How Best to Assure Patient Co-Operation during a Pediatric Echocardiography Examination?

One of the important challenges inherent in using echocardiography (and other diagnostic testing methods) in young children is how best to ensure patient cooperation during testing. This is particularly important because increasingly, decisions about treatment, including complex cardiac surgical procedures and interventional cardiac catheterization, are based on noninvasive test results. Accordingly, it is increasingly important that echocardiographic studies in children be of high quality and as complete as necessary to answer the relevant questions. Every pediatric echocardiography laboratory has developed its own approach, and no single best strategy has been established. The practices range from distraction by video viewing to the sedation of nearly all infants and toddlers presenting for echocardiography. Although indications for sedation differ among the pediatric echocardiography labs, there are times when sedation clearly is required for an uncooperative infant or toddler. Different medications and combinations of medications have been used for this purpose. Safety, rates of side effects and complications, time from administration to beginning echocardiography, length of sedation, ease of administration and patient monitoring, cost, and the effects of sedation on the measured parameters are all important considerations in this decision. Because an ideal medication does not exist, almost every pediatric echocardiography laboratory has developed expertise with a “favorite” drug that it prefers to use.

Two studies published in the present issue describe the sedation experiences of two high-volume pediatric echocardiography laboratories. Warden et al evaluated Cincinnati Children’s Hospital echocardiography laboratory’s 12-year experience using pentobarbital in 9,796 patients. They found that nearly 99% of patients were successfully sedated. Of those, 61% were sedated for 30 to 60 minutes. Nearly 20% were sedated for >1 hour. Fifty-one patients had adverse effects; these were more common in children aged 1 to 4 years. The authors conclude that pentobarbital is an effective and safe sedative but acknowledge that alternative sedation strategies may be beneficial in children aged 1 to 4 years.

A second study from Children’s Hospital of Philadelphia by Nicolson et al compared the efficacy and safety of chloral hydrate with inhaled anesthesia using a mixture of oxygen and sevoflurane, and on occasion nitrous oxide, for transthoracic echocardiography. From July 2006 to August 2008, a total of 538 patients were sedated for echocardiography; 507 were included in the study. They were divided into two statistically comparable groups. Patients sedated with chloral hydrate required longer times from sedation to imaging and longer image acquisition times. Nearly one third of those sedated with chloral hydrate needed second doses of the medicine, and 6% did not fall asleep at all. Adverse effects were observed in 3 patients sedated with inhaled anesthesia and in 18 of those sedated with chloral hydrate. The adverse effects were not significant. The additional cost of an echocardiogram with sedation by inhalation anesthesia was $1,476 per patient. The authors conclude that anesthesia, although more costly, is associated with significantly shorter patient stay, less sedation variability, and greater parent and hospital staff member satisfaction.

These two interesting studies raise a number of equally interesting questions. One key question is, What proportion of infants and toddlers actually needs to be sedated to obtain an adequate echocardiographic study? Many would probably agree that if a study can be done without sedation, it should be done without sedation.

In the report from Cincinnati, 9l796 patients were sedated during a 130-month period. That corresponds to 75.3 sedations per month. In Philadelphia, the average number of monthly sedations was 21.2. Although the papers do not provide data about the total number of studies performed at each institution, the corresponding hospitals’ Web sites state that 8,524 outpatient echocardiograms were performed at the Cincinnati Children’s Hospital echocardiography laboratory in 2008, and a total of >50,000 tests (electrocardiography, echocardiography, and magnetic resonance imaging) are performed yearly at the Children’s Hospital of Philadelphia. Therefore, one might assume that the Children’s Hospital of Philadelphia echocardiography laboratory performs at least as many studies as does the laboratory at Cincinnati Children’s Hospital. Under that assumption, the chance of a patient being sedated in Philadelphia would be 3.5 times smaller than that of a patient in Cincinnati. Could the frequency of sedation use be even lower? At the Pittsburgh Children’s Hospital echocardiography laboratory, where the decision about sedation is made on the basis of presedation patient assessments, 100 pediatric patients required sedation during the period from May 2006 to June 2008. That would correspond to just 3.8 sedated patients per month. Almost 20 years ago, Stevenson et al tested the use of video viewing to distract infants and toddlers during echocardiography. They reported that complete examinations were obtained without sedation in 92% of subjects who otherwise would have required sedation. Our own experience at Children’s Hospital of Michigan suggests that video viewing is especially successful in distracting toddlers when the screen is movable and is placed directly in front of the patient’s face. This allows for a good quality study even in a toddler who is anxious initially. Does the rate of significant diagnostic discrepancies, important enough to alter catheterization or surgical intervention, differ with different approaches to indication for sedation? No studies have answered this question.

All studies mentioned above came from highly respected pediatric echocardiography laboratories that provide high-quality echocardiographic studies. In the series they report, the different sedation strategies were thought to provide information that met the diagnostic needs in an adequate manner. However, the definition of an “adequate” study may not be uniform from one echocardiography laboratory to another. It could be a study that collects all possible details that might be useful for future retrospective research projects, if such projects come to mind later. Conversely, it could be a study that provides necessary information for today’s clinical decision making. Although the former study might take slightly longer, the time needed for these two types of studies might not differ significantly, because the majority of measurements could be done offline at a later time. The question, then, is how long a patient needs to stay sedated for an “adequate” study to be performed. The study by Nicolson et al could be used as a reference, because their anesthesia-sedated patients were awakened immediately after the acquisitions were finished. The time of echocardiography was 38 to 42 minutes. Sedation time in the study of Warden et al was longer: half of the patients were sedated for >45 minutes, and 20% of all patients stayed sedated for >1 hour. At the other end of this spectrum is a small study from the Naval Regional Medical Center in San Diego, where the average duration of sedated studies was between 21.7 and 25.6 minutes. Because of anesthesia involvement, the lengths of echocardiographic procedures in the Philadelphia and San Diego reports were defined by study goals. The lengths of echocardiographic procedures in the Cincinnati study were probably also influenced by the pharmacodynamic properties of the sedative medication used.

The effect of sedation on hemodynamic indices measured by echocardiography is another important consideration. It is known that sedation decreases heart rate and blood pressure and could alter myocardial contractility. Therefore, moderate sedation achieved in almost all subjects in the study of Warden et al probably affected measured pressure gradients. This assumption is supported by the data from Stevenson et al demonstrating a minimal reduction in the accuracy of prediction of catheterization pressure gradients when using echocardiographic data from nonsedated toddlers. Because catheterization-derived gradients are currently used as a reference for surgical or catheter interventions, this potential change might have some clinical significance. On the other hand, every patient undergoing inhaled sedation in the study of Nicolson et al was receiving oxygen, a potent pulmonary vasodilator. Therefore, flow measurements across the right-sided structures of the heart were probably artificially increased in all studied patients. These effects could be insignificant; however, they complicate the comparison of studies from different institutions.

Chloral hydrate, one of the first medications used for pediatric echocardiographic sedation, has been extensively studied. Adverse effects have been reported in a range from 2.7% to 18%. Children aged <6 months have a higher incidence of adverse reactions, whereas those aged >3 years often require repeat doses of chloral hydrate. Although pentobarbital has a better safety profile, its sedative effect is long, and patients stay sedated after studies are completed. Midazolam, another agent used in pediatric echocardiography, has an excellent safety profile but works more as an anxiolytic than a sedative and commonly requires a repeat dose, thereby significantly prolonging the study time. As none of the oral medications routinely used for pediatric echocardiographic sedation is ideal, the data from Nicolson et al demonstrating very high effectiveness and a low adverse effect rate of mask-inhaled sedation are appealing. However, this approach adds almost $1,500 to the cost of a routine echocardiographic procedure. The additional expense for inhalation sedation may be offset to some degree by shorter duration of sedation and the resulting opportunity to perform a greater number of sedated echocardiographic studies on a given day. Although there are situations in which anesthesia involvement in an echocardiographic study is unavoidable (eg, the evaluation of an uncooperative mentally challenged teenager), this should be an exception rather than a routine in the current era of rising medical costs.

At the present time, there exists no single best strategy to ensure patient cooperation during a pediatric echocardiographic study. Although every pediatric laboratory is comfortable with its own approach, it might be reasonable to combine the vast experiences of different centers and create a common strategy that the majority of labs could agree on. Thus, when distraction techniques fail to work and sedation is necessary, sedatives will be chosen depending on the goal of the study as well as the age and anxiety level of the patient.

Editorial Comments published in the Journal of the American Society of Echocardiography (JASE) reflect the opinions of their author(s), and do not necessarily represent the views of JASE, its editors, or the American Society of Echocardiography.

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Jun 16, 2018 | Posted by in CARDIOLOGY | Comments Off on How Best to Assure Patient Co-Operation during a Pediatric Echocardiography Examination?

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