Paulette J. Fontaine

Dexmedetomidine for pediatric sedation for computed tomography imaging studies

Dexmedetomidine is a sedative with limited experience in the pediatric population. This is the first study that prospectively evaluates the sedation profile of a dexmedetomidine pilot program for pediatric sedation for radiological imaging studies. In March 2005, our hospital sedation committee approved the replacement of IV pentobarbital with dexmedetomidine as the standard of care for CT imaging. Detailed Quality Assurance (QA) data sheets collect relevant information on each patient, which is then logged into a computerized sedation database. After IRB approval, all QA data was accessed. Sixty-two patients with a mean age of 2.8 years (SD = 1.8, range 0.5–9.7) received IV (IV) dexmedetomidine administered as a 2 mcg/kg loading dose over 10 minutes, followed by repeat boluses of 2 mcg/kg over 10 minutes until target of Ramsay Sedation Score 4 (RSS) achieved. Patients were then maintained on 1 mcg/kg/hr infusion until imaging is completed. Repeated-measures ANOVA indicated that compared to pre-sedation values, the heart rate and mean arterial blood pressure decreased an average of 15% during bolus, infusion and recovery (P < 0.01). No significant changes were observed in respiratory rate or end-tidal CO2. Mean recovery time was 32 ± 18 minutes. Based on our pilot results, dexmedetomidine may provide a reliable and effective method of providing sedation.

Hemodynamic effects of dexmedetomidine sedation for CT imaging studies

Background:  Dexmedetomidine sedation for radiological imaging studies is a relatively recent application for this drug. Previous studies have demonstrated some haemodynamic effects of dexmedetomidine, however, the effects remain poorly described in children. The aim of this study was to better define the effect of age on heart rate (HR) and blood pressure changes in children sedated for CT imaging with dexmedetomidine.

Incidence and predictors of hypertension during high-dose dexmedetomidine sedation for pediatric MRI

This study reviewed the hypertensive response of a large population of children to high‐dose dexmedetomidine sedation with the aim of determining the incidence and predictors of hypertension.

Pediatric CT sedation: comparison of dexmedetomidine and pentobarbital.

OBJECTIVE Our institution replaced pentobarbital with dexmedetomidine for pediatric CT sedation. The purpose of this study was to compare the efficacy, incidence of adverse events, and cardiovascular and respiratory profiles of these two sedatives. MATERIALS AND METHODS Quality assurance data were accessed for a review of demographics, outcome parameters, and adverse events among all children who received either pentobarbital or dexmedetomidine. RESULTS From January 2004 through June 2009 there were 388 pentobarbital sedations and 1,274 dexmedetomidine sedations. Age, sex, weight, and duration of imaging study were similar in the two groups. Average time to achieve sedation was 12 ± 4 minutes with dexmedetomidine and 6 ± 3 minutes with pentobarbital (p < 0.001). Recovery time was 32 ± 18 minutes with dexmedetomidine and 95 ± 28 minutes with pentobarbital (p < 0.001). There were no differences between groups in incidence of oxygen desaturation and need for brief positive pressure ventilation. The odds of needing additional sedative agents to complete the study were significantly higher with pentobarbital than with dexmedetomidine (odds ratio, 4.0; 95% CI, 2.0-8.4; p < 0.001). There was a significantly lower incidence of agitation and rage with dexmedetomidine (p < 0.01) but higher risk of hypotension (p < 0.01). There was one failed sedation in each group (p = 0.99). CONCLUSION Dexmedetomidine is a safe and effective alternative to pentobarbital for pediatric CT, being associated with a much shorter recovery time and less need for adjuvant sedatives.

Dexmedetomidine Offers an Option for Safe and Effective Sedation for Nuclear Medicine Imaging in Children

PURPOSE To determine the safety, efficacy, and outcomes of bradycardia, hypotension, and hypertension with dexmedetomidine (DEX), a recently approved sedative used for procedural sedation that has not been described previously for pediatric nuclear medicine imaging. MATERIALS AND METHODS Between March 2005 and August 2011, 669 patients (mean age, 5.7 years ± 4.5 [standard deviation]; median age, 4.5 years; age range, 0.1-22.5 years) received DEX in this HIPAA-compliant study. Sedation was administered with DEX, an α-2 adrenergic agonist, as an intravenous bolus (2 μg per kilogram of body weight) over a 10-minute period; this was followed by continuous infusion at a rate of 1 μg/kg/h until imaging was complete. The bolus could be repeated up to two times, if needed, to achieve the targeted level of a Ramsay sedation score of 4. After institutional review board approval, collected quality assurance data were reviewed. RESULTS Adequate sedation was achieved within 8.6 minutes ± 4.6 (median, 8.0 minutes; range, 1.0-40.0 minutes) on average in studies that averaged 41.3 minutes ± 25.5 (median, 31.5 minutes; range, 9.0-183.0 minutes). Of 669 studies, 667 (99.7%) were completed successfully. Six children (0.9%) had brief periods of oxygen desaturation below 95%, none of which required airway intervention. Hypotension, hypertension, and bradycardia (all defined as deviations of more than 20% from age-adjusted awake norms), occurred in 58.7% (n = 393), 2.1% (n = 14), and 4.3% (n = 29) of patients, respectively. Both hypotension and bradycardia were related to age (P = .033 and P = .002, respectively); older children tended to experience more of these events. None of these fluctuations required pharmacologic therapy. Discharge criteria (modified Aldrete score ≥ 9) were met, on average, within 41.4 minutes ± 27.9 (median, 36.0 minutes; range, 1.0-220.0 minutes). CONCLUSION DEX offers advantages for pediatric sedation for nuclear medicine imaging. DEX produces a condition similar to natural sleep, with no detrimental effect on respiration. The hemodynamic variability anticipated with DEX did not require pharmacologic treatment, and the drug was well tolerated.

Value of bispectral index monitor in differentiating between moderate and deep Ramsay Sedation Scores in children

Background:  Pediatric patients who undergo diagnostic radiological imaging studies routinely require moderate or deep sedation to a Ramsay Sedation Score (RSS) of 4 or 5, respectively. The correlation between moderate and deep RSS and bispectral index (BIS) in children has never been validated. This study was designed to determine whether the BIS values correlate with RSS of children sedated for diagnostic imaging studies.

Is Propofol a Safe Alternative to Pentobarbital for Sedation during Pediatric Diagnostic CT

PURPOSE To prospectively compare the incidence of adverse respiratory events, the need for airway interventions, and the recovery time after propofol sedation with similar data from a retrospective review of data obtained in patients who underwent pentobarbital sedation. MATERIALS AND METHODS This HIPAA-compliant study was conducted with institutional review board approval and parental informed consent. The hospital sedation committee approved a 2-month pilot program of propofol sedation as a potential alternative to pentobarbital sedation. Parents were given the choice of having their child sedated with intravenously administered propofol or pentobarbital. Fifty-two patients (18 female, 34 male; mean age, 2.9 years +/- 2.4 [standard deviation]) received propofol. An equal number of patients (21 female, 31 male; mean age, 2.5 years +/- 1.7) who previously received pentobarbital were included. The sample sizes provided 80% power to detect differences in airway manipulations, adverse respiratory events, and recovery time between the groups by using the Fisher exact test and the Student t test. A two-tailed P value of less than .05 indicated a significant difference. RESULTS Patients sedated with propofol underwent significantly more airway manipulations to relieve obstruction than did patients sedated with pentobarbital (23% vs 0%, P < .001). More adverse respiratory events occurred in the propofol group than in the pentobarbital group (12% vs 0%, P = .03). Patients in the propofol group had a faster recovery profile than did patients in the pentobarbital group (34 minutes +/- 17 vs 100 minutes +/- 30, P < .001). CONCLUSION Propofol is associated with a significantly greater incidence of adverse respiratory events than is pentobarbital.

Radiologist-Supervised Ketamine Sedation for Solid Organ Biopsies in Children and Adolescents

OBJECTIVE Pediatric interventional radiologists are frequently challenged when faced with organ biopsies. Because of the need for patient immobility and the potential risk of morbidity with patient movement during biopsies, many radiologists prefer general anesthesia to sedation. We present our experience with radiologist-supervised ketamine sedation in pediatric patients undergoing renal and hepatic biopsies. MATERIALS AND METHODS Quality assurance data were accessed from a computerized database that prospectively collects demographics, outcome parameters, and adverse events on all patients who receive ketamine sedation. Patients received an IV ketamine bolus of 2 mg/kg followed by a continuous infusion of ketamine of up to 150 mcg/kg/min titrated to the responsiveness of the patient. RESULTS Sixty-five children received ketamine for liver (n = 35) and renal (n = 30) biopsies. The mean age of the study group was 7.0 +/- 2.7 (SD) years. The cohort included patients with an American Society of Anesthesiologists (ASA) physical status classification of ASA 1 (3%), ASA 2 (78%), and ASA 3 (19%). The duration of ketamine sedation averaged 39 +/- 20 (SD) minutes, with an average procedure time of 32 +/- 19 (SD) minutes. All procedures were successfully completed, and there were no major adverse events. CONCLUSION Interventional radiologists performing solid organ biopsies in the pediatric population often use general anesthesia to ensure immobility, adequate analgesia, and safe conditions. Our experience suggests that interventional radiologists may supervise a nurse-administered ketamine protocol to provide safe, effective analgesia and sedation for liver and renal biopsies.

Pediatric Sedation in a Community Hospital–Based Outpatient MRI Center

OBJECTIVE Although the demand for pediatric MRI is increasing, it is uncommon to find sedation being offered at community hospital-based outpatient centers. We present our safety, efficacy, and outcome data at a community hospital-based outpatient imaging center. MATERIALS AND METHODS I.v. dexmedetomidine sedation was administered as a bolus of 3 μg/kg and maintained with a continuous infusion of 1 μg/kg/hr until imaging was complete. The dexmedetomidine bolus could be repeated up to two times, if needed. Quality assurance data were reviewed. RESULTS From April 2009 to July 2010, 279 children (mean age, 4.2 years; age range, 0.2-17.2 years) were sedated. All received a first bolus, 46 required a second dose, and two received a third. The average time to achieve sedation was 7.8 minutes (SD, ± 3.8 minutes). Total duration of imaging (82% brain MRI) averaged 38.1 minutes (range, 8.0-126.0 minutes). On average, discharge criteria were met within 21.3 minutes of arrival in recovery room (± 17.8 minutes). The heart rate and blood pressure deviated from baseline by more than 20% in 5% and 33% of the patients, respectively. No pharmacologic therapy was administered to treat the hemodynamic variability. There were no adverse respiratory events. All imaging studies were successfully completed. CONCLUSION Dexmedetomidine offers an option for pediatric sedation for MRI at community hospital-based outpatient settings. It preserves respiration but elicits deviations in blood pressure and heart rate that have not required pharmacologic intervention. Dexmedetomidine offers a safe, effective, and efficient agent for sedation for children undergoing MRI in an outpatient setting.

Hemodynamic Response to Fluid Management in Children Undergoing Dexmedetomidine Sedation for MRI

OBJECTIVE Dexmedetomidine is administered for pediatric sedation for MRI studies. It has the advantage of preserving respiratory function and producing a sedation state identical to that of natural sleep. It can, however, cause a dose-dependent decrease in systemic blood pressure in children. The purpose of this study was to investigate whether i.v. fluid loading with normal saline solution before the initiation of dexmedetomidine administration would affect the frequency of hypotension. MATERIALS AND METHODS Quality assurance data on consecutively registered children who were sedated with dexmedetomidine for MRI were reviewed. All children received a bolus of 3 μg/kg dexmedetomidine followed by a continuous infusion of 2 mg/ kg/h. A normal saline fluid bolus consisting of 0, 10, or 20 mL/kg was administered to each child within 1 hour before initiation of dexmedetomidine administration. Hypotension was defined as a greater than 20% decrease in mean arterial blood pressure from baseline. RESULTS Sedation was administered to 1692 children. Data on fluid administration were missing in three cases. In the other cases, 252 (14.9%) children received 0 mL/kg of normal saline solution, 598 (35.3%) received 10 mL/kg, and 839 (49.6%) received 20 mL/kg. In a multiple logistic regression model controlled for confounding variables, the odds of development of hypotension with 10 mL/kg of fluid decreased 53% (odds ratio, 0.47; 95% CI, 0.28-0.79; p = 0.004) compared with 0 mL/kg. CONCLUSION Administration of 10 mL/kg of normal saline solution before the initiation of dexmedetomidine administration for pediatric MRI sedation is effective in decreasing the incidence of observed hypotension.