|Year : 2017 | Volume
| Issue : 4 | Page : 230-235
Effects of low-dose intravenous dexamethasone combined with caudal analgesia on post-herniotomy pain
Omotayo Felicia Salami1, Simbo Daisy Amanor-Boadu2, Olayinka Ranti Eyelade2, Simeon Olugbade Olateju3
1 Department of Anaesthesia and Intensive Care, Ben Carson School of Medicine, Babcock University, Ogun State, Nigeria
2 Department of Anaesthesia and Intensive Care, College of Medicine, University of Ibadan, Ibadan, Oyo State, Nigeria
3 Department of Anaesthesia and Intensive Care, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
|Date of Web Publication||18-Jan-2018|
Dr. Omotayo Felicia Salami
Department of Anaesthesia and Intensive Care, Babcock University, Ogun State
Source of Support: None, Conflict of Interest: None
Background: Caudal analgesia for postoperative pain relief in paediatric day-case surgery has been found to be of short duration, hence the need for addition of adjuncts to prolong the analgesia. Objective: The objective of the study was to compare the analgesic effects of caudal block with or without low-dose intravenous dexamethasone in children undergoing day-case herniotomy. Patients and Methods: This was a prospective randomised controlled study conducted in male patients, aged between 1 and 7 years scheduled for herniotomy. A total of 94 patients were randomised into two groups. Group A received intravenous 0.25 mg/kg dexamethasone in 5 ml solution, whereas Group B received equivalent volume of intravenous normal saline. All the patients had a caudal block. Post-operative pain was assessed and recorded in post-anaesthesia care unit (PACU) using objective pain scale. Time to first analgesia request (TFA), pain scores and complications were documented. Data were analysed using Statistical Package for the Social Sciences version 21.0. Results: A total of 94 patients were analysed with a mean age of 3.30 ± 1.67 and 3.06 ± 1.50 years for Groups A and B, respectively. The TFA request was 654.18 ± 31.56 and 261.50 ± 10.82 min in Groups A and B, respectively, P = 0.0001. Postoperatively, in the PACU, there was statistically significant difference in pain score between the two groups at 0, 30, 60, 120, 180 and 240 min (P = 0.0001) all through. Conclusion: The use of low-dose intravenous dexamethasone (0.25 mg/kg) in combination with caudal block prolonged duration of analgesia, reduced pain scores and analgesic consumption postoperatively, in children undergoing day-case herniotomy.
Keywords: Bupivacaine, caudal, dexamethasone, herniotomy
|How to cite this article:|
Salami OF, Amanor-Boadu SD, Eyelade OR, Olateju SO. Effects of low-dose intravenous dexamethasone combined with caudal analgesia on post-herniotomy pain. Niger Postgrad Med J 2017;24:230-5
|How to cite this URL:|
Salami OF, Amanor-Boadu SD, Eyelade OR, Olateju SO. Effects of low-dose intravenous dexamethasone combined with caudal analgesia on post-herniotomy pain. Niger Postgrad Med J [serial online] 2017 [cited 2019 Dec 12];24:230-5. Available from: http://www.npmj.org/text.asp?2017/24/4/230/223457
| Introduction|| |
Pain in the paediatric patient has become a major concern worldwide, such that there has been introduction of new analgesic agents and newer ways of application of old ones. In 2001, the Society of Paediatric Anaesthesia, at its 15th annual meeting in New Orleans, Louisiana, clearly defined the alleviation of pain as a 'basic human right', irrespective of age, medical condition, treatment, or medical institution.
Despite this, pain remains the most frequent complication after day-case surgery. In a study by Faponle and Usang in Nigeria, it was observed that, in paediatric day-case surgery, post-operative pain constituted 72% of symptoms recorded by parents at home.,,
Day-case or ambulatory surgery is one in which the patient is admitted, operated and discharged that same day. Some procedures performed on day-case basis include orchidopexy, circumcision, inguinal hernia procedures, tonsillectomy and myringotomy. Minor surgery, like circumcision, has been observed to cause significant pain in children. Therefore, pain relief in children is of paramount importance. Specifically, the goal of post-operative pain relief in day-case procedures is to reduce or eliminate pain with minimum side effects.
In current practice, a multimodal approach is employed in pain management. Psychological methods, mild analgesics such as paracetamol, non-steroidal anti-inflammatory drugs, opioids and local and regional analgesia, are often combined to achieve superior pain relief and to minimise the side effects of individual drugs. In a day-case setting, opioids are often avoided because of potential side effects such as sedation, respiratory depression, nausea and vomiting which may delay discharge.
Caudal epidural block is a common regional technique used to provide intra- and post-operative analgesia for surgical procedures below the umbilicus in paediatric patients. It is usually a single shot technique. However, the relatively short duration of single-shot caudal injection with local anaesthetic is amongst the limitations of the procedure.,
Several adjuncts which have been added to the local anaesthetics to prolong analgesia of 'single-shot' caudal include clonidine, midazolam, ketamine, neostigmine and tramadol, but their use has been limited by unacceptable adverse effects or safety not being fully established, especially in preservative-containing agents.,
Dexamethasone is a corticosteroid with strong anti-inflammatory properties. Traditionally, in anaesthetic practice, the use of dexamethasone is to reduce the incidence of post-operative nausea and vomiting (PONV). It is usually given for prophylaxis. Some side effects such as insomnia, increased appetite, weight gain, impaired skin healing, dyspepsia and hyperglycaemia, have been linked with chronic use.
Dexamethasone, when administered intravenously, has been documented to provide prolonged post-operative analgesia. Intravenous dexamethasone, when combined with caudal block, has been documented to increase postoperative analgesia. Hong et al. showed that it prolongs the duration of post-operative analgesia when 0.5 mg/kg was used intravenously in addition to caudal block, the same was reported in the study by Bangash et al., Srinivasan et al. in a recent study utilising intravenous 1.5 mg/kg dexamethasone in addition to caudal block also showed prolonged post-operative analgesia. However, there is a dearth of data regarding the use of low-dose (0.25 mg/kg) dexamethasone in combination with a caudal block in our population.
The aim of the study was to compare the analgesic effects of caudal block with or without low-dose intravenous dexamethasone in children undergoing day-case unilateral inguinal herniotomy.
The objectives of the study were to determine the time to first analgesic request when caudal block is given alone and in combination with intravenous dexamethasone. Second, to compare blood sugar levels in patients given single-dose intravenous dexamethasone in addition to caudal bupivacaine and in those who had only caudal bupivacaine.
| Patients and Methods|| |
Ethical approval/informed consent
Institutional Ethics Committee approval was obtained from the UI/UCH Ethics Board with informed consent from the parents/guardians of the children recruited in the study (UI/UCH Ethics committee assigned number UI/SC/112/0129).
Children planned for bilateral herniotomy, patients who had failed caudal block and received intraoperative pentazocine, those with infection at the site of caudal injection or sepsis, pre-existing neurological deficits or spinal deformity, coagulopathy and patients with allergy or hypersensitivity to local anaesthetic drug were excluded from the study.
This was a prospective randomised double-blind controlled study conducted in children aged between 1 and 7 years undergoing unilateral inguinal herniotomy as a day-case procedure at the University College Hospital Ibadan, from September to December 2013.
Ninety-four male patients, aged 1–7 years, American Society of Anaesthesiologists I and II, were recruited into the study after obtaining informed consent from the parents or guardians. Sample size formula for randomised clinical trials was used.
Where n = sample size per group, Zα= 1.96 at 10%, Zβ= 1.28 at 90%, α = type I error, β = type II error, б = pooled standard deviation of time of first dose of oral analgesic calculated from a similar study is 177.36 min (time of first dose of oral analgesic given); δ = 125 min smallest clinical important difference to be detected with at least 90% difference in the duration of analgesia assumed. Substituting,
Therefore; n = 42 in each group;
Minimum sample size = 42 + 42 = 84
Sample size will be increased by 10% to provide for non-response (r = 0.1) = n/1 − r
42/1–0.1 = 46.66; Approximate sample size per group 47; Total sample size = 94.
At the pre-anaesthetic visit, a detailed history of presenting complaint, developmental milestones, medical disease, chronic drug use and allergy or complication following previous surgery or blood transfusion was obtained. Physical examination of the cardiorespiratory, gastrointestinal and the genitourinary systems were performed and documented. Routine investigations (full blood count, genotype and urinalysis) were done on all the eligible patients before surgery. The parents/guardians were informed about routine pre-operative fasting of 6 h to solids and baby formula, 4 h to breast milk and 2 h to clear fluids before surgery. Pain was to be assessed at home in the 1st h, then 4 hourly, in the pre-verbal children until they were perceived to be in pain and until complaint of pain in the verbal children. Premedication was omitted in all the patients. The patients were randomised into two Groups A and B. Group A received intravenous 0.25 mg/kg dexamethasone in 5 ml plain solution, whereas Group B received equivalent volume of intravenous normal saline. All the patients had caudal block with 1 ml/kg of 0.25% bupivacaine. Before induction of anaesthesia, 94 sealed envelopes containing slips of paper were prepared, with Group A written on half of the slips of paper and Group B on the other half. This was presented in a box to the parent/guardian who randomly picked one slip each. The study drugs were prepared under aseptic conditions by an anaesthetist and administered by the researcher who was blinded to the identity of the intravenous study drugs. Resuscitation drugs, which included adrenaline and atropine, were made readily available.
In the theatre, a multiparameter monitor (Marathon Z, manufactured by Health Care Equipment and Suppliers Co. Ltd., UK) to measure heart rate, blood pressure, respiratory rate, electrocardiograph and pulse oximetry for arterial oxygen saturation was attached to the patient, and baseline readings were obtained and recorded. Patients were pre-oxygenated with 100% oxygen for 3–5 min and anaesthesia was induced using a stepwise increment of halothane from 0.5% to 3% in 100% oxygen, using a Mapleson F breathing system for patients <25 kg or Bain Circuit for patients weighing >25 kg with appropriate size face mask until the patient lost consciousness. Pre-operative capillary blood sugar sample was taken, as a baseline using the glucometer. Intravenous access was then secured with a 21- or 23-gauge cannula on the dorsum of the hand, when the depth of anaesthesia was adequate. Normal saline was then infused at a rate of 4 ml/kg/h for the first 10 kg, then 2 ml/kg/h for the next 10 kg and 1 ml/kg/h for subsequent kg (4:2:1 ml/kg/h). After induction of general anaesthesia, patients in Group A received intravenous 0.25 mg/kg dexamethasone (Hubei Tianyao Pharmaceutical Limited) in 5 ml plain solution, whereas those in Group B received intravenous normal saline made up to the same 5 ml volume.
Caudal epidural block was administered following standard procedure guideline. The sacral hiatus was identified as the apex of an equilateral triangle facing inferiorly with a line joining the posterior superior iliac spine as the base, with the patient in the left lateral position and the legs flexed. Under sterile condition, the palpating finger was directed caudally from the midpoint of the line joining the posterior superior iliac spines or cranially from the coccyx until a depression was felt. A 23-gauge cannula was inserted into the sacral hiatus at 45° to the skin until a click was felt then it was angulated cephalad. A 2 ml syringe filled with normal saline as test dose was then used to exclude subcutaneous placement before the local anaesthetic agent (bupivacaine 0.25% 1 ml/kg) was injected slowly after negative aspiration test. Patients were then positioned supine, and surgery allowed to commence 15–20 min later with patients breathing spontaneously through a facemask. Monitoring of vital signs continued at 5 min interval until the end of surgery.
Anaesthesia was maintained with halothane 0.5%–1% in oxygen, and adequate anaesthesia was judged by a lack of movement and stable vital signs following skin incision. Failed caudal block was judged by movement of the limbs to surgical incision, and >20% increase in haemodynamic parameters compared to baseline values. Patients with failed caudal block had their anaesthesia deepened with increased halothane and intravenous pentazocine 0.5 mg/kg was given were excluded from the study. At the end of surgery, halothane was discontinued and oxygen administered until recovery. After emergence from anaesthesia, patients were managed by a nurse unaware of group allocation in the post-anaesthesia care unit (PACU).
Postoperative pain was assessed and recorded on arrival at PACU, 0 (baseline), 30, 60, 120, 180 and 240 min after surgery using the Objective Pain Score (OPS).,
The Objective Pain Scale (OPS; minimum score: 0 = no pain and maximum score: 10 = extreme pain) is composed of five parameters; systolic blood pressure, crying, movements, agitation and complaints of pain. Each parameter has a score of 0–2. The reliability of the OPS has been demonstrated by Norden et al. to effectively assess pain in both the pre-verbal and verbal children with a minimum score of 0 and a maximum score of 10 or 8 (in children too young to complain of pain). The observer scored pain based on points (none/insignificant pain [1–3], moderate pain [4–6] and severe pain [7–10]). Pain score of ≥4 or complaints of pain had rescue analgesic of intravenous 0.5 mg/kg pentazocine. Oxygen saturation, blood pressure and pulse rate were documented in the recovery room at 15 min interval. The time to first analgesic requirement was the duration from the time of administration of study drugs to the time of first request for analgesic (TFA). The time to first micturition was also documented.
Patients were discharged to the ward from the PACU after 1 h and according to hospital protocol and when they satisfied the Aldrete score value of ≥9. The Aldrete recovery score is commonly used to evaluate discharge from the recovery room. It consists of five parameters; activity level, respiration, circulation (blood pressure), consciousness and oxygen saturation as determined by pulse oximetry. Each score has a maximum of 2 and a minimum of 0 with the maximum score being 10.
Blood sugar sample was taken again before discharge from the recovery room. Patients were discharged home from the ward on oral paracetamol at 20 mg/kg. After discharge, information regarding the pain and any other complications at home were obtained from parents through a phone call 24 h post-surgery. Both the investigator and patients were blinded to the study drugs.
Demographic characteristics, blood sugar values, pain scores, time to first analgesia request (TFA), time to first micturition and postoperative complications were documented. Numerical data were expressed as a mean ± standard deviation and categorical data as frequencies for both study groups. Comparisons of means were done using the Student's t-test and comparison of categorical data using the Chi-square test. P ≤ 0.05 was considered statistically significant. Statistical analysis was done using Statistical Package for the Social Sciences (SPSS 21.0 Inc., Chicago, Illinois, USA).
| Results|| |
Ninety-four patients were analysed with 47 patients in each group. The demographic characteristics (age and weight) of the two groups were comparable, as shown in [Table 1].
[Table 2] summarises that the time to first analgesic requirement (TFA) of 654.18 ± 31.56 min was longer in Group A, compared to 261.50 ± 10.82 min in Group B. The time to micturition was shorter in Group A compared to B; 241.91 ± 86.24 and 326.00 ± 68.65 min, respectively. The mean oral paracetamol dose given by parents at home was less in Group A, 38.30 ± 17.95 mg compared with 55.30 ± 2015 mg in Group B (P = 0.0001). No patient reported PONV.
|Table 2: Comparison of time to first analgesia, total oral paracetamol and time to first micturition|
Click here to view
Pre-induction blood glucose was 95.30 ± 7.91 mg/dl in Group A, compared to 91.21 ± 12.99 mg/dl in Group B, P = 0.069. Postoperatively, blood glucose in Group A increased to 101.91 ± 9.48 mg/dl and to 100.2 ± 14.94 mg/dl in Group B, but the difference between the groups was also not statistically significant (P = 0.495) as shown in [Table 3].
Postoperative pain measurement in PACU showed a significant difference in the mean baseline pain score between Group A and B. At 60 min, pain score in Group A had reduced from 1.5 ± 0.17 at 30 min to 1.00 ± 0.19, compared to an increase in pain score from 2.2 ± 0.21 to 2.50 ± 0.19 at 60 min in Group B (P = 0.0001). There was also a statistically significant difference in pain score between the two groups at 120, 180 and 240 min, P = 0.0001, as shown in [Table 4].
| Discussion|| |
This study revealed that a single dose of intravenous dexamethasone in combination with caudal epidural bupivacaine (0.25%) prolonged the TFA and decreased post-operative analgesic consumption compared with caudal bupivacaine alone.
The mean TFA was significantly longer in the dexamethasone group (654.18 ± 31.56 min), compared to the control group (261.50 ± 10.82 min), P = 0.0001.
This finding is similar to that obtained by Hong et al. (646 ± 149 min) in a comparative study of intravenous dexamethasone 0.5 mg/kg combined with caudal ropivacaine versus ropivacaine alone for post-operative pain control following orchidopexy. Srinivasan et al. in a recent prospective study also reported the prolonged duration of analgesia in their intravenous dexamethasone group of 720.0 min.
The time to first analgesic request in the control group of this study (261.50 ± 10.82 min) is similar to that obtained by Srinivasan et al., who recorded 220 min, while Hong et al. in their control group reported 430 ± 205 min. This is almost double the value in our control group; this difference may be due to a higher volume of a different local anaesthetic (1.5 ml/kg ropivacaine of 0.15%) utilised in the Hong's study. Edomwonyi and Egwakhide also observed similar time to first analgesic request of 420 min using a lower volume (0.5 ml/kg) of 0.25% bupivacaine in their caudal group compared to a volume of 1 ml/kg (0.25%) utilised in this study. This may result from variations in population characteristics, the potency and brand of local anaesthetic agent used.
The time to first analgesic (TFA) requirement in our caudal only group is, however, longer compared to that of Akinyemi and Soyannwo, who utilised 0.5 ml/kg of 0.25% bupivacaine (TFA,170 min) for the caudal block compared to 1 ml/kg of 0.25% bupivacaine used in this study. The shorter duration in TFA in their study may be as a result of the low volume of local anaesthetic (0.5 ml/kg) used, compared to the 1 ml/kg used in this study.
Although the exact mechanism of action is not known, dexamethasone in prolongation of analgesia is said to act through strongly mediated anti-inflammatory process.
The dose of dexamethasone (0.25 mg/kg), employed in this study, was low compared to that used in some studies, but similarly prolonged duration of analgesia was obtained. Hong et al. and Srinivasan et al. utilised intravenous dexamethasone dose of 0.5 mg/kg in their studies and obtained a TFA request of about 646 and 620 min, respectively., This may result from a higher volume of ropivacaine (1.5 ml/kg) was used in both studies compared to bupivacaine 1 ml/kg in our study. Bangash, however, utilised a higher dose of dexamethasone, 1.5 mg/kg, but obtained a similar TFA request of 621.60 min compared to the 654 min in our study  The similarity in time to first analgesic request in ours and Bangash's et al. study, despite different dexamethasone dose may result from a higher volume of bupivacaine utilised in our study (1 ml/kg of 0.25%) compared to 0.5 ml/kg used in their study.
Although the caudal epidural administration of dexamethasone in children is uncommon, Yousef et al. in a study of 105 children scheduled for inguinal hernia repair under caudal block with 0.1 mg/kg dexamethasone and 1.5 ml/kg ropivacaine (1.5%), reported more prolonged duration of analgesia of 12 h in their dexamethasone group. However, the slightly prolonged time obtained in their dexamethasone group may be as a result of the epidural administration of dexamethasone.
As advised by Desmet et al., the intravenous routes for dexamethasone may be safer as the drug has not been licensed for the perineural or neuraxial routes. This advice has been reiterated in an editorial review of the route of dexamethasone administration during peripheral nerve block.,
The OPS, a validated pain scoring tool in children, was used in the PACU to assess pain in the patients. On arrival at the PACU, immediate pain scores (baseline) for Groups A and B were low (2.00 ± 0.22 and 3.00 ± 0.17, respectively) but statistically significant (P = 0.0001). In a study of 100 children undergoing orchidopexy under caudal block (0.5 ml/kg of 0.25% bupivacaine alone or in addition to intravenous dexamethasone [1.5 ml/kg]), Bangash et al. reported similarly low and significant pain score differences between the caudal and the caudal plus intravenous dexamethasone (0.5 mg/kg) group of his study.
Intravenous 0.5 mg/kg dexamethasone is considered to be a high dose in children, and blood sugar changes may result; therefore, half this dose was investigated for any blood sugar increase in our study.
Post-operative increase in blood glucose was observed within the group, in both groups, compared to the preoperative levels, but there was no statistically significant difference between the groups. This may be due to perioperative stress, as documented in adults day-case surgical patients. In a study on the effect of single-dose intravenous administration of dexamethasone (0.15 mg/kg) in obese and normal children, elevated blood sugar documented within the group was within normal limits. Further studies to investigate the ideal or appropriate dosage are required so that blood sugar remains within normal limits.
Pain was to be assessed at home in the 1st h, then 4 hourly, in the pre-verbal children until they were perceived (behavioural pattern) to be in pain and until complaint of pain in the verbal children. From our study, patients in Group A consumed less paracetamol (38.30 ± 17.95 mg) compared to children in Group B (55.30 ± 20.15 mg). This supports most studies that low post-operative pain scores result in less analgesic consumption.,
Caudal bupivacaine has been associated with a delay in time to first micturition and this has been an issue of concern regarding its use in day-case surgery. The incidence is low with low concentration of bupivacaine as used in this study. Furthermore, time to first micturition was prolonged in both groups but was significantly longer in the control compared to the dexamethasone group (326 ± 168.65 vs. 241.91 ± 86.24 min). Postoperative pain in addition to blockade of sacral nerve fibres may be attributed to the slightly prolonged duration in the control group. Edomwonyi and Egwakhide also reported delay in time to first micturition (4.02 ± 1.69 h) in the caudal group in a study comparing caudal versus local anaesthesia in children undergoing unilateral inguinal herniotomy.
The time to first micturition in the bupivacaine alone group in this study was 5 h, compared with similar findings of 4 h plus by Edomwonyi and Egwakhide in their study. This may be as a result of population variation and local anaesthetic potency. However, there are other causes of delay in urination after surgery which includes drugs such as anticholinergic agents, opioids, β-blockers and sympathomimetics in children, but these should not cause delay on discharge.
| Conclusion/recommendation|| |
This study has shown that the use of low-dose intravenous dexamethasone 0.25 mg/kg, in combination with caudal bupivacaine prolonged the duration of analgesia and reduced postoperative pain scores and analgesic consumptions in children undergoing day-case unilateral inguinal herniotomy.
It is recommended that low-dose intravenous dexamethasone could be considered as an adjunct to caudal bupivacaine in day-case herniotomy.
The administration of oral paracetamol at home after discharge was based on parents' sole assessment of pain and discretion to administer analgesics.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]