Background
Because patient movement during echocardiography interferes with diagnostic quality, many institutions sedate children who are unable to cooperate. The purpose of this review was to determine the efficacy and safety of oral pentobarbital for sedation during pediatric transthoracic echocardiography.
Methods
Echocardiography laboratory quality assurance data were recorded for 12 years. Sedation data included adverse events, dosing, and failed sedation. The study population was grouped by age: neonates (<1 month), infants (1-12 months), and young children (1-4 years).
Results
A total of 9796 patients underwent sedation by oral pentobarbital. The overall sedation success rate was 98.7%, and 99% of these patients remained sedated long enough for study. The overall adverse event rate was 0.5%. Second doses, failed sedation, and adverse events were more common in the young children.
Conclusion
Oral pentobarbital is an effective and safe sedative for pediatric transthoracic echocardiography. Because of decreased efficacy and an increased incidence of adverse events, alternative sedation strategies may be beneficial in children aged 1 to 4 years.
Echocardiography remains the prime diagnostic modality in pediatric heart disease. Children undergoing echocardiography must remain motionless for extended periods of time to gather the high-quality, reliable results needed before cardiac surgery. This may require the use of a sedative to ensure cooperation.
As a result, multiple strategies have been developed to sedate young patients who find it difficult to remain still during echocardiography. Oral pentobarbital is one sedative that can be used for this purpose, but its use in echocardiography has not been evaluated. This retrospective observational review was conducted to determine the efficacy and safety of oral pentobarbital.
Methods
A retrospective observational review of echocardiography laboratory quality assurance data at the Children’s Hospital Medical Center (Cincinnati, OH) from July 1997 to March 2009 was conducted in compliance with institutional review board requirements.
Sedation
Prior to echocardiography, patients and their families were notified of preprocedural fasting guidelines, which were adapted from the American Academy of Pediatrics and the American Society of Anesthesiologists. The guidelines entailed the following: for patients ranging from 0 to 5 months in age, no milk or solids for 4 hours before the scheduled procedure; for patients ranging from 6 to 36 months in age, no milk or solids for 6 hours before the scheduled procedure; and for patients aged >36 months, no milk or solids for 8 hours before the scheduled procedure. Oral intake of clear liquids, including breast milk, was permitted up to 2 hours before the scheduled procedure for patients of any age.
After patient history was collected and a physical examination was performed by a registered nurse, consent was obtained and sedation was ordered by either a cardiology fellow or an attending physician. Procedures took place in the echocardiography laboratory, were staffed by a registered nurse, and were supervised by a pediatric cardiologist, both with pediatric advanced life support certification.
Patients were sedated with the intravenous form of pentobarbital (50 mg/mL) given orally (first dose, 5 mg/kg; second dose, 2.5 mg/kg, administered 30 minutes after a failed first dose, maximum cumulative dose, 100 mg).
Echocardiography laboratory rooms were equipped with oxygen supply, mask, bag, and suction apparatus for situations potentially requiring intervention. Prior to sedation, baseline vital signs (oxygen saturation, heart rate, respiratory rate, and blood pressure) were recorded. During sedation, a sedation level score designed for hospital-wide use was administered ( minimal = responds normally to verbal commands, cognitive function and coordination may be impaired, ventilatory and cardiovascular function unaffected; moderate = depressed consciousness but responds purposefully to verbal commands, ventilatory function may be impaired, may require light tactile stimulation, patent airway without intervention with adequate ventilation, cardiovascular function maintained; deep = cannot be easily aroused but responds purposefully following repeated or painful stimulation, independent airway may be impaired, spontaneous ventilation may be inadequate, cardiovascular function is maintained; anesthesia = not arousable even with painful stimulation, ability to independently maintain ventilatory function is often impaired, may require assistance to maintain a patent airway, cardiovascular function may be impaired). Following sedation, blood pressure was recorded once again. The other vital signs were measured at 5-minute intervals for the duration of the procedure.
Complete echocardiographic studies lasted 15 to 90 minutes, depending on the nature of the study. When the study was completed, nurses roused patients with audio and physical stimuli. Patients were then offered clear liquids as tolerated. Next, patients were evaluated by nurses for discharge qualifications, which required that patients be awake, alert, and capable of drinking clear fluids. At the time of discharge, parents were given instructions on postprocedural protocol. These instructions summarized the potential side effects of sedation with oral pentobarbital, safety precautions, instructions for eating and drinking following sedation, and relevant contact information.
Follow-up phone calls were made 24 hours after sedated studies to document adverse events following patient discharge. If a guardian could not be reached, a voice message was left and the call was repeated another 24 hours later. After this attempt, no further calls were made. These follow-up phone calls not only provided updates on adverse reactions that were known to occur at the time of the echocardiographic study but also allowed capture of adverse reactions that occurred after discharge from the laboratory. Unfortunately, although these later reactions were captured, quantitation of when adverse reactions occurred (ie, in the laboratory or after discharge) is not possible from the database. From a qualitative standpoint, the overwhelming majority of adverse reactions were present before discharge from the laboratory.
Data Collection and Analysis
From July 1997 to March 2009, data regarding adverse events, time to sedation, length of sedation, overall sedation success, and follow-up phone calls were recorded and reviewed quarterly for quality assurance. From January 2008 to March 2009, additional data were recorded, including success rates of first and second dose administration. Success of sedation was defined as the obtaining of a complete and comprehensive study (as defined by our echocardiography laboratory’s protocol) with minimal or no movement artifacts.
For the purpose of analysis, patients who underwent sedation were grouped according to age: neonatal patients (<1 month), infants (1-12 months), and young children (1-4 years). Occurrences of adverse events were then analyzed on the basis of age group as well as for the overall population. Adverse events were defined as the following: emesis (volume ≥ 20 mL, not merely spit-ups), respiratory complication (≥5% decrease in oxygen saturation, or stridor, or coughing, or wheezing), prolonged sedation (marked lethargy following the study, ie, responding to verbal stimuli but decreased tone and some disinterest in feeding), and paradoxical reaction (hyperactivity) during or following sedation. The sedation scoring system described above was of limited use. It is relatively broad based, making the scoring of finer changes in clinical status difficult. For instance, a patient who has a decrease in oxygen saturation without any other changes in sedation or arousal status may be considered to have a deep sedation score because of the need for supplemental oxygen but have a moderate sedation score on the basis of arousal state. Indeed, all patients were scored as moderate during successful sedation and minimal as they were being awakened, and no patients were ever scored as deep or anesthesia. Because of these limitations in the hospital-based scoring system, adverse reactions were recorded separately and distinctly, without attempting to fit them into the scoring system. Sedation was considered failed if the patient was not quiet enough to perform a complete and comprehensive study (as defined by our echocardiography laboratory’s protocol), with minimal or no movement artifacts after ≤2 doses or the maximum allowed dose.
Data are represented in terms of total patients (n), total patients associated with a denominator (percentage), and rate of occurrence (percentage). Fischer’s exact test was used to test differences in first and second dose efficacy as well as the prevalence of adverse events across age groups.
Results
Efficacy
From July 1997 to March 2009, 9796 consecutive patients were sedated (297 neonates, 4616 infants, and 4883 young children). The overall success rate of sedation by oral pentobarbital was 98.7%. It was only until recently (ie, since January 2008) that sedation success or failure was tracked in relation to patient age and the need for a second dose. Analysis of these more recent data concerning the need for a second dose showed that 87% (902 of 1035) were successfully sedated after one dose only. First doses were significantly more successful in infants than young children (466 of 504 vs 436 of 531, P < .001). Of the 133 (13% overall, 8% of infants, 18% of young children) patients who required second doses, 25 (19%) failed, which yielded an overall second dose success rate of 81% ( Table 1 ). Second doses were significantly more successful in young children than in infants (80 of 95 vs 28 of 38, P = .02).
| Neonates and infants | Young children | Overall | |
|---|---|---|---|
| Variable | (n = 504) | (n = 531) | (n = 1035) |
| First dose success rate | 466/504 (93%) | 436/531 (82%) | 902/1035 (87%) |
| Second dose success rate | 28/38 (74%) | 80/95 (84%) | 108/133 (81%) |
| Overall success rate | 494/504 (98%) | 516/531 (97%) | 1010/1035 (98%) |
Figure 1 illustrates time to sedation in all 9796 patients. The series shows time passed until sedation was achieved in relation to a percentage of the population. Most patients (73%) achieved sedation in <30 minutes. However, 16% required 30 to 45 minutes to reach sedation, and 11% did not reach sedation until after a period of ≥45 minutes had elapsed.
The majority of patients (80%) were sedated for a range of 15 to 60 minutes, allowing for echocardiographic completion ( Figure 2 ). A small percentage of patients (1%) remained sedated for <15 minutes and could not be adequately studied. A significant proportion of patients (19%) experienced sedation for a prolonged period of time (60 to >90 minutes), a time period traditionally considered unnecessary for adequate imaging. These patients underwent echocardiography early in the 12-year experience, when the echocardiography laboratory was undergoing a transition in leadership and experiencing a large sonographer turnover. During this period, image times were significantly longer because echocardiography physicians frequently obtained additional images after the completion of the sonographer portion of a study.
Safety
Table 2 shows that there were only 51 adverse events in the 9796 patients sedated. Adverse reactions were significantly less prevalent in infants than young children ( P < .0001) and neonates ( P = .01). Neonates and infants primarily experienced respiratory complications (all decreased oxygen saturation without upper or lower airway obstruction, nor cough, nor wheezing), while young children exhibited a small, but varied, number of adverse effects, such as emesis, respiratory complications (again, decreased oxygen saturation only), prolonged sedation, and hyperactive paradoxical reactions. Respiratory complications occurred while patients were sedated and resolved before awakening or on awakening. Emesis and hyperactivity occurred on awakening.
| Neonates | Infants | Young children | Total | |
|---|---|---|---|---|
| Event | (n = 297) | (n = 4616) | (n = 4883) | (n = 9796) |
| Emesis | — | — | 17 | 17 |
| Respiratory complication | 2 | 5 | 10 | 17 |
| Prolonged sedation | — | — | 8 | 8 |
| Paradoxical reaction | — | 1 | 8 | 9 |
| Total | 2 | 6 | 43 | 51 |
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