Clonidine in paediatric anaesthesia

Novel drug treatments for pain in advanced cancer and serious illness: a focus on neuropathic pain and chemotherapy-induced peripheral neuropathy

Drugs that are commercially available but have novel mechanisms of action should be explored as analgesics. This review will discuss haloperidol, miragabalin, palmitoylethanolamide (PEA), and clonidine as adjuvant analgesics or analgesics. Haloperidol is a sigma-1 receptor antagonist. Under stress and neuropathic injury, sigma-1 receptors act as a chaperone protein, which downmodulates opioid receptor activities and opens several ion channels. Clinically, there is only low-grade evidence that haloperidol improves pain when combined with morphine, methadone, or tramadol in patients who have cancer, pain from fibrosis, radiation necrosis, or neuropathic pain. Miragabalin is a gabapentinoid approved for the treatment of neuropathic pain in Japan since 2019. In randomized trials, patients with diabetic neuropathy have responded to miragabalin. Its long binding half-life on the calcium channel subunit may provide an advantage over other gabapentinoids. PEA belongs to a group of endogenous bioactive lipids called ALIAmides (autocoid local injury antagonist amides), which have a sense role in modulating numerous biological processes in particular non-neuronal neuroinflammatory responses to neuropathic injury and systemic inflammation. Multiple randomized trials and meta-analyses have demonstrated PEA's effectiveness in reducing pain severity arising from diverse pain phenotypes. Clonidine is an alpha2 adrenoceptor agonist and an imidazoline2 receptor agonist, which is U.S. Federal Drug Administration approved for attention deficit hyperactivity disorder in children, Tourette's syndrome, adjunctive therapy for cancer-related pain, and hypertension. Clonidine activation at alpha2 adrenoceptors causes downstream activation of inhibitory G-proteins (Gi/Go), which inhibits cyclic Adenosine monophosphate (AMP) production and hyperpolarizes neuron membranes, thus reducing allodynia. Intravenous clonidine has been used in terminally ill patients with poorly controlled symptoms, in particular pain and agitation.

Is PONV still a problem in pediatric surgery: a prospective study of what children tell us

Background

Postoperative nausea and vomiting (PONV) is an unpleasant complication after surgery that commonly co-occurs with pain. Considering the high prevalence among pediatric patients, it is important to explore the main risk factors leading to PONV in order to optimize treatment strategies. The objectives of this study are as follows: (1) to determine the prevalence of PONV on the day of surgery by conducting interviews with pediatric patients, (2) to assess PONV prevalence in the recovery room and on the ward by analyzing nursing records, and (3) to collect information on PONV risk factors on the day of surgery and the following postoperative days. We wanted to investigate real-life scenarios rather than relying on artificially designed studies.

Methods

A prospective analysis [according to STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) guidelines] of PONV on the day of surgery and the following postoperative days was conducted by evaluating demographic and procedural parameters, as well as conducting interviews with the children under study. A total of 626 children and adolescents, ranging in age from 4 to 18 years, were interviewed on the ward following their surgery. The interviews were conducted using a questionnaire, as children aged 4 and above can participate in an outcome-based survey.

Results

On the day of surgery, several multivariable independent predictors were identified for PONV. The type of surgery was found to be a significant factor (p = 0.040) with the highest odds ratio (OR) in patients with procedural investigations [OR 5.9, 95% confidence interval (CI): 1.8-19.2], followed by abdominal surgery (OR 3.1, 95% CI: 0.9-11.1) when inguinal surgery was used as the reference category. In addition, the study identified several predictors, including the amount of fentanyl administered during anesthesia (µg/kg body weight) (OR 1.4, 95% CI: 1.1-1.8), intraoperative use of piritramide (OR 2.6, 95% CI: 1.5-4.4) and diclofenac (OR 2.0, 95% CI: 1. 3-3.1), opioid administration in the recovery room (OR 3.0, 95% CI: 1.9-4.7), and piritramide use on the ward (OR 4.5, 95% CI: 1.7-11.6).

Conclusions

The main risk factors for PONV include the intraoperative administration of opioids during the recovery room stay and at the ward, the intraoperative use of non-opioids (diclofenac), and the specific type of surgical procedure. Real-life data demonstrated that in clinical praxis, there is a gap between the adherence to established guidelines and the use of antiemetic prophylaxis in surgeries that are generally not associated with a high PONV prevalence. Further efforts are needed to improve the existing procedures and thus improve the overall outcome.

Effectiveness of oral clonidine and gabapentin on peripheral neuropathy in diabetic patients in southwestern Iran: a randomized clinical trial

BACKGROUND

Peripheral neuropathy is not only the most prevalent consequence of diabetes but also the main reason for foot ulceration, disability, and amputation. Therefore, the current study aims to determine the effectiveness of oral clonidine and gabapentin on peripheral neuropathy in diabetic patients.

METHODS

This 12-week, randomized, and parallel-group trial was conducted to compare the efficacy of oral clonidine and gabapentin with gabapentin alone in diabetic patients in southwest Iran during the first half of 2021. Thirty patients with type 2 diabetes with peripheral neuropathy as assessed by a visual analog scale (VAS) and divided into two groups of 15 patients, treated for up to three months. The data were analyzed using SPSS-21 software. In order to report the results, descriptive indices, independent t-test, one-way analysis of covariance (ANCOVA) and analysis of variance with repeated measures were used.

RESULTS

The mean and standard deviation of the age of the participants in the clonidine + gabapentin group was equal to 50.20 ± 7.44, and in the gabapentin group was equal to 50.47 ± 7.57 (t = 0.10, P-value = 0.923). This research showed a significant difference between the clonidine + gabapentin group and with gabapentin group in terms of neuropathic pain and the severity of neuropathic pain (P < 0.001).

CONCLUSIONS

According to this research results, clonidine + gabapentin can reduce neuropathic pain and the severity of neuropathic pain in diabetic patients. Therefore, it is recommended that healthcare professionals with diabetes expertise prescribe these medications to reduce neuropathic pain and its severity.

TRIAL REGISTRATION

This study was registered in the Iranian Clinical Trials System with the ID (IRCT20211106052983N1) on 14/01/2022.

The Perioperative Anesthetic Management of the Pediatric Patient with Special Needs: An Overview of Literature

The perioperative management of pediatric patients with psycho-physical disorders with related relational and cognitive problems must be carefully planned, in order to make the entire hospitalization process as comfortable and as less traumatic as possible. This article reports an overview of the anesthetic management of non-cooperative patients between 6 and 14 years old. The pathologies most frequently responsible for psycho-physical disorders can be summarized into three groups: (1) collaboration difficulties (autism spectrum disorders, intellectual impairment, phobia); (2) motor dysfunction (cerebral palsy, epilepsy, other brain pathologies, neuromuscular disorders), and (3) craniofacial anomalies (Down syndrome, other genetic syndromes). Anesthesia can be performed safely and successfully due to careful management of all specific problems of these patients, such as a difficult preoperative evaluation (medical history, physical examination, blood sampling, evaluation of vital parameters and predictive indices of difficult airway) and the inapplicability of a "standard" perioperative path (timing and length of the hospitalization, anesthetic premedication, postoperative management). It is necessary to ensure a dedicated perioperative process that is safe, comfortable, tailored to specific needs, and as less traumatic as possible. At the same time, all necessary precautions must be taken to minimize possible complications.

The addition of clonidine to ropivacaine in rectus sheath nerve blocks for pediatric patients undergoing laparoscopic appendectomy: A double blinded randomized prospective study

STUDY OBJECTIVE

The primary goal of this study was to determine if the addition of clonidine to ropivacaine prolonged periumbilical numbness compared to ropivacaine alone in pediatric patients receiving ultrasound guided rectus sheath nerve blocks for laparoscopic appendectomy. The secondary goals were to evaluate differences in perioperative pain scores, analgesic consumption, sedation, anxiolysis, and hemodynamic effects from clonidine.

DESIGN

This was a single center, randomized, double-blinded prospective study.

SETTING

This study was conducted within the pediatric operating rooms at the Children's Hospital of Pittsburgh, a large university-based academic medical center.

PATIENTS

Fifty pediatric patients (ages 10-17 years old) without pre-existing cognitive impairment, developmental delay or chronic pain undergoing laparoscopic appendectomy during weekday hours were enrolled and randomized to control versus intervention groups.

INTERVENTION

Ultrasound guided rectus sheath nerve block injections were performed at the beginning of surgery with either ropivacaine 0.5% plus normal saline or ropivacaine 0.5% plus clonidine (2 mcg/kg, maximum of 100 mcg).

MEASUREMENTS

The duration of periumbilical numbness, Numeric Pain Rating Scale scores, University of Michigan Sedation Scale, State-Trait Anxiety Inventory for Children, analgesic consumption, heart rate, blood pressure, and mean arterial pressures, were recorded for each patient at several time points in the perioperative setting.

MAIN RESULTS

There were no significant differences in demographic characteristics between groups. The median duration of periumbilical numbness did not significantly differ between the ropivacaine only and the ropivacaine plus clonidine groups 540.0 minutes [360.0 -1015.0] (median [interquartile range (IQR)]) versus 823.5 minutes [509.5- 1080.0], p = 0.451. There were no significant differences in perioperative analgesic consumption, pain and anxiety scores, PACU sedation, or hemodynamic instability.

CONCLUSIONS

The addition of clonidine did not significantly prolong rectus sheath nerve block duration and was well tolerated in pediatric patients. Perioperative analgesia, hemodynamics, anxiety, and PACU sedation did not differ between groups.

TRIAL REGISTRATION

Clinical Trials NCT02439281.

Clinical pharmacology and dosing regimen optimization of neonatal opioid withdrawal syndrome treatments

In this paper, we review the management of neonatal opioid withdrawal syndrome (NOWS) and clinical pharmacology of primary treatment agents in NOWS, including morphine, methadone, buprenorphine, clonidine, and phenobarbital. Pharmacologic treatment strategies in NOWS have been mostly empirical, and heterogeneity in dosing regimens adds to the difficulty of extrapolating study results to broader patient populations. As population pharmacokinetics (PKs) of pharmacologic agents in NOWS become more well‐defined and knowledge of patient‐specific factors affecting treatment outcomes continue to accumulate, PK/pharmacodynamic modeling and simulation will be powerful tools to aid the design of optimal dosing regimens at the patient level. Although there is an increasing number of clinical trials on the comparative efficacy of treatment agents in NOWS, here, we also draw attention to the importance of optimizing the dosing regimen, which can be arguably equally important at identifying the optimal treatment agent.

Premedication and Induction of Anaesthesia in paediatric patients

Perioperative anxiety has been associated with adverse clinical outcomes such as emergence delirium, increased analgesic requirements and negative postoperative behavioural changes such as sleep disturbance, separation anxiety, eating problems and new-onset enuresis. Predictors of preoperative anxiety have been identified, and these include, among other factors, the age and temperament of the child. Any plan for anaesthetic induction in a child must take into account these factors. The anaesthetic plan must be individualised for special situations, for example, the child with behavioural disorder or at risk of aspiration. This article details the pharmacological and nonpharmacological methods to minimise preoperative anxiety and the techniques of anaesthetic induction in infants and children undergoing surgery. The benefits and limitations of inhalational and intravenous induction and the current status of rapid sequence induction in children are discussed. MEDLINE database was searched for this narrative review using the keywords including preoperative anxiety, child, premedication, paediatric and anaesthetic induction. Search was restricted to articles in English, but without any publication date restrictions.

Efficacy and Safety of Clonidine as an Adjuvant to Bupivacaine for Caudal Analgesia in Paediatric Infra-Umbilical Surgeries

INTRODUCTION

Caudal analgesia, has gained popularity in paediatric intraoperative and postoperative pain management, more so with the use of adjuvants to prolong its duration, each of them having various results. Clonidine, an alpha2-adrenergic agonist is being used for its analgesic effects in various doses with 0.25% Bupivacaine.

AIM

The study was conducted to compare the analgesic efficacy, haemodynamic safety and side effects of 1 μg/kg Clonidine added to 1 ml/kg of 0.125% Bupivacaine solution for caudal analgesia.

MATERIALS AND METHODS

A prospective, randomised, double-blind, controlled study was carried out in 60 children of ASA Physical Status I, aged 1-10 years, scheduled for infraumbilical operations in a tertiary care centre. They were randomly assigned for caudal analgesia, to either group B: 1ml/kg of 0.125% Bupivacaine solution or group BC: 1ml/kg of 0.125% Bupivacaine and preservative free Clonidine 1μ/kg. All were premedicated with midazolam 0.75 mg/kg orally 30 minutes prior to induction of anaesthesia. Heart rate (HR), Mean Arterial blood Pressure (MAP) and oxygen saturation (SpO2) were monitored. General anaesthesia was induced with thiopentone (1.25%) 5mg/kg and inhalation of oxygen, nitrous oxide and sevoflurane. Postoperative pain, sedation and motor block was assessed by the various scores and patients were monitored for adverse effects.

RESULTS

The mean duration of postoperative analgesia was 3 times longer in group BC. Group B received significantly more doses of rescue analgesic than group BC (p-value of 0.004). There was no significant bradycardia, hypotension, sedation or urinary retention in either of the groups. There was no residual motor blockade at 6 hours. Incidence of vomiting was similar in both the groups.

CONCLUSION

Caudal Clonidine in the dose of 1 μg/kg in children is a satisfactory and efficacious adjuvant to caudal Bupivacaine for producing prolonged postoperative analgesia with minimum side effects.

The effect of infraorbital nerve block on emergence agitation in children undergoing cleft lip surgery under general anesthesia with sevoflurane

BACKGROUND

Sevoflurane is widely used in pediatric anesthesia. However, a high incidence of emergence agitation (EA) after general anesthesia with sevoflurane has been reported and pain has been regarded as a significant contributing factor. The objective of this prospective randomized, placebo-controlled trial was to determine whether infraorbital nerve block reduces EA in children undergoing repair of cleft lip after sevoflurane.

METHODS

In this randomized, placebo-controlled trial, we enrolled 110 children (5 months to 6 years of age), who were scheduled for cleft lip surgery, and randomized them to the following two groups: Group S and Group B, where 1.5 ml saline (Group S) or 1.5 ml 0.25% bupivacaine (Group B) were administered in the infraorbital foramen. Emergence behavior was assessed in the postanesthesia care unit using the Pediatric Anesthesia Emergence Delirium (PAED) scale and a 5-point scale described by Cole. Pain was evaluated using the Children and Infants Postoperative Pain Scale (CHIPPS).

RESULTS

One-hundred children (n = 50 per group) completed the study. The endtidal concentration of sevoflurane in Group B was lower than that in Group S. The incidence of EA was 16% in Group B and 42% in Group S (P = 0.008). The PAED scale score in Group B (mean [95% CI] 9 [8-12]) was lower than that in Group S (11.5 [9.8-15]). The duration of EA in Group B was shorter than that in Group S. CHIPPS score in postanesthetic care unit were lower in Group B (mean [95% CI] 3 [2-3.3]) compared with that in Group S (5 [4-6]).

CONCLUSION

In children undergoing cleft lip repair surgery, infraorbital nerve block at the beginning of surgery significantly decreased the incidence of EA and the duration of EA, and provided satisfactory postoperative analgesia without delaying the time to extubation with sevoflurane anesthesia.

Comparative evaluation of midazolam and clonidine as pediatric oral premedication

BACKGROUND

Clonidine provides many desirable effects like sedation, analgesia, anxiolysis, and hemodynamic stability and these properties make it a potentially useful anesthetic premedication in the pediatric settings. The aim of this study was to compare oral midazolam (0.5 mg/kg), which is considered gold standard with oral clonidine (5 mcg/kg) as a premedication in pediatric patients.

MATERIALS AND METHODS

Sixty children classified as American Society of Anesthesiologists physical status I, aged between 2 and 12, who were scheduled to undergo an elective surgery, were enrolled for a prospective, randomized, and double blind controlled trial. They received either oral midazolam (Group M) or oral clonidine (Group C) 60 minutes before induction of anesthesia and were submitted to an evaluation of anxiety and sedation scores. We also evaluated secondary outcomes such as palatability, parental separation, effect on hemodynamic status, co-operation during venipuncture and facemask application, postoperative analgesic requirement, and recovery profile.

RESULTS

Oral midazolam had better efficacy in the preoperative period as sedative and anxiolytic (P < 0.001), allowed better cooperation during venipuncture and facemask application (P < 0.001), whereas, oral clonidine provided better palatability (P < 0.001), parental satisfaction (P < 0.001), stable perioperative hemodynamics (P < 0.001), better postoperative analgesia (P < 0.001), and night sleep pattern (P < 0.05) without any noticeable side effects (P > 0.05).

CONCLUSION

We conclude that under the conditions of this study, oral midazolam is a better medication than clonidine in children in preoperative period while clonidine is a better medication postoperatively with added advantage of palatability, hemodynamic stability, and no significant side effects.

Sciatic lateral popliteal block with clonidine alone or clonidine plus 0.2% ropivacaine: effect on the intra-and postoperative analgesia for lower extremity surgery in children: a randomized prospective controlled study

BACKGROUND

The effect of adding clonidine to local anesthetics for nerve or plexus blocks remains unclear. Most of the studies in adults have demonstrated the positive effects of clonidine on intra- and postoperative analgesia when used as an adjunctive agent or in some cases as a single to regional techniques. In the pediatric population, there are only few trials involving clonidine as an adjunct to regional anesthesia, and the analgesic benefits are not definite in this group of patients. The evidence concerning perineural administration of clonidine is so far inconclusive in children, as different types and volume of local anesthetic agents have been used in these studies. Moreover, the efficacy of regional anesthesia is largely affected by the operator's technique, accuracy and severity of operation.

METHODS

The use of clonidine alone or combined with 0.2% ropivacaine for effective analgesia after mild to moderate painful foot surgery was assessed in 66 children, after combined sciatic lateral popliteal block (SLPB) plus femoral block. The patients were randomly assigned into three groups to receive placebo, clonidine, and clonidine plus ropivacaine. Time to first analgesic request in the groups was analyzed by using Kaplan-Meier and the log-rank test (mean time, median time, 95% CI).

RESULTS

In our study, clonidine administered alone in the SLPB seems promising, maintaining intraoperatively the hemodynamic parameters SAP, DAP, HR to the lower normal values so that no patient needed nalbuphine under 0.6 MAC sevoflurane anesthesia, and postoperatively without analgesic request for a median time of 6 hours. In addition, clonidine administered as adjuvant enhances ropivacaine's analgesic effect for the first postoperative day in the majority of children (p = 0.001). Clonidine and clonidine plus ropivacaine groups also didn't demonstrate PONV, motor blockade, and moreover, the parents of children expressed their satisfaction with the excellent perioperative management of their children, with satisfaction score 9.74 ± 0.45 and 9.73 ± 0.70 respectively. On the contrary all the patients in the control group required rescue nalbuphine in the recovery room, and postoperatively, along with high incidence of PONV, and the parents of children reported a low satisfaction score (7.50 ± 0.70).

CONCLUSIONS

Clonidine appears promising more as an adjuvant in 0.2% ropivacaine and less than alone in the SLPB plus femoral block in children undergoing mild to moderate painful foot surgery, with no side effects.

TRIAL REGISTRATION

ClinicalTrials.gov, ISRCTN90832436, (ref: CCT-NAPN-20886).

Efficacy of clonidine as an adjuvant to bupivacaine for caudal analgesia in children undergoing sub-umbilical surgery

Caudal epidural analgesia with bupivacaine is very popular in paediatric anaesthesia for providing intra- and postoperative analgesia. Several adjuvants have been used to prolong the action of bupivacaine. We evaluated the efficacy of clonidine added to bupivacaine in prolonging the analgesia produced by caudal bupivacaine in children undergoing sub-umbilical surgery. One hundred children, age one to three years, undergoing sub-umbilical surgery, were prospectively randomized to one of two groups: caudal analgesia with 1 ml/kg of 0.25% bupivacaine in normal saline (Group A) or caudal analgesia with 1 ml/kg of 0.25% bupivacaine with 1 µg/kg of clonidine in normal saline (Group B). Post-operative pain was assessed for 24 hours using the FLACC scale. The mean duration of analgesia was significantly longer in Group B (593.4 ± 423.3 min) than in Group A (288.7 ± 259.1 min); P < 0.05. The pain score assessed using FLACC scale was compared between the two groups, and children in Group B had lower pain scores, which was statistically significant. The requirement of rescue medicine was lesser in Group B. Clonidine in a dose of 1 µg/kg added to 0.25% bupivacaine for caudal analgesia, during sub-umbilical surgeries, prolongs the duration of analgesia of bupivacaine, without any side effects.

Oral bioavailability of clonidine in children

BACKGROUND

Oral clonidine is used as premedication in children. The bioavailability of clonidine given orally in adults is 75-100% but is unknown in children.

METHODS

Children (3-10 years) undergoing adenotonsillectomy were administered oral clonidine 4 mcg·kg(-1) mixed with apple fruit drink as premedication. Intravenous plasma was assayed for clonidine concentration at 5, 15, 30, 45 min and 1, 2, 4, 6, 12, 18 h after administration. Clonidine plasma concentrations were determined by liquid chromatography-mass spectroscopy, and pharmacokinetic parameters were calculated using nonlinear effects mixed-effects models. Current data were pooled with published time-concentration profiles from children (n = 49) administered intravenous clonidine to determine oral bioavailability.

RESULTS

There were eight children studied (age 3-10 years, weight 10.5-36 kg). A two-compartment model with first-order absorption and elimination was used to describe time-concentration profiles. Population parameter estimates (CV%; 95% CI), standardized to a 70-kg person, were absorption half-life (Tabs), 0.45 (85.1; 0.221-0.884) h, absorption lag time (Tlag), 0.148 (91.2; 0.002-0.316) h, Clearance (CL) 17.9 (30.3; 16-20.3) l·h(-1) per 70 kg, between compartment clearance (Q) 121 (44.3; 80.1-165) l·h(-1) per 70 kg, central volume (V1) 81.2 (71.5; 60.7-105) l·70 kg(-1), peripheral volume of distribution (V2) 113 (33.9; 91-131) l·70 kg(-1). The oral bioavailability was 55.4% (CV 6.4%; 95% CI 0.469, 0.654).

CONCLUSIONS

Clonidine administered with an apple fruit drink displays a variable and relatively slow absorption after oral administration (T(max) 1.04 h, C(max) 0.77 mcg·l(-1)). The oral bioavailability was 55.4%, which is less than reported in adults. Consequently, higher oral doses of clonidine (per kg) are required when this formulation is used to achieve concentrations similar to those reported in adults.

Effect of epidural clonidine on minimum local anesthetic concentration (ED50) of levobupivacaine for caudal block in children

BACKGROUND

Clonidine has the potential to significantly prolong the duration of caudal epidural anesthesia. We investigated the effect of the addition of clonidine to the MLAC of levobupivacaine in a randomized controlled dose-response trial.

METHODS

A group of 120 children aged <6 years of age received caudal anesthesia with levobupivacaine and 1, 2, or 3 μg·kg(-1) of clonidine. The MLAC was determined according to a Dixon-Massey protocol. The primary outcome was effective surgical anesthesia. Secondary outcomes were the duration of postoperative analgesia, postoperative pain scores, clonidine side effects, and time to hospital discharge.

RESULTS

The MLAC of caudal levobupivacaine was 0.106%, 0.077%, and 0.035% with 1, 2, and 3 μg·kg(-1) of clonidine, respectively. There were significant dose-dependent increases in median duration of analgesia. The incidence of delayed discharge, somnolence, and PONV was significantly increased in the 3 μg·kg(-1) of clonidine group.

CONCLUSIONS

Clonidine produces a local anesthetic sparing effect with a dose-dependent decrease in levobupivacaine MLAC for caudal anesthesia. In addition, there is a dose-dependent prolongation of postoperative analgesia following lower abdominal surgery in children. A dose of 2 μg·kg(-1) of clonidine provides the optimum balance between improved analgesia and minimal side effects.

Emergence agitation after cataract surgery in children: a comparison of midazolam, propofol and ketamine

OBJECTIVES

The aim of this study was to determine whether the concurrent use of either of a subhypnotic dose of midazolam, propofol or ketamine with fentanyl just before discontinuing the sevoflurane anesthesia would effectively sedate the children as they recovered and significantly decrease the incidence and severity of emergence agitation and would not delay patient awakening and discharge.

BACKGROUND

Postoperative emergence agitation may occur in children after general anesthesia with volatile anesthetics. Children who undergo cataract surgery after sevoflurane induction and sevoflurane-remifentanil maintenance may experience this type of agitation.

METHODS/MATERIALS

In 120 un-premedicated children aged 1-7 years, mask induction with sevoflurane was performed and they were then randomly assigned to one of the three antiagitation postoperative groups (n = 40). We studied the postoperative antiagitation effects of subhypnotic doses of midazolam combined with fentanyl, propofol with fentanyl or ketamine with fentanyl administered just before discontinuing the sevoflurane anesthesia. A score for the level of agitation can be assigned based on the recovery mental state (RMS) scale and the recently published pediatric anesthesia emergence delirium scale (PAED). Postoperative factors assessed included emergence behaviors, the time to eye opening, the time to discharge from the postanesthesia care unit (PACU) to the ward.

RESULTS

There were significantly more agitated children in the ketamine-group when compared to the midazolam-group or to the propofol-group at all time P < 0.05), especially at 10 and 15 min. The PAED scale showed a significant advantage for midazolam-fentanyl [5 (2-15)] and propofol-fentanyl [6 (3-15)] versus ketamine-fentanyl [10 (3-20)] (P < 0.05). The time to discharge from the PACU to the ward was not significantly different among the groups.

CONCLUSIONS

Intravenous administration of a subhypnotic dose of midazolam or propofol in addition to a low dose of fentanyl just before discontinuing the sevoflurane anesthesia was both effective on decreasing the incidence and severity of emergence agitation in children undergoing cataract extraction without significant delaying recovery time and discharge. The effect of midazolam was clearer than that seen with propofol.

Pharmacological prevention of sevoflurane- and desflurane-related emergence agitation in children: a meta-analysis of published studies

BACKGROUND

Emergence agitation (EA) in children is increased after sevoflurane anaesthesia. The efficacy of prophylactic treatment is controversial. The aim of this study was to provide a meta-analysis of the studies of the pharmacological prevention of EA in children.

METHODS

A comprehensive literature search was conducted to identify clinical trials that focused on the prevention of EA in children anaesthetized with sevoflurane, desflurane, or both. The data from each trial were combined using the Mantel-Haenszel model to calculate the pooled odds ratio (OR) and 95% confidence interval. I(2) statistics were used to assess statistics heterogeneity and the funnel plot and the Begg-Mazumdar test to assess bias.

RESULTS

Thirty-seven articles were found which included a total of 1695 patients in the intervention groups and 1477 in the control ones. Midazolam and 5HT(3) inhibitors were not found to have a protective effect against EA [OR=0.88 (0.44, 1.76); OR=0.39 (0.12, 1.31), respectively], whereas propofol [OR=0.21 (0.16, 0.28)], ketamine [OR=0.28 (0.13, 0.60)], alpha(2)-adrenoceptors [OR=0.23 (0.17, 0.33)], fentanyl [OR=0.31 (0.18, 0.56)], and peroperative analgesia [OR=0.15 (0.07, 0.34)] were all found to have a preventive effect. Subgroup analysis according to the peroperative analgesia given does not affect the results.

CONCLUSIONS

This meta-analysis found that propofol, ketamine, fentanyl, and preoperative analgesia had a prophylactic effect in preventing EA. The analgesic properties of these drugs do not seem to have a role in this effect.

The place of premedication in pediatric practice

Behind the multiple arguments for and against the use of premedication, sedative drugs in children is a noble principle that of minimizing psychological trauma related to anesthesia and surgery. However, several confounding factors make it very difficult to reach didactic evidence-based conclusions. One of the key confounding issues is that the nature of expectations and responses for both parent and child vary greatly in different environments around the world. Studies applicable to one culture and to one hospital system (albeit multicultural) may not apply elsewhere. Moreover, the study of hospital-related distress begins at the start of the patient's journey and ends long after hospital discharge; it cannot be focused completely on just the moment of anesthetic induction. Taking an example from actual practice experience, the trauma caused by the actual giving of a premedication to a child who absolutely does not want it and may struggle may not be recorded in a study but could form a significant component of overall effect and later psychological pathology. Clearly, attitudes by health professionals and parents to the practice of routine pediatric premedication, vary considerably, often provoking strong opinions. In this pro-con article we highlight two very different approaches to premedication. It is hoped that this helps the reader to critically re-evaluate a practice, which was universal historically and now in many centers is more selective.

Long-term consequences of drugs on the paediatric cardiovascular system

Many pharmacological and toxicological actions of drugs in children cannot be fully predicted from adult clinical experience or from standard non-clinical toxicology studies. Numerous drugs have direct or indirect pharmacological effects on the heart and are prescribed for children of all ages. Toxicity or secondary effects may be immediate or delayed for years after drug exposure has ceased. Originally, the aim of this review was to compile information on the effect of specific drugs on the post-natal development of the cardiovascular system and to examine long-term follow-up of the use of cardio-active drugs in children. The limited database of published information caused the original question to evolve into an examination of the medical literature for three areas of information: (i) whether vulnerable developmental windows have been identified that reflect the substantial functional development that the cardiovascular system undergoes after birth; (ii) what is known about pharmacological perturbation of development; and (iii) what the likelihood is of drug exposure during childhood. We examined different scenarios for exposure including random, isolated exposure, conditions historically associated with adults, primary or secondary cardiac disease, psychiatric and neurological conditions, asthma, cancer and HIV. Except for random, isolated drug exposures, each category of possible exposure contained numerous drugs known to have either primary or secondary effects on the cardiovascular system or to influence factors associated with atherosclerosis. It is likely that a significant number of children will be prescribed drugs having either direct or indirect effects upon the immature cardiovascular system. A confounding factor is the simultaneous use of over-the-counter medications and herbal or nutraceutical preparations that a patient, parent or guardian does not mention to a prescribing physician. Metabolism is also important in assessing drug effects in children. Differences in body water : body fat ratio, age-related gastrointestinal absorption, distribution, excretion, renal function and drug metabolizing capabilities make it possible for children to have a different metabolite profile for a drug compared with adults. There is little examination of drug effects on the interdependent processes of cardiac maturation and less examination of metabolite effects. It is difficult to identify delayed toxicities in children as these adverse events may take years to manifest with many patients lost to follow-up. Clearly this is an area of study where intermediate endpoints and surrogate markers would be of great benefit. Pharmacogenomics may be useful in providing markers of increased risk or susceptibility. A perspective must be kept in balancing the possibility of a problem with the very real benefits that many children experience from the use of these pharmaceuticals.

Safety and efficacy of patient controlled epidural analgesia following pediatric spinal surgery

BACKGROUND

Patient controlled epidural analgesia (PCEA) is uncommon in pediatric anesthesia. Because PCEA offers superior pain control compared with continuous epidural infusions in adults, we prospectively evaluated the analgesia efficacy and safety of PCEA in children and adolescents following extensive spinal surgery.

METHODS

Following ethics committee approval, 100 consecutive children [age median (range) 14 (6-19) years] undergoing spinal surgery were studied until the seventh postoperative day, and 98 children received a PCEA. One or two epidural catheters were positioned under direct vision by the surgeon based on the number of vertebral segments operated upon. The epidural solution consisted of bupivacaine 0.0625%, fentanyl 1 microg.ml(-1) and clonidine 0.6 microg.ml(-1), delivered at a basal rate of 0.2 ml.kg(-1).h(-1) and a PCEA dose of 0.1 ml.kg(-1).h(-1)(max. 2 h(-1)). On the fourth postoperative day, PCEA was stopped and analgesia was continued with patient controlled analgesia (PCA) with morphine.

RESULTS

During the PCEA regimen, the maximal scores of the revized facial scale were below 4 at rest with a very high satisfaction rate (>90%). Pain scores were higher during mobilization on the first postoperative day and when PCEA was switched to PCA. The overall incidence of adverse events was low and consisted primarily of technical problems and postoperative nausea and vomiting. Only two children experienced a complication requiring the discontinuation of the PCEA but there were no consequent adverse sequelae.

CONCLUSIONS

The present study demonstrates that PCEA provides excellent pain relief following extensive spinal surgery and is associated with a low incidence of adverse events. The use of PCEA should be encouraged in children and adolescents following extensive spinal surgery.

Oral clonidine vs midazolam in the prevention of sevoflurane-induced agitation in children. A prospective, randomized, controlled trial †

BACKGROUND

This randomized, double-blind study tested the hypothesis that, in comparison with midazolam, premedication with oral clonidine reduces the incidence of emergence agitation in preschool children anaesthetized with sevoflurane.

METHODS

Sixty-eight ASA I-II children undergoing circumcision were randomized into three groups to receive different oral premedication given 30 min before anaesthesia: midazolam 0.5 mg kg-1, clonidine 2 microg kg-1, and clonidine 4 microg kg-1. Sevoflurane anaesthesia was administered via a facemask (O2/N2O: 40/60). Analgesia was with penile block (bupivacaine 0.5% 0.3 ml kg-1) and rectal paracetamol (30 mg kg-1). During the first postoperative hour, children were evaluated using a modified 'objective pain scale'.

RESULTS

Only the 4 microg kg-1 dose of clonidine was associated with a significant reduction in emergence agitation. Fewer children in the clonidine 4 microg kg-1 group displayed agitation (25%) than in the midazolam group (60%) (P=0.025). Incidence of hypotension and bradycardia, time to first micturition and first drink did not differ among groups.

CONCLUSIONS

In comparison with midazolam, clonidine 4 microg kg-1 reduced sevoflurane-induced emergence agitation without increasing postoperative side-effects.

Dexmedetomidine decreases emergence agitation in pediatric patients after sevoflurane anesthesia without surgery

BACKGROUND

The purpose of the present study was to determine whether prophylactic use of 1 microg x kg(-1) dexmedetomidine affected the incidence of emergence agitation (EA) after sevoflurane based anesthesia without surgery in children.

METHODS

In a double-blinded trial, 42 children (ASA I-II,18 months to 10 years) undergoing magnetic resonance imaging (MRI) examination were randomly assigned to receive dexmedetomidine 1 microg x kg(-1) iv or placebo after induction of anesthesia. Heart rate (HR), mean arterial pressure (MAP), hemoglobin oxygen saturation (SpO2) were monitored. Anesthesia was induced in all patients, irrespective of group, with 8% sevoflurane in 50-50% O2/N2O and maintained with 1.5% sevoflurane in 50/50% O2/N2O. Agitation parameters were assessed with a 5-point scale and measured every 5 min. Delirium was defined as agitation score of > or =4 for > or =5 min. Anesthesia and procedure times and per- and postoperative side effects were recorded.

RESULTS

The HR, MAP, and SpO2, spontaneous arm or leg motion times and purposeful movement times showed no significant differences between the two groups. The time of removing the LMA, and the time of eye opening with verbal stimuli was shorter in group P than the group D (P = 0.007 and P = 0.01). The time of discharge to recovery room and the time of discharge from hospital were similar in the two groups. The mean agitation scores in the dexmedetomidine group were significantly lower than the placebo group except at 30 min (P < 0.0001, P = 0.001, P = 0.002, P = 0.013 and P = 0.001). The incidence of emergence agitation was 47.6% in group P, and 4.8% in group D (P = 0.002).

CONCLUSION

We concluded that a 1 microg x kg(-1) dose of i.v. dexmedetomidine reduces EA after sevoflurane anesthesia in children undergoing MRI.

Clonidine: an alternative to benzodiazepines for premedication in children

PURPOSE OF REVIEW

The aim of this review is to summarize the use of clonidine for paediatric premedication and to make a comparison with benzodiazepines. A routine clonidine premedication protocol is also presented.

RECENT FINDINGS

In the US 50% of young children undergoing surgery receive premedication and midazolam is the most frequently used drug. The number of trials that compare midazolam with active controls are few and this premedicant is not adequately validated. Clonidine is still used as premedication in a small number of centres but the literature on paediatric use of clonidine is steadily growing. A recent review article has concluded that the use of clonidine does enhance the quality of perioperative management in infants and children and more recent publications support the use of clonidine for premedication. Its effect on the circulation is mild but routine atropine administration is recommended. Contraindications to the use of clonidine are few. Apart from a general overview on the effects of clonidine this article will also summarise the published trials that have compared clonidine with benzodiazepines for premedication in children.

SUMMARY

Midazolam the most commonly used drug for paediatric premedication worldwide. Despite having a number of beneficial effects it is far from an ideal premedicant, especially concerning its effect on cognition/amnesia, confusion and long-term behavioural disturbances. Clonidine lacks the majority of the negative effects associated with midazolam and is associated with a number of beneficial perioperative effects. Our clinical experience of replacing midazolam with clonidine as premedicant in children, including also outpatients, has been favourable.

Clonidine in paediatric anaesthesia: review of the literature and comparison with benzodiazepines for premedication

BACKGROUND

Children undergoing anaesthesia and surgery can experience significant anxiety and distress during the peri-operative period, but whether routine premedication is necessary is currently debated. Benzodiazepines are the most frequently used drugs as premedication in paediatric anaesthesia. In the US, 50% of young children undergoing surgery receive premedication and midazolam is the most frequently used drug in this context (1). Nishina and coworkers (2) concluded in a review article in 1999 that clonidine, administered via an oral, rectal, or caudal route, is a promising adjunct to anaesthetics and analgesics to enhance quality of peri-operative management in infants and children. Later publications also support the use of clonidine for premedication (3-6). The aim of this communication is to review the use of clonidine in paediatric anaesthesia and to propose clonidine as a promising alternative to midazolam. Clonidine is associated with a number of beneficial effects in the context ofanaesthesia both in adults and children. Why clonidine is not routinely use in clinical practice despite the massive publication list is to a large extent due to the lack of marketing efforts from the pharmaceutical industry since multiplegeneric preparations are now readily available on most markets. Midazolam is also associated with a number of beneficial effects, but is far from an ideal premedicant in children, especially with regards to the amnesia, confusion and long term behavioural disturbances. Clonidine has contrary to midazolam no effect on respiration. We believe that clonidine is a good alternative to midazolam as premedication in infants and children.

Oral clonidine does not change ventilatory response to carbon dioxide in sevoflurane-anesthetized children

BACKGROUND

Clonidine is a useful premedicant for pediatric anesthesia. The drug has potential for ventilatory depression. The aim of the current study was to determine the effects of clonidine premedication on the ventilatory response to hypercapnia during sevoflurane anesthesia using the carbon dioxide (CO(2)) steady state method.

METHODS

Sixty children (3-13 yr) were assigned to receive clonidine 4 microg x kg(-1) or placebo. Anesthesia was maintained with spontaneous breathing and 2% sevoflurane. Minute ventilation (VE), respiratory rate (RR), endtidal CO(2) pressure (P(ECO(2)), and arterial hemoglobin oxygen saturation (SpO2) were measured with a facemask tightly fitted before and during 7% CO(2) inhalation.

RESULTS

Compared with placebo, oral clonidine failed to reduce VE volume before CO(2) loading under general anesthesia with 2% sevoflurane. Inhalation of CO(2) increased VE. Oral clonidine did not attenuate the increase in VE induced by hypercapnic challenge under sevoflurane anesthesia. There were no differences in RR, P(ECO(2), or SpO2 between the placebo and clonidine groups before and during CO(2) loading.

CONCLUSION

These data suggest that oral clonidine is a suitable premedication for sevoflurane anesthesia under spontaneous breathing conditions in children.

Nonopioid additives to local anaesthetics for caudal blockade in children: a systematic review

BACKGROUND

Caudal epidural injection with local anaesthetics is a popular regional technique used in infants and children. A disadvantage of caudal blockade is the relatively short duration of postoperative analgesia. Opioids have traditionally been added to increase the duration of analgesia but have been associated with unacceptable side-effects. A number of nonopioid additives have been suggested to increase the duration of analgesia.

METHODS

A systematic review was conducted to identify randomized control trials comparing the use of local anaesthetic to local anaesthetic with nonopioid additives for caudal blockade in children. The increase in duration of analgesia and side-effects were compared.

RESULTS

The addition of clonidine to the local anaesthetic solution produces an increase in the duration of analgesia following caudal blockade in children (pooled weighted mean difference of 145 min with 95% confidence interval of 132-157 min). Side-effects include sedation and the potential for neonatal respiratory depression. Ketamine and midazolam further increase the duration of analgesia, however, the potential for neurotoxicity remains a concern.

CONCLUSION

The evidence examined shows an increased duration of analgesia with clonidine, ketamine and midazolam. However, we are not convinced that the routine use of these adjuvants in the setting of elective outpatient surgery shows improved patient outcome. It is unclear if the potential for neurotoxicity is outweighed by clinical benefits. Further testing, including large clinical trials, is required before recommending routine use of nonopioid additives for caudal blockade in children.