|Year : 2015 | Volume
| Issue : 1 | Page : 134-139
The effect of adding ketamine to bupivacaine in greater palatine nerve block in platoplasty
Dalia M El Fawy MD , Niven Gerges, Yasser A Salem
Department of Anesthesiology, Intensive Care and Pain Management, Faculty of Medicine, Ain Shams University, Cairo, Egypt
|Date of Submission||13-Sep-2014|
|Date of Acceptance||17-Dec-2014|
|Date of Web Publication||25-Mar-2015|
Dalia M El Fawy
Department of Anesthesiology, Intensive Care and Pain Management, Faculty of Medicine, Ain Shams University, Cairo
Source of Support: None, Conflict of Interest: None
Greater palatine nerve block anesthetizes the posterior part of the hard palate and its overlying soft tissue. It is performed for pain relief in children undergoing cleft palate surgery. This study was conducted to compare the efficacy and the duration of this block using the local anesthetic bupivacaine 0.25% alone with that of ketamine 0.5 mg/kg plus bupivacaine 0.25%.
Patients and methods
After institutional ethical committee approval and parental consent were obtained, 40 ASA I, II children aged 1-6 years undergoing palatoplasty were enrolled in this prospective randomized double-blind study. A standardized technique of general anesthesia was used, and then patients were classified into two groups: in group B (n = 20), the greater palatine nerve block was performed using 0.5 ml bupivacaine 0.25% alone; and in group K (n = 20), the block was performed using ketamine 0.5 mg/kg added to bupivacaine 0.25%. The heart rate, the systolic blood pressure, the pain score, the time to rescue analgesics, and the total amount of analgesics used in 24 h were assessed.
Group KB had a significantly longer time to first rescue analgesia (8.62 ± 0.5 vs. 4.25 ± 1.1 h) and significantly lower doses of rectal diclofenac (0, 0, 0 vs. 0, 0, 12.5 mg) than group B. The Children's Hospital Eastern Ontario Pain Scale pain scale was significantly lower in group BK than in group B (P < 0.05) at 4, 8, 12, 18, and 24 h postoperatively. There was a significant difference between the groups in dysphagia to solid and sleep disturbance at 6 and 12 h.
Addition of ketamine to bupivacaine in greater palatine nerve block increased the quality and the duration of analgesia, and also decreased the total dose of postoperative analgesic requirement in children undergoing cleft palate repair surgery.
Keywords: block, greater palatine, ketamine, platoplasty
|How to cite this article:|
El Fawy DM, Gerges N, Salem YA. The effect of adding ketamine to bupivacaine in greater palatine nerve block in platoplasty. Ain-Shams J Anaesthesiol 2015;8:134-9
|How to cite this URL:|
El Fawy DM, Gerges N, Salem YA. The effect of adding ketamine to bupivacaine in greater palatine nerve block in platoplasty. Ain-Shams J Anaesthesiol [serial online] 2015 [cited 2021 Apr 21];8:134-9. Available from: http://www.asja.eg.net/text.asp?2015/8/1/134/153955
| Introduction|| |
Cleft palate is one of the most common craniofacial abnormalities in pediatric pathology  .
Its repair is associated with severe postoperative pain, and so, it needs good analgesia to prevent complications such as wound dehiscence and pulmonary complications such as chest infection  .
Different modalities for pain management can be used such as opioids, paracetamol, NSAIDs, and regional blocks  . Paracetamol and NSAIDs may produce inadequate analgesia and opioids have side effects such as respiratory depression, especially that these patients have narrowed airway , .
Regional anesthesia provides analgesia without the risk of respiratory depression  ; however, it may be of limited duration and this can be overcome by the addition of various adjuvants to local anesthetics with the aim of potentiation and prolongation of the analgesic effect  .
Ketamine is an N-methyl-d-aspartate receptor antagonist, preventing central sensitization, and thus reducing postoperative pain; it also has a peripheral analgesic effect , .
This is the first prospective randomized study to compare the analgesic efficacy of bupivacaine with that of a bupivacaine ketamine mixture. We hypothesized that the addition of 0.5 mg/kg ketamine to 0.25% bupivacaine would prolong the duration of analgesia of greater palatine nerve block compared with bupivacaine 0.25% alone in children undergoing palatoplasty.
| Patients and methods|| |
After institutional ethics committee approval and parental consent were obtained, 40 children ASA I or II physical status, aged 1-6 years, who were scheduled for repair of their complete cleft palate in the Ain Shams Specialized Hospital during the period from November 2013 to June 2014, were enrolled in this prospective, randomized, double-blind study.
Exclusion criteria included a history of allergic reactions to local anesthetics, coagulopathy, children with comorbid conditions such as congenital heart disease, respiratory pathology, central nervous system disorders, other associated craniofacial anomalies such as micrognathia and Pierre Robin syndrome, and also children posted for combined palatoplasty with cheiloplasty. All operations were performed by the same experienced surgeon.
A preoperative visit was arranged to allay the anxiety of parents and give preoperative instructions. Children were fasted for 8 h for solids and 2 h for clear fluids; they were premedicated with 0.5 mg/kg of midazolam and atropine 0.3 mg/kg orally 1 h before the surgery.
General anesthesia was induced by the inhalation of 1-8% sevoflurane in 100% oxygen through a face mask with spontaneous ventilation. A peripheral intravenous cannula was inserted, and oral endotracheal intubation of the appropriate size was performed with 0.5 mg/kg atracurium; it was secured centrally over the lower lip. The patient was placed in the supine position with extended head.
Anesthesia was maintained with oxygen (FiO 2 0.4), isoflurane (MAC 1), and intermittent doses of atracurium. Lactated Ringer's solution was infused at a rate of 10-15 ml/kg. Dexamethasone 1 mg/kg intravenously was given to all patients before the start of the surgery. No additional analgesics were given.
At the end of the surgery, muscle relaxation was reversed with 0.05 mg/kg of neostigmine and 0.02 mg/kg of atropine.
Children were monitored for their heart rate (HR), ECG, noninvasive blood pressure, pulse oximetry (SpO 2 ), end-tidal carbon dioxide (ETCO 2 ), and temperature.
Patients were allocated randomly using computer-generated randomization numbers with a closed-seal envelop into two equal groups: in group BK (n = 20), the greater palatine nerve block was performed bilaterally using total 0.5 ml (bupivacaine 0.25% plus ketamine 0.5 mg/kg); in group B (n = 20), the block was performed with 0.5 ml bupivacaine 0.25% only.
The greater palatine foramen can be located by pressing a small cotton swab opposite to the first molar receeding posteriorly till it falls into a depression opposite the posterior part of the second molar tooth, anterior to the junction of the hard and the soft palate. The syringe was positioned from the opposite side of the mouth and at right angle to the target area  . The opposite side was carried out in the same manner. Pressure was applied and the injection site was massaged to prevent the occurrence of hematoma. Surgical intervention was started 5 min after injection.
The success of the block was assessed by the absence of an increase in HR and/or systolic blood pressure of more than 20% compared with the baseline values. If the block failed, fentanyl (1 μg/kg intravenously) was given, and these patients were excluded from the study. After completion of the surgery, the child spent 6 h in the post operative care unit (PACU) before being transferred to the ward.
Hemodynamic variables (HR systolic blood pressure) were recorded:
Post operative pain was assessed using the Children's Hospital Eastern Ontario Pain Scale (CHEOPS) ([Table 1]); hemodynamics and the quality of analgesia were evaluated immediately on arrival in the PACU and every 4 h postoperatively for 24 h.
- Preoperative (after the induction of anesthesia and before performing the block).
- Postoperative in the PACU.
|Table 1 Modifi ed Children's Hospital Eastern Ontario pain scale pain scoring |
Click here to view
Dysphagia and sleep disturbance were assessed every 6 h postoperatively.
Rescue analgesia consisting of rectal diclofenac 12.5 mg was administered when CHEOPS was greater than 4. The time to the first analgesic requirement and the amount of analgesic consumption in the first 24 h were recorded.
Using PASS for sample size calculation, it was calculated that a sample size of 17 per group will achieve 80% power to detect a difference of 3 h in the time of the first analgesic requirement with an estimated group SD of 3.0 and a significance level (α) of 0.05 using a two-sided two-sample t-test; 20 patients per group were included to replace any dropouts.
Statistical analysis was performed using a standard SPSS software package version 17 (SPSS Inc., Chicago, Illinois, USA). Data were expressed as mean values ± SD, n (%), or median (interquartile range). Student's t-test was used to analyze parametric data, and discrete (categorical) variables were analyzed using the χ2 -test; nonparametric data were compared using the Mann-Whitney U-test, with P-values less than 0.05 considered statistically significant.
| Results|| |
The current study included 40 infants and children scheduled for surgical palatoplasty. The patients were divided into group BK (greater palatine nerve block with bupivacaine and ketamine, n = 20) and group B (greater palatine nerve block with bupivacaine only, n = 20). No significant differences existed between both groups with respect to patient characteristics and the time of anesthesia ([Table 2]). For intraoperative clinical data, we noticed a significant increase in the HR and decrease in the systolic blood pressure after induction (compared with preinduction) in both groups; there was also a significant difference between both groups at 2 and 4 h postoperatively in the HR and the systolic blood pressure, which denotes an increase in pain ([Table 3] and [Table 4]).
No rescue analgesic was used in both groups intraoperatively. Using the CHEOPS at different time intervals between both groups, the pain (CHEOPS) scale was significantly lower in group BK than in group B at 4 h (P < 0.001), 8 h (P < 0.028), 12 h (P = 0.02), 18 h (P = 0.01), and 24 h (P = 0.04). Although there was a statistically significant difference, clinically, the difference was nonsignificant at 12, 18, and 24 h postoperatively ([Table 5]) ([Figure 1]). Regarding sedation scores, there was no difference between both groups ([Table 6]).
|Figure 1: The middle line in each box represents the median, the outer margins of the box represents the interquartile range and whiskers are minimum and maximum.|
Click here to view
Time to the first analgesic requirement was significantly longer (P < 0.001) in group BK than in group B (8.62 ± 0.5 vs. 4.25 ± 1.1 h) ([Table 7]) with a significant decrease in the number of doses of postoperative rectal diclofenac rescue analgesia [0 (0-1) as against 2 (1-3) doses] (P = 0.039) ([Table 7]). Seven patients in group B expressed dysphagia to solids compared with only one patient in group BK (P = 0.02), which was statistically significant; there was also a significant difference in sleep disturbance between the two groups (two patients in BK vs. eight patients in B group at 6 h and one patient in BK group vs. seven in group B at 12 h) ([Table 8]).
| Discussion|| |
Pain after palatal surgery is severe and difficult to control. Adequate pain control has the advantage of reducing postoperative bleeding, also promoting early resumption of feeding  .
This is achieved either by opioids or by local anesthesia with nerve blocks. Opioids have several adverse effects such as respiratory depression, nausea, vomiting, and aspiration, especially because children with cleft palate tend to have a compromised airway due to association with other congenital anomalies; also, after surgical correction, they are more liable to develop postoperative respiratory difficulty due to a narrowed airway , .
A combination of regional and general anesthesia techniques has drastically cut down the risks of both procedures, especially in pediatrics , .
The study conducted by Hodges and Hodges proved that opioids are better avoided and intraoperative and postoperative analgesia can be achieved by either nerve blocks or local infiltration with local anesthetics. However, they did not mention about the possibility of greater palatine nerve block for analgesia in postpalatal repair  .
Our study was conducted to compare the effect of the addition of ketamine to bupivacaine with the usage of bupivacaine alone in greater palatine nerve block in children undergoing palatal repair.
Central sensitization induced by surgery has two phases: incisional and inflammatory. A-delta and C-fibers are activated by both incision and inflammatory mediators producing central sensitization.
The local anesthetic bupivacaine prevents central sensitization by blocking the activation and the propagation of action potential in pain fibers stimulated by incision and inflammatory mediators , .
Ketamine is a noncompetitive N-methyl-d-aspartate receptor antagonist that blocks the release of the excitatory neurotransmitter glutamate and provides anesthesia, amnesia, and analgesia when given intravenously; it is also an agonist to opiate receptors , .
It produces a state of dissociative anesthesia that leads to analgesia and amnesia, but without loss of consciousness. However, the exact mechanism of action of ketamine is not known up till now. It also has high lipid solubility that causes a rapid onset of action.
In previous studies, peripheral local ketamine was shown to have an antihyperalgesic effect  .
Tverskoy et al.  proved that the analgesic efficacy of bupivacaine with ketamine infiltration was through peripheral mechanisms.
Also, a previous study indicated that ketamine acts through a peripheral mechanism, which profoundly enhances the anesthetic and analgesic actions of local anesthetic infiltration after herniorrhaphy  .
The local effect of ketamine could be due to its interaction with sodium channels in a local anesthetic-like manner, sharing a binding site with the commonly used local anesthetic  .
The local anesthetic effect of ketamine lasts for 1 week after infiltration  . However, we did not assess pain beyond 24 h.
Honarmand et al.  compared the efficacy of preincisional peritonsillar infiltration of two doses of ketamine (0.5 and 1 mg/kg) with saline on postoperative pain relief. They observed lower pain scores in ketamine groups as compared with the control group till 24 h after surgery.
Also in agreement with our results, the study conducted by Dal et al.  observed significant reduction in the pain score in the ketamine infiltration group compared with normal saline for post-tonsillectomy pain.
In our study, the CHEOPS pain scale was significantly lower in group K than in group B (P > 0.05) at 4, 8, 12, 18, and 24 h postoperatively; also, group K had a significantly longer time to first rescue analgesia (8.62 ± 1.1 h) and significantly lower doses of diclofenac (0, 0, 0 vs. 0, 0, 12.5 mg) compared with group B.
In contrast, Pedersen et al.  could not demonstrate a clinically relevant effect of peripheral ketamine to be effective in postoperative pain.
Dysphagia interferes with feeding, which may be distressing for the child. Ketamine has been shown to decrease the incidence of dysphagia after tonsillectomy  . 0, no dysphagia; 1, dysphagia for solids; 2, dysphagia for liquids; 3, complete dysphagia. Our results showed a significant decrease in the dysphagia grade in those who received ketamine with bupivacaine as compared with bupivacaine alone at 6 and 12 h.
Peaceful sleep is an indirect indicator of pain relief: those who received ketamine had a better sleep pattern and woke up less (significantly at 6 and 12 h postoperatively), which indicates better pain relief.
The limitation of this study is that plasma levels of ketamine or nor ketamine were not measured, and so we cannot be certain whether the analgesic effect was due to peripheral mechanisms alone or systemic absorption had occurred. Second, we did not assess pain beyond 24 h. Therefore, the long-lasting effect of ketamine could not be ascertained. Third, the assessment of pain is a challenging task in children because of the interference of anxiety and/or hunger.
Another limitation of this study was that there was no control group with injection of saline.
| Conclusion|| |
The addition of ketamine to bupivacaine in greater palatine nerve blocks in children undergoing cleft palate repair is superior to bupivacaine alone in terms of the requirement of rescue analgesia, a peaceful sleep pattern, and early resumption of feeding.
| Acknowledgements|| |
Dalia M. EL Fawy, Niven Gerges and Yasser A. Salem helped design the study, conduct the study, and write the manuscript. All Dalia M. El Fawy and Niven Gerges have seen the original study data, reviewed the analysis of the data, and approved the final manuscript. Niven Gerges is the author responsible for archiving the study files Dalia M. El Fawy.
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8]