Sublingual midazolam premedication in children: a dose response study

Serum concentration of oral midazolam as pediatric preanesthetic medication and factors related to the sedation level

BACKGROUND

Preanesthetic medication is important to eliminate surgical anxiety in pediatric patients and facilitate their smooth transfer to the operating room. Midazolam is the most commonly used preanesthetic medication. However, it has been reported that the sedative effect varies from patient to patient. In this study, the pharmacokinetics of midazolam were examined, and the aim was to assess the factors affecting the quality of sedation.

METHODS

The participants were children ranging in age from 6 months to 8 years scheduled for surgery. Midazolam 0.5 mg/kg was administered orally 30 min before entering the operating room, and the sedation level was evaluated at the time of mask application. Blood was collected after slow induction, and the serum concentration of midazolam was measured using high-performance liquid chromatography.

RESULTS

A total of 98 patients were registered. There was no difference in serum concentrations between the effective sedation group and the ineffective sedation group (48.0 vs. 49.1 ng/mL), regardless of the effect of midazolam. Percentages of ineffective sedation by age (0 to 7 years) were 66.6%, 60%, 33.3%, 11.1%, 0%, 0%, 12.5%, and 0%, respectively. On multivariate logistic regression analysis, siblings (OR = 3.9, CI: 1.1-14.0, p = .03) and age (OR = 3.2, CI:1.2-8.5, p = .02) were related to an insufficient sedative effect.

CONCLUSION

The serum concentration of oral midazolam reached effective levels even in patients in whom the sedative effect was inadequate. It is important to manage the perioperative period with appropriate concurrent premedication taking into account patient age and social background characteristics.

CLINICAL TRIAL REGISTRATION

Clinical trial registry: UMIN R000052504.

Evaluation of intranasal Midazolam spray as a sedative in pediatric patients for radiological imaging procedures

CONTEXT

Preoperative anxiety and uncooperativeness experienced by pediatric patients are commonly associated with postoperative behavioral problems.

AIMS

We aimed to evaluate the efficacy and safety of intranasal Midazolam as a sedative in a pediatric age group for radiological imaging procedures and to note onset of sedation, level of sedation, condition of patient during separation from parents and effect on the cardio-respiratory system.

SETTINGS AND DESIGN

Randomized double-blinded study.

SUBJECTS AND METHODS

Fifty patients of the pediatric age group of American Society of Anesthesiologist grade 2 and 3 who came for any radiological imaging procedures were studied. Patients were randomly allocated to receive, intranasally, either Midazolam 0.5 mg/kg (group A N = 25) or normal saline (group B N = 25) in both nostrils (0.25 mg/kg in each) 15 min before the procedure. Time for onset of sedation and satisfactory sedation, sedation score, separation score, hemodynamic changes and side-effects were recorded.

STATISTICAL ANALYSIS USED

Student's t-test.

RESULTS

Intranasal Midazolam group had a significantly shorter time for onset of sedation and satisfactory sedation. Mean sedation score and mean separation score at 10 min and 15 min intervals were significant in intranasal Midazolam as compared with normal saline (P < 0.001).

CONCLUSIONS

Intranasal Midazolam 0.5 mg/kg is safe and effective and provides adequate sedation for easy separation from the parents and reduced requirement of intravenous supplementation during radiological imaging procedures without any untoward side-effects.

Comparison of a morphine and midazolam combination with morphine alone for paediatric displaced fractures: a randomized study

AIM

To compare the efficacy of sublingual midazolam with oral morphine versus that of oral morphine with placebo in a paediatric population attending an emergency department (ED) with acute long-bone fractures.

METHODS

A sample of children aged 5-16 years with clinically deformed closed long-bone fractures was randomized to groups receiving either oral morphine (0.5 mg/kg)/sublingual placebo or oral morphine (0.5 mg/kg)/sublingual midazolam (0.2 mg/kg). The main exclusion criteria were narcotic or benzodiazepine use, significant head injury, multiple organ failure, femoral fracture and allergy. Pain scores were rated on a 100-mm visual analogue scale (VAS) at 0, 15, 30, 60, 90 and 120 min.

RESULTS

Fifty-eight children were enrolled (mean age: 10.5 years, SD 2.7). Fractures concerned the radius or ulna in 43 cases (74.1%), the humerus (22.4%) and the tibia or fibula (3.5%). No significant difference in VAS scores was observed between the two treatment arms (p = 0.72). Drowsiness was significantly more frequent in the midazolam group (p = 0.007) during the first 2 h after administration. No serious adverse event was observed.

CONCLUSION

The analgesic performances of morphine and the combination of morphine with midazolam assessed by VAS were similar in children presenting at the ED with a long-bone fracture.

Evidence-based clinical update: does premedication with oral midazolam lead to improved behavioural outcomes in children?

PURPOSE

The purpose of this evidence-based clinical update was to identify the best evidence to determine if behavioural outcomes are improved in children after oral midazolam premedication.

METHODS

A literature search was conducted using both PubMed and OVID programs, utilizing the terms "midazolam", and either "premedication" or "preoperative treatment". Search limits that were employed included randomized controlled trials (RCTs), English language, human studies, children aged 0-18 yr, and publication dates 1990 - present (January 2006). A review of the 171 abstracts obtained was undertaken and, of these, 30 papers were identified that concerned oral midazolam in children prior to general anesthesia, and that involved a RCT with a placebo or control arm. These studies were assigned levels of evidence, and grades of recommendation were made according to Centre for Evidence-Based Medicine criteria.

RESULTS

Oral midazolam premedication in children was found to reduce the anxiety associated with separation from parents/guardians, and with induction of anesthesia. Recovery times are not significantly delayed. There is no consistent evidence to suggest a reduction in the phenomenon of emergence agitation. Evidence suggesting an improvement in behavioural outcomes at home is also inconsistent.

CONCLUSION

Premedication with midazolam 0.5 mg x kg(-1) po administered 20-30 min preoperatively, is effective in reducing both separation and induction anxiety in children (grade A recommendation), with minimal effect on recovery times. However improved postoperative behavioural outcomes in the postanesthesia care unit, or at home cannot be predicted on a consistent basis.

Evaluation of cuffed tracheal tube size predicted using the Khine formula in children

BACKGROUND

The correct size of cuffed endotracheal tube (CET) limits the risk of postintubation tracheal damage. The aim of this study was to compare the size of the CET used in children with the size predicted by the Khine formula [age (years)/4 + 3].

METHODS

After ethical committee approval, 204 children aged 1 day-15 years were included prospectively in the study. The choice of the size of the CET was made at the discretion of the attending anesthesiologist. The main criterion of judgment was the comparison of the leak before and after inflating the cuff at a pressure of 20 cm.H(2)O. Demographic data, tracheal tube size used and that predicted by Khine's formulae and side-effects were recorded.

RESULTS

Overall, 21% of the CET were in accordance with the size predicted by the Khine formula. In the remaining patients, 72% were oversized and 7% undersized. In 12 cases, the size of CET chosen initially was modified: for a larger size in eight children and for a smaller size in four others. Six children (2.9%) presented with minor postoperative complications.

CONCLUSIONS

Our data suggest that Khine's formula for predicting the appropriate tracheal tube size underestimates optimal size by 0.5 mm. We therefore recommend the use of the following formula: internal diameter of the CET = [age/4 + 3.5] in children >1 year of age which may be applied without increased risk of complications. The rate of tracheal reintubation as well as the detected leaks supports these recommendations.

Maternal heart rate variability just before surgery significantly correlated with emergence behavior of children undergoing general anesthesia

BACKGROUND

Emergence agitation in pediatric anesthesia is associated with preanesthesia child anxiety, which is strongly influenced by maternal mental conditions. Mental stress affects the autonomic nervous system, thereby influencing heart rate variability (HRV). The present study tested the correlations between preanesthesia maternal HRV and perioperative child behavior.

METHODS

A total of 27 pairs of mothers and children were analyzed in the present study. Maternal HRV was recorded from the night before the child's surgery to arrival to the operation room and thereafter recorded data were analyzed. The children underwent minor plastic surgery under general anesthesia, and induction and emergence behavior were assessed.

RESULTS

Quality of mask induction did not correlate with the ratio of low-frequency (LF) components to high-frequency (HF) components (LF/HF ratio) of preanesthesia maternal HRV either obtained during 21:00-06:00 (stage I) or 06:00-08:00 (stage II). Scores of the child's emergence behavior did not correlate with the LF/HF ratio of maternal HRV of stage I; however, the LF/HF ratio of maternal HRV of stage II significantly correlated with emergence behavior.

CONCLUSIONS

Two-hour maternal HRV just before surgery significantly correlated with emergence behavior of children undergoing general anesthesia.

A randomised placebo-controlled trial of the effects of midazolam premedication on children's postoperative cognition

This randomised, placebo-controlled study assessed the effects of midazolam premedication on children's postoperative cognition and physical morbidity. In all, 179 children aged 5-10 years were randomly assigned to receive buccal midazolam (0.2 mg x kg(-1)) or placebo before sevoflurane-nitrous oxide anaesthesia for multiple dental extractions. They performed tests of choice reaction time, attention, psychomotor co-ordination and memory pre-operatively (baseline), before discharge and at 48 h. The reaction time of both groups was significantly slower before discharge compared to baseline, with the midazolam group being significantly slower than placebo. Psychomotor co-ordination was also significantly impaired postoperatively after midazolam. Performance on both tests had recovered to baseline by 48 h. Midazolam was also associated with significant anterograde amnesia, both postoperatively and at 48 h, for information presented in the interval between premedication and surgery. The results show significant short-term impairment of children's cognitive function and amnesia enduring for 48 h after low-dose midazolam premedication.

Parental presence during induction enhances the effect of oral midazolam on emergence behavior of children undergoing general anesthesia

BACKGROUND

Pre-anesthetic anxiety and emergence agitation are major challenges for anesthesiologists in pediatric anesthesia. Thus, sedative premedication and parental presence during induction of anesthesia (PPIA) are used to treat pre-anesthetic anxiety in children. The aim of the present study was to test if a combination of mother presence and midazolam premedication is effective for improving emergence condition in children undergoing general anesthesia.

METHODS

Sixty children were allocated to one of three groups: a sedative group (0.5 mg/kg oral midazolam), a PPIA group or a sedative and PPIA group. When anesthesia was induced with 7% sevoflurane in 100% oxygen, qualities of mask induction were rated. Anesthesia was maintained with sevoflurane (1.5-2.5%) in 60% oxygen and intravenous fentanyl 4 microg/kg. During emergence from anesthesia, the score of the child's emergence behavior was rated.

RESULTS

The children in the midazolam group showed a better quality of mask induction compared with those in the PPIA group, the addition of parental presence to oral midazolam did not provide additional improvement of mask induction. In contrast, the children in the midazolam + PPIA group were less agitated than those in the other groups at emergence from anesthesia.

CONCLUSION

Parental presence during induction of anesthesia enhanced the effect of oral midazolam on emergence behavior of children undergoing general anesthesia.

Oral versus intranasal midazolam premedication for infants during echocardiographic study

Movement and anxiety during echocardiographic study may reduce the reliability and affect the quality of echocardiographic images. Thus, sedation is an essential component when it is performed in infants. This randomized, single-blinded, placebo-controlled study was undertaken to evaluate the acceptability and effectiveness of intranasal midazolam (INM) versus oral midazolam (OM) in infants during transthoracic echocardiography. Eighty patients between the ages of 6 mo and 3 y who presented for elective echocardiographic study were divided into 3 groups: the OM group received 0.4 mg/kg of injectable midazolam mixed with an equal volume of cherry juice, the INM group received 0.2 mg/kg as drops,and the control group was given oral cherry juice or intranasal serum physiologic. A blinded clinician assessed and scored the level of sedation and comfort during the procedure for each child, and a score for ease of administration was recorded by the nurse. The intranasal route was more acceptable to infants than the oral route (P<.001). No significant difference in the effects of sedation was observed between the OM group and the INM group (P=.583), but significant differences were observed between the sedated groups and the control group (P<.001). The procedure was significantly more comfortable in groups given OM and INM than in the control group (P<.001). Although no difference in sedation score was seen between the oral and nasal routes, INM was better accepted by infants than OM. Echocardiography was performed more reliably and comfortably in those given midazolam than in those in the control group.

Midazolam in the reduction of surgical stress: a randomized clinical trial

OBJECTIVE

The objective of this study was to assess the role of midazolam in reducing surgical stress as measured using subjective and objective variables.

STUDY DESIGN

The study was a double-blind randomized controlled trial. Thirty-eight male patients undergoing surgical removal of third molars under general anesthesia were recruited for this study, each patient was given premedication (midazolam or placebo) and subjective variables (HAD scale) were obtained and objective variables (salivary cortisol samples and vital signs) were collected pre-, peri-, and postoperatively. The salivary samples were analyzed by direct immunofluorimetric assay using the "DELFIA" system.

RESULTS

There were no significant differences in anxiety between the treatment group and the control group before the administration of the premedication. Following the administration of premedication, the majority of the control group showed high cortisol levels on the day of surgery, compared with relatively low cortisol levels in the majority of the treatment group. A few patients in the control group gave a placebo effect (sedative effect) and a number of the treatment group were unresponsive to the drug. There was a slight drop in the blood pressure and respiration rate with a slight increase in the heart rate in the treatment group; however these results were not statistically significant. The HAD scores were not statistically different between the 2 groups.

CONCLUSION

Midazolam has proved to be very successful in reducing anxiety and stress pre-, peri-, and postoperatively with no significant effect on the vital signs of a healthy patient. Salivary cortisol technique is an easy, noninvasive method to assess anxiety and stress level in patients undergoing surgery.

Comparison of a combination of midazolam and diazepam and midazolam alone as oral premedication on preanesthetic and emergence condition in children

BACKGROUND

Preanesthetic anxiety and emergence agitation are major challenges for anesthesiologists in pediatric anesthesia. Thus, midazolam has been used as premedication for children. However, midazolam alone is not effective for emergence agitation. The present study tested the effect of a combination of midazolam and diazepam on the preanesthetic condition and emergence behavior in children.

METHODS

Forty-two children were allocated to one of three groups: the NoPre group received no premedication; the Mi group received midazolam 0.5 mg kg(-1) orally; and the Mi + Di group received midazolam 0.25 mg kg(-1) and diazepam 0.25 mg kg(-1) orally. When anesthesia was induced with 7% sevoflurane in 100% oxygen, qualities of mask induction and sedation were rated. Anesthesia was maintained with sevoflurane (3-5%) in 100% oxygen. During emergence from anesthesia, the score of the child's emergence behavior was rated.

RESULTS

Children in the Mi and Mi + Di groups were more sedated than those in the NoPre group. A combination of midazolam and diazepam provided a better quality of mask induction, when compared with no premedication. Also, the children in the Mi + Di group were less agitated than those in the other groups during the emergence.

CONCLUSION

Children in the Mi + Di group were significantly more sedated at induction of anesthesia and less agitated during emergence from anesthesia.

Potential new methods for antiepileptic drug delivery

Use of novel drug delivery methods could enhance the efficacy and reduce the toxicity of antiepileptic drugs (AEDs). Slow-release oral forms of medication or depot drugs such as skin patches might improve compliance and therefore seizure control. In emergency situations, administration via rectal, nasal or buccal mucosa can deliver the drug more quickly than can oral administration. Slow-release oral forms and rectal forms of AEDs are already approved for use, nasal and buccal administration is currently off-label and skin patches for AEDs are an attractive but currently hypothetical option. Therapies under development may result in the delivery of AEDs directly to the regions of the brain involved in seizures. Experimental protocols are underway to allow continuous infusion of potent excitatory amino acid antagonists into the CSF. In experiments with animal models of epilepsy, AEDs have been delivered successfully to seizure foci in the brain by programmed infusion pumps, acting in response to computerised EEG seizure detection. Inactive prodrugs can be given systemically and activated at the site of the seizure focus by locally released compounds. One such drug under development is DP-VPA (or DP16), which is cleaved to valproic acid (sodium valproate) by phospholipases at the seizure focus. Liposomes and nanoparticles are engineered micro-reservoirs of a drug, with attached antibodies or receptor-specific binding agents designed to target the particles to a specific region of the body. Liposomes in theory could deliver a high concentration of an AED to a seizure focus. Penetration of the blood-brain barrier can be accomplished by linking large particles to iron transferrin or biological toxins that can cross the barrier. In the near future, it is likely that cell transplants that generate neurotransmitters and neuromodulators will accomplish renewable endogenous drug delivery. However, the survival and viability of transplanted cells have yet to be demonstrated in the clinical setting. Gene therapy also may play a role in local drug delivery with the use of adenovirus, adeno-associated virus, herpesvirus or other delivery vectors to induce brain cells to produce local modulatory substances. New delivery systems should significantly improve the therapeutic/toxic ratio of AEDs.

Management of the paediatric airway: new developments

During the last 2 years, some interesting new devices have been made available to improve airway management in children and infants, and several studies have advanced our understanding concerning risks and benefits of the current practice in the field. Certain risk factors for airway related problems during anaesthesia in children having a cold have been identified, and new aspects of the controversy concerning the use of cuffed endotracheal tubes in children presented. Novel video-assisted systems have been introduced for the management of the difficult airway in paediatric patients, and new applications for well known devices have been suggested, such as the laryngeal mask airway serving as guidance for fibreoptic intubation. Recent studies also demonstrated specific problems with the laryngeal mask airway in infants, as well as the advantages of a new prototypic laryngeal mask airway for children, similar to the ProSeal (LMA International S.A. Group, USA). Furthermore, the following review presents new data about the use of the cuffed oropharyngeal airway, the laryngeal tube, and the Arndt bronchus blocker in paediatric patients.

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.

A survey of practice of tracheal intubation without muscle relaxant in paediatric patients

BACKGROUND

Because of the renewed interest in intubation in children without relaxants, over a period of 1 month, the anaesthesiologists of five paediatric universitary teaching hospitals were asked to complete a questionnaire each time they performed a tracheal intubation without muscle relaxant.

METHODS

Intubating conditions were assessed with five items. Each item was graded on a four-point scale. Intubating conditions were judged acceptable when all items scored 2 or less. Episodes of oxygen desaturation and failed intubations were noted. Data are expressed as mean +/- SD (extremes).

RESULTS

Five hundred and two questionnaires were completed during the study period. Children were aged 61 +/- 50 (1-180) months old. Induction of anaesthesia was performed with sevoflurane for 62.6% of the children (endtidal concentration 5.9 +/- 1.5%) and propofol for 28.9% (dose 5.8 +/- 4.2 mg x kg(-1). Opioids were associated with these hypnotics in 53.2% of the children. Tracheal intubation was successful in 87.1% of the children. Sevoflurane produced better intubating conditions than propofol. Sevoflurane requirements for tracheal intubation may be higher in infants aged less than 6 months old than in older children. A severe decrease in SpO2 (< or = 90%) was observed in 15.9% of the infants aged less than 1 year old and in 1.7% of the children, respectively (P < 0.0001).

CONCLUSIONS

Sevoflurane is the most commonly used agent for tracheal intubation without relaxants with higher doses being required in infants aged less than 6 months. Propofol, even with opioids, was not so successful.

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.

Sublingual morphine may be a suitable alternative for pain control in children in the postoperative period

The purpose of this pilot study was to compare the effects of sublingual morphine with intravenous morphine in the treatment of postoperative pain following adenotonsillectomy in children. Twenty-nine children scheduled for adenotonsillectomy were randomly assigned to group 1 (n=14) receiving 0.1 mg x kg(-1) sublingual morphine and group 2 (n=15) 0.1 mg x kg(-1) intravenous morphine followed by 1 mg x kg(-1) diclofenac rectally in both groups after induction of anaesthesia. Postoperatively, time to first eye opening, sedation score, pain score, time for further analgesia requests and incidence of nausea and vomiting were recorded. There was no statistical significant difference in any of these parameters between the two groups. The results suggest that sublingual morphine may be a suitable alternative to various other routes of opioid administration in children, but further investigations of the sublingual route of administration of opioids in children are required.

Management of the paediatric patient

Recent introduction of new fast-onset short-duration anaesthetic drugs and the use of regional anaesthesia techniques in children have resulted in good control of anaesthesia and perioperative pain with few adverse effects. Ambulatory surgery has gained popularity in paediatric practice, particularly as children are often otherwise healthy and usually undergo minor surgery.

New developments in the management of the paediatric airway: cuffed or uncuffed tracheal tubes, laryngeal mask airway, cuffed oropharyngeal airway, tracheostomy and one-lung ventilation devices

The use of a cuffed endotracheal tube should no longer be limited by the age of the child but by his or her clinical condition (e.g. poor lung compliance). To prevent pharyngeal damage, overinflation of the cuff of the laryngeal mask airway should be avoided by inflating it with the minimum volume required to maintain an effective seal and by monitoring intracuff pressure if nitrous oxide is used. Percutaneous tracheostomy in children is still in the experimental stage. New and older devices to perform one-lung ventilation in children are also described.