Ain-Shams Journal of Anaesthesiology

ORIGINAL ARTICLE
Year
: 2016  |  Volume : 9  |  Issue : 2  |  Page : 274--279

Enhancement of bupivacaine caudal analgesia by using dexamethasone or clonidine in children undergoing subumbilical surgery


M Solanki Nilesh, R Engineer Smita, B Patel Rahul, K Vecham Pavan 
 Department of Anaesthesia, B.J. Medical College and Civil Hospital, Ahmedabad, Gujarat, India

Correspondence Address:
M Solanki Nilesh
44-Devshrusti Bungalows-II, B/h Kena Bungalows, Motera Stadium Road, Motera, Sabarmati, Ahmedabad 380005, Gujarat
India

Abstract

Background and aims Caudal analgesia produces profound intraoperative, as well as postoperative analgesia, with minimal psychological alteration in children. Because of its short duration, various additives have been used to prolong the duration of analgesia. The present study aimed to evaluate the effect of adding dexamethasone and clonidine to bupivacaine in caudal analgesia for children undergoing subumbilical surgeries. Patients and methods We conducted a prospective, randomized, single-blinded study on 100 patients of either sex belonging to the American Society of Anesthesiologists«SQ» physical status I, II in the age group 1-12 years, and undergoing subumbilical surgery under general anesthesia, were enrolled. Written informed consent was obtained from their parents. Patients were randomly divided into two groups (group D and C). Group D received 1 ml/kg of 0.25% bupivacaine with 0.2 mg/kg of dexamethasone in normal saline and group C received 1 ml/kg of 0.25% bupivacaine with 1 mg/kg of clonidine in normal saline, with maximum volume of 12 ml in both the groups. All patients were assessed intraoperatively for hemodynamic changes and requirement of sevoflurane concentration and postoperatively for pain by using FLACC pain score and for sedation by using four-point sedation score. Results The mean duration of analgesia was 18-24 h in group D, whereas in group C it was 12-15 h. Group C had a higher sedation score up to 2 in immediate postoperative period for 1 h compared with below 1 h in group D. Conclusion Postoperative analgesia is longer with dexamethasone compared with clonidine without any side effects.



How to cite this article:
Nilesh M S, Smita R E, Rahul B P, Pavan K V. Enhancement of bupivacaine caudal analgesia by using dexamethasone or clonidine in children undergoing subumbilical surgery.Ain-Shams J Anaesthesiol 2016;9:274-279


How to cite this URL:
Nilesh M S, Smita R E, Rahul B P, Pavan K V. Enhancement of bupivacaine caudal analgesia by using dexamethasone or clonidine in children undergoing subumbilical surgery. Ain-Shams J Anaesthesiol [serial online] 2016 [cited 2021 Dec 2 ];9:274-279
Available from: http://www.asja.eg.net/text.asp?2016/9/2/274/182268


Full Text

 Introduction



Pain is an unpleasant emotional, sensory experience with actual or potential tissue damage. Postoperative pain produces or precipitates psychological and systemic side effects. Postoperative analgesia administered through the caudal epidural route is appropriate and satisfactory in pediatric anesthesia [1,2]. Bupivacaine is a commonly used local anesthetic in caudal anesthesia, which has a short duration of action [3]. Different drugs like tramadol, fentanyl, clonidine, midazolam, and dexamethasone with bupivacaine prolong the postoperative analgesia.

We evaluated the duration of postoperative analgesia, intraoperative hemodynamic changes, requirement of inhalation agent, and any side effects of caudal block using bupivacaine with dexamethasone or clonidine in children undergoing subumbilical surgery.

 Patients and methods



After obtaining local ethical committee's approval, written and informed consent was obtained from patients' parents. This prospective, randomized, single-blinded study was conducted in the pediatric surgical operation theater in Civil Hospital between August 2014 and December 2014, and a total of 100 patients of either sex, belonging to American Society of Anesthesiologists' physical status I-II, aged 1-12 years, weighing 5-30 kg, and undergoing elective subumbilical surgeries under general anesthesia were included. Patients having infection at the site of caudal block, congenital anomaly of the spine, bleeding diathesis, pre-existing neurological disease, or hypersensitivity to any local anesthetic drugs or steroid were excluded from the study. An intravenous access was secured and glycopyrrolate injection (0.004 mg/kg) and ondansetron injection (0.15 mg/kg) were administered. Standard monitoring was achieved through ECG, non invasive blood pressure (NIBP), SpO 2 , and EtCO 2 . Anesthesia was induced with sevoflurane (1-6%) and 50% nitrous oxide in oxygen or intravenous thiopental 5-6 mg/kg. In left lateral position, caudal block was performed using a 22-G epidural needle under complete aseptic precaution. After confirmation and negative aspiration for blood and cerebrospinal fluid, the study drugs were introduced into the caudal space slowly with continuous ECG monitoring. The patients included were divided before the induction of anesthesia using computer-generated randomization into two equal groups (groups D and C). Group D received 1 ml/kg of 0.25% bupivacaine with 0.2 mg/kg of dexamethasone in normal saline and group C received 1 ml/kg of 0.25% bupivacaine with 1 mg/kg of clonidine in normal saline, with maximum volume 12 ml in both groups. The anesthesiologist performing the caudal block was blinded to the drug used.

The patients were placed in the supine position. To facilitate the insertion of an I-gel or endotracheal tube, intravenous succinylcholine 1-2 mg/kg was administered. Intraoperatively no analgesic was supplemented. Anesthesia was maintained with assisted ventilation using sevoflurane (2-0.6%) or with controlled ventilation using atracurium injection (0.5 mg/kg) with 50% nitrous oxide in oxygen and sevoflurane (2-0.6%). Glucose/saline solution was infused as per the requirement and perioperative blood loss was replaced as required.

During surgery, adequate analgesia was assessed by using hemodynamic stability, as indicated by the absence of an increase in heart rate and systolic blood pressure more than 15% compared with baseline values obtained just before the surgical incision with decreased requirement of sevoflurane concentration at ~0.6%. An increase in heart rate and systolic blood pressure within 20 min of skin incision indicated failure of caudal anesthesia. At the end of the surgery, residual neuromuscular block was antagonized with neostigmine injection (0.05 mg/kg) and glycopyrrolate injection (0.008 mg/kg) intravenously.

Required intraoperative concentration of sevoflurane was recorded at every 15 min. Heart rate, NIBP, SpO 2 , EtCO 2 , and temperature were recorded every 15 min till the end of the surgery and every hour postoperatively, till the rescue analgesic was given. Duration of surgery, duration of anesthesia, and perioperative complications, like bradycardia/tachycardia, hypotension/hypertension, respiratory depression, nausea, vomiting and urinary retention, were also recorded.

In the recovery room, hemodynamic parameters, sedation, and pain score at hourly interval were observed and recorded till the rescue analgesic was given. Postoperative sedation was assessed by using the four-point sedation score [4] (0: spontaneous eye opening, 1: eye open on speech, 2: eye open on shake, 3: unarousable) and pain was evaluated by using FLACC score [5] (F = face, L = leg, A = activity, C = cry, C = consolability) at 1-h interval for first 3 h and thereafter every 2 h till the score of greater than 4, and then the rescue analgesic was given. The score 0 = no pain, 1-3 = mild pain, 4-7 = moderate pain, 8-10 = severe pain, and the scale had a maximum score of 10.

In this study, sample size was calculated using the formula, n = 4pq/E2 , which is based on the Hardy-Weinberg principle. In this formula, p is the prevalence of subumbilical pediatric surgery at the civil hospital. A total of 100 patients were allocated randomly to two equal groups (50 patients/group). Collected data were presented as mean ± SD, numbers and percentages, as appropriate. Categorical variables were analyzed using the c2 -test with Yate's correction and Fisher's exact test (two tailed) as appropriate. Continuous variables were tested using an unpaired Student's t-test. Statistical calculations were carried out using Microsoft Office Excel 2010 and Graph Pad Prism 6.05 (Quickcalc) software (GraphPad Software, Inc.7825 Fay Avenue, Suite 230La Jolla, CA 92037 USA). P value of less than 0.05 was considered statistically significant.

 Results



No statistically significant difference was observed in both groups regarding age, sex, weight, ASA grade, duration of surgery, and device used to secure an airway [Table 1]. Majority of the children in both groups underwent hypospadias, hernia repair, and posterior sagittal anorectoplasty) surgeries [Table 2].{Table 1}{Table 2}

Baseline heart rate, systolic blood pressure, and diastolic blood pressure, recorded before the induction of general anesthesia, were same in both groups. Compared with the baseline value, after 5 min of caudal block, heart rate decreased significantly in group C compared with group D. No patients in the either group had a drop in heart rate to less than 80 beats/min [Table 3]. After 30 min of caudal blocks, systolic blood pressure decreased below 90 mmHg in group C, whereas in group D systolic blood pressure remained above 90 mmHg [Table 4]. Diastolic blood pressure did not decrease significantly [Table 5].{Table 3}{Table 4}{Table 5}

Mean hourly pain scores in the recovery room in both groups were similar up to 8 h after injection. Thereafter, the mean score in group C was significantly higher than that in group D [Figure 1]. The duration of analgesia was 12-15 h for group C and 18-24 h for group D.{Figure 1}

Sedation score was between 1 and 2 (opening eye on shake) in group C for 1½ h. In group D it was below 1. All children were able to open their eyes on speech from immediate postoperative period in group D [Figure 2].{Figure 2}

Postoperative complications such as nausea, vomiting, urinary retention, and respiratory depression were not observed in any of the group.

As shown in [Figure 3] and [Figure 4], after 15 min of caudal block, 25 patients in group C required 1% sevoflurane concentration compared with 12 patients in group D to maintain adequate depth of anesthesia.{Figure 3}{Figure 4}

 Discussion



Caudal epidural anesthesia with general anesthesia in children undergoing subumbilical surgery is safe, simple, and provides very effective postoperative analgesia. The duration of caudal analgesia with longer acting local anesthetic is limited, and thus various drugs were tried to prolong the duration of analgesia with minimal side effects [2].

In the present study, dexamethasone or clonidine with 0.25% 1 ml/kg bupivacaine was given caudally to evaluate the duration of postoperative analgesia, intraoperative hemodynamic changes, and requirement of inhalation agent.

Opioids are commonly used as adjuncts for caudal blockade and have been shown to consistently increase the duration of analgesia. Unacceptable side effects, including nausea, vomiting, pruritus, and the risk of respiratory depression, have limited the use of opioid additives in children [3].

Clonidine, a centrally acting selective a-2 adrenoreceptor, when given epidurally, exerts analgesic action by stimulating descending noradrenergic medullospinal pathway and inhibiting the release of nociceptive neurotransmitters in the dorsal horn of spinal cord. It also interacts with a-2 adrenergic receptors located on superficial laminae of spinal cord and brain stem nuclei implicated in pain, and thus analgesia may be produced at peripheral, spinal and brain stem sites [6,7].

Dexamethasone, a corticosteroid with strong anti-inflammatory effects, provides postoperative analgesia [8]. The exact mechanism by which dexamethasone exerts an analgesic effect is not fully understood. Systemic administration of steroids has been found to suppress tissue levels of bradykinin and inflammatory cytokine release, along with the release of cytokine and neuropeptides from nerve endings, which can enhance nociception in inflamed tissue. The established reduction in prostaglandin production might further contribute to analgesia by inhibiting the synthesis of the cyclooxygenase isoform-2 in peripheral tissues and in the central nervous system. Despite the fact that the mechanism is not yet fully understood, a reduction in pain by steroids has been supported by many studies. The clinical effects of dexamethasone are related to changes in the transcription of DNA to proteins and continue for some time after the drug is cleared from plasma. The plasma elimination half-life is only about 6 h and thus there seems to be ongoing drug effects for a significant period of time after drug clearance from the plasma [8,9].

Shukla and colleagues studied the duration of postoperative analgesia by adding clonidine or fentanyl to ropivacaine and concluded that both agents prolong the duration of analgesia after single-shot caudal epidural anesthesia. Clonidine offers some advantages over fentanyl as it does not produce clinically and statistically significant undesirable side effects like respiratory depression, vomiting, and bradycardia. They recommended the use of clonidine as an additive to ropivacaine in caudal anesthesia, in children, as it has a more favorable side effect profile than does fentanyl [2].

A review by Ansermino and colleagues mentioned that in eight of the 12 studies examining the addition of clonidine (1-5 mg/kg) to local anesthetic for caudal blockade showed an increase in the duration of analgesia in the clonidine group. The associated side effects, typically mild sedation, with doses less than 2 mg/kg appear to be minimal or even beneficial in pediatric patients [3].

We observed postoperative analgesia with mild sedation for 1½ h after giving clonidine 1 mg/kg with bupivacaine.

Many studies have shown wide variation in the duration of analgesia. It may be because of different doses of additive drugs used, differences in premedication and volatile anesthetic solution used, type of surgery, indications for rescue analgesia, assessment of pain, and statistical analysis.

The effect of systemic dexamethasone in reducing pain has been studied in children. With its stronger anti-inflammatory effect, dexamethasone is beneficial in acute surgical pain [8]. Intravenous dexamethasone 0.5 mg/kg, in combination with a caudal block with ropivacaine, prolonged the duration of analgesia after pediatric orchidopexy [8]. The addition of 0.1 mg/kg dexamethasone to ropivacaine for caudal blocks significantly prolonged the duration of analgesia in children undergoing inguinal hernia repair [9] and in orchidopexy [10] surgery without any side effects. In children with lower abdominal surgery, single-shot caudal epidural clonidine 2 mg/kg with 0.25% ropivacaine prolonged the duration of analgesia without any adverse effects [11]. The combination of caudal epidural clonidine 2 mg/kg with 0.25% bupivacaine is safe and effective for postoperative analgesia in pediatric day-care surgeries [12]. In other studies, the combination of clonidine 1 mg/kg and 0.25% bupivacaine significantly prolonged the duration of analgesia without any side effect in pediatric patients undergoing subumbilical surgeries [13,14]. The side effects of neuraxial clonidine administration include hypotension and bradycardia. In our study no hypotension or bradycardia were observed.

Addition of dexamethasone in local anesthetic drug in brachial plexus block can prolong the duration of analgesia without any side effects [15]. Tissue injury, induced acute inflammation, is known to play a significant role in the genesis of surgical pain, and dexamethasone could theoretically be beneficial in the management of acute surgical pain because of its potent anti-inflammatory effect [8]. Systemic administration of dexamethasone in combination with caudal block can relieve postoperative pain and prolonged caudal analgesia in pediatric patients [8].

In our study, the dexamethasone group had caudal analgesia for 21-24 h in postoperative period as compared with 12-15 h in the clonidine group.

Perioperative bradycardia and hypotension was not observed in any patient of both group. Intraoperatively, in the first 15 min, 2% concentration of sevoflurane was required in 18 patients in group D compared with none in group C. In immediate postoperative period, up to 1½ h, sedation scores were higher in the clonidine group compared with the dexamethasone group.

 Conclusion



Enhancement of bupivacaine caudal analgesia by using dexamethasone and clonidine was regarded as clinically successful because none of the patients required additional analgesia doses during surgery. The dexamethasone group provided longer duration of analgesia in the postoperative period compared with the clonidine group. Both groups provided hemodynamic stability perioperatively. No side effects were observed in any group except mild sedation with clonidine in immediate postoperative period.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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