Reevaluation of rectal ketamine premedication in children: comparison with rectal midazolam

BACKGROUND: Results of previous studies of rectal ketamine as a pediatric premedication are clouded because of lack of dose-response relation, inappropriate time of assessing sedative effects, and previous administration or coadministration of benzodiazepines. Therefore, the authors reevaluated the efficacy of rectally administered ketamine in comparison with 1 mg/kg rectal midazolam. METHODS: Sixty-six infants and children (age, 7-61 months) who were American Society of Anesthesiologists physical status I and who were undergoing minor surgeries as in-patients were randomized to receive 5 mg/kg ketamine (n = 16), 7 mg/kg ketamine (n = 16), 10 mg/kg ketamine (n = 17), or 1 mg/kg midazolam (n = 17) via rectum. A blinded observer scored sedation 45 min and 15 min after administration of ketamine and midazolam, respectively, when children were separated from parent(s) for inhalational induction. All children underwent standardized general anesthesia with sevoflurane, nitrous oxide, and oxygen with endotracheal intubation. Blood pressure, heart rate, and oxyhemoglobin saturation were determined before, during, and after anesthesia. Postoperative recovery characteristics and incidence of adverse reactions were also assessed. RESULTS: Most children (88%) who received rectally 10 mg/kg ketamine or 1 mg/kg midazolam separated easily from their parents compared with those (31%) who received 7 or 5 mg/kg rectal ketamine (P < 0.05). Similarly, more children who received 10 mg/kg ketamine or 1 mg/kg midazolam underwent mask induction without struggling or crying compared with those who received 7 or 5 mg/kg ketamine (P < 0.05). There were no clinically significant changes in blood pressure, heart rate, and oxyhemoglobin saturation after administration of either drug. Immediately after surgery, more children receiving midazolam or 5 mg/kg ketamine were agitated compared with 7 or 10 mg/kg ketamine. Ketamine, 7 and 10 mg/kg, provided postoperative analgesia, but the largest dose of ketamine was associated with delayed emergence from general anesthesia. CONCLUSIONS: The results indicate that rectally administered ketamine alone produces dose-dependent sedative effects in children, when evaluated at its predicted peak plasma concentration. Ketamine, 10 mg/kg, has a delayed onset but is as effective as 1 mg/kg midazolam for sedating healthy children before general anesthesia. However, 10 mg/kg rectal ketamine is not recommended for brief surgeries because of prolonged postoperative sedation.     

Reevaluation of Rectal Ketamine Premedication in Children: Comparison with Rectal Midazolam

Background: Results of previous studies of rectal ketamine as a pediatric premedication are clouded because of lack of dose-response relation, inappropriate time of assessing sedative effects, and previous administration or coadministration of benzodiazepines. Therefore, the authors reevaluated the efficacy of rectally administered ketamine in comparison with 1 mg/kg rectal midazolam.

Methods: Sixty-six infants and children (age, 7-61 months) who were American Society of Anesthesiologists physical status I and who were undergoing minor surgeries as in-patients were randomized to receive 5 mg/kg ketamine (n = 16), 7 mg/kg ketamine (n = 16), 10 mg/kg ketamine (n = 17), or 1 mg/kg midazolam (n = 17) via rectum. A blinded observer scored sedation 45 min and 15 min after administration of ketamine and midazolam, respectively, when children were separated from parent(s) for inhalational induction. All children underwent standardized general anesthesia with sevoflurane, nitrous oxide, and oxygen with endotracheal intubation. Blood pressure, heart rate, and oxyhemoglobin saturation were determined before, during, and after anesthesia. Postoperative recovery characteristics and incidence of adverse reactions were also assessed.

Results: Most children (88%) who received rectally 10 mg/kg ketamine or 1 mg/kg midazolam separated easily from their parents compared with those (31%) who received 7 or 5 mg/kg rectal ketamine (P < 0.05). Similarly, more children who received 10 mg/kg ketamine or 1 mg/kg midazolam underwent mask induction without struggling or crying compared with those who received 7 or 5 mg/kg ketamine (P < 0.05). There were no clinically significant changes in blood pressure, heart rate, and oxyhemoglobin saturation after administration of either drug. Immediately after surgery, more children receiving midazolam or 5 mg/kg ketamine were agitated compared with 7 or 10 mg/kg ketamine. Ketamine, 7 and 10 mg/kg, provided postoperative analgesia, but the largest dose of ketamine was associated with delayed emergence from general anesthesia.     

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.     

Ketamine reduces swallowing-evoked pain after paediatric tonsillectomy

BACKGROUND: Ketamine efficacy as an analgesic adjuvant has been studied in several clinical settings with conflicting results. The aim of this study was to investigate the effect of ketamine on spontaneous and swallowing-evoked pain after tonsillectomy. METHODS: Fifty children were randomized to receive premedication with either ketamine 0.1 mg kg(-1) i.m. or placebo given 20 min before induction of a standard general anaesthesia. All children received rectal diclofenac 2 mg kg(-1) and fentanyl 1 micro g kg(-1) i.v. before surgery. RESULTS: The ketamine group showed significantly lower pain scores both at rest and on swallowing, with less total paracetamol consumption (P < 0.05) during the 24 h after surgery. Significantly more patients required postoperative morphine titration in the control group (P < 0.05). The time to the first oral intake, and duration of i.v. hydration, were significantly shorter and the quality of oral intake was significantly better in the ketamine group (P < 0.05). There were no differences in the incidence of vomiting or dreaming between the groups. CONCLUSION: Premedication with a small dose of ketamine reduces swallowing-evoked pain after tonsillectomy in children who received an analgesic regimen combining an opioid and a NSAID.     

Diclofenac and flurbiprofen with or without clonidine for postoperative analgesia in children undergoing elective ophthalmological surgery

We conducted a prospective, randomized study to compare the efficacy of preoperative diclofenac, flurbiprofen, and clonidine, given alone, as well as the combination of diclofenac and clonidine, and flurbiprofen and clonidine in controlling postoperative pain in 125 children. The patients (ASA I, 2-12 years) undergoing elective ophthalmological surgery were allocated to one of five groups: rectal diclofenac 2 mg.kg(-1) following oral placebo premedication, i. v. flurbiprofen 1 mg.kg(-1) following placebo premedication, oral clonidine premedication, rectal diclofenac 2 mg.kg(-1) following clonidine, and i.v. flurbiprofen 1 mg.kg(-1) following clonidine. The children received clonidine (4 microg.kg(-1)) or placebo 105 min before anaesthesia. Diclofenac or flurbiprofen was given immediately after induction of anaesthesia. Anaesthesia was induced and maintained with sevoflurane and nitrous oxide in oxygen. Postoperative pain was assessed by a blinded observer using a modified objective pain scale (OPS). No opioids were administered throughout the study. Rectal diclofenac 2 mg.kg(-1) i.v. flurbiprofen 1 mg.kg(-1), oral clonidine 4 microg.kg(-1) provided similar OPS scores and requirement for supplementary analgesics during 12 h after surgery. Combination of oral clonidine and one of these nonsteroidal analgesics minimized postoperative pain. Our findings suggest that this combined regimen may be a promising prophylactic approach to postoperative pain control in children undergoing ophthalmological surgery.     

Analgesia for paediatric tonsillectomy and adenoidectomy with intramuscular clonidine

BACKGROUND: After undergoing tonsillectomy and adenoidectomy (T&A), children may experience significant pain. Clonidine, an alpha2 agonist, exhibits significant analgesic properties. The current investigation sought to determine whether intramuscular (I.M.) clonidine would decrease pain in paediatric patients undergoing T&A. METHODS: Thirty-nine children undergoing elective T&A were studied. Following inhalational anaesthetic induction, fentanyl (2 microg x kg(-1)) was given intravenously, acetaminophen (paracetamol) (30 mg.kg-1) was given rectally and the children then randomly received an i.m. injection of either normal saline or clonidine (2 microg x kg(-1)). Perioperative analgesic requirements in the postanaesthesia care unit and at home following hospital discharge were evaluated. RESULTS: There were no significant demographic, analgesic consumption, haemodynamic or pain score differences between the groups. CONCLUSIONS: We do not recommend adding i.m. clonidine (2 microg x kg(-1)) to the analgesic regimen of children undergoing tonsillectomy and adenoidectomy.     

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.     

Oral atropine enhances the risk for acid aspiration in children

Two modes of administration of an anticholinergic drug were compared in 58 healthy children undergoing adenoidectomy. The study was double-blind and randomized. All children were premedicated with oral midazolam 0.5 mg/kg. Twenty-nine children received oral atropine 0.03 mg/kg (Group A) and the rest were given i.v. glycopyrrolate 0.005 mg/kg at the induction of anaesthesia (Group G). In Group A, of 29 children, the stomach was empty in 2, pH was less than 2.5 in 23, the gastric volume was greater than 0.4 ml/kg in 19, and both these risk factors were present in 17 children. The same figures in Group G were 5 (NS), 14 (P less than 0.05), 10 (P less than 0.05) and 9 (P less than 0.05) children, respectively. The antisialagogue effect was similar in both groups.     

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 different doses of oral ketamine for premedication of children

BACKGROUND AND OBJECTIVE: A need exists for a safe and effective oral preanaesthetic medication for use in children undergoing elective surgery. The study sought to define the dose of oral ketamine that would facilitate induction of anaesthesia without causing significant side-effects. METHODS: We studied 80 children undergoing elective surgery under general anaesthesia who received oral ketamine 4, 6 or 8 mg kg(-1) in a prospective, randomized, double-blind placebo controlled study. We compared the reaction to separation from parents, transport to the operating room, the response to intravenous cannula insertion and application of an anaesthetic facemask, the induction of anaesthesia and recovery from anaesthesia. RESULTS: In the group receiving ketamine 8 mg kg(-1), the children were significantly calmer than those of the other groups, and anaesthesia induction was more comfortable. Recovery from anaesthesia was longer in the group receiving ketamine 8 mg kg(-1) compared with the other groups, but no differences between the groups were observed after 2 h in the recovery room. CONCLUSIONS: It is concluded that oral ketamine 8 mg kg(-1) is an effective oral premedication in inpatient children undergoing elective surgery.     

Effects of oral clonidine premedication on side effects of intravenous ketamine anesthesia: a randomized, double-blind, placebo-controlled study

STUDY OBJECTIVE: To determine the effects of oral clonidine premedication on hemodynamic changes during the entire course of ketamine anesthesia and incidence of postoperative adverse reactions. DESIGN: Randomized, prospective, double-blind, placebo-controlled study. SETTING: Department of Anesthesiology, University of Tsukuba Hospital, Ibaraki, Japan. PATIENTS: 39 ASA physical status I and II patients undergoing superficial surgeries. INTERVENTIONS: Placebo, clonidine 2.5 micrograms/kg, and clonidine 5 micrograms/kg groups received respective doses of oral clonidine 90 minutes prior to surgery. Anesthesia was induced with ketamine 2 mg/kg intravenously (i.v.), trachea was intubated, and anesthesia was maintained with 67% nitrous oxide, oxygen, and supplemental ketamine (1 mg/kg) when systolic blood pressure and heart rate (HR) exceeded 180 mmHg and 100 bpm, respectively. MEASUREMENTS AND MAIN RESULTS: In the clonidine 2.5 micrograms/kg group, HR response to tracheal intubation was significantly less, while in the clonidine 5 micrograms/kg group both mean arterial pressure and HR responses were significantly suppressed, compared with the placebo group. Intraoperative coefficients of variations of HR were significantly less in both clonidine groups than the placebo group. Incidence of nightmare and degree of salivation were significantly less in the clonidine 5 micrograms/kg group than in the placebo group. CONCLUSION: Oral clonidine 2.5 micrograms/kg and clonidine 5 micrograms/kg attenuates cardiostimulatory effects, while clonidine 5 micrograms/kg was associated with reduced incidence and severity of nightmare and salivation attributable to i.v. ketamine.     

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.     

Rectal administration of midazolam as an adjuvant in the premedication of infants

In a randomized, double-blind study of premedication in 69 infants aged between 13 and 48 months the effects of 0.82 mg/kg midazolam or diazepam rectally plus 2.0 mg/kg ketamine i.m., or the administration of 2.4 mg/kg ketamine i.m. alone was studied. A satisfying result of 94.1% following the premedication with midazolam/ketamine, of 82.9% with diazepam/ketamine and of 81.3% with ketamine alone was observed. Premedication with midazolam/ketamine was the best one in the review of vigilance, agitation, and behaviour of defence against the mask at the beginning of anaesthesia. The amnestic action of midazolam extinguished the infants' memory of the i.m.-injection. The dose of midazolam/ketamine is suitable as an effective and positive method for premedication of infants within 20 min.     

Comparison of methohexital and pentobarbital for premedication in children

Thirty children scheduled for elective orchiopexy or herniotomy were consecutively assigned at random to premedication with methohexital 80 mg/ml, 20 mg/kg rectally, 15 min before transportation to the operating room, or pentobarbital 28 mg/ml, 7 mg/kg rectally, 45 min before transportation. The quality of premedication was recorded at induction with halothane 1-2% and 60% N2O in O2 by mask. All patients received a caudal injection of bupivacaine 1.9 mg/ml, 1.25 ml/kg before surgery. Following completion of anaesthesia, the postoperative wake-up time and the duration of stay in the post-operative recovery room were recorded. The degree and quality of recovery were assessed using the Aldrete score every 30 min until discharge from the recovery room. The group of children receiving methohexital showed a highly significantly shorter awakening time, and a highly significantly shorter stay in the recovery room compared to the pentobarbital group. The children in both groups had a quiet, easy recovery without significant signs of confusion or agitation, and no difference in quality of recovery could be shown. Emergence delirium or agitation in connection with pentobarbital premedication and a possible relation to postoperative pain is discussed.     

The influence of midazolam on the plasma concentrations of bupivacaine and lidocaine after caudal injection of a mixture of the local anesthetics in children

Twenty children undergoing surgery received a caudal block using 1 ml per kg of a mixture of 50% lidocaine (1%) and 50% bupivacaine (0.25%). They were randomly allocated to two groups, one of which received midazolam 0.4 mg/kg rectally as premedication. Midazolam administration resulted in a significantly lower AUC value for lidocaine but did not influence the plasma concentrations of bupivacaine.     

Comparative clinical studies on parenteral and oral premedication in childhood with special regard to the volume and acidity of the gastric juice

90 children of age between 1 and 10 years who were scheduled for adenotomy were randomized into 3 premedication-groups. Group 1 received no premedication, group 2 chlorprothixene 1 mg/kg i.m. and group 3 chlorprothixene 2 mg/kg orally. Prior to induction of anaesthesia 63.3% of the unpremedicated children were anxious or crying, in contrast to 23.3% of the children given oral or i.m. premedication. With respect to the reaction on venepuncture with a Butterfly G 23, there was no significant difference between the groups. The volume of gastric acid (median values) was 0.056 ml/kg in group 1, 0.063 ml/kg in group 2, and 0.068 ml/kg in group 3, with a pH of 2.0, 1.5 and 2.0 respectively. One hour after operation 44.8% of the children in group 1, 92.6% in group 2 and 84.6% in group 3 were calm or sleeping. Premedication definitively improves the pre- and postoperative management of children. We now recommend oral chlorprothixene for the premedication of children because the effect of this oral premedication is equivalent to i.m. application, and the oral route has no influence on the quantity or acidity of gastric contents.     

A comparison of midazolam with trimeprazine as an oral premedicant for children

The effect of oral premedication was investigated in a double-blind, randomised trial in 85 children undergoing tonsillectomy and/or adenoidectomy. Orally administered midazolam 0.5 mg.kg⁻¹ given 30 min pre-operatively was compared with trimeprazine 2 mg.kg⁻¹ given 90 min pre-operatively and a placebo preparation. Compliance, sedation and ease of induction were assessed as were the duration and quality of recovery. Following premedication with midazolam none of the patients was anxious, crying or distressed on leaving the ward, compared with 2/28 in the trimeprazine group and 5/28 in the placebo group (p =0.0007). More patients were calm and quiet on arrival in the anaesthetic room following midazolam than following trimeprazine, with both premedicant agents comparing favourably with placebo. There was no significant difference between the three groups in the time to recovery or the sedation score on discharge to the ward. Midazolam is a safe and effective oral premedicant for children.     

Arterial oxygen saturation in children receiving rectal midazolam as premedication for oral surgical procedures

Eighty healthy children, between the ages of 2 and 7 years, undergoing dental procedures were monitored with a pulse oximeter for changes in arterial oxygen saturation. The children were randomly allocated into 4 groups in this double-blind study. Three groups received rectal midazolam, and the other group a placebo (saline) as premedication 30 min prior to induction of anesthesia. Group A children received midazolam 0.25 mg/kg, Group B 0.35 mg/kg and Group C 0.45 mg/kg. The results from this trial show no statistical significant difference between the treatment groups as to the effect on either systolic or diastolic blood pressure, respiration, or pulse rates at either pre- or post-sedation levels. However, the oxygen saturation levels for groups B and C differed significantly from those of the placebo groups 30 minutes after premedication (P = 0.0259).     

Premedication with midazolam delays recovery after ambulatory sevoflurane anesthesia in children.

We studied the effect of oral premedication with midazolam on the recovery characteristics of sevoflurane anesthesia in small children. In a randomized, double-blinded study, 60 children (1-3 yr, ASA physical status I or II) undergoing ambulatory adenoidectomy received either midazolam 0.5 mg/kg (Group M) or placebo (Group P) PO approximately 30 min before the induction of anesthesia. All children received atropine 0.01 mg/kg IV and alfentanil 10 microg/kg IV before the induction of anesthesia with sevoflurane up to 8 vol% inspired concentration in N2O 67% in O2. Tracheal intubation was facilitated with mivacurium 0.2 mg/kg. Anesthesia was continued with sevoflurane adjusted to maintain hemodynamic stability. In the postanesthesia care unit, predetermined recovery end points (emergence, recovery, discharge) were recorded. A pain/ discomfort scale was used to determine the quality of recovery. A postoperative questionnaire was used to evaluate the well-being of the patient at home 24 h after surgery. Emergence (spontaneous eye opening), recovery (full points on the modified Aldrete scale), and discharge were achieved later in Group M than in Group P (15+/-6 vs. 11+/-3 min [P = 0.002], 25+/-17 vs. 16+/-6 min [P = 0.01], and 80+/-23 vs. 70+/-23 min [P = 0.03]). Side effects, postanesthetic excitement, and analgesic treatment did not differ significantly between groups. At home, more children in Group P (30%) experienced disturbed sleep during the night compared with those in Group M (4%) (P = 0.007). IMPLICATIONS: In this randomized, double-blinded, placebo-controlled study, premedication with midazolam 0.5 mg/kg PO delayed recovery in children 1-3 yr of age after brief (<30 min) sevoflurane anesthesia. Except for more peaceful sleep at home, premedication did not affect the quality of recovery.     

Midazolam and ketamine for rectal premedication and induction of anesthesia in children

Fifteen healthy children 2-10 years old and scheduled for elective surgery, received midazolam 0.35 mg/kg body weight and atropine 0.025 mg/kg as rectal premedication about 35 min before the induction of anesthesia. The induction itself was carried out in a separate and quiet room next to the operating theatre by rectal administration of ketamine 10 mg/kg and midazolam 0.2 mg/kg. With the children breathing spontaneously, anesthesia was maintained by repetitive i.v. bolus injections of ketamine. The sedative and anticholinergic effects of the premedication were satisfactory. Induction of anesthesia was smooth. Consciousness was lost after 9-15 (mean 13) min. No significant adverse effects on hemodynamics or respiration were noted. Recovery from anesthesia was uneventful. No cases of rectal irritation or unpleasant dreams were reported. Post-operative analgesia was good. In conclusion, rectal administration of midazolam and atropine for premedication, followed by ketamine and midazolam for the induction of anesthesia, proved to be a pleasant, safe, and reliable method in pediatric anesthesia.