Postoperative analgesia in pediatric herniotomy - Comparison of caudal bupivacaine to bupivacaine infiltration with diclofenac suppository.

CONTEXT: Perioperative analgesia in paediatric herniotomies demand safe, effective and less invasive strategies. Local infiltration with Bupivacaine, rectal Diclofenac and caudal Bupivacaine are widely used for pain relief. AIMS: To compare the analgesic effects of caudal epidural using 1 mlkg(-1) of 0.25% Bupivacaine against a combination of local infiltration 0.25% Bupivacaine 0.5 mlkg(-1) with Diclofenac suppository 2 mgkg(-1) in the management of post-operative pain following paediatric inguinal herniotomy. SETTINGS AND
DESIGN: This is an observational study from a tertiary care teaching hospital. METHODS AND MATERIAL: A total of 60 children for elective unilateral inguinal herniotomy were assigned to two groups of 30 each. Patients who received caudal block with 1 mlkg(-1) of 0.25% Bupivacaine were allocated to Group A and who received Diclofenac suppository 2 mgkg(-1) and infiltration with 0.25% Bupivacaine 0.5 mlkg(-1) were allocated to Group B. Post operative Pain was assessed using Hannallah's modified objective pain scale. At score ≥3 rescue analgesic oral Paracetamol 15 mgkg(-1) was given. Pain was assessed at 0,15,30,45,60 minutes and half hourly thereafter until 8 hours following surgery or until patient requires rescue analgesic whichever happens first. STATISTICAL ANALYSIS USED: Employed SPSS software. Data was analysed using sample t test and P-value was calculated.
RESULTS: The demographic profile was comparable between two groups. The mean analgesic duration in group A and group B was 228.5 and 331.0 minutes respectively and is found to be statistically significant (P < 0.05).
CONCLUSIONS: Diclofenac suppository with local infiltration is a less invasive and effective alternative to caudal Bupivacaine for analgesia in paediatric herniotomy.

INTRODUCTION

Sophistication and research in anesthesiology had led practicing anesthesiologists to think pain as an attainable goal, not for just sake of alleviating the suffering, but also beyond it like improved wound healing, better functional residual capacities, a better postoperative course in the hospital, early discharge, and less number of readmissions.[1]

Although the spectrum of options for effective perioperative pain management in children ranges from simple oral medication to invasive epidural,[2] it is sad to observe that there is a wide incongruity between available technology and clinical practice.[3] Caudal extradural block[4] is a popular, technique followed around the globe, in conjunction with general anesthesia for perioperative pain management in procedures involving abdominal surgery below the umbilicus, perennial, genitourinary, and lower limbs.[56] Caudal epidural not only reduces the dose of general anesthetics but also attenuates the stress responses to surgery.[789] However, it is often associated with side effects such as vomiting, urinary retention, delayed ambulation, and rarely neurological deficits.[1011] There are also few reports of systemic toxicity such as convulsions, hypotension, and arrhythmias.[1213] Performing caudal epidural block in an anesthetized child demands proper positioning, identifying proper space and the cumbersome manoeuvre of positioning and repositioning without compromising the airway. In our study, we compared the analgesic effectiveness of local wound infiltration of 0.25% bupivacaine and rectal diclofenac suppository against 0.25% bupivacaine administered caudally.

SUBJECTS AND METHODS

After obtaining the approval of the Research Ethical Committee; and after informed patient consent, 60 American Society of Anesthesiologists (ASA) Grade I and II children, undergoing elective inguinal herniotomy was included in this observational study.

Inclusion criteria

Elective inguinal herniotomy

Age group 4–8 years

ASA I and II patients

Weight - 10–20 kg.

Exclusion criteria

Patient or parent refusal

History of allergy to any drugs used in study

History of bleeding diathesis

Infection at the site of caudal injection.

Patients had a thorough preanesthetic check-up. Solid foods restricted for 8 h, but clear fluids allowed up to 2 h prior to surgery. Venous access achieved after local anesthesia and was premedicated with injection midazolam 0.02mg/kg and injection atropine 0.02 mg/kg. Children were brought to the operation room and preinduction monitors such as a precordial stethoscope, pulse oximeter, electrocardiogram, and noninvasive blood pressure (NIBP) were attached. Children were induced with injection ketamine 2 mg/kg intravenous and maintained with 40% oxygen, 60% nitrous oxide, and sevoflurane at a concentration ranging from 0.5% to 2.0% using Jackson-Rees circuit on spontaneous respiration.

Patients who received caudal block with 1 ml/kg of bupivacaine 0.25% (limiting the dose to 2.5 mg/kg) were allocated to Group A, while patients who received a combination of rectal diclofenac suppository 2 mg/kg (corrected to 25 mg or 37.5 mg) and preincisional infiltration with 0.25% bupivacaine 0.5 ml/kg were allocated to Group B. Vital signs such as pulse rate, NIBP, respiratory rate, and oxygen saturation were monitored throughout. At the end of surgery, anesthetic agents were discontinued, and 100% oxygen through face mask was administered for 3–5 min. The total duration of surgery was also recorded for comparison. Once the vital signs were stable, the child was shifted to the recovery room and placed in the recovery position. When fully awake and hemodynamically stable, children were transferred to the postoperative ward.

Postoperative pain was assessed using, modification of objective pain scale by Hannallah et al.[14] [Table 1]. Pain was assessed 0, 15, 30, 45, 60 min, and half hourly thereafter until 8 h following surgery or until patient requires rescue analgesic. Whichever happened earlier was considered as the end point of observation. At the score ≥3 rescue analgesic oral paracetamol 15 mg/kg was given. Time of requirement of first rescue analgesic was also noted. The incidence of vomiting, urinary retention, or any relevant side effects were recorded.

Table 1

Modification of objective pain scale by Hannallah and collegues

RESULTS

Data such as age, weight, and duration of surgery in both groups were compared using the independent sample t-test. Data derived were reported as mean ± standard deviation. P< 0.05 was considered statistically significant. Here, P value was found to be >0.05 in all three parameters measured. Hence, the difference is not statistically significant [Table 2]. Gender of the patient was compared by the Pearson Chi-square test, and the P value was found to be 0.688 which is statistically insignificant [Table 3].

Table 2

Age, weight, duration of surgery, duration of analgesia, time for first micturition

Table 3

Incidence of vomiting and gender

Duration of analgesia in both groups were also analyzed by applying the independent samples t-test, and the P value was found to be <0.001 indicating high significance. Duration of analgesia is significantly longer in Group B compared to Group A [Table 2].

In Group A, patients started presenting with a pain score of more than 3 by 180 min, while in Group B patients started presenting with pain score of more than 3 by 300 min only [Figure 1]. By 300 min, all the 30 patients in Group A presented with pain score of more than 3. However, it took 390 min in Group B for all the 30 patients to be presented with pain score of more than 3. All patients received a rescue analgesic on attaining pain score of 3.

Figure 1

Patients with pain score more than three

It was also observed that time for first voiding of urine after surgery is significantly prolonged in Group A compared with Group B [Table 2]. Vomiting was reported in 6 patients in Group A and none in Group B. It is found to be statistically significant with P = 0.01 [Table 3].

DISCUSSION

Caudal anesthesia, one of the most common performed analgesic techniques in pediatrics is not without risk. There are arguments re-evaluating its role and indications. Herniotomy requires a block up to T12 or higher, requiring a larger dose of local anesthetic (1 ml/kg) for a reliable block. The required dermatomes are blocked last and recover first as the block regresses, providing a relatively short period of analgesia at the surgical site. Most herniotomies are done as day care procedures, so leg weakness can be a problem in older children unless a lower concentration of the solution is used. Another less invasive analgesic technique in pediatric herniotomy is local infiltration of the surgical site with 0.25% bupivacaine along with simultaneous insertion of diclofinac rectal suppository. This technique need only lower dose of bupivaine compared to caudal anesthesia. Furthermore, easier to perform, faster acting, and consumes less time. Hence, this technique makes more sense. We compared the duration of analgesia between the two techniques, i.e., the combination of local wound infiltration with 0.25% bupivacaine and diclofenac suppository (Group A) to caudal block with 0.25% bupivacaine (Group B).

The mean duration of analgesia in Groups A and B were 228.5 and 331.0 min, respectively. Indicating the analgesic duration was significantly longer in Group B, who received local infiltration and diclofenac suppository.

Moores et al.[15] compared the effects of rectal diclofenac with 0.25% bupivacaine administered caudally for postoperative analgesia in pediatric inguinal herniotomy. Forty-three children were assigned randomly to receive either 1 ml/kg caudal bupivacaine 0.25% or rectal diclofenac 0.25 mg/kg intraoperatively to provide postoperative analgesia. They found that caudal bupivacaine although provided more pain-free patients at first; later the incidence of pain was similar in both groups and concluded that rectal diclofenac is a useful alternative to caudal blockade in this group of patients. In our study, none of the patients presented with pain in the early postoperative period, i.e. up to 180 min postoperatively. This may be because of the additional local infiltration of bupivacaine received by those in the diclofenac group.

Seyed et al.[16] compared the analgesic effects of an acetaminophen (NSAID) suppository, bupivacaine wound infiltration, and caudal block with bupivacaine on postoperative pain in pediatric inguinal herniorrhaphy and observed that in children, bupivacaine infiltration group and the group who received caudal bupivacaine produce better analgesia than the third group who received suppository acetaminophen. They concluded that bupivacaine infiltration is better than a caudal block because of its simplicity, lower incidence of complications, and reduced failure rates.

William and Splinter, Juan Bass, Lydia Komocar, et al.[17] compared the analgesic efficacy, adverse effects and the cost associated with supplementation of local infiltration with either intravenous ketorolac or caudal analgesia in children having an inguinal hernia repair. They concluded that, supplementation of intraoperatively administered local anesthesia with ketorolac results in a small improvement in pain, a lower incidence in vomiting and a more notable decrease in the time to micturition than a caudal block. These findings are consistent with our present study. However, the nonsteroidal anti-inflammatory drug used here was intravenous ketorolac instead of diclofenac suppository.

Machotta et al.[18] compared between instillation of bupivacaine versus caudal analgesia for postoperative analgesia following inguinal herniotomy in children. They concluded that instillation of Bupivacaine into a wound provides postoperative pain relief following hernia repair, which is as effective as that provided by a postoperative caudal block. In our study, there was better analgesia in local infiltration group compared to caudal. This may be because we added diclofenac suppository to local infiltration group.

Bhattarai et al.[19] in their study compared the combination of ilioinguinal and iliohypogastric nerve blocks and wound infiltration against caudal block with 0.25% bupivacaine in children undergoing pediatric herniotomy. They observed that simplified ilioinguinal and iliohypogastric nerve blocks described by Dalens in combination with small volume local anesthetic wound infiltration with its longer analgesia and better safety margin. These findings are consistent with the results of our study. The mean duration of analgesia in a caudal group of their study was 219.6 min and in local infiltration with block group it is 253 min. In our study, it was 228.5 and 331.0 min respectively. This extended analgesia observed in our local infiltration group may be attributed to the rectal diclofenac suppository.

Borkar and Dave[20] compared the analgesic efficacy of caudal block against diclofenac suppository with local anesthetic infiltration in children undergoing laparoscopy. They found that the analgesic efficacy of diclofenac suppository combined with local anesthetic infiltration at port sites were comparable to caudal block. Given the necessarily invasive nature of caudal block, they suggested the combined use of diclofenac suppository with local anesthetic infiltration at port sites as a useful and more economical alternative for analgesia following pediatric laparoscopy. Although these observations were for laproscopy, their conclusions are consistent with that of ours.

Gupta et al.[21] studied postoperative analgesia in children undergoing infraumbilical surgeries. They concluded that rectal diclofenac in combination with caudal block provides good postoperative analgesia in early as well as later in the postoperative period, in comparison to caudal block alone which provides analgesia only in early postoperative period or rectal diclofenac alone which does not provide good analgesia in the early or immediate postoperative period.

Chipde et al.[22] compared caudal bupivacaine and ropivacaine in pediatric patients who underwent urogenital surgeries under general anesthesia. Mean duration of analgesia in patients who received Bupivacaine were 276.8 min which is more compared to our study. It can be attributed to additional opioids received in this study.

Nayna et al.[23] studied bupivacaine infiltration versus diclofenac suppository for posttonsillectomy pain relief in pediatric patients. The study compared the effect of preincisional infiltration of bupivacaine 0.25% versus diclofenac suppository on postoperative pain relief in children. They found that diclofenac suppository is a better option as compared to preincisional bupivacaine infiltration because of its convenience and efficacy equivalent to that of bupivacaine infiltration and duration of analgesia more than bupivacaine infiltration.

Ejnell et al.[24] demonstrated in their study that diclofenac sodium is the only nonsteroidal anti-inflammatory drug for postoperative pain relief, which is safe to administer in its therapeutic range with least or no side effects. Our study also suggested that significant analgesic activity of diclofenac, and it was also free from major side effects.

In our study, time for first voiding of urine postoperatively was significantly prolonged in caudal group. The incidence of vomiting was also significantly more in the caudal group compared to those obtained bupivacaine local infiltration with diclofenac suppository.

Although the pain assessment tool used in our study has been employed by previous investigators,[5] it may be noted that the child's cry, movement, and agitation could not be entirely attributed to pain. The dose of rectal diclofenac used has been corrected according to availability. Technical, as well as anatomical factors, can also affect the results observed.

CONCLUSION

Duration of analgesia obtained from the combination of bupivacaine local infiltration with diclofenac suppository is significantly longer than the duration of analgesia obtained from the caudal epidural block with bupivacaine. Hence, a less invasive, less time consuming and comparatively easier method of analgesia provided by diclofenac suppository and local infiltration of bupivacaine can be a better alternative to caudal bupivacaine for pediatric herniotomy.

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Nil.

Conflicts of interest

There are no conflicts of interest