A Comparison of the Efficacy and Safety of Chloral Hydrate Versus Inhaled Anesthesia for Sedating Infants and Toddlers for Transthoracic Echocardiograms


Pediatric patients may need sedation for a transthoracic echocardiogram. Due to the unpredictability and safety concerns with chloral hydrate, we offered mask anesthesia as an alternate strategy.


A retrospective chart review of 507 pediatric patients sedated for transthoracic echocardiography was conducted to compare the use of oral chloral hydrate (n = 297) with the face mask administration of sevoflurane anesthesia (n = 210).


Anesthesia had a shorter time from administration of sedation to hospital discharge (112 vs 155 minutes), largely because of a shorter, more predictable, and less variable time to achieve satisfactory study conditions. Using anesthesia, an average 43-minute difference would allow for an additional procedure using the same resources. Anesthesia was not associated with sedation failure (0% vs 6%), and the duration of examination was shorter (40 vs 46 minutes). There were no significant adverse events in either cohort.


Anesthesia, although more costly, is balanced by more the efficient use of hospital and parental resources, with greater family and staff satisfaction.

Transthoracic echocardiography (TTE) is one of the primary noninvasive imaging tools used to diagnose and formulate treatment plans for patients with congenital heart disease (CHD). The ability to acquire a complete study of quality images is predicated on the patient’s ability to cooperate and remain relatively immobile for upward of 45 minutes. The ability to cooperate is dependent on chronologic and developmental age, so young children and those with behavioral disorders often require sedation to complete TTE. Oral chloral hydrate has long served as the mainstay for sedating young children for noninvasive imaging, including TTE. Over the past several years, clinicians have been increasingly dissatisfied with chloral hydrate because of the unpredictable onset and offset of sedation and concern for its safety profile. Additionally, the variability seen with chloral hydrate can be costly in terms of personnel and bed utilization, lost revenue from failed procedures, and inconvenience to patients and families.

The cardiologists performing TTE at our institution approached the cardiothoracic anesthesia group to identify an alternative drug to sedate these children. They sought a drug that was safe, resulted in the rapid onset of sedation, introduced minimal or no side effects, and did not require patients to have intravenous catheters (IVs). Other drugs or drug combinations, administered via routes other than IVs, that had been reported as being successfully used to sedate young children for TTE were examined. Each of these drugs, including midazolam and pentobarbital, had significant issues resulting in their not meeting the prescribed goals, leading us to conclude that no better drug than chloral hydrate was available that could be given by the sedation team. It was proposed that anesthetic gas delivered via face mask by an anesthesiologist would meet the desired goals.

In July 2007, the pediatric cardiothoracic anesthesia staff offered anesthesia 4 days per week as an alternative to chloral hydrate. The cardiologist requesting and/or the cardiologist performing TTE selected between the two options. A retrospective chart review was undertaken to compare the two strategies.


This study received approval from the institutional review board. Investigators retrospectively analyzed the charts of all outpatients receiving sedation for TTE as a single procedure in the Cardiac Preparation and Recovery Unit (CPRU) procedure room from when the unit opened in July 2006 until August 2008. From July 2006 through June 2007. the only sedation option was chloral hydrate. Beginning in July 2007, sevoflurane anesthesia was offered as an alternative strategy. The cardiologist ordering the study and/or the cardiologist performing TTE selected between the two options. Cases were identified by a manual review of the CPRU log. Clinical data, including demographics, choice of sedation strategy, drug dose(s), timing of the procedure, and adverse events through hospital discharge, were extracted from the electronic anesthesia and/or the sedation record. Hospital records were searched for patient return within 24 hours of the procedure. A failure was defined as inability to obtain all the required images after 3 separate administrations of chloral hydrate or following the administration of face mask anesthesia. Continuous variables were assessed for normality, and parametric or nonparametric methods were applied accordingly (Stata SE 10; StataCorp LP, College Station, TX).

Features Common to Both Strategies


In 2006, The Cardiac Center at The Children’s Hospital of Philadelphia constructed a unit (the CPRU) dedicated to the preparation and recovery of patients with CHD undergoing diagnostic and interventional procedures, both cardiac and noncardiac. The CPRU is a 13-bed unit consisting of two 5-bed pods and 3 private rooms, which is contiguous with 53 inpatient cardiac beds. All patients with CHD requiring sedation and/or anesthesia, other than those in the cardiac intensive care unit, are cared for in this unit by a dedicated team of physicians and nurses. Bedside and advance practice nurses are trained to provide all aspects of care, including administering conscious sedation and recovering patients after sedation and/or general anesthesia. The unit houses a procedure room with a fully equipped anesthetizing location. A pediatric cardiac anesthesiologist is assigned for part of each weekday to sedate and/or anesthetize both outpatients and inpatients undergoing diagnostic studies (TTE and transesophageal echocardiography) and minor procedures (eg, the placement of pleural catheters, wound debridement, endoscopy, myringotomy tubes) in this venue.

Patient Selection

At our institution, patients can be scheduled for sedated TTE only by a cardiologist. Criteria that cardiologists use when selecting sedation include the inability of the patient to cooperate because of young age or a behavioral problem, projected study duration in excess of 30 to 45 minutes, a previous failed study without sedation, and/or TTE performed along with another diagnostic procedure that requires sedation or anesthesia. Patients scheduled for face mask anesthesia had preanesthetic assessments to determine their suitability by an advance practice nurse and/or attending anesthesiologist. Exclusion criteria include a history of adverse events surrounding a previous anesthetic or a family history of malignant hyperthermia (MH), the presence of a full stomach, examination identifying anatomic features predicting a difficult airway, morbid obesity, and hemodynamic or other issues that preclude the administration of a volatile anesthetic without an IV.

Fasting Guidelines

Patients for both sedation and general anesthesia were fasted in an identical fashion. Patients aged <1 month were allowed formula and fortified breast milk until 4 hours prior to receiving sedation, infants 1 to 4 months of age were allowed formula and solids until 6 hours before sedation, and patients aged >4 months were fasted for milk and solids for 8 hours. All patients were allowed clear liquids, including nonfortified breast milk, up to 2 hours before being sedated.


Both strategies included the same routine noninvasive monitoring modalities of electrocardiography, blood pressure, and pulse oximetry; temperature monitoring was included for anesthesia patients. All studies were performed by a sonographer in the procedure room, with a staff echocardiographer reading from a remote location in real time and coming to the procedure room only if the requisite images could not be obtained.

Postprocedural Recovery

On the completion of sedated TTE, patients must transition through phase I and phase II recovery and meet discharge criteria prior to going home. Recovery phases are criteria, not time, based at our institution. Criteria for phase I and phase II recovery are outlined in Table 1 . Phase I commences at the time the child arrives back in his or her room on the completion of TTE until the child has a recovery score of 5, at which time the child enters phase II, where he or she remains until meeting discharge criteria. Discharge criteria include a recovery score of 6, no more than 2 episodes of emesis, none within 30 minutes of discharge, and the ability to ingest a minimum of 30 mL of fluid.

Table 1

Subject ages and time intervals

Chloral hydrate Anesthesia
Variable (n = 297) (n = 210) P
Age (mo) 16.9 (15.5-18.3) 19.6 (16.8-22.5) .34
0-30 d 3 (1%) 0 (0%) .27
1-6 mo 69 (23%) 49 (23%) 1.00
6 mo to 1 y 53 (18%) 25 (12%) .08
1-2 y 100 (34%) 81 (39%) .26
>2 y 72 (24%) 55 (26%) .68
Time from sedation onset to discharge (min) 155.4 (147.7-163.1) 112.1 (106.7-117.5) <.001
Time from sedation onset to start of TTE (min) 34.7 (31.5-37.9) 3.6 (3.1-4.1) <.001
Duration of TTE (min) 46.4 (44.0-48.8) 40.5 (38.2-42.7) .01
Time from end of TTE to discharge (min) 75.1 (68.6-81.5) 63.5 (58.5-68.4) .20

Data are expressed as mean (95% confidence interval).

Mann-Whitney U test and Fischer’s exact test as appropriate.

Features Unique to Each Strategy

Chloral Hydrate

The protocol for chloral hydrate administration included an initial oral dose of 60 to 75 mg/kg (60 mg/kg for patients aged <18 months, 75 mg/kg for those aged ≥18 months), with a maximum total dose of 2 g, administered by the bedside nurse. The patient was continuously observed by the bedside nurse and if at the end of 30 minutes was not deemed to be satisfactorily sedated, half of the initial dose was given. A third dose, consisting of half of the initial dose, was given if the child was not sedated after a second 30 minutes. Any time in this continuum that the patient was deemed adequately sedated by the bedside nurse, the child was transferred to the procedure room for the initiation of TTE, during which the nurse recorded vital signs every 5 minutes for the duration of the study. At the completion of 60 minutes from the initial dose if the conditions were not met, the patient was discharged to return another day for TTE. When the procedure was completed, the patient was transferred back to his or her room, on a portable monitor, by the nurse administering the sedation.


All patients for whom face mask anesthesia was requested had preanesthetic evaluations performed by an advance practice nurse or staff anesthesiologist to ensure that they met inclusion criteria. The protocol for anesthesia included no premedication. On arrival in the procedure room, a face mask delivering oxygen, sevoflurane, and on occasion nitrous oxide was applied until the patient lost consciousness. The concentrations of anesthetics were adjusted to maintain immobility along with respiratory and hemodynamic stability. When the procedure was completed, the anesthetics were discontinued, and upon return to consciousness, the patient was transferred to his or her room, on a portable monitor, by the anesthesiologist.

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Jun 16, 2018 | Posted by in CARDIOLOGY | Comments Off on A Comparison of the Efficacy and Safety of Chloral Hydrate Versus Inhaled Anesthesia for Sedating Infants and Toddlers for Transthoracic Echocardiograms

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