables recorded were compared within the age group and in between the age groups for any statistical significance by analysis of variance. The 'P' value was considered significant if it was less than 0.05. Side effects such as motor weakness vomitings, retention of urine and respiratory depression were also recorded during the 24 hours postoperative period.
| Results|| |
50 patients were studied as two groups, 25 in each group. Group I was given bupivacaine only and group II bupivacaine with midazolam. The age of patients in group I (6.12 ± 2.6975 years) was comparable with that in group II patients (5.68 ± 2.4617, P=NS) and the sex ratio in the two groups was also comparable as shown in [Table 2]. Mean basal values of systolic blood pressure in both the group were comparable before starting the procedure without any statistical significance (P>0.05).
Intraoperative vital parameters, pulse rate and blood pressure did not show any statistical significance and there was not much significant increase in BP, pulse rate, respiratory rate to surgical stimulus in both the groups, indicating adequate analgesia. All the children were observed post operatively and pain scores at 0, 15 minutes, 30 minutes, 45 minutes, 1 hour, 1½ hour, 2 hours, 3 hours, 6 hours and 12 hours and 24 hours were recorded.
Upto 68% of children in the bupivacaine group were pain free (laughing, happy, cheerful, playful and asleep) until 3 hours after surgery. 80% of children were pain free in bupivacaine and midazolam group up to 3 hours [Figure 1]. Only 4% of children in bupivacaine group were pain free until 6 hours postoperatively compared to 7.2% of children in bupivacaine and midazolam indicating the duration of analgesia was prolonged [Figure 2]. There were no significant changes in pulse rate and blood pressure in both groups.
| Discussion|| |
Postoperative pain is annoying for the child and parents. Genital and perineal surgical procedures are followed by moderate to severe post operative pain. This may cause discomfort leading to surgical complications like bleeding, infection and also long term psychological problems in children. Lack of verbal communication by children, defective and prejudiced interpretation of pain by the attending staff makes assessment of pain difficult leading to under treatment.
Non-acceptance of injections, short duration of narcotics to control moderate to severe pain makes post operative pain much difficult to control in children. Caudal bupivacaine (0.25%) with a dose of 1 ml/kg and midazolam (preservative free) with a dose of 0.50 microgram/kg body weight has given prolonged pain free post operative pain in children with minimal side effects.
The children were between 2 months to 11 years. Though the number was fifty, they were reasonably distributed between age group of 2 months to 11 years. All the children under went procedures such as inguinal hernia repair, orchidopexy and urological procedures which are very painful post operatively [Table 3]. Intra operatively there is not much rise in heart rate, blood pressure to surgical stimulus in both groups indicating adequacy of analgesia. 68% children in the bupivacaine group were pain free (cheerful, playful and asleep) until 3 hours after surgery. 80% of children were pain free in Bupivacaine with midazolam group upto 3 hours following surgery. Only 4% of children in Bupivacaine group were pain free until 6 hours after surgery. 72% of children in Bupivacaine + midazolam were pain free up to 6 hours, indicating the duration of analgesia was prolonged in Bupivacaine with midazolam group. There results are in correlation with the study of Naguib et al.  84% children received inj paracetemol in bupivacaine group by 6 hours postoperatively, compared to only 4% children in bupivacaine and midazolam group indicating prolonged analgesia in most of the children in this group. Vomiting was reported in 18% of the children in the present study compared to Naguib et al.  reported 21.66% of the cases. This can be attributed to inhalation agents used in intra operative period. Caudal block is more reliable and produced longer duration of post operative pain relief in children with low incidence of adverse effects.
| Conclusion|| |
Caudal extradural analgesia with bupivacaine and midazolam prolonged the duration of postoperative pain relief significantly in children and drastically reduced the use of parenteral analgesics in the post operative period with minimal side effects.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3]