Midazolam with ketamine: Who benefits?

Procedural Sedation Outside of the Operating Room Using Ketamine in 22,645 Children: A Report From the Pediatric Sedation Research Consortium

OBJECTIVE

Most studies of ketamine administered to children for procedural sedation are limited to emergency department use. The objective of this study was to describe the practice of ketamine procedural sedation outside of the operating room and identify risk factors for adverse events.

DESIGN

Observational cohort review of data prospectively collected from 2007 to 2015 from the multicenter Pediatric Sedation Research Consortium.

SETTING

Sedation services from academic, community, free-standing children's hospitals and pediatric wards within general hospitals.

PATIENTS

Children from birth to 21 years old or younger.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Describe patient characteristics, procedure type, and location of administration of ketamine procedural sedation. Analyze sedation-related adverse events and severe adverse events. Identify risk factors for adverse events using multivariable logistic regression. A total of 22,645 sedations performed using ketamine were analyzed. Median age was 60 months (range, < 1 mo to < 22 yr); 72.0% were American Society of Anesthesiologists-Physical Status less than III. The majority of sedations were performed in dedicated sedation or radiology units (64.6%). Anticholinergics, benzodiazepines, or propofol were coadministered in 19.8%, 57.9%, and 35.4%, respectively. The overall adverse event occurrence rate was 7.26% (95% CI, 6.92-7.60%), and the frequency of severe adverse events was 1.77% (95% CI, 1.60-1.94%). Procedures were not completed in 39 of 19,747 patients (0.2%). Three patients experienced cardiac arrest without death, all associated with laryngospasm.

CONCLUSIONS

This is a description of a large prospectively collected dataset of pediatric ketamine administration predominantly outside of the operating room. The overall incidence of severe adverse events was low. Risk factors associated with increased odds of adverse events were as follows: cardiac and gastrointestinal disease, lower respiratory tract infection, and the coadministration of propofol and anticholinergics.

Ketamine: use in anesthesia

The role of ketamine anesthesia in the prehospital, emergency department and operating theater settings is not well defined. A nonsystematic review of ketamine was performed by authors from Australia, Europe, and North America. Results were discussed among authors and the final manuscript accepted. Ketamine is a useful agent for induction of anesthesia, procedural sedation, and analgesia. Its properties are appealing in many awkward clinical scenarios. Practitioners need to be cognizant of its side effects and limitations.

Predictors of emesis and recovery agitation with emergency department ketamine sedation: an individual-patient data meta-analysis of 8,282 children

STUDY OBJECTIVE

Ketamine is widely used in emergency departments (EDs) to facilitate painful procedures; however, existing descriptors of predictors of emesis and recovery agitation are derived from relatively small studies.

METHODS

We pooled individual-patient data from 32 ED studies and performed multiple logistic regression to determine which clinical variables would predict emesis and recovery agitation. The first phase of this study similarly identified predictors of airway and respiratory adverse events.

RESULTS

In 8,282 pediatric ketamine sedations, the overall incidence of emesis, any recovery agitation, and clinically important recovery agitation was 8.4%, 7.6%, and 1.4%, respectively. The most important independent predictors of emesis are unusually high intravenous (IV) dose (initial dose of > or =2.5 mg/kg or a total dose of > or =5.0 mg/kg), intramuscular (IM) route, and increasing age (peak at 12 years). Similar risk factors for any recovery agitation are low IM dose (<3.0 mg/kg) and unusually high IV dose, with no such important risk factors for clinically important recovery agitation.

CONCLUSION

Early adolescence is the peak age for ketamine-associated emesis, and its rate is higher with IM administration and with unusually high IV doses. Recovery agitation is not age related to a clinically important degree. When we interpreted it in conjunction with the separate airway adverse event phase of this analysis, we found no apparent clinically important benefit or harm from coadministered anticholinergics and benzodiazepines and no increase in adverse events with either oropharyngeal procedures or the presence of substantial underlying illness. These and other results herein challenge many widely held views about ED ketamine administration.

The incidence of unpleasant dreams after sub-anaesthetic ketamine

RATIONALE

Ketamine is an N-methyl-D: -aspartate (NMDA) receptor antagonist with psychotogenic effects and for which there are diverse reports of whether pleasant or unpleasant dreams result during anaesthesia, post-operatively or after sub-anaesthetic use.

OBJECTIVE

To assess in healthy volunteers the incidence of unpleasant dreams over the three nights after receiving a sub-anaesthetic dose of ketamine, in comparison to placebo, and with retrospective home nightmare frequency as a covariate.

METHOD

Thirty healthy volunteers completed questionnaires about retrospective home dream recall and were then given either ketamine (n = 19, males = 9, mean age = 23.5 years; mean ketamine blood plasma = 175.29 ng/mL) or placebo (n = 11, males = 5, mean age = 25.4 years). Dream recall and pleasantness/unpleasantness of dream content were recorded by questionnaire at home for the three nights after infusion.

RESULTS

Ketamine resulted in significantly more mean dream unpleasantness relative to placebo and caused a threefold increase in the odds ratio for the incidence of an unpleasant dream. The number of dreams reported over the three nights did not differ between the groups. The incidence of unpleasant dreams after ketamine use was predicted by retrospectively assessed nightmare frequency at home.

CONCLUSIONS

Ketamine causes unpleasant dreams over the three post-administration nights. This may be evidence of a residual psychotogenic effect that is not found on standard self-report symptomatology measures or a result of disturbed sleep electrophysiology.

Predictors of airway and respiratory adverse events with ketamine sedation in the emergency department: an individual-patient data meta-analysis of 8,282 children

STUDY OBJECTIVE

Although ketamine is one of the most commonly used sedatives to facilitate painful procedures for children in the emergency department (ED), existing studies have not been large enough to identify clinical factors that are predictive of uncommon airway and respiratory adverse events.

METHODS

We pooled individual-patient data from 32 ED studies and performed multiple logistic regressions to determine which clinical variables would predict airway and respiratory adverse events.

RESULTS

In 8,282 pediatric ketamine sedations, the overall incidence of airway and respiratory adverse events was 3.9%, with the following significant independent predictors: younger than 2 years (odds ratio [OR] 2.00; 95% confidence interval [CI] 1.47 to 2.72), aged 13 years or older (OR 2.72; 95% CI 1.97 to 3.75), high intravenous dosing (initial dose > or =2.5 mg/kg or total dose > or =5.0 mg/kg; OR 2.18; 95% CI 1.59 to 2.99), coadministered anticholinergic (OR 1.82; 95% CI 1.36 to 2.42), and coadministered benzodiazepine (OR 1.39; 95% CI 1.08 to 1.78). Variables without independent association included oropharyngeal procedures, underlying physical illness (American Society of Anesthesiologists class >or = 3), and the choice of intravenous versus intramuscular route.

CONCLUSION

Risk factors that predict ketamine-associated airway and respiratory adverse events are high intravenous doses, administration to children younger than 2 years or aged 13 years or older, and the use of coadministered anticholinergics or benzodiazepines.

Effect of ketamine anesthesia on daily food intake in Macaca mulatta and Cercopithecus aethiops

Ketamine hydrochloride is frequently administered to non-human primates as a means of chemical restraint. This procedure can be a frequent source of stress to monkeys at research facilities, impacting animal health, well-being and research quality. This study was designed to measure ketamine's effect on daily food intake, a parameter that reflects and influences animal well-being and directly impacts research studies. On five occasions, baseline daily food intake was compared to daily food intake occurring 24, 48, 72, 96, and 120 h after an intramuscular injection of 10 mg/kg ketamine in male African green monkeys (AGMs) (Cercopithecus aethiops) and male and female rhesus macaques (Macaca mulatta). AGMs and female rhesus macaques had significantly reduced daily food intake during the first 4 days after receiving ketamine. The AGMs continued to display significantly reduced daily food intake on the fifth day after ketamine. The male rhesus macagues showed a trend toward reduced daily food intake, greatest during the first 2 days and remaining less than baseline intake through the fifth day following ketamine. The degree of observed food intake reduction was most severe at the 24 h (mean percent intake reduction: AGMs: 57%; rhesus males: 48%; rhesus females: 40%) and 48 h time points (AGMs: 24%; rhesus males: 14%; rhesus females: 13%). A subset of the AGMs that did not receive ketamine, but observed other animals in the room receive ketamine, showed reduced food intake at 24 and 48 h after ketamine, though not to the degree associated with ketamine administration. These results indicate that ketamine anesthesia is associated with a prolonged reduction in daily food intake in AGMs and rhesus macaques. Frequent use of ketamine in non-human primates may have a significant impact on animal health and well-being, and alternatives to its use warrant consideration.

A randomized comparison of nitrous oxide plus hematoma block versus ketamine plus midazolam for emergency department forearm fracture reduction in children

OBJECTIVES

Ketamine provides effective and relatively safe sedation analgesia for reduction of fractures in children in the emergency department. However, prolonged recovery and adverse effects suggest the opportunity to develop alternative strategies. We compared the efficacy and adverse effects of ketamine/midazolam to those of nitrous oxide/hematoma block for analgesia and anxiolysis during forearm fracture reduction in children.

METHODS

Children 5 to 17 years of age were randomly assigned to receive intravenous ketamine (1 mg/kg)/midazolam (0.1 mg/kg; max: 2.5 mg) or 50% nitrous oxide/50% oxygen and a hematoma block (2.5 mg/kg of 1% buffered lidocaine). All of the children received oral oxycodone 0.2 mg/kg (max: 15 mg) at triage > or = 45 minutes before reduction. Videotapes were obtained before (baseline), during (procedure), and after (recovery) reduction and scored using the Procedure Behavioral Checklist by an observer blinded to study purpose. The primary outcome measure was the mean change in Procedure Behavioral Checklist score from baseline to procedure, with greater change indicating greater procedure distress. Other outcome measures of efficacy included recovery times and visual analog scale scores to assess patient distress, parent report of child distress, and orthopedic surgeon satisfaction with sedation. Adverse effects were assessed during the emergency visit and by telephone 1 day after reduction. Data were analyzed using repeated measures, that is, analysis of variance, chi2, and t tests.

RESULTS

There were 102 children (mean age: 9.0 +/- 3.0 years) who were randomly assigned. There was no difference in age, race, gender, and baseline Procedure Behavioral Checklist scores between ketamine/midazolam (55 subjects) and nitrous oxide/hematoma block (47 subjects). Mean changes in Procedure Behavioral Checklist scores were very small for both groups. The mean change in Procedure Behavioral Checklist was less for nitrous oxide/hematoma block, and patients and parents reported less pain during fracture reduction with nitrous oxide/hematoma block. Recovery times were markedly shorter for nitrous oxide/hematoma block compared with ketamine/midazolam. Orthopedic surgeons were similarly satisfied with the 2 regimens. Of the ketamine/midazolam subjects, 11% had O2 saturations < 94%. Other adverse effects occurred in both groups, but more often in ketamine/midazolam both during the emergency visit and at 1-day follow-up.

CONCLUSIONS

In children who had received oral oxycodone, both nitrous oxide/hematoma block and ketamine/midazolam resulted in minimal increases in distress during forearm fracture reduction at the doses studied. The nitrous oxide/hematoma block regimen had fewer adverse effects and significantly less recovery time.

Use of midazolam and ketamine as sedation for children undergoing minor operative procedures

OBJECTIVES

We used intravenous midazolam and ketamine for children undergoing minor operative procedures with satisfactory results. We aimed to further evaluate its efficacy and adverse effects in pediatric ward setting.

METHODS

This was a prospective study of all children undergoing minor operations with sedation in our pediatric general and oncology wards from July 1998 to June 1999. The procedures included lumber puncture+/-intrathecal chemotherapy, bone marrow aspiration+/-trephine biopsy, central venous catheter removal, skin biopsy, or their combination. All sedation procedures were started with midazolam 0.1 mg/kg and ketamine 1 mg/kg; they were increased gradually to 0.4 and 4 mg/kg, respectively, if necessary. Heart rate and SaO2 were continuously monitored.

RESULTS

Altogether, 369 minor operations were performed in 112 patients (male:female=2:1, median age 6 years, range 5 months-17 years). All achieved adequate sedation, with 96% within 30 s and 75% required just the starting dose. Younger children required a higher dosage (p=0.003 for midazolam, p<0.001 for ketamine). The median recovery time was 87 min, with no association with age, sex, or dosage of sedation, but was longer in patients having hallucination (p=0.001). Adverse effects included tachycardia (27.9%), increased secretion (17.6%), agitation (13.6%), nausea and vomiting (9.2%), hallucination (8.7%), desaturation (8.4%), and cataleptic reaction (0.8%). All desaturation episodes were transient and responded to oxygen supplement alone. None developed bronchospasm or convulsion. Some adverse effects were dose-related. Half of the children who received 0.3 mg/kg midazolam developed desaturation.

CONCLUSIONS

Intravenous midazolam-ketamine can provide rapid, effective, and safe sedation for children undergoing minor operations in ward setting. Adverse effects are mild. Midazolam above 0.3 mg/kg should be used with caution.

Clinical practice guideline for emergency department ketamine dissociative sedation in children

We present an evidence-based clinical practice guideline for the administration of the dissociative agent ketamine for emergency department pediatric procedural sedation and analgesia. Substantial research in recent years has necessitated updates and revisions to the widely disseminated 1990 recommendations. We critically discuss indications, contraindications, personnel requirements, monitoring, dosing, coadministered medications, recovery issues, and future research questions for dissociative sedation.

Emergency department management of pain and anxiety related to orthopedic fracture care: a guide to analgesic techniques and procedural sedation in children

Orthopedic fractures and joint dislocations are among the most painful pediatric emergencies. Safe and effective management of fracture-related pain and anxiety in the emergency department reduces patient distress during initial evaluation and often allows definitive management of the fracture. No consensus exists on which pharmacologic regimens for procedural sedation/analgesia are safest and most effective. For some children, control of fracture pain is the primary goal, whereas for others, relief from anxiety is an additionally important objective. Furthermore, strategies for the management of fracture pain may vary by fracture location and patient characteristics; thus, no single regimen is likely to provide the best means of analgesia and anxiolysis for all patients. Effective analgesia can be provided by local or regional anesthesia, such as hematoma, Bier, or nerve blocks. Alternatively, induction of deep sedation with analgesic agents such as ketamine or fentanyl, often combined with sedative-anxiolytic agents such as midazolam, may be used to manage distress associated with fracture reduction. A combination of local anesthesia with moderate sedation, for example nitrous oxide, is another attractive option.

Safety and effectiveness of ketamine as a sedative agent for pediatric GI endoscopy

BACKGROUND

The ideal sedation for children undergoing GI endoscopy remains elusive. After ketamine was introduced as a sedative agent in our GI procedure suite, improved sedation and reduced complications were observed. The aim of this study was to assess the safety and effectiveness of ketamine as a sedative agent for GI endoscopy in pediatric patients.

METHODS

A retrospective cohort study of 402 procedures (EGD, colonoscopy) was performed. Sedation-related complications were defined as hypoxia (oxygen saturation <95% by pulse oximetry), agitation, emergence reactions, stridor, laryngospasm, nausea, vomiting, aspiration, and muscle twitching, or any combination thereof. Sedation groups were defined as the following: Group I, midazolam and meperidine (n=192); Group II, midazolam, meperidine, and ketamine (n=82); and Group III, midazolam and ketamine (n=128).

RESULTS

Group 1 (midazolam and meperidine) had the highest frequency of complications, most commonly hypoxia. Group 3 (midazolam and ketamine) had the lowest rate of complications (p=0.001) and the highest rate of adequate sedation, although the difference was not significant (p=0.07).

CONCLUSIONS

The combination of midazolam and ketamine appears to provide safe and effective sedation for pediatric patients undergoing endoscopy.

Comparison of propofol/fentanyl versus ketamine/midazolam for brief orthopedic procedural sedation in a pediatric emergency department

PURPOSE

To compare the effectiveness of 2 medication regimens, propofol/fentanyl (P/F) and ketamine/midazolam (K/M), for brief orthopedic emergency department procedural sedation. This study was powered to compare recovery times (RT) and procedural distress as measured by the Observational Score of Behavioral Distress-revised (OSBD-r; range: 0-23.5 with 23.5 representing maximal distress).

METHODS

We conducted a prospective, partially-blinded controlled comparative trial comparing intravenous P/F with K/M in a convenience sample of 113 patients aged 3 to 18 years old undergoing orthopedic procedural sedation. All medications were administered by the intermittent intravenous bolus method. An independent sedation nurse recorded total sedation time and RT. Effectiveness was measured using 6 parameters: 1) patient distress as assessed by independent blinded observers after videotape review using the OSBD-r; 2) orthopedic satisfaction score (Likert scale 1-5); 3) sedation nurse satisfaction score (Likert 1-5); 4) parental perception of procedural pain using a 0 to 100 mm Visual Analog Scale with the upper limit being "most pain"; 5) patient recall of the procedure; and 6) 1 to 3 week follow-up.

RESULTS

RT and total sedation time were significantly less in the P/F group than in the K/M group (33.4 minutes vs 23.2 minutes). The mean OSBD-r scores during manipulation were 0.084 and 0.278 for the K/M and P/F groups, respectively. Although this difference was statistically significant (95% confidence interval for the mean difference -0.34 to -0.048), both regimens were successful in keeping the scores low. There was no statistical difference between the groups in the other measures of effectiveness. There was a statistically significant difference between the groups in the occurrence of desaturation and late side effects.

CONCLUSIONS

RT with P/F is shorter than with K/M. P/F is comparable to K/M in reducing procedural distress associated with painful orthopedic procedures in the pediatric emergency department. Although propofol has a greater potential of respiratory depression and airway obstruction as compared with ketamine, it offers some unique advantages including a quicker offset and smoother recovery profile.

Office-based anesthesia for children

The use of office-based surgery and anesthesia will continue to grow. The anesthesia community has embraced the opportunity to become a driving force of office-based surgery and has organized into rapidly growing groups that promote safe practice in the office setting. The Society for Office-Based Anesthesia was developed to continuously improve patient safety and outcomes in office surgery. This group has an active Web site (www.soba.org) that allows for online discussions and widespread participation in working toward the society's stated goal. This Web site may be used as a reference for physicians in the process of considering the move to office-based anesthesia. The advantages of office-based anesthesia are numerous. The financial incentives are tremendous and the convenience to the patient and surgeon is important. For office anesthesia to be successful in children, patient safety, proof of improved outcomes, and family and surgeon satisfaction must be the goals. Anesthesia providers must continue to take active roles in organizing the office environment to ensure that safety is paramount. As the field grows, additional ways to study and improve the overall care children receive in the office should be sought. In the near future, office practice for surgery and anesthesia for children undergoing minor procedures should be a safe and effective alternative to current practices.

Pharmacological management of pain and anxiety during emergency procedures in children

Painful procedures are frequently required during treatment of children in the emergency department and are very stressful for the children, their parents and healthcare providers. Pharmacological methods to safely provide almost painless local anaesthesia, analgesia and anxiolysis have been increasingly studied in children. With knowledge of these methods, and patience, the emergency care provider can greatly reduce the distress often associated with emergency care of children. Topical local anaesthetics such as LET [lidocaine (lignocaine), epinephrine (adrenaline), tetracaine] or buffered lidocaine injected through the wound with fine needles can almost painlessly anaesthetise lacerations for suturing. Topical creams such as lidocaine/ prilocaine (EMLA) or tetracaine, iontophoresed lidocaine, or buffered lidocaine subcutaneously injected with fine needles can make intravenous catheter placement virtually 'painless'. When anxiety is significant, and mild to moderate analgesia/ anxiolysis/amnesia is needed, nitrous oxide can be administered if the proper delivery devices are available. Alternatively, when intensely painful fracture reduction, burn debridement, or abscess drainage is necessary, well tolerated and effective deep sedation can be achieved with careful use of midazolam and either ketamine or fentanyl.

Does midazolam alter the clinical effects of intravenous ketamine sedation in children? A double-blind, randomized, controlled, emergency department trial

STUDY OBJECTIVE

This study was conducted to investigate the frequency and severity of adverse effects, specifically emergence phenomena, experienced by patients receiving intravenous ketamine with or without midazolam for sedation in a pediatric emergency department.

METHODS

Patients aged 4.5 months to 16 years receiving ketamine sedation were prospectively enrolled in a double-blind, randomized, controlled study at a university-affiliated children's hospital-pediatric ED. All patients received ketamine (1 mg/kg) and glycopyrrolate (5 microgram/kg) intravenously. Patients were randomly assigned to receive midazolam (0.1 mg/kg) intravenously or no midazolam. Total time of sedation, sedation efficacy, and adverse effects were recorded. Adverse effects were compared between patients receiving ketamine versus those who received ketamine and midazolam. Additional comparisons were made based on age and number of ketamine doses administered.

RESULTS

Two hundred sixty-six patients were studied; 129 received ketamine and 137 patients received ketamine and midazolam. Time of sedation and efficacy of sedation were equivalent between groups. Overall, adverse effects with ketamine sedation included respiratory events (12 [4.5%]), vomiting (50 [18.7%]), emergence phenomena in the pediatric ED (71 [26.7%]), and emergence phenomena at home (60 [22.4%]). Significant emergence phenomena in the pediatric ED (ie, nightmares, hallucinations, and severe agitation) occurred in 7.1% of the ketamine group and in 6.2% of the ketamine-midazolam group, a rate difference of 0.8 (95% confidence interval [CI] -5.3 to 7.0). The addition of midazolam led to an increased incidence of oxygen desaturation events (ketamine 1.6% versus ketamine-midazolam 7.3%; rate difference -5.7, 95% CI -10.6 to -0.9) but a decreased incidence of vomiting (ketamine 19.4%, ketamine-midazolam 9.6%, rate difference 9.8, 95% CI 1.4 to 18.2). The incidence of emergence phenomena and significant emergence phenomena was not affected by the addition of midazolam. However, the addition of midazolam was associated with more agitation in the pediatric ED in children 10 years or older (ketamine 5.7% versus ketamine-midazolam 35.7%; rate difference -30.0, 95% CI -10.7 to -49.3). Age breakdown further showed 6.3% (95% CI 0.9 to 11.6) more episodes of oxygen desaturation in the ketamine-midazolam group in children younger than 10 years, and 12.1% (95% CI 1.5 to 22.6) more vomiting episodes in the ketamine group in children younger than 10 years.

CONCLUSION

Ketamine and combined ketamine and midazolam provided equally effective sedation. The addition of midazolam did not alter the incidence of emergence phenomena. Vomiting occurred more frequently in the ketamine only group, whereas oxygen desaturation occurred more frequently in the ketamine-midazolam group. These findings were more pronounced in patients younger than 10 years. Parental and physician satisfaction remained high for all patients receiving intravenous ketamine sedation.