Ain-Shams Journal of Anaesthesiology

ORIGINAL ARTICLE
Year
: 2015  |  Volume : 8  |  Issue : 3  |  Page : 396--401

Caudal bupivacaine plus ketamine compared with bupivacaine plus tramadol for postoperative analgesia in children


Reda S Abdelrahman, Ahmad A Eldaba 
 Department of Anesthesia and Surgical Intensive Care, Tanta University Hospital, Tanta, Egypt

Correspondence Address:
Reda S Abdelrahman
Department of Anesthesia and Surgical Intensive Care, Tanta University Hospital, Tanta
Egypt

Abstract

Background Caudal epidural block has been used commonly in pediatric postoperative pain management. However, the analgesic effect of caudal of bupivacaine lasts for 4-12 h. Aim The aim of this study was to compare the analgesic efficacy of the coadministration of tramadol (2 mg/kg) and ketamine (0.25 mg/kg) on the duration of caudal block produced by 0.25% bupivacaine 0.75 ml/kg on postoperative pain after an elective subumbilical surgery in children. Settings and design This is a controlled, randomized, single-blinded study. Patients and methods This study was carried out on 40 children between 2 and 12 years of age, ASA grade 1, of both sexes in Tanta University after obtaining the approval of the local hospital organization and parents«SQ» consent. The patients were divided into two equal groups. The patients in the bupivacaine plus ketamine group (group 1) received caudal bupivacaine 0.25%, 0.75 ml/kg mixed with ketamine 0.25 mg/kg, diluted in a 0.9% NaCl solution to a total volume of 1 ml/kg. The patients in the bupivacaine plus tramadol group (group 2) were administered caudal bupivacaine 0.25%, 0.75 ml/kg mixed with tramadol 2 mg/kg, diluted in a 0.9% NaCl solution to a total volume of 1 ml/kg. Statistical analysis Mean and SD were calculated as numerical data. Continuous variables were compared using the unpaired Student«SQ»s t-test. Nominal nonparametric data were analyzed using the χ2 -test. Results Patients were monitored over the first 24 h postoperatively to assess analgesia using the All India Institute of Medical Science (AIIMS) objective pain discomfort scale and associated hemodynamic and respiratory changes. Our results showed that the addition of tramadol in group 2 significantly prolonged the analgesic effect of bupivacaine; also, there was hemodynamic stability and pain scores indicated minimal pain. Conclusion Caudal epidural tramadol has been proven to be safe at the concentration used and to prolong bupivacaine«SQ»s analgesic duration postoperatively in children.



How to cite this article:
Abdelrahman RS, Eldaba AA. Caudal bupivacaine plus ketamine compared with bupivacaine plus tramadol for postoperative analgesia in children.Ain-Shams J Anaesthesiol 2015;8:396-401


How to cite this URL:
Abdelrahman RS, Eldaba AA. Caudal bupivacaine plus ketamine compared with bupivacaine plus tramadol for postoperative analgesia in children. Ain-Shams J Anaesthesiol [serial online] 2015 [cited 2020 Mar 29 ];8:396-401
Available from: http://www.asja.eg.net/text.asp?2015/8/3/396/161717


Full Text

 Introduction



Caudal anesthesia is the first technique of epidural anesthesia and is the most commonly used technique for the management of pain following a vast range of surgical procedures within the distribution of T10-S5 dermatomes for young children because of its technical simplicity, reliability, safety, and low failure rate [1] .

Various additives to the local anesthetic solution have been used in an attempt to prolong the duration of a single caudal epidural injection [2] . Opioids and nonopioids have traditionally been added to increase the duration of analge sia, but opioids have been associated with unacceptable side effects as well as risks of late respiratory depression, prolonged sedation, urine retention, or hypotension.

Ketamine binds to a subset of glutamate receptors stimulated by the agonist N-methyl d-aspartate and thus exerts its analgesic action [3] . These receptors are found throughout the central nervous system, including the lumbar spinal cord. Ketamine has a potent analgesic action when used at subdissociative doses [3] . Moreover, it does not cause respiratory depression [4] and therefore seems to be a suitable drug for pain relief.

Tramadol is a synthetic analog of codeine that has analgesic potency approximately equal to that of pethidine, but without a respiratory depressant effect [5] .

The aim of this study was to compare the analgesic efficacy of coadministration of tramadol (2 mg/kg) versus ketamine (0.25 mg/kg) on the duration of caudal block produced by 0.25% bupivacaine 0.75 ml/kg in the management of postoperative pain after an elective subumbilical surgery in children.

 Patients and methods



This was randomized-controlled trial carried out from 1 February 2014 to 1 August 2014 at the Department of Anesthesia, Tanta University Hospital, after obtaining the approval of the local hospital organization and parents' consent.

The study was carried out on forty children 2-6 years of age, ASA (American Society of Anesthesiologists) grades I-II, of both sexes, scheduled for elective surgery for congenital inguinal hernia, hydrocele, or undescended testes.

Patients were randomized (using a sealed envelope and a random number table) into two equal groups.

Group 1: Twenty patients received a caudal injection of plain bupivacaine 0.25%, 0.75 ml/kg mixed with ketamine 0.25 mg/kg diluted in a 0.9% NaCl solution to a total volume of 1 ml/kg.

Group 2: Twenty patients received a caudal injection of plain bupivacaine 0.25%, 0.75 ml/kg combined with tramadol 2 mg/kg, diluted in a 0.9% NaCl solution to a total volume of 1 ml/kg.

Exclusion criteria

Children with bleeding diathesis or coagulopathy, local skin infections of the caudal area, and pre-existing neuromuscular or spinal diseases were excluded.

All patients were fasted for 4 h preoperatively. No premedications such as benzodiazepines or opioids were administered so as not to interfere with our results. Patients in all groups received a standard general anesthetic technique of inhalational induction with 100% oxygen and sevoflurane delivered through an Ayres T-piece with spontaneous respiration, followed by insertion of a peripheral venous access; when the child was deeply anesthetized, an I-Gel of the proper size was introduced.

Dextrose 5% with 0.9% NaCl was infused at a rate 4-6 ml/kg/h.

Maintenance of anesthesia: anesthesia was maintained with oxygen 100% and isoflurane. All patients were monitored for heart rate, oxygen saturation, noninvasive blood pressure, respiratory rate, three-lead ECG, and a precordial stethoscope. No sedatives, opioids, or analgesics were administered intraoperatively. Patients were placed in the left lateral position, with flexed hips and knees. After complete sterilization, a caudal block was performed using a 23 G short beveled needle guided by the two sacral cornu and the tip of the coccyx. After perforation of the tectorial sacro coccygeal membrane, which occludes the sacral hiatus, the needle should only be minimally advanced not more than 1 to 3 mm to avoid a bloody puncture or an intrathecal injection. After negative aspiration to ensure no blood or cerebrospinal fluid, the drug mixture was injected according to each group. After the end of the caudal technique, the patient was returned to the supine position. Surgical intervention started 10-15 min after the caudal injection of the analgesic medications. During surgery, adequate analgesia was defined by hemodynamic stability, and absence of an increase in mean arterial blood pressure, heart rate, and respiratory rate by more than 15% of the preincision baseline values. Extubation was performed after full recovery from general anesthesia. Patients were transferred to the recovery room with continuous monitoring of vital data.

Postoperative assessment

All patients were observed in the recovery room for 30 min before transferring to postanesthesia care unit. The following parameters were recorded at 5 and 30 min, and then 1, 2, 4, 6,8, 12, 18, and 24 h after recovery from anesthesia.

Recovery time (time from discontinuation of anesthesia to spontaneous eye opening.Hemodynamic parameters (heart rate, respiratory rate, blood pressure, and oxygen saturation).Complications

Delayed motor weakness.Respiratory depression.Toxic reaction.Urine retention.Pruritis, nausea, and vomiting.Time and amount of rescue analgesia through which we administered analgesia for pain score of 4 or more. The duration of postoperative analgesia was defined as the time between caudal drug injection and the first rescue analgesia. The analgesic was intravenous paracetamol (15 mg/kg).Sedation score: Assessment of sedation was performed at 1 and 4 h using an objective score based on eye opening: eyes open spontaneously = 0, eyes open in response to speech = 1, eyes open in response to response to speech = 1, eyes open in response to physical stimulation = 2, and unarousable = 3 [6] .Pain score was assessed using the All India Institute of Medical Sciences (AIIMS) pain discomfort scale: this scale includes physiological changes such as heart rate and respiratory rate, which can be measured without causing discomfort to the patient. Patients were evaluated by the nursing staff (who were unaware of the treatment administered).It is a clinically relevant scoring system and has been validated for use in children [7] .

Interpretation

Minimum score: 0.

Maximum score: 10.

The higher the score, the more the behavior reflecting discomfort and pain.

0 = relaxed.

1-3 = mild discomfort(cry and pain).

4-6 = moderate pain.

7-10 = severe pain.

Statistical analysis

The initial sample size estimation was performed on the basis of a number of assumptions from previous studies of caudal anesthesia in children. Sequential randomization was used to allocate patients to the two equal groups. This was a single-blinded study.

The findings of the two groups were analyzed statistically and compared using SPSS, version 12 (SPSS Inc., Chicago, Illinois, USA). Mean and SD were determined as numerical data. Continuous variables (e.g. the results for arterial blood pressure, heart rate, SpO 2 , and blood chemistry) were compared using an unpaired Student's t-test. Nominal nonparametric data were analyzed using the χ2 -test. P-values less than 0.05 were considered statistically significant.

 Results



The study included 40 patients divided into two groups. Patients' demographic data are shown in [Table 1]. There were no statistically significant differences (P > 0.05) between the two groups in age, weight, sex, duration of surgery, and time to additional analgesia.{Table 1}

The mean value of the respiratory rate in group 1 preoperatively was 21.3 ± 2.5 cycle/min; this changed nonsignificantly (P > 0.05) intraoperatively and postoperatively, and then increased significantly (P < 0.05) at 8, 18, and 24 h postoperatively to a mean value of 26.1 ± 4.5, 25.1 ± 3.7, and 25.1 ± 3.5 cycle/min, respectively, whereas the mean value of the respiratory rate in group 2 was 21.8 ± 2.4 cycle/min preoperatively and changed nonsignificantly (P > 0.05) intraoperatively and postoperatively, and then increased significantly (P < 0.05) postoperatively at 24 h to a mean value of 27.9 ± 3.1. Comparison between the two groups of the respiratory rate indicated a significant difference between the two groups at 8, 12, 18, and 24 h [Table 2]. In terms of heart rate and mean arterial pressure; there were also significant differences between the two groups at 8, 12, 18, and 24 h [Table 3] and [Table 4].{Table 2}{Table 3}{Table 4}

For the pain score, it was found that the score was 2 up to 4 h and then started to increase and reached a score of 4 only after 6 h in group 1, whereas in group 2, the pain score started to attain 3 at 8 h and reached a score of 4 only after 18 h [Table 5]. There was no difference in the sedation score between the two groups after recovery [Table 6].{Table 5}{Table 6}

 Discussion



Caudal epidural analgesia is one of the most popular and commonly performed regional blocks in pediatric anesthesia. Wide acceptance of caudal block is because of its technical simplicity, reliability, safety, and rapid performance in large series of infants and children, and because it can be used with general anesthesia for intraoperative and postoperative analgesia in patients undergoing abdominal and lower limb surgery [8] .

A single dose of a local anesthetic for caudal block usually leads to early disappearance of the analgesic effect during the postoperative period, necessitating additional analgesia. Bupivacaine produces conduction blockade of neural impulses by preventing the passage of sodium ions through ion-selective sodium channels in the nerve membrane, and stabilizes and maintains sodium channels in the inactivated closed state by binding to specific receptors located in the inner portion of sodium channels [9] .

Ketamine and local anesthetic combinations have been shown to prolong the duration of caudal analgesia, and reduce the incidence of ineffective analgesia compared with local anesthetics alone [10] .

Tramadol, a synthetic analog of codeine, is a racemic mixture of two enantiomers; thus, it has a moderate affinity for the opioid μ-receptor and also inhibits serotonin uptake and is a potent norepinepherine inhibitor [11] .

Adding tramadol to bupivacaine not only increases the duration of analgesia, but markedly decreases the dose of both agents, thereby decreasing the incidence of side effects.

The combination of bupivacaine and tramadol was chosen for caudal block because caudal bupivacaine provides analgesia in the immediate postoperative period, whereas caudal tramadol provides analgesia in the late postoperative period, thereby increasing the total duration of analgesia (additive effect) [11] .

In this study, we observed that the prolonged postoperative analgesia and total consumption of rescue analgesic was significantly lower in group 2, indicating the efficacy of tramadol in enhancing the postoperative analgesia. Our results were in agreement with those of Prosser et al. [12] , who compared the time to additional analgesia between tramadol (2 mg/kg in 0.8 ml/kg physiological saline) and bupivacaine (2 mg/kg) in pediatric patients undergoing hypospedius surgery. This time interval was longer for tramadol than for bupivacaine (10.7 ± 2.2 vs. 9.3 ± 3.0 h). In addition, Shrestha et al. [13] found the addition of tramadol to bupivacaine in the caudal analgesic technique provides longer analgesia and lesser need for rescue analgesic in the postoperative period compared with bupivacaine. The duration of analgesia in group 2 was longer than group 1, with a statistically significant difference. Similar results were reported by Güneş et al. [14] , who concluded that caudal tramadol (2 mg/kg) provided better and long-lasting postoperative analgesia than intravenous tramadol (2 mg/kg).

In this study, there was no respiratory depression as evidenced by normal oxygen saturation in both groups throughout the period of study and no decrease in the respiratory rate below 12 cycle/min. was recorded in any of the groups. In our study, none of the children had hypotension, bradycardia, respiratory depression, or urine retention. No residual motor block could be detected in any of the patients.

 Conclusion



Bupivacaine ketamine and bupivacaine-tramadol are caudal mixtures that produced a longer duration of postoperative analgesia after lower abdominal surgeries in pediatrics, with no side effects. The bupivacaine-tramadol mixture induced a longer duration of analgesia.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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