|Year : 2008 | Volume
| Issue : 6 | Page : 794
A Multimodal Approach to Post-Operative Pain Relief in Children Undergoing Ambulatory Eye Surgery
VV Jaichandran1, Bhanulakshmi Indermohan2, V Jagadeesh3, R Sujatha1, JJ Kavitha Devi1, N Manimaran1
1 Consultant, Department of Anaesthesiology, Sankara Nethralaya, Vision Research Foundation, Chennai, India
2 Director, Department of Anaesthesiology, Sankara Nethralaya, Vision Research Foundation, Chennai, India
3 Deputy Director, Department of Anaesthesiology, Sankara Nethralaya, Vision Research Foundation, Chennai, India
|Date of Acceptance||14-Oct-2008|
|Date of Web Publication||19-Mar-2010|
V V Jaichandran
Department of Anaesthesiology, Vision Research Foundation, 18, College Road, Chennai 600 006
This study was carried to assess the efficacy of multimodal analgesia using ketorolac and fentanyl, for postoperative pain relief in children undergoing ambulatory eye surgery. Total of 161 children, aged 1 to 5 years, were randomly stratified to three different analgesic regimens: Group A Ketorolac 0.75 mg.kg -1 I.M. , Group B Fentanyl 0.75 µg.kg -1 I.V. and Group C Ketorolac 0.50mg.kg -1 I.M. and Fentanyl 0.50µg.kg -1 I.V. Ketorolac I.M. was given 45 minutes before extubation and fentanyl I.V. was given soon after extubation in the respective groups. Post-operative pain was assessed in a double blinded manner using Children's Hospital of Eastern Onatario Pain Scale (CHEOPS) scoring system and by recording the heart rate at 10, 30 and 60 minutes. If the score was above 8, the child was left with the parents. In case the score did not improve and persisted to be greater than 8, fentanyl 0.50µg.kg -1 I.V. was given as the rescue analgesia. The incidence of nausea, vomiting, sleep disturbances or any other complaints were recorded by a staff nurse 24 hours post operatively. Mean CHEOPS score at 10, 30 and 60 minutes and mean heart rate at 10 and 30 minutes were significantly higher for Group A compared with Group C. Mean pain score emerged significantly higher for Group B compared with Group C at 30 and 60 minutes, (P<0.01). Rescue analgesia required was significantly higher in Group A compared to Groups B and C, (P<0.0001). Post-operatively, significant incidence of drowsiness was reported in children in Group B compared to Groups A and C, (P<0.01). A multimodal approach using both ketorolac and fentanyl at low doses produce effective and safe analgesia in children undergoing ambulatory eye surgery.
Keywords: Paediatric, Pain, Post-operative, Ketorolac, Fentanyl, Ambulatory surgical procedure
|How to cite this article:|
Jaichandran V V, Indermohan B, Jagadeesh V, Sujatha R, Kavitha Devi J J, Manimaran N. A Multimodal Approach to Post-Operative Pain Relief in Children Undergoing Ambulatory Eye Surgery. Indian J Anaesth 2008;52:794
|How to cite this URL:|
Jaichandran V V, Indermohan B, Jagadeesh V, Sujatha R, Kavitha Devi J J, Manimaran N. A Multimodal Approach to Post-Operative Pain Relief in Children Undergoing Ambulatory Eye Surgery. Indian J Anaesth [serial online] 2008 [cited 2013 Jun 19];52:794. Available from: http://www.ijaweb.org/text.asp?2008/52/6/794/60690
| Introduction|| |
Post-operative pain in children, especially those undergoing ambulatory surgical procedures, is inadequately treated for one or more of the following reasons: 1) The myth that children do not feel pain the way adults do, 2) inadequate assessment of pain, 3) lack of knowledge of pain treatment, 4) fear of adverse effects of analgesic medications including nausea, vomiting and respiratory depression  and 5) the myth that ambulatory procedures are associated with mild pain only  . So much so that inadequate post-operative pain management causes delay in discharge of ambulatory patients, increases healthcare costs and produces nausea, vomiting and sleep disturbances, besides leading to parents dissatisfaction , .
Adequate pain management in children involves accurate evaluation using pain assessment scoring appropriate to the child's age and treating them with safe and effective analgesics. A multimodal approach, i.e. using combinations of drugs with different mechanism of action at lower doses, is said to produce more effective analgesia than if they were used alone at larger doses ,,,,, .
In the present study two different drugs used for evaluating multimodal pain management in children undergoing ambulatory eye surgery were a non steroidal anti-inflammatory drug (ketorolac) and an opioid (fentanyl).
| Methods|| |
After obtaining approval from the institutional ethics committee and written informed consent from the parents, 161 children of ASA physical status I or II, aged 1 to 5 years undergoing ambulatory unilateral eye surgery were enrolled for this prospective double blinded study. Exclusion criteria included children with a history of bronchial asthma, coagulopathies, albuminuria (urine:++ or >), renal and liver disorders, family history or history of hypersensitivity to aspirin or NSAIDs..
Glycopyrrolate 0.005 mg.kg -1 I.M. and syrup triclofos 50mg.kg -1 orally were given 45 minutes preoperatively as premedication for children in all the three groups. If the child was cooperative an IV access was established. If not, inhalational induction with sevoflurane was carried out till IV access was established and propofol 1.5-2 mg.kg -1 I.V. was given for induction. Fentanyl 1µg.kg -1 I.V. was given for intra operative analgesia. Vecuronium bromide 0.1 mg.kg -1 I.V facilitated intubation with a portex endotracheal tube. Ventilation was controlled mechanically with Ohmeda ventilator. Anaesthesia was maintained with N 2 O/O 2 (70/30%) and 0.6% isoflurane. 0.45% normal saline with dextrose was infused to all the children, based on their body weight in kg. Routine intraoperative monitoring included non-invasive blood pressure (NIBP), ECG, pulse oximeter and capnograph. At the end of the surgical procedure volatile agent was discontinued and residual neuromuscular blockade was reversed with neostigmine 0.05 mg.kg -1 I.V. and glycopyrrolate 0.01 mg.kg -1 I.V. Based on the following criteria extubation was done: purposeful movement, regular respiratory pattern and return of normal reflexes. After extubation, children were transferred to the postanaesthetic care unit (PACU).
One hundred sixty one children were randomly stratified soon after enrollment in the study according to a computer generated random table, into three groups A, B and C based on the following analgesic regimen:
Group A: ketorolac 0.75 mg.kg -1 I.M.
Group B: fentanyl 0.75 mcg.kg -1 I.V.
Group C: ketorolac 0.50 mg.kg -1 I.M. and fentanyl 0.5 mcg.kg -1 I.V.
Ketorolac was given 45 minutes before extubation and fentanyl was given immediately after the child was received in PACU.
In the PACU a second blinded anaesthetist evaluated pain using Children's Hospital of Eastern Ontario Pain Scale (CHEOPS), [Table 1] and by recording the heart rate at 10, 30 and 60 minutes. If the CHEOPS score was greater than 6, the child was considered to have pain and if the score was greater than 8, parents were allowed to be with the child to see whether they were responding to tender loving care (TLC). If the score was greater than 8, even after 10 minutes of reunion of the child with parents, rescue analgesia fentanyl 0.5 µg.kg -1 I.V. was given. Rescue analgesia was supplemented every 10 minutes until the score decreased to 6 or below. The incidence of retching/nausea and vomiting in PACU was recorded. If the child vomited twice in an hour, ondansetron 0.1 mg.kg -1 I.V. was given. All the children were observed in PACU for 60 minutes following which they were transferred to the ambulatory ward before discharge.
At 60 minutes the level of sedation was assessed based on a five point scoring system (University of Michigan Medical Centre)  as follows:
Score 0 - does not arouse to deep or significant stimulation
Score 1 - requires vigorous stimulation to arouse
Score 2 - asleep but aroused with mild stimulation
Score 3 - drowsy sleepy, easily aroused
Score 4 - - awake and alert
Score 5 - agitated, uncontrollable and excessive motion.
Any delay in transferring the child from the PACU due to deep sedation score (score 0/1) was noted. In the ambulatory ward, children were given syrup paracetamol 20mg.kg -1 orally 6 hourly for analgesia. Children were discharged when they were awake, had stable vital signs for at least one hour, had mild or no pain, had not vomited for one hour, were able to tolerate clear fluids and had no bleeding. A blinded staff nurse recorded the incidence of nausea, vomiting, sleep disturbances and any other complaints, from the parents, 24 hours post-operatively.
A pilot study of 30 children, 10 in each group was done initially. The sample size (n=55), was calculated based on the results (comparison of means) for the first 10 patients in each group with an a equal to 0.05, and the power of the study was 80%.
All the results were expressed as mean + SD or number (%). For statistical analysis, One- Way Anova was made and Bonferroni Post-Hoc multiple comparisons test was applied to test the equality of means between the groups. For comparing the variables obtained after 24 hours, Pearson's Chi-Square and Fischer's exact tests were used. Results were considered significant if p was <0.05.
| Results|| |
The three groups were similar with respect to mean age, gender, weight and duration of surgery [Table 2]. The nature of surgery performed for the children enrolled in the study is shown in [Table 3].
Both the mean CHEOPS score at 10, 30 and 60 minutes and mean heart rate at 10 and 30 minutes were found to be significantly higher in Group A compared to Group C [Table 4]
Also, in Group A, 27.3% of children even after reunion with parents required rescue analgesia and 3.6% of children required supplementation of rescue analgesia.
Mean CHEOPS score at 30 and 60 minutes was significantly higher in Group B compared to Group C. There was no significant difference in pulse rate between Groups B and C in PACU. At 60 minutes interval there was no significant difference between the three groups either in the mean sedation score or the time of transferring the children from the PACU to the ambulatory ward.
Incidence of nausea, vomiting, sleep disturbances and complaints, if any, recorded from the parents after 24 hours post-operatively, are shown in [Table 5]. In Groups A and B, 3.6% and 7.4% of the children respectively had sleep disturbances but none of the children in Group C had sleep disturbances in the night. A significant incidence of drowsiness was reported in children in Group B compared to Groups A and C, p<0.01.
| Discussion|| |
Adequate post-operative analgesia is a prerequisite for successful ambulatory surgery. Post-operative pain control should be effective and safe with minimal side effect. It should also facilitate rapid recovery and be easily managed at home. The choice of anaesthetic technique can influence post-operative morbidity at home.
NSAIDs and paracetamol are the first line of drug therapy followed by opioids and local anaesthetics in paediatric pain control  . NSAIDs block the synthesis of prostaglandins and thereby block the afferent pain mediators and impulses to the brain. They are metabolized by the liver and excreted by the kidneys, so they are not recommended in infants aged below 1 year where both these organs are immature. Other side effects of NSAIDs are gastric irritation and platelet dysfunction. They also have a ceiling effect, a dose above which there is increase of side effects , . Severe adverse effects are very rare in children  . There is conflicting evidence of the potential for increased surgical site bleeding after tonsillectomy following the use of ketorolac in children  . In the present study, however, none of the surgeons complained of any increased bleeding during surgery. NSAIDs are effective in mild to moderate pain ,, . Pain following eye surgery is of moderate intensity  . Hence, NSAIDs as a sole analgesic agent may not be effective and they should be combined with an opioid  . This was clearly evident from our study, wherein 27.3% of children in Group A required rescue analgesia, which is significantly high compared with less than 4% in Groups B and C, P<0.0001.
Opioids are the basis of postoperative management of moderate to severe pain  . Their action is at specific receptors along the central nervous system inhibiting neurotransmitter release. Unlike NSAIDs they do not have a ceiling effect and the dose is increased until the analgesic action is adequate  . The major concern, however, is the proportional increase in side effects with increasing doses such as respiratory depression, drowsiness, nausea, vomiting, pruritus, urinary retention and delay in gastrointestinal function. Thus, in our study, 24 hours post-operatively, 13% and 1.9% of the children had drowsiness in Groups B and C respectively. Retrospectively it was noted that the child who had drowsiness in Group C had received rescue analgesia, in PACU.
Fentanyl given I.V. in PACU had an immediate onset of action, and hence there was no significant difference in mean CHEOPS score between Groups B and C at 10 minutes. But since it is a short acting opioid, there occurred a significant difference in mean CHEOPS score between Groups B and C at 30 and 60 minutes (P< 0.01) but this did not produce any significant difference in mean heart rate compared to Group C during the stay in the PACU.
Contrary to the findings in the previous studies which reported higher incidence of vomiting following opioids , , in this study 14.5% of children in Group A vomited in PACU. But on retrospective analysis of the children who vomited in Group A, it was found that 62.5% of them had received rescue analgesia. This could have acted as a confounding factor for this increased incidence of vomiting (although not significant, P>0.05) in Group A.
To reduce the observer variation , pain was evaluated by a single anaesthetist in the PACU. Also, at 24 hours post-operatively same staff nurse recorded the incidence of nausea, vomiting and sleep disturbances at night from the parents.
Drowsiness in the child was reported by the parents without any leading question from the staff nurse. From previous studies, post-operative drowsiness following ambulatory surgery was found to be influenced by the age of the patient and duration of anaesthesia , .Since both these variables were similar for the three groups in the study, drowsiness reported in Group B might be due to I.V. fentanyl. However, the sample size was too small to detect a significant difference in the incidence of sleep disturbances in the children, a rather uncommon finding.
The limitations encountered in the study was the non-availability of ketorolac in intravenous preparation, in Indian market. Hence, for intraoperative analgesia the study was designed in such a way that children in all the three groups received I.V. fentanyl at equivalent doses. Also, for ethical considerations ketorolac was not given intramuscularly as premedication when the child was awake.
Administering both ketorolac and fentanyl at lower doses, as in Group C, produced lower mean CHEOPS score and heart rate, required less rescue analgesia (3.2%), produced a mean sedation score of 3.06+0.96 at 60 minutes, caused no delay in transferring/discharge of the child and also had no post-operative morbidity.
A multimodal approach of administering both ketorolac and fentanyl produced more effective and safer post-operative analgesia in children undergoing ambulatory eye surgery.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]