|Year : 2015 | Volume
| Issue : 4 | Page : 628-633
A comparative study of caudal epidural bupivacaine and bupivacaine plus nalbuphine in postoperative analgesia in children
Mohamed F Mohamed, Reham M Husein, Mohamed I El Sonbaty, Sara M Khattab
Department of Anesthesia, Faculty of Medicine, Cairo University, Cairo, Egypt
|Date of Submission||07-Nov-2014|
|Date of Acceptance||16-Mar-2015|
|Date of Web Publication||29-Dec-2015|
Mohamed I El Sonbaty
Department of Anesthesia, Faculty of Medicine, Cairo University, 6 Manail Street, Cairo 202, 123432
Source of Support: None, Conflict of Interest: None
Caudal anesthesia (CA) is used in pediatrics to avoid the possible side effect of postoperative opioids and allows for smooth and rapid emergence from anesthesia. Opioids were added to the injection in CA to prolong the effect of anesthesia.
To compare the effect of bupivacaine alone and with nalbuphine in CA.
Patients and methods
A total of 40 patients scheduled for operations under general anesthesia combined with CA were divided into two groups: in group B, CA was carried out by injection of bupivacaine 0.25% in a dose of 1 ml/kg, and in group NB, CA was carried out by injection of bupivacaine 0.25% 1 ml/kg with nalbuphine 0.1 mg/kg. Hemodynamic changes, oxygen saturation, pain score at 2, 4, 6, 12, 24 h postoperative, sedation score, incidence of postoperative urine retention, and duration of motor block were compared in both groups. The respiratory depression effect of nalbuphine was also recorded.
There were no significant differences between the two groups regarding the hemodynamic changes. There were significant differences in postoperative pain score and sedation as group NB had prolonged analgesia and prolonged sedation time than group B. There were no significant differences in urine retention and motor block between both groups.
Nalbuphine added to bupivacaine in CA provides longer postoperative analgesia and sedation without respiratory depression.
Keywords: abdominal surgery, bupivacaine, caudal anesthesia, hemodynamics, nalbuphine, postoperative analgesia
|How to cite this article:|
Mohamed MF, Husein RM, El Sonbaty MI, Khattab SM. A comparative study of caudal epidural bupivacaine and bupivacaine plus nalbuphine in postoperative analgesia in children
. Ain-Shams J Anaesthesiol 2015;8:628-33
|How to cite this URL:|
Mohamed MF, Husein RM, El Sonbaty MI, Khattab SM. A comparative study of caudal epidural bupivacaine and bupivacaine plus nalbuphine in postoperative analgesia in children
. Ain-Shams J Anaesthesiol [serial online] 2015 [cited 2021 Dec 7];8:628-33. Available from: http://www.asja.eg.net/text.asp?2015/8/4/628/172756
| Introduction|| |
Caudal anesthesia (CA) for pediatric surgery was first reported in 1933  . Since then, studies have described the indications for pediatric caudal block, the level of analgesia, recommended doses, and pharmacokinetics of local anesthetics used in CA and the general or specific advantages and disadvantages of this technique ,,, . In children, CA is most effectively used as adjunct to general anesthesia and has an opioid-sparing effect, permitting faster and smoother emergence from anesthesia  .
A single-shot CA provides relatively brief analgesia for 4 to 8 h depending on the agent used  . Prolongation of anesthesia can be achieved by adding various adjuvants, such as opioids and nonopioids such as clonidine, ketamine, midazolam, and neostigmine, with varying degrees of success ,,,, .
Nalbuphine was also added in epidural analgesia for adults and provided an increase in the efficacy and the duration of postoperative analgesia  . The effect of nalbuphine addition in CA in pediatrics is not well established. We wished to compare the effects of plain bupivacaine 0.25% versus bupivacaine 0.25% plus nalbuphine 0.1 mg/kg single-shot caudal epidural for postoperative pain relief in children undergoing surgeries of lower half of the body as hypospadias and herniorrhaphy.
| Patients and methods|| |
The study was conducted in Abou El-Reesh Pediatric Hospital, Cairo University, after approval of Ethical Committee and obtaining informed written consent from the parents. We studied 40 children aged 1-9 years scheduled for surgeries of lower half of the body. We excluded patients with local infection at the site of caudal block, allergy to local anesthetics, bleeding tendency, pre-existing neurological or spinal diseases, and pre-existing skeletal deformities.
Children under 2 years of age were allowed to receive food up to 4 h preoperatively, whereas children over 2 years were offered clear fluid up to 2 h preoperatively. The children were visited preoperatively on the day of surgery for comprehensive history and physical examination.
Complete blood count, liver functions, kidney functions and coagulation profile (prothrombin time, international normalized ratio, and partial thromboplastin time) were ordered preoperatively and the results were available at the time of surgery. No premedication was given.
On arrival to the operating room, all patients were connected to the monitor including ECG, noninvasive blood pressure, and pulse oximeter. Induction of anesthesia was initiated by inhalational route using sevoflurane 4%, and then an intravenous cannula was inserted and injection of atropine 0.01 mg/kg administrated, and an endotracheal tube of appropriate size was placed without the use of neuromuscular blocking agents. Anesthesia was maintained with isoflurane 2-3% and 100% oxygen with total fresh gas flow 3 l/min. Children were breathing spontaneously and no sedatives or opioids were administered during the procedure. Isoflurane concentration was titrated to maintain heart rate (HR) and systolic blood pressure within ± 20% of their baseline values.
Patients were randomly allocated to one of two groups by a computer-generated table of random numbers: in group B, caudal block was carried out using bupivacaine 0.25% with the dose of 1 ml/kg after the induction of general anesthesia; and in group NB, caudal block was carried out in this group using bupivacaine 0.25% with the dose of 1 ml/kg and nalbuphine 0.1 mg/kg after the induction of general anesthesia.
An increase in the HR or mean arterial pressure (MAP) within 15 min of skin incision indicated failure of CA. If the readings increased by more than 15%, the child will receive a rescue opioid (pethidine 1 mg/kg initially and subsequently 0.5 mg/kg as dictated by hemodynamic variables), and the CA considered failed and the patient was excluded from the study.
Fluid therapy was standardized during and after therapy. During surgery, children received lactated Ringer's solution 4 ml/kg/h. An intraoperative decrease of MAP or HR by more than 30% was defined as hypotension or bradycardia, respectively, and was treated by fluid bolus, a vasoconstrictor (ephedrine) or atropine as necessary.
Anesthesia was discontinued at the completion of skin closure. Patients were transported to the recovery room with routine monitoring to the HR, noninvasive arterial blood pressure, oxygen saturation, and pain scoring. The following parameters were recorded: HR, MAP (systolic and diastolic), and oxygen saturation at the following times before performing the block, every 10 min after caudal block, and every 15 min after recovery for 2 h.
Pain score was recorded after extubation at 2, 4, 6, 12, 24 h, by All India Institute of Medical Sciences (AIIMS). Pain Discomfort Scale measures five variables: respiratory rate, HR, discomfort, cry, and pain at the site of operation  . Each variable scores from 0 to 2 to give a possible total score of 0 to 10. A lower score is associated with less pain. The duration of absolute analgesia was defined as the time from caudal injection until a pain score was more than or equal to 2. Rescue analgesia was given for a Pain Discomfort Scale score of more than or equal to 4 in the form of oral paracetamol (10 mg/kg) [Table 1].
Assessment of sedation was carried out at 30 min, 1, 2, 4, and 6 h by using an objective score based on eye-opening (eyes open spontaneously = 0, eyes open in response to verbal stimulation = 1, eyes open in response to physical stimulation = 2).
On the basis of the literature, considering duration of analgesia (mean ± SD) 6.5 h in both treatment groups, with an a of 5% and a b of 20%, 40 cases are required to reach a power of 80% and level of significance of 5% to the determinant of the new protocol.
Data management and analysis were performed using statistical package for social sciences, SPSS Inc., Chicago, IL, USA version 15 for windows. Numerical data were summarized using mean and SDs or medians and ranges. Categorical data were summarized as percentages. Comparisons between groups with respect to normally distributed numeric variables were done using the t-tests. Non-normally distributed numeric variables were compared by MannWhitney test. c2 -test was used to compare between the groups with respect to categorical data. To examine the differences between the two groups as well as changes from before to after treatment, for normally distributed variables, a two-way analysis of variance with repeated measure on one factor was performed using a two-way repeated measures analysis of variance. For non-normally distributed variables, differences between before and after treatment were tested using the Friedman's test. P-values less than 0.05 were considered significant.
| Results|| |
A total of 40 patients completed the study and were randomized into two groups: group B received bupivacaine 0.25%; and group B + N received bupivacaine 0.25% and nalbuphine 0.1 mg/kg. There was no statistically significant difference among the two groups with regard to age and sex [Table 2]. There was also no statistically significant difference among the two groups with regard to HR at different times, but there was a significant difference between the preoperative value and both intraoperative and postoperative values in each group with the preoperative readings being significantly high [Table 3] (P < 0.001).
The results show no statistically significant difference among the two groups with regard to MAP at different times [Table 4]. There was also no significant difference between the preoperative value and both intraoperative and postoperative values in the both groups (P > 0.001) [Table 4].
[Table 5] shows significant difference between the two groups in pain score at 4, 6, and 12 h postoperative. This shows that the duration of analgesia in the B+N group was longer than the other group. The time to first administration of rescue analgesia was 6.2 ± 1.4 h in group B and 10.1 ± 1.5 h in group B+N. The time to first analgesia was significantly shorter in group B (P < 0.05) than that in the other group [Table 6].
|Table 6 Time to first analgesia in postoperative hours among the two groups|
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The results show that there was significant difference in the sedation score between the two groups in the first hour postoperative. The B+N group had more sedation scores at 30 min and at 1 h postoperative [Table 7]. The results show no statistically significant difference among the two groups with regard to oxygen saturation at different times [Figure 1]. There was no significant difference in the two groups in the time to first void. None of the patients had motor block on emergence from anesthesia. No child required bladder catheterization.
|Figure 1: Oxygen saturation among the two groups. This diagram shows possible respiratory adverse effects in the two groups. The results show no statistically significant difference among the two groups as regards oxygen saturation at different times. In addition, there was no difference between the preoperative value and both intraoperative and postoperative values in the two groups (P > 0.001 )|
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| Discussion|| |
CA is one of the most used popular regional blocks in children. One of the major limitations of the single-injection technique is the relatively short duration of postoperative analgesia. The most frequently used method to further prolong postoperative analgesia following caudal block is to add opioids to local anesthetics. Mok et al.  , studied efficacy of epidural nalbuphine in postoperative pain control. They used nalbuphine compared with normal saline in the epidural space during postoperative period after full recovery from effect of anesthesia and at complaining of severe pain. Patient's pain intensities were evaluated by visual analog scale (VAS) and numbers of intramuscular analgesics needed were recorded through the 48 h observation period. They found that pain scores were significantly lower in the nalbuphine group (no patient in the nalbuphine group required intramuscular analgesics in the first 6 h, whereas 65% of the patient in the control group required analgesics), no evidence of sensory, motor, or autonomic block were observed in any patient; also no pruritis or respiratory depression was noticed in any patient.
Their results were in consistence with the results of the current study in postoperative pain reduction and no respiratory depression were observed, but their study was different than the current study in the use of nalbuphine without bupivacaine, injection was postoperative instead of preoperative, the age group used and different scoring system than that we used; yet, this scoring system was not expected to make a difference in results.
Moyao-Garcνa et al.  , compared nalbuphine versus tramadol through continuous intravenous infusion for postoperative pain control in children, the children were randomly allocated to receive either an intravenous bolus dose of nalbuphine 100 mg/kg immediately before the end of surgery followed by an infusion of 0.2 mg/kg/min for 72 h, or an intravenous bolus dose of tramadol 1000 mg/kg followed by an infusion of 2.0 mg/kg/min for 72 h. Postoperative pain control was assessed by using CHEOPS (Children Hospital of Eastern Ontario behavioral scale) for children less than 6 years and VAS for patient more than 6 years every 1 h for 24 h then every 4 h until the end of 72 h, the following parameters were also recorded: heart and respiratory rates, diastolic and systolic blood pressure, SaO 2 and, sedation was also assessed. They found that three patients in the nalbuphine group received bolus dose of nalbuphine in the first 12 h postoperatively versus one patient in the tramadol group received bolus dose of tramadol; however, in a similar number of patients the infusion rate was increased within the 72 postsurgery hours in the two study groups, sedation was observed in two children in the nalbuphine group and in one child in the tramadol group; no significant differences were observed between the two groups regarding respiratory rate and SpO 2 and no patient required postoperative tracheal intubation.
These results were against that of the current study regarding the analgesic effect of nalbuphine during the first 12 h postoperative also they used nalbuphine through intravenous infusion, whereas we used nalbuphine as single caudal epidural injection. However, this study was convenient with the current study in the age group, the sedation effect of the nalbuphine and there was no respiratory depression recorded.
Pascal García et al.  , studied the effect of nalbuphine in obstetric analgesia when given in epidural space. The nalbuphine group was administered epidurally 100 mg/kg of nalbuphine in 12 ml of normal saline, and the bupivacaine group received 12 ml of solution saline with 15 mg of bupivacaine concentrated 0.125%. The pain was evaluated at 5, 15, 30, 60, 90, and 120 min after injection by a VAS. In addition, the presence of side effects such as pruritus, urinary retention, respiratory depression, hypotension, nausea, vomiting, or bradycardia were recorded. It was concluded that the use of nalbuphine, in doses of 100 mg/kg epidurally, is effective to obtain adequate analgesia during labor. It is as effective as the administration of bupivacaine (0.125%). The use of epidural nalbuphine is also clinically safe for both the mother and the newborn.
Their results were in consistence with the results of the current study in the effectiveness of nalbuphine as analgesic when used through the epidural route; in addition, there were no side effects such as pruritus, urinary retention, respiratory depression, hypotension, nausea, vomiting, or bradycardia recorded. However, their study differed from the current study in age group and the use of 100 mg/kg of nalbuphine in 12 ml normal saline as epidural dose instead of 0.1 mg/kg of nalbuphine plus 1 ml/kg of bupivacaine 0.25% as single caudal epidural dose that we used; in addition, sedation effect of nalbuphine was not recorded in their study.
Culebras et al.  studied the advantages of intrathecal nalbuphine compared with intrathecal morphine, after cesarean delivery; they compared the effect of morphine 0.2 mg and nalbuphine in three doses (0.2, 0.8, 1.6 mg) in 1 ml volume mixed with 10 mg of hyperbaric bupivacaine 0.5% (total volume 3 ml) as single intrathecal dose; pain score was evaluated by using VAS, HR, SpO 2 , blood pressure, respiratory rate, sensory level, and motor block were evaluated every 15 min. They found that the overall satisfaction of patients at 24 h, as evaluated with VAS, showed no differences between the four groups, with less side effects observed in the nalbuphine group (pruritis, postoperative nausea and vomiting, and respiratory depression).
This study agreed with the current study that nalbuphine provides satisfactory postoperative analgesia and there were no statistically significant changes in hemodynamics between the studied groups, but it differed from the current study in age group. They used nalbuphine in doses of (0.2, 0.8, 1.6 mg) in 1 ml volume mixed with 10 mg of hyperbaric bupivacaine 0.5% (total volume 3 ml) as single intrathecal dose instead of 0.1 mg/kg of nalbuphine plus 1 ml/kg of bupivacaine 0.25% as single caudal epidural dose that we used, and sedation effect of nalbuphine was not observed.
| Conclusion|| |
Caudal epidural nalbuphine is safe in pediatric surgeries in the lower half of the body and effectively reduces postoperative pain. Although it may cause early postoperative sedation, yet without respiratory depression. Further studies are needed involving different types of local anesthetics (i.e. levobupivacaine, ropivacaine) in combination with nalbuphine. Different age groups may be included and also dose response studies for reaching the best dose.
| Acknowledgements|| |
This study has been approved by Ethical Committee of Department of Anesthesia in our institution.
The study is self-funded.
Conflicts of inerest
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]