Efficacy of Caudal Epidural Block with 0.2% Ropivacaine in Paediatric Patients Undergoing Laparoscopic Unilateral Hernia Repair: A Prospective Randomized Study

Keywords

Paediatric; Ropivacaine; Caudal; Laparoscopic; Regional.

Background

In paediatric patients, though general anaesthesia is the commonly used technique, regional anesthetic technique is often used for intra-operative as well as postoperative pain relief. Caudal epidural block is commonly used as it is a safe, reliable, and easy to administer technique for lower abdominal surgeries [1].

Caudal block allows rapid recovery from anaesthesia, as it decreases the requirement of other systemic anesthetic drugs, with effective postoperative analgesia [2]. This technique is a useful adjunct during general anaesthesia. The quality and level of the caudal block depends upon the dose, volume, and concentration of the injected drug.

In comparison to bupivacaine, ropivacaine is known to have lesser cardiotoxicity and motor blockade, with similar pain relief at equivalent analgesic doses. It is considered to be a better agent for caudal epidural analgesia in children [3-6].

Prophylactic analgesia with local anesthetics is an attractive concept, especially in paediatric practice, because the evaluation of pain can be very challenging in young children [7]. Local anesthetics can be administered safely in contrast to opioids. The global experience with paediatric regional anesthesia is still quite low inspite of good safety records and even the most commonly performed procedure, caudal block represents only 2.5% of all central neuraxial blocks performed [8, 9].

This prospective randomized double blind study was designed to evaluate perioperative effect of caudal epidural block in children undergoing laparoscopic hernia repair regarding intraoperative hemodynamic changes, postoperative pain score, rescue analgesia requirement and any complication related to caudal block.

Methods

After institutional ethical committee approval, sixty children aged 2–12 years of either sex, with ASA grade I or II scheduled for laparoscopic unilateral hernia repair were included in our study.

Patients with history of developmental delay or mental retardation, history of Diabetes mellitus type I, known allergy or contraindication to any local anesthetics, known congenital anomaly in the inguinal region, infection at local site were excluded from the study.

Patients were randomly allocated into two groups using a computer generated coding system.

Group A: (General anaesthesia with caudal block with 0.2% Ropivacaine 1ml/kg).

Group B: (General anaesthesia without caudal block).

All the patients scheduled for surgery visited a day prior to surgery. A thorough pre- anesthetic check up was done including the detailed history, systemic and airway examination. Specific questions were asked related to previous anesthetic exposure of any surgery and any major cardiovascular, neurological or respiratory illness. All the necessary routine investigations were done as per institutional protocol. Parents of children were informed and explained about the procedure and any doubts or apprehensions were clarified. A written informed consent was obtained from the parents. No premedication was advised.

On the day of surgery, children were monitored by means of ECG, pulse oximeter, and noninvasive blood pressure after shifting to the operating room table. In all patients intra-venous (i.v.) cannula was secured in nondominating forearm. After preoxygenation for 3 min, induction was done with 50% oxygen 50% nitrous oxide and sevoflurane using Jackson Rees circuit. Induction was carried out by increasing the concentration of sevoflurane in stepwise manner starting from 1% and gradually increasing to 5-6% i.e. 1% every 6-8 breaths. After induction Injection 1 μg/ kg fentanyl was administered intravenously and adequate size endotracheal tube was placed and secured in position. In group A, children received caudal block with 0.2% ropivacaine at 1 ml/kg. For caudal block, the sacral hiatus was identified and a 22 G short length caudal needle ( Epican short length caudal needle, B.Braun) was passed through the sacrococcygeal ligament to inject a local anesthetic after confirmation of space by loss of resistance technique. After caudal block the patient was turned into supine position, surgeon was allowed to clean and drape. General anaesthesia was maintained with oxygen 40%, nitrous oxide 60% and isoflurane (0.6% -1%). Intra-operatively injection atracurium was used as skeletal muscle relaxant. No other narcotic, analgesic, sedative, or antiemetic was used intraoperatively.

During anaesthesia patients were monitored by ECG, pulse oximetry, capnography and non-invasive measurements of arterial pressure. Parameters were recorded 1 min after creation of carboperitoneum and then every 10 min until the surgery was over. After surgery patients were shifted to surgery intensive care unit for further observation and monitoring. Post -operative pain by pediatric observational pain scale score (FLACC score) was determined on emergence from anaesthesia and 1,2,3,4,5,6 hour until the first dose of rescue analgesia was given in form of paracetamol 15mg/kg when score was ≥4. Other adverse effects such as nausea, vomiting, respiratory depression, bradycardia, hypotension, urinary retention, facial flushing and pruritus were also observed. The observer and parents of the children were blinded to the technique.

Postoperative pain was assessed using the Faces Legs Activity Cry Consolability tool (FLACC, 0- 10) as in the table given below:

Statistical analysis

Sample size was calculated based on pilot study on 10 patients in both the groups. With 95% confidence interval and 80% power of study, sample size was determined to be 60 with 30 patients in each group.

Data was statistically analyzed using SPSS (Statistical Package for Social Sciences) Version 15.0 statistical Analysis Software. Quantitative data were described as mean ± SD and qualitative data as frequency and proportions. The chi square-test was used to compare qualitative data between two groups while Student t-test was used for quantitative data. P values of 0.05 or less were considered significant.

Results

All children were comparable in terms of demographic profile (p>0.05). The mean age of the patients in group A (6.7 ± 2.7) was comparable to group B (7.2 ± 2.8 yrs). The mean weight of the patients in group A and group B was 20.1 + 6.33 and 21.06 +6.6 kg respectively. There were 14 females and 16 Males in group A as compared to 12 females and 18 males in group B. [Table 1]

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Both group A and B were comparable in respect to baseline heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure, oxygen saturation and end tidal carbon dioxide (p>0.05).

The mean heart rate values were comparable in both the groups at entire time interval (p> 0.05). None of the patients in either group required treatment with atropine as the heart rate never fell below 60 beats per minute [Table 2].

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There was no statistically significant difference in mean systolic and diastolic pressures at entire time interval. (p>0.05) [Table 3 and 4].

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The postoperative pain score was significantly lower in group A (2.98 ± 1.08) in comparison to group B (3.63 ± 1.49) (p = 0.002). 11 (36%) patients in group A and 25 (83%) patients in group B needed rescue analgesics postoperatively [Table 5].

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The incidence of adverse effects was higher in group A (30%) than group B (13%). 5 patients in group A developed urinary retention and 4 patients experienced nausea or vomiting. In group B urinary retention was present in 1 patient and nausea or vomiting was present in 3 patients. [Table 6]

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Discussion

Management of postoperative pain is a great challenge to the clinicians, especially in paediatric age group. If not treated it may result into various physiological changes, including rise in heart rate, blood pressure, restricted physical activity and sleepless nights. Attenuation of perioperative Pathophysiology that occurs during the surgery through reduction of nociceptive input into the CNS and optimization of postoperative analgesia may decrease complication and facilitates recovery of the patients in the immediate postoperative period and after discharge from the hospital.

Many options are available for treatment of postoperative pain, including systemic (opioids and non opioids) analgesics and regional (neuraxial and peripheral) analgesic techniques. Neuraxial blockade especially caudal epidural blocks assume an integral role in the management of lower abdominal surgeries in paediatric patients as they are used not only to provide surgical analgesia but can be used in the postoperative period to provide effective pain relief.

We decided to use Ropivacaine in our study because in comparison to bupivacaine, it has a wider margin of safety, less motor blockade, less cardiovascular or neurological toxicity. It can be safely used for regional anesthesia and analgesia in ambulatory setting of pediatric patients [3, 8]. Ivani et al., reported a significantly increased duration of analgesia for ropivacaine in comparison to bupivacaine. While comparing ropivacaine with bupivacaine for pediatric caudal block in 245 children they found that the mean time to first analgesia after bupivacaine was earlier than that after ropivacaine [10].

Kay et al., [11] was one of the early advocates of caudal bupivacaine to provide intra- and postoperative analgesia for circumcision in day cases, and Lunn et al., [12] demonstrated the superiority of caudal block over intramuscular morphine for postoperative analgesia.

Cheon et al., [13] who compared caudal block with local infiltration in children undergoing inguinal herniorrhaphy noticed that children in the caudal group did not need rescue analgesic; however, in that study postoperative pain was assessed for 2 h only. In our study, 11 patients in group required rescue analgesia postoperative period.

Also, a meta-analysis comparing caudal block with noncaudal regional techniques for inguinal surgeries in children found that caudal block might be a better analgesic in early and late postoperative periods, but with a significant risk for motor block and urinary retention which was similar to our study, in which postoperative pain score was significantly lower in group A (2.98±1.08) in comparison to group B (3.63±1.49) (p= 0.002) although urinary retention was higher in caudal group [14].

However, Bramwell et al., [15] noted a significantly greater consumption of analgesic drugs between 2 and 8 hours postoperatively in patients who received caudal analgesia in comparison to those given intramuscular dihydrocodeine while in our study, there was lesser consumption of analgesic drug within 6 hours of postoperative period.

Yeoman et al., [16] demonstrated a 42% incidence of urinary retention at 6 hours in patients who received caudal block, which was greater than our study in which only 36% patients developed urinary retention. Moores et al., [17] reported 11% incidence of unsteadiness of gait in the caudal group at 4 hours while no patient in our study developed such type of complication.

Conclusion

We concluded from our study that caudal block with 0.2 % ropivacaine provided effective postoperative analgesia following laparoscopic surgery in paediatric patients. It also provided better intraoperative hemodynamic stability and less postoperative analgesic requirement.