Oral sedation with midazolam and diphenhydramine compared with midazolam alone in children undergoing magnetic resonance imaging

BACKGROUND: The purpose of this study was to compare the safety and efficacy of oral midazolam and midazolam-diphenhydramine combination to sedate children undergoing magnetic resonance imaging (MRI). METHODS: We performed a prospective randomized double-blind study in 96 children who were randomly allocated into two groups. Group D received oral diphenhydramine (1.25 mg x kg(-1)) with midazolam (0.5 mg x kg(-1)), and Group P received oral placebo with midazolam (0.5 mg x kg(-1)) alone. Sedation scores, onset and duration of sleep were evaluated. Adverse effects, including hypoxemia, failed sedation, and the return of baseline activity, were documented. RESULTS: Diphenhydramine facilitated an earlier onset of midazolam sedation (P < 0.01), and higher sedation scores (P < 0.01). In children who received midazolam alone, 20 (41%) were inadequately sedated, compared with 9 (18%) children who received midazolam and diphenhydramine combination (P < 0.01). Time to complete recovery was not significantly different between the two groups. CONCLUSIONS: Our study indicates that the combination of oral diphenhydramine with oral midazolam resulted in safe and effective sedation for children undergoing MRI. The use of this combination might be more advantageous compared with midazolam alone, resulting in less sedation failure during MRI.     

Oral midazolam in children: effect of time and adjunctive therapy.

The purpose of this study was to determine the influence of timing and concomitant administration of atropine and/or meperidine on the perioperative effects of oral midazolam in children. In 154 healthy children, 1-8 yr old, we studied six oral preanesthetic medication regimens according to a randomized, double-blind protocol. Group A (placebo) received 5 mL of apple juice. The other five groups received medication with apple juice to a total volume of 5 mL, 20-60 min before induction of anesthesia. Group B received atropine (0.02 mg/kg); group C received midazolam (0.5 mg/kg); group D received midazolam (0.5 mg/kg) and atropine (0.02 mg/kg); group E received meperidine (1.5 mg/kg) and atropine (0.02 mg/kg); and group F received meperidine (1.5 mg/kg), atropine (0.02 mg/kg), and midazolam (0.5 mg/kg). The sedative effect of midazolam was maximal 30 min after oral administration. Ninety-five percent of the children who were separated from their parents within 45 min after oral midazolam administration (with or without atropine) had satisfactory separation scores (vs 66% of those separated after 45 min; P less than 0.02). Midazolam-treated patients were more cooperative with a mask induction of anesthesia compared with non-midazolam-treated children (83% vs 56%). Neither atropine nor meperidine appeared to significantly improve the effectiveness of oral midazolam. No preoperative changes in heart rate, respiratory rate, or hemoglobin oxygen saturation were noted in any of the treatment groups. Finally, oral midazolam did not prolong recovery even after outpatient procedures lasting less than 30 min. In conclusion, midazolam (0.5 mg/kg) given orally 30-45 min before induction of anesthesia is safe and effective without delaying recovery after ambulatory surgery.     

Premedication with midazolam in young children: a comparison of four routes of administration

BACKGROUND: We undertook a study to determine the effects of four routes of administation on the efficacy of midazolam for premedication. METHODS: In a randomized double-blind study, 119 unmedicated children, ASA I-II, aged 1.5-5 years, who were scheduled for minor elective surgery and who had been planned to received midazolam as a premedicant drug, were randomly assigned to one of four groups. Group I received intranasal midazolam 0.3 mg.kg-1; group II, oral midazolam 0.5 mg x kg(-1); group III, rectal midazolam 0.5 mg x kg(-1); and group IV, sublingual midazolam 0.3 mg x kg(-1). A blinded observer assessed the children for sedation and anxiolysis every 5 min prior to surgery. Quality of mask acceptance for induction, postanaesthesia care unit behaviour and parents' satisfaction were evaluated. Thirty patients were enrolled in each of groups I, III and IV. Twenty-nine patients were enrolled in group II. RESULTS: There were no significant differences in sedation and anxiety levels among the four groups. Average sedation and anxiolysis increased with time, achieving a maximum at 20 min in group I and at 30 min in groups II-IV. Patient mask acceptance was good for more than 75% of the children. Although the intranasal route provides a faster effect, it causes significant nasal irritation. Seventy-seven percent of the children from this group cried after drug administration. Most parents in all groups (67-73%) were satisfied with the premedication. CONCLUSIONS: Intranasal, oral, rectal and sublingual midazolam produces good levels of sedation and anxiolysis. Mask acceptance for inhalation induction was easy in the majority of children, irrespective of the route of drug administration.     

Oral transmucosal midazolam premedication for preschool children

PURPOSE: To evaluate the acceptance and effectiveness of 0.2 mg x kg(-1) of oral transmucosal midazolam as a premedicant in infants and preschool children. METHOD: In a randomized, prospective double-blind placebo controlled study, 44 healthy children, between the ages of eight months to six years, presenting for elective surgery were divided in two groups. The medicated group received 0.2 mg x kg(-1) of injectable midazolam mixed with an equal volume of strawberry syrup and the placebo group received plain syrup 0.08 ml x kg(-1). Medications were placed on the anterosuperior aspect of the child's tongue in 3-5 aliquots of 0.2-0.4 ml. A blinded observer assessed the acceptance of the medication by willingness to open the mouth for the next aliquot and the efficacy of the medication was assessed by ease of separation from the parent. RESULTS: Ninety-six percent of the children in the placebo group and 95% in the midazolam group willingly accepted the medication. Separation of children from parents was successful in 95% of the medicated children compared with 59% in the placebo group (P = 0.006). CONCLUSION: Oral midazolam in thick strawberry syrup, administered in small aliquots via the oral transmucosal route was well accepted and proved to be an effective premedicant in infants and preschool children.     

A comparison of two different doses of ketamine with midazolam and midazolam alone as oral preanaesthetic medication on recovery after sevoflurane anaesthesia in children

BACKGROUND: This investigation prospectively evaluated the effect of oral premedication of two different doses of ketamine with midazolam and midazolam alone on the recovery of children after sevoflurane anaesthesia. METHODS: In a randomized, double-blind study, 79 children (aged 1-8 years, ASA physical status I or II) were assigned to receive one of three premedications in a volume of 0.5 ml x kg(-1): group 1 received midazolam 0.5 mg x kg(-1) (MD); group 2 received midazolam 0.5 mg x kg(-1) with ketamine 1.8 mg x kg(-1) (MK-1); and group 3 received midazolam 0.5 mg x kg(-1) with ketamine 3 mg x kg(-1) (MK-2). The reactions of the children during administration were noted. Anaesthesia was induced by facemask with incremental sevoflurane administration. All children received alfentanil (15 micro g x kg(-1)). Tracheal intubation was facilitated by mivacurium (0.2 mg x kg(-1)). Anaesthesia was maintained with sevoflurane and an additional dose of alfentanil, if necessary. During recovery, the time interval between discontinuation of anaesthesia and arousal (spontaneous ventilation, extubation) were recorded. RESULTS: Emergence (spontaneous ventilation, extubation) and recovery times (discharge, Aldrete score=9) did not differ significantly between groups (P=0.24, P=0.59 and P=0.145, respectively). CONCLUSIONS: The combination of midazolam and ketamine as oral preanaesthetic medication did not significantly affect the recovery time of children after sevoflurane anaesthesia.     

Oral ketamine or midazolam or low dose combination for premedication in children

This randomized controlled trial was designed to evaluate whether the combination of low dose oral midazolam (0.25 mg/kg) and low dose oral ketamine (3 mg/kg) provides better premedication than oral midazolam (0.5 mg/kg) or oral ketamine (6 mg/kg). Seventy-eight children of ASA physical status I or II scheduled for elective ophthalmic surgery were randomly divided into three groups and given premedication in the holding area 30 minutes before surgery. Two subjects from each group vomited the medication and were excluded, leaving 72 subjects for further analysis. The onset of sedation was earlier in the combination group than the other two groups. At 10 minutes after premedication 12.5% in the combination group had an acceptable sedation score compared with none in the other two groups. After 20 minutes 54% in the combination group had an acceptable sedation score, 21% in the midazolam group and 16% in the ketamine group (P<0.05). There were no significant differences in the parental separation score, response to induction and emergence score. The mean time for best parental separation score was significantly less in the combination group (19+/-8 min) than either the midazolam (28+/-7) or ketamine (29+/-7 min) groups (P<0.05). Recovery was earlier in the combination group, as the time required to reach a modified Aldrete score of 10 was significantly less in the combination group (22+/-5 min) than in the oral midazolam (36+/-11 min) or ketamine (38+/-8 min) groups. The incidence of excessive salivation was significantly higher in the ketamine alone group (P<0.05). In conclusion, the combination of oral ketamine (3 mg/kg) and midazolam (0.25 mg/kg) has minimal side effects and gives a faster onset and more rapid recovery than ketamine 6 mg/kg or midazolam 0.5 mg/kg for premedication in children.     

A comparison of three doses of a commercially prepared oral midazolam syrup in children.

Midazolam is widely used as a preanesthetic medication for children. Prior studies have used extemporaneous formulations to disguise the bitter taste of IV midazolam and to improve patient acceptance, but with unknown bioavailability. In this prospective, randomized, double-blinded study we examined the efficacy, safety, and taste acceptability of three doses (0.25, 0.5, and 1.0 mg/kg, up to a maximum of 20 mg) of commercially prepared Versed((R)) syrup (midazolam HCl) in children stratified by age (6 mo to <2 yr, 2 to <6 yr, and 6 to <16 yr). All children were ASA class I-III scheduled for elective surgery. Subjects were continuously observed and monitored with pulse oximetry. Ninety-five percent of patients accepted the syrup, and 97% demonstrated satisfactory sedation before induction. There was an apparent relationship between dose and onset of sedation and anxiolysis (P < 0.01). Eight-eight percent had satisfactory anxiety ratings at the time of attempted separation from parents, and 86% had satisfactory anxiety ratings at face mask application. The youngest age group recovered earlier than the two older age groups (P < 0.001). There was no relationship between midazolam dose and duration of postanesthesia care unit stay. Before induction, there were no episodes of desaturation, but there were two episodes of nausea and three episodes of emesis. At the time of induction, during anesthesia, and in the postanesthesia care unit, there were several adverse respiratory events. Oral midazolam syrup is effective for producing sedation and anxiolysis at a dose of 0.25 mg/kg, with minimal effects on respiration and oxygen saturation even when administered at doses as large as 1.0 mg/kg (maximum, 20 mg) as the sole sedating medication to healthy children in a supervised clinical setting. IMPLICATIONS: Commercially prepared oral midazolam syrup is effective in producing sedation and anxiolysis in doses as small as 0.25 mg/kg; there is a slightly faster onset with increasing the dose to 1.0 mg/kg. At all doses, 97% of patients demonstrated satisfactory sedation, whereas 86% demonstrated satisfactory anxiolysis when the face mask was applied.     

Jet injector compared with oral midazolam for preoperative sedation in children

BACKGROUND: This study compared onset of sedation and satisfaction with two needleless jet injectors with the oral route for the administration of midazolam. METHODS: Forty-five children ages 1-6 years were randomly assigned to receive either 0.5 mg kg(-1) oral midazolam, 0.2 mg kg(-1) subcutaneous midazolam by J-Tip injector or 0.2 mg kg(-1) intramuscular midazolam by Bioject injector. After midazolam administration the children were monitored for oxygen saturation, heart rate and level of sedation (0, alert; 1, calm; 2, drowsy; 3, dozing; 4, asleep) every 2 min for 20 min by a physician blinded to the route of administration. Patient satisfaction, resistance to treatment, success of delivery, problems with separation, and acceptance of mask at the time of induction were evaluated after midazolam treatment. RESULTS: The Bioject showed a faster onset of sedation than either the J-Tip injector or the oral midazolam (P < 0.05). The children were significantly less satisfied with the Bioject and J-Tip administration vs oral midazolam (P < 0.05). There were no differences in resistance, success of delivery, problems with separation, mask acceptance, arterial oxygen saturation or heart rate. CONCLUSION: Despite children being less satisfied with Bioject injection of midazolam, the procedure is safe, effective and provides a more rapid onset of preoperative sedation in children than either the J-Tip injection or oral route.     

Structured sedation programme for magnetic resonance imaging examination in children

One thousand, eight hundred and fifty-seven patients underwent magnetic resonance imaging following the establishment of a structured sedation programme. Forty-eight of these patients came from the intensive care unit with a secure airway and were therefore excluded from any further analysis. Oral sedation was to be given to children aged 5 years and below. For children >/= 6 years old, oral sedation could be given only if their level of co-operation was judged to be inadequate by the referring physician. Oral sedation consisted of chloral hydrate 90 mg x kg-1 (maximum 2.0 g) orally with or without rectal paraldehyde 0.3 ml x kg-1. All magnetic resonance imaging requests for children who failed oral sedation as well as those referred for general anaesthesia from the outset were reviewed by a consultant anaesthetist who then allocated patients to undergo the procedure with either general anaesthesia or intravenous sedation. Scans requiring intravenous sedation or general anaesthesia were performed in the presence of a consultant anaesthetist. Intravenous sedation consisted of either a propofol 0.5 mg x kg-1 bolus followed by an infusion (maximum 3 mg x kg-1 x h-1) or midazolam 0.2-0.5 mg x kg-1 boluses. General anaesthesia was given using spontaneous ventilation with a mixture of 66% nitrous oxide in oxygen and isoflurane following either inhalation (sevoflurane) or intravenous (propofol) induction. One thousand and thirty-nine (57.4%) of the scans were done without sedation whereas 93 scans were performed during the consultant anaesthetist supervised sessions. Oral sedation failed in 50 out of 727 patients (6.9%). Eighty-seven per cent of children aged 5 years and below needed sedation compared with 4.5% of those aged over 10 years. Two patients who had only received chloral hydrate developed significant respiratory depression. This structured sedation programme has provided a safe, effective and efficient use of limited resources.     

Oral midazolam with an antacid may increase the speed of onset of sedation in children prior to general anaesthesia

BACKGROUND: The aim of the study was to see whether sodium citrate solution would speed the gastric absorption of oral midazolam. METHODS: Forty presurgical ASA I and II patients (aged 2-6 years) were randomly assigned to one of two groups. Group I received midazolam 0.5 mg x kg(-1) mixed with sodium citrate while group II (control) received midazolam 0.5 mg x kg(-1) mixed with Hawaiian fruit punch. RESULTS: There was no statistical difference between the ages, weights, preoperative sedation and anxiety scores in the two groups. After premedication, the onset of sedation (mean +/- SD) measured by the first change in sedation score was found to be significantly faster (P < 0.05) in group I (17.8 +/- 7.11) compared with group II (21.9 +/- 5.34). There was no statistical difference in anxiety at any time intervals, separation or induction scoring for both groups. Gastric volumes and the pH of gastric aspirates between the two groups were not statistically significant. CONCLUSIONS: The time to onset of sedation can potentially be shortened, by using a preparation of intravenous midazolam and antacid, given orally.     

Comparison of the safety and efficacy of intranasal midazolam or sufentanil for preinduction of anesthesia in pediatric patients.

Nasal administration of sufentanil or midazolam is effective for preinduction of pediatric patients, but there are no data on which to base a choice between them. This blinded randomized study compares behavioral and physiologic responses to sedation with one of these medications followed by inhalation or intravenous induction. Ninety-five patients aged 0.5-10 yr scheduled for elective surgery were stratified by age: 30 infants 0.5-2 yr, 38 preschoolers 2.1-5 yr, and 27 school-age children 5.1-10 yr. They were randomized to receive 0.04 ml/kg of midazolam (0.2 mg/kg) or sufentanil (2 micrograms/kg). Hemoglobin oxygen saturation by pulse oximetry (SpO2) and sedation score were recorded prior to drug administration, at 2.5-min intervals for 10 min, at separation, and during induction with graded halothane in oxygen. Intubation was performed under deep halothane or 3 mg/kg of thiopental and 0.1 mg/kg of pancuronium. Chest wall compliance was assessed qualitatively in all patients prior to intubation. To assess the effects of a mild standardized stress on unpremedicated patients, 75 of the children with parents present were scored before and after oximeter probe placement: of these, in 63% the sedation score did not change; 33% appeared more anxious; and only 4% seemed reassured. Children of all ages reacted negatively to physicians, and 23% were crying prior to administration of drugs. Sufentanil appeared less unpleasant to receive than midazolam: children cried 46 +/- 100 versus 76 +/- 73 s (P less than 0.05), respectively, but by 7.5 min, no child was crying. Median behavior scores at maximum anxiolysis were not different, but response to sufentanil was more variable.(ABSTRACT TRUNCATED AT 250 WORDS)     

A comparison of midazolam, alfentanil and propofol for sedation in oupatient intraocular surgery

PURPOSE: To determine the ideal sedative regimen for intraocular surgery under peribulbar or retrobulbar block. The addition of alfentanil and or propofol to midazolam was evaluated with regard to hemodynamic variables, respiratory rate, pain, anxiety, sedation, postoperative recovery and patient satisfaction. METHODS: Eighty two patients aged between 50 and 85 were recruited into this prospective, randomised, double blind study. Patients, in four groups, received 0.015 mg x kg(-1) midazolam, 5 microg x kg(-1) alfentanil and 0.15 mg x kg(-1) propofol; 0.015 mg x kg(-1) midazolam and 0.15 mg x kg(-1) propofol; 0.015 mg x kg(-1) midazolam and 5 microg x kg(-1) alfentanil or 0.015 mg x kg(-1) midazolam alone. Blood pressure, heart rate, respiratory rate, pain, anxiety and sedation scores were measured. Times to discharge from the Post Anesthesia Care Unit (PACU) and Day Surgery Unit (DSU) were documented. A 24 hr telephone interview was carried out to determine patient satisfaction. RESULT: Systolic blood pressure of patients in groups that had received alfentanil was 6% lower than that of patients who had not (P<0.05) at the time of insertion of intraocular block. Patients in the alfentanil groups also had lower respiratory rates during the first 15 min after drug administration, but all patients were given supplemental oxygen therefore oxygen saturation was unaffected. Pain scores of patients who had been given alfentanil were lower during the first postoperative hour than those who had not. CONCLUSION: The addition of alfentanil to midazolam is advantageous in providing sedation for insertion of intraocular block.     

Comparative evaluation of midazolam and ketamine with midazolam alone as oral premedication

BACKGROUND: Oral premedication with midazolam and ketamine is widely used in pediatric anesthesia to reduce emotional trauma and ensure smooth induction. However, various dosing regimens when used alone or in combination have variable efficacy and side effect profile. The aim of our study was to investigate and compare the efficacy of oral midazolam alone with a low-dose combination of oral midazolam and ketamine. METHODS: We performed a prospective randomized double-blind study in 100 children who were randomly allocated into two groups. Group M received 0.5 mg.kg(-1) oral midazolam and group MK received 0.25 mg.kg(-1) oral midazolam with 2.5 mg.kg(-1) oral ketamine. The preoperative sedation score, ease of parental separation and ease of mask acceptance were evaluated on a 4-point scale. The time to recovery from anesthesia and to achieve satisfactory Aldrete score was also noted. RESULTS: Uniform and acceptable sedation scores were seen in both the groups (group M 95.9%; group MK 97.96%), without any serious side effects. However, the combination offered significantly more children in an awake, calm and quiet state, who were easily separated from their parents (73.46% in MK vs 41% in group M). The induction scores were comparable between the groups. The recovery room characteristics and time to achieve satisfactory Aldrete score were also comparable between the two groups. CONCLUSIONS: Oral midazolam alone and a combination of midazolam with ketamine provide equally effective anxiolysis and separation characteristics. However, the combination provided more children in an awake, calm and quiet state who could be separated easily from parents.     

Pentobarbital vs chloral hydrate for sedation of children undergoing MRI: efficacy and recovery characteristics

BACKGROUND: Chloral hydrate (CH) sedation for magnetic resonance imaging (MRI) is associated with significant failure rates, adverse events and delayed recovery. Pentobarbital (PB), reportedly produces successful sedation in 98% of children undergoing diagnostic imaging. This study compared the efficacy, adverse events and recovery characteristics of CH vs PB in children undergoing MRI. METHODS: With Institutional Review Board approval and written consent, children were randomly assigned to receive intravenous (i.v.) PB (maximum 5 mg x kg(-1) in incremental doses) or oral CH (75 mg x kg(-1)) prior to MRI. Sedation was augmented with 0.05 mg x kg(-1) doses of i.v. midazolam (maximum 0.1 mg x kg(-1)) as necessary. Adverse effects, including hypoxaemia, failed sedation, paradoxical reactions and behavioural changes, the return of baseline activity, and parental satisfaction were documented. The quality of MRI scans was evaluated by a radiologist blinded to the sedation technique. RESULTS: PB facilitated an earlier onset of sedation (P = 0.001), higher sedation scores (P = 0.01), and less need for supplemental midazolam compared with CH. Severe hypoxaemia occurred in two children (6%) in the PB group. Fourteen per cent of the PB group experienced a paradoxical reaction, 9% sedation failure and 11% major motion artefact, compared with 0% (P = 0.05), 3 and 2% (P = NS), respectively, in the CH group. CH and PB were both associated with a high incidence of motor imbalance, and agitation. However, children who received PB had a slower return to baseline activity (P = 0.04). CONCLUSIONS: Although PB facilitated a quicker sedation onset and reduced the requirement for supplemental sedation, it produced a higher incidence of paradoxical reaction and prolonged recovery with a similar failure rate compared with CH.     

A comparison of oral clonidine and oral midazolam as preanesthetic medications in the pediatric tonsillectomy patient

We compared the effects of oral clonidine (4 microg/kg) and midazolam (0.5 mg/kg) on the preanesthetic sedation and postoperative recovery profile in children during tonsillectomy with or without adenoidectomy. In a double-blinded, double-dummy study design, 134 ASA physical status I-II children aged 4-12 yr were randomized to receive a combination of either clonidine and placebo (Group A), or placebo and midazolam (Group B) at 60-90 min and 30 min, respectively, before the induction of anesthesia. Children in the clonidine group exhibited more intense anxiety on separation and during induction of anesthesia via a mask as measured by the modified Yale Preoperative Anxiety Scores. They also had significantly lower mean intraoperative arterial blood pressures, shorter surgery, anesthesia, and emergence times, and a decreased need for supplemental oxygen during recovery compared with the midazolam group. However, the clonidine group had larger postoperative opioid requirements, maximum excitement and pain scores based on the Children's Hospital of Eastern Ontario scale in the Phase 1 postanesthetic care unit. There were no differences between the two groups in the times to discharge readiness, postoperative emesis, unanticipated hospital admission rates, postdischarge maximum pain scores, and 24 h analgesic requirements. The percentage of parents who were completely satisfied with the child's preoperative experience was significantly higher in the midazolam group. There were no differences in parental satisfaction with the recovery period. We conclude that under the conditions of this study, oral midazolam is superior to oral clonidine as a preanesthetic medication in this patient population. Implications: We compared preanesthetic sedation and postoperative recovery after oral clonidine (4 microg/kg) and midazolam (0.5 mg/kg) in children during tonsillectomy. The clonidine group had greater preoperative anxiety and shorter surgery and anesthesia times, but required more postoperative analgesia. Delayed recovery and discharge times did not differ. Midazolam was superior to clonidine as oral preanesthetic medication for these patients.     

Premedication of children with oral midazolam

In a randomized, double-blind, placebo-controlled study, the safety, efficacy and feasibility of oral midazolam premedication in children were evaluated in an ambulatory surgery unit. Eighty unmedicated children (ASA PS I or II, ages 1-6 yr) were randomly assigned to one of four groups receiving midazolam 0.5, 0.75, or 1.0 mg.kg-1 or a placebo 30 min before separation from parents. Heart rate, systolic blood pressure, arterial oxygen saturation, respiratory rate, sedation and anxiolysis scores were recorded before premedication, every five minutes for 30 min and then during induction of anaesthesia and recovery. We found that heart rate, systolic blood pressure, arterial oxygen saturation and respiratory rate were unchanged during the study. Sedation and anxiolysis scores in the midazolam-treated groups were greater than those in the placebo group and that anxiolysis at the time of separation from the parents was judged excellent in 80-90% of the children who received midazolam. However, sedation and anxiolysis did not differ among the three midazolam groups. Mean times to discharge from hospital were similar for all four groups. The side effects, loss of balance and head control, blurred vision and dysphoric reactions were observed only in the 0.75 and 1.0 mg.kg-1 midazolam groups. We conclude that oral midazolam 0.5 mg.kg-1 is a safe and effective premedication and that 0.75 and 1 mg.kg-1 while offering no additional benefit, may cause more side effects.     

Premedication in children: a comparison of oral midazolam and oral clonidine

BACKGROUND: Oral premedication is widely used in pediatric anesthesia to reduce preoperative anxiety and ensure smooth induction. Midazolam is currently the most commonly used premedicant, but good results have also been reported with clonidine. The aim of the present study was to compare clinical effects of oral midazolam and oral clonidine. METHODS: We performed a prospective open study in 64 children who were randomly assigned to receive either oral midazolam 0.5 mg.kg (-1) (group M) or oral clonidine 4 microg.kg (-1) (group C) prior to mask induction. Drug acceptance, preoperative sedation and anxiolysis, quality of mask acceptance, recovery profile and parental satisfaction were evaluated. RESULTS: The taste of oral clonidine was judged as significantly better; 14% of children rejected oral midazolam. Onset of sedation was significantly faster after premedication with midazolam (30+/-13.1 min) than with clonidine (38.5+/-14.6 min), but level of sedation was significantly better after premedication with clonidine. Quality of mask induction was equally successful in both groups. A steal-induction was performed in 66% of patients of group C, but none in group M. We observed a trend towards an increased incidence of emergence agitation after premedication with midazolam. Parental satisfaction was significantly higher in group C. CONCLUSIONS: In this study, premedication with oral clonidine appeared to be superior to oral midazolam. Quality of mask acceptance was comparable between groups, but oral clonidine was better accepted by the child, produced more effective preoperative sedation, showed a trend towards better recovery from anesthesia and had a higher degree of parental satisfaction.     

枸橼酸钠对先天性心脏病患儿咪达唑仑口服术前用药效果的影响

目的 探讨枸橼酸钠对先天性心脏病患儿咪达唑仑口服术前用药效果的影响.方法 选择拟行房缺修补术、室缺修补术或动脉导管结扎术的患儿40例,年龄2～6岁,体重12～20 kg,ASA分级Ⅱ或Ⅲ级,随机分为2组(n=20):对照组(C组)和枸橼酸钠组(S组).口服术前用药:S组为咪达唑仑0.12 ml/kg、氯胺酮0.12 ml/kg、葡萄糖0.12 ml/kg和枸橼酸钠0.12 ml/kg,等容积混合;C组为咪达唑仑0.12 ml/kg、氯胺酮0.12 ml/kg和葡萄糖0.24 ml/kg,等容积混合.用pH值1.75的盐酸模拟胃液,与两组配置好的药液在体外混合,分别测定两组混合药液的pH值.记录术前焦虑评分,口服术前药(0.48 ml/kg)后,记录咪达唑仑起效时间、镇静评分和与父母分离评分.入室后记录HR、MAP和SpO2,记录患儿对静脉穿刺反应评分和服药后的不良反应发生情况.结果 与盐酸混合后C组药物pH值为1.97,S组为4.52.两组患儿均成功口服术前药物.与C组比较,S组与父母分离评分、镇静评分和静脉穿刺反应评分降低,咪达唑仑起效时间缩短(P＜0.05),术前焦虑评分差异无统计学意义(P＞0.05);两组患儿入室时HR、MAP和SpO2均在正常范围.两组患儿在服药后均未出现恶心呕吐、呼吸抑制等不良反应.结论 作为先天性心脏病患儿口服术前用药时,枸橼酸钠可提高药液的pH值,缩短咪达唑仑起效时间,加强镇静效果.     

Effects of preanesthetic administration of midazolam, clonidine, or dexmedetomidine on postoperative pain and anxiety in children

BACKGROUND: A growing interest in the possible influences of pre- and postoperative anxiety and pain scores as outcomes of surgical treatment and benefits of anxiety or pain-reducing interventions has emerged. The aim of this study was to evaluate the influence of three different premedication regimens on postoperative pain and anxiety in children. METHODS: A prospective, randomized, open-label clinical trial enrolled 60 schoolchildren. They were randomized for premedication with oral midazolam 0.5 mgxkg(-1), oral clonidine 4 microgxkg(-1), or transmucosal dexmedetomidine (DEX) 1 mug.kg(-1), submitted to a pre- and postoperative evaluation of anxiety with the State-Trait Anxiety Inventory for Children and asked to report any pain in verbal and visual analog scales. We also evaluated secondary outcomes such as parents' anxiety, sedation, separation from parents, adverse effects and hemodynamic status. RESULTS: Dexmedetomidine and clonidine were related to lower scores of pain than midazolam. alpha(2)-agonists produced lower scores of peroperative mean arterial pressure and heart rate than midazolam. Both groups had similar levels of postoperative state-anxiety in children. There was no difference in preanesthesia levels of sedation and response to separation from parents between groups. CONCLUSIONS: These findings indicate that children receiving clonidine or DEX preoperatively have similar levels of anxiety and sedation postoperatively as those receiving midazolam. However, children given alpha(2)-agonists had less perioperative sympathetic stimulation and less postoperative pain than those given midazolam.     

Dexmedetomidine for pediatric MRI sedation: a review of a series of cases

BACKGROUND: The aim of this review was to determine whether dexmedetomidine alone provided satisfactory conditions for children undergoing magnetice resonance imaging (MRI). METHODS: A retrospective review of 21 patients was undertaken, (age range: 1-8 years, weight 10-27 kg) who received dexmedetomidine to provide deep sedation for an MRI procedure. RESULTS: In the initial eight patients who received dexmedetomidine (bolus 0.5-1.5 mg.kg(-1) and infusion rate 1-1.5 mg.kg(-1).h(-1)) by itself, movement occurred in five of them, even when the maximum suggested dose was used (1 microg.kg(-1).h(-1)). Midazolam (0.1 mg.kg(-1)) i.v. was given as an adjunct to the following 13 patients (dexemdetomidine doses were lower: bolus 1 mg.kg(-1), infusion 0.5-1 mg.kg(-1).h(-1)). Only one patient moved within this group. The mean time to discharge postprocedure was 90 min. There were no differences with respect to recovery or discharge times between those who did or did not receive midazolam. No cardiac or respiratory complications were noted. CONCLUSIONS: The use of dexmedetomidine for MRI sedation by itself was more unpredictable than anticipated from the published case reports of its use.