|Year : 2015 | Volume
| Issue : 4 | Page : 634-638
Comparative study between caudal dexmedetomidine with bupivacaine versus ketamine with bupivacaine for postoperative analgesia after inguinoscrotal surgery in pediatric patients
Abd El-Aziz A Abd El-Aziz MD , Waleed Abd Alla
Department of Anesthesiology, Intensive Care, and Pain Management, Faculty of Medicine, Ain-Shams University, Cairo, Egypt
|Date of Submission||27-Feb-2015|
|Date of Acceptance||21-Jul-2015|
|Date of Web Publication||29-Dec-2015|
Abd El-Aziz A Abd El-Aziz
Department of Anesthesiology, Intensive Care, and Pain Management, Faculty of Medicine, Ain-Shams University, Cairo 11371
Source of Support: None, Conflict of Interest: None
The aim of this randomized, double-blinded study was to compare the duration of postoperative analgesia and sedation, and the incidence of any side effect of single-dose caudal dexmedetomidine with bupivacaine versus ketamine with bupivacaine in pediatric patients undergoing inguinoscrotal surgeries.
Patients and methods
A total of 60 pediatric patients, 2-5 years of age, American Society of Anesthesiologists physical status I or II, scheduled for inguinoscrotal surgeries were included in the study. The patients were divided into two equal groups: group A patients (n = 30) received dexmedetomidine with bupivacaine, whereas group B patients (n = 30) received ketamine with bupivacaine. For each patient, postoperative sedation score, pain score, duration of analgesia, and postoperative complications were recorded.
The duration of postoperative analgesia was longer in group A than in group B, and sedation score was lower in group B than in group A, which was statistically significant. No significant postoperative complications were recorded in both groups.
The use of dexmedetomidine, as an additive to the local anesthetic bupivacaine in caudal epidural analgesia, during single-dose injection, prolonged the duration of postoperative analgesia following inguinoscrotal surgery compared with caudal administration of ketamine with bupivacaine, but with more sedation compared with ketamine. Both groups showed few side effects.
Keywords: bupivacaine, caudal block, dexmedetomidine, ketamine, postoperative analgesia
|How to cite this article:|
Abd El-Aziz AAA, Alla WA. Comparative study between caudal dexmedetomidine with bupivacaine versus ketamine with bupivacaine for postoperative analgesia after inguinoscrotal surgery in pediatric patients. Ain-Shams J Anaesthesiol 2015;8:634-8
|How to cite this URL:|
Abd El-Aziz AAA, Alla WA. Comparative study between caudal dexmedetomidine with bupivacaine versus ketamine with bupivacaine for postoperative analgesia after inguinoscrotal surgery in pediatric patients. Ain-Shams J Anaesthesiol [serial online] 2015 [cited 2019 Sep 15];8:634-8. Available from: http://www.asja.eg.net/text.asp?2015/8/4/634/172757
| Introduction|| |
The misconception of many anesthesiologists that children do not experience pain led to undertreatment of pain in children and prevented them from using regional analgesic techniques, which further resulted in undertreatment of pain in pediatric patients  .
The caudal epidural block is one of the most commonly used regional anesthetic techniques in pediatric surgeries because it is proved to be a simple and effective technique in children. Despite using long-acting local anesthetics, the main disadvantage of caudal block remains the relatively short duration of action  . Different additives have been used to improve the duration and quality of analgesia of the local anesthetic used in the single-dose caudal block technique, such as opioids, epinephrine, clonidine, and neostigmine  .
Ketamine, an anesthetic agent, has also attracted some interest as an additive to local anesthesia. Ketamine, at subanesthetic doses, can provide marked analgesia without inducing respiratory depression. Ketamine is classified as an N-methyl D-aspartate receptor antagonist. These receptors are located throughout the central nervous system, including the spinal cord  .
Dexmedetomidine is a potent and a highly selective a2-adrenergic agonist having a sympatholytic, sedative, and analgesic effect and has been described as a safe and effective additive in many anesthetic and analgesic techniques , . Dexmedetomidine has high affinity to a2-adrenergic receptors (more than eight-fold) and lower affinity to a1-receptors, compared with clonidine, besides its great selectivity to a2A -adrenergic receptors, which is responsible for its analgesic effect  .
| Patients and methods|| |
After approval of the ethical committee and obtaining informed consent from the parents or guardian, 60 pediatric patients, of both sex, aged 2-4 years, American Society of Anesthesiologists (ASA) physical status I or II, admitted to the Pediatric Surgery Unit of Ain-Shams University Hospitals, from November 2013 to May 2014, scheduled for inguinoscrotal surgeries (e.g. hernia, undescended testis, and hydrocele) were included in the study. The patients were randomized in a double-blinded manner using closed envelop method into two equal groups: group A patients (n = 30) received single-dose caudal epidural analgesia using dexmedetomidine with bupivacaine, whereas group B patients (n = 30) received single-dose caudal epidural analgesia using ketamine with bupivacaine.
Exclusion criteria included parents' refusal, age less than 2 years or more than 4 years, ASA grade III or more, patients whom a caudal block is contraindicated (infection at the site of block, bleeding diathesis, pre-existing neurological or spinal disease, or congenital anomalies such as cardiac or sacral anomalies), known or suspected allergy to local anesthetics.
Patients were made to fast according to the ASA guidelines for water (2 h), breast milk (4 h), and infantile formula or light meals (6 h).
The standard monitors were applied, including noninvasive blood pressure, ECG, and pulse oximetry. General anesthesia was induced using 8% sevoflurane in 100% oxygen, and a 24-G intravenous cannula was inserted. Laryngeal mask airway of appropriate size was inserted. Anesthesia was maintained using isoflurane 1-2% in 100% oxygen with spontaneous ventilation; no analgesia was given to any patient. The patients were made to lie in the left lateral position with both legs flexed 90° at hip joints and 90° at knee joints. After all aseptic precautions were taken, sacral hiatus was identified by palpating sacral cornua and a short length short bevel needle of 23-G was penetrated at 90° until a pop was felt and then angled down to 30° and slightly advanced in the cephaled direction. After negative aspiration for blood and cerebrospinal fluid, the drugs were introduced slowly into the caudal epidural space; careful inspection of soft tissues was carried out to rule out subcutaneous injection.
Patients of group A were given 1 mg/kg of dexmedetomidine in 1 ml/kg of 0.25% bupivacaine, whereas patients of group B were given 0.5 mg/kg of ketamine in 1 ml/kg of 0.25% bupivacaine. Surgery was started after 15 min from caudal analgesia. Intraoperatively, systolic blood pressure (SBP) and diastolic blood pressure, heart rate (HR), and oxygen saturation (SpO 2 ) were recorded every 5 min. Any intraoperative increase in SBP or HR more than 20% of the baseline was managed by increasing the level of isoflurane concentration and by administration of rescue analgesia (fentanyl 1 mg/kg intravenously). At the end of surgery, the laryngeal mask airway was removed and patients were shifted to the postanesthesia care unit (PACU). The time and type of surgery were recorded. Postoperative sedation score was recorded using the Ramsay sedation score:
Score 1: Anxious and agitated or restless, or both;
Score 2: Cooperative, oriented, and calm;
Score 3: Responsive to commands only;
Score 4: Exhibiting brisk response to light glabellar tap or loud auditory stimulus;
Score 5: Exhibiting a sluggish response to light glabellar tap or loud auditory stimulus; and
Score 6: Unresponsive.
Postoperative pain was assessed using the pediatric observational 10-point scale, the 'Face, Leg, Activity, Cry, Consolability (FLACC) pain score  '; the scale is scored between a range of 0-10 [Table 1].
|Table 1 The FLACC scale [(extracted from the FLACC: a behavioral scale for scoring postoperative pain in young children ]|
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The score of the FLACC scale are interpreted as follows:
0 = Relaxed and comfortable.
1-3 = Mild discomfort.
4-6 = Moderate pain.
7-10 = Severe pain or discomfort or both.
Patients with a pain score of 4 or greater were given rescue analgesia in the form of 15 mg/kg of intravenous acetaminophen (perfalgan). Postoperatively, pain score was observed and recorded every hour for the first 24 h. Any side effect, including nausea and vomiting, respiratory depression (oxygen saturation <95%), bradycardia, or hypotension, was recorded.
Statistical analysis was carried out using the Statistical Package for Social Sciences, version 17.0 (SPSS© v. 16.0; SPSS Inc., Chicago, Illinois, USA). Qualitative data were analyzed using the Pearson c2 -test and were presented as number and percentage. Quantitative data were analyzed using the unpaired Student t-test for between-group comparison; data were presented as mean (SD). A P-value of less than 0.05 was considered statistically significant.
Sample size calculation was carried out using the PASS 11 software program (Power Analysis and Sample Size calculation; NCSS, LLC, Chicago, USA). The power analysis was performed on the basis of the duration of analgesia as the primary outcome, with an expected mean value of 15 (4.4) for dexmedetomidine and 10.9 (4.4) for ketamine. A sample size of 24 participants per group was found to achieve a difference of 4 h, with an a error less than 0.05 and a power of 80% using a two-sided t-test. Thirty patients per group were included to replace any dropouts.
| Results|| |
As regards age, sex, body weight of patients, and the duration and type of surgery, no statistically significant differences between the two groups were found (P > 0.05) [Table 2].
Intraoperatively, rescue analgesia (fentanyl) was not administered to any patient, although two patients in group A and 11 patients in group B were given postoperative analgesia in the form of 15 mg/kg of acetaminophen (perfalgan). Moreover, the total dose of acetaminophen was significantly higher in group B than in group A [Table 3].
As regards the vital signs and hemodynamic stability intraoperatively, the recorded SBP and diastolic blood pressure, HR, and SpO 2 showed no statistically significant difference between the two groups [Table 4].
|Table 4 Intraoperative vital data: systolic and diastolic blood pressures, pulse, and SpO2|
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The incidence of complications in the PACU after recovery was as follows: one patient of group A had vomiting, whereas in group B two patients had vomiting. The other complications in the PACU, such as hypotension, bradycardia, and respiratory depression (SpO 2 <95%), were not recorded [Table 5].
As regards the total duration of postoperative analgesia as indicated by the FLACC score when it becomes 4 or greater, there was a statistically significant difference between group A (19.6 ± 1.4) and group B (11.4 ± 1.2) (P < 0.05) [Table 6].
Finally, sedation time was longer in group A (6.7 ± 1.6) than in group B (6.7 ± 1.6), with the difference between the two groups being statistically significant (P < 0.001; [Table 6].
| Discussion|| |
This study showed that the use of dexmedetomidine added to bupivacaine in comparison with ketamine added to bupivacaine, during single-dose caudal epidural injection for postoperative analgesia following inguinoscrotal surgeries, increased the duration of analgesia in both groups, with longer duration in group A (dexmedetomidine) than in group B (ketamine), and it was statistically significant. Moreover, the duration of sedation was prolonged in group A than in group B, and it was also statistically significant.
No postoperative side effects, such as hypotension, bradycardia, or respiratory depression, were recorded in the PACU, although one patient in group A and two patients in group B had postoperative vomiting, which was not statistically significant.
Intraoperatively, rescue analgesia (fentanyl) was not administered to any patient, although two patients in group A and 11 patients in group B were given postoperative analgesia in the form of 15 mg/kg of acetaminophen (perfalgan).
The findings of many authors support the result of our study. El-Hennawy et al.  compared the use of a single-dose caudal epidural injection of dexmedetomidine, clonidine, or normal saline added to bupivacaine and proved that the duration of analgesia was found to be significantly prolonged with dexmedetomidine, and to a lesser extent with clonidine than with plain bupivacaine, without any increase in the incidence of side effects.
Xiang and colleagues studied the effect of caudal dexmedetomidine on 60 children, aged 12-72 months, undergoing unilateral inguinal hernia repair and received either 1 ml/kg of 0.25% bupivacaine (group B) or bupivacaine plus 1 mg/kg of dexmedetomidine (group BD). They concluded that the supplementation of caudal bupivacaine with dexmedetomidine reduces the response to hernia sac traction in the inguinal hernia repair in pediatric surgery; besides, it prolongs the duration of postoperative analgesia  .
El Shamaa and Ibrahim studied 50 pediatric patients, 1-5 years of age, scheduled for lower abdominal and perineal surgeries, divided into two equal groups: group A patients received dexmedetomidine with bupivacaine, whereas group B patients received morphine with bupivacaine. They concluded that use of dexmedetomidine as an additive to the local anesthetic bupivacaine in caudal epidural analgesia prolongs the duration of postoperative analgesia compared with caudal morphine, with no side effects on the vital signs. Most postoperative side effects such as vomiting, itching and urine retention were seen with caudal morphine injection rather than with dexmedetomidine  .
Fares and colleagues studied the effect of general anesthesia combined with caudal analgesia on 40 pediatric patients, 3-12 years of age, scheduled for major abdominal cancer surgeries. They were divided into two groups: group I received 1 ml/kg of 0.25% bupivacaine with 1 mg/kg of dexmedetomidine and group II received 1 ml/kg of 0.25% bupivacaine. They found that addition of dexmedetomidine to caudal bupivacaine in pediatric major abdominal cancer surgeries achieved significant postoperative pain relief for up to 19 h, with less use of postoperative analgesics and prolonged duration of arousable sedation  .
In another study, Anand and colleagues studied the effect of adding dexmedetomidine to caudally injected ropivacaine on the intensity of postoperative analgesia and its safety in the children undergoing abdominal surgeries. They reported that dexmedetomidine achieved a remarkable relief of postoperative analgesia leading to better quality of sleep and minimal agitation during recovery from anesthesia. They also reported a prolonged postoperative sedation  .
Moreover, supporting the results of the current study was that of Nasr and Abdelhamid, who studied the effect of caudal dexmedetomidine versus fentanyl with bupivacaine on the stress response and postoperative analgesia in pediatric cardiac surgery. They reported that dexmedetomidine attenuated the stress response and produced better analgesia; however, in their study they used a lower dose of dexmedetomidine and the shorter acting opioid, fentanyl. Furthermore, they showed a significant drop in the mean arterial pressure and HR after caudal injection, unlike that reported in the current study  .
Saleem and colleagues studied the postoperative analgesic effect of ketamine when given with caudally administered bupivacaine in children undergoing inguinoscrotal surgeries.
The study included 60 patients who were divided into two groups: group A received 0.75 ml/kg of 0.25% bupivacaine caudally, and group B received 0.75 ml/kg of 0.25% bupivacaine and 0.25 mg/kg of ketamine caudally. They found that the addition of ketamine to caudally administered bupivacaine resulted in significantly longer postoperative analgesic period (11.4 ± 2.8 h), whereas in group A in which only bupivacaine was used, the mean duration of analgesia was 3.14 ± 0.94 h (P < 0.0005)  .
Cook and colleagues studied 60 children with three different adjuncts, clonidine, adrenaline, and aetamine, at a dose of 0.5 ml/kg and 0.25% of bupivacaine. They found prolonged analgesic period (12 h) with 0.5 mg/kg of ketamine, compared with 3.2 and 5.8 h with adrenaline and clonidine, respectively  .
Similarly, Simple and colleagues worked on the optimal dose of ketamine with bupivacaine for caudal epidural blockade in children. They concluded that the optimal dose would be 0.25-0.5 mg/kg for analgesic effects without any adverse effects  .
Panjabi and colleagues compared the addition of ketamine in three doses to 60 children, between 6 months and 10 years of age, undergoing inguinal herniotomy, to identify the optimal dose of ketamine that produces the maximum duration of caudal analgesia with minimal adverse effects as an adjuvant to bupivacaine for caudal epidural block. Patients were divided into three groups. All received caudal block with 0.75 ml/kg of 0.25% bupivacaine, and then they added ketamine as an additive in three doses: group I received 0.25 mg/kg, group II received 0.5 mg/kg, and group III received 1 mg/kg. The mean duration of caudal analgesia was 8.8 h in group I compared with 22.1 h in group II (P < 0.001) and 25.2 h in group III (P < 0.001). Group III had a significantly higher incidence of behavioral side effects such as odd behavior, agitation, or restlessness compared with groups I and II. Thus, they concluded that the optimal dose of ketamine was 0.5 mg/kg added to 0.75 ml/kg of 0.25% bupivacaine for caudal epidural block, without an increase in side effects  .
| Conclusion|| |
The results of this study showed that the addition of dexmedetomidine to local anesthetic bupivacaine for single-dose caudal analgesia produced longer postoperative analgesia when compared with ketamine, with fewer side effects, but the sedation score with dexmedetomidine was higher than that with ketamine.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]