Intraoperative Transesophageal Echocardiography for Pediatric Patients with Congenital Heart Disease

Perioperative Echocardiography

Echocardiography has been utilized perioperatively since the 1970s and many studies have been conducted to prove its efficacy. Epicardiac echocardiography (EE) is the modality of choice when transesophageal echocardiography (TEE) is contraindicated or when aortic atherosclerosis is suspected. Perioperative TEE has shown to be an excellent tool in the operating room for assessment, diagnosis, surgical guidance, and outcome evaluation. Pediatric surgery has also shown better surgical outcomes for congenital disease states with the guidance of TEE. The cardiac Sonographer’s role in the operating room is a very important one because it involves operating the ultrasound machine and communicating image interpretations to surgeons in a timely and efficient manner. Cardiac Sonographers eager to progress in their careers can take advantage of this opportunity to enhance their clinical and educational qualifications. Technology is advancing quickly with the breakthrough of 3D and 4D TEE, where images are captured in real time, providing improved diagnoses and prognosis. This article discusses the evolution of echocardiography in the operating room and its future impact on perioperative evaluation, with attention paid to the role of cardiac Sonographers and the future clinical progression in their scope of practice.

The role of transesophageal echocardiography during surgery for patients with tetralogy of Fallot

Routine use of intraoperative transesophageal echocardiography (TEE) is a safe monitoring and diagnostic method during pediatric congenital cardiac surgery. However, the question of whether intraoperative TEE is accurate and cost effective for patients with tetralogy of Fallot (TOF) has not been raised. This study aimed to analyze the cost-benefit of routine TEE during the repair of TOF. The medical records, including TEE results, for patients who underwent correction of TOF between January 1997 and June 2007 were reviewed and retrospectively analyzed. Intraoperative TEE was performed for 340 patients (85 %). Residual problems were detected in 17.9 % (61/340), and a return to bypass was needed for 10 % (34/340) of the patients. The degree of agreement between the intraoperative TEE and early postoperative transthoracic echocardiography (TTE) was relatively high. Surgeons with less surgical experience more frequently used intraoperative TEE (p = 0.007) and performed repeat bypass surgery at a higher rate (p = 0.00). Even relatively unskilled surgeons might be able to achieve surgical outcomes similar to those of experienced surgeons using intraoperative TEE. By avoiding late surgical revision, the possible cost savings were estimated to be 1,726,000 Korean won (US$1,489) per TEE examination. Intraoperative TEE can be used as a tool for surgeons in making decisions in the operating room. In addition, intraoperative TEE decreased the frequency of reoperations and postoperative interventions. The results of this study demonstrate that routine intraoperative TEE during repair of TOF was both clinically beneficial and cost effective.

Transesophageal echocardiography in critically ill acute postoperative infants: comparison of AcuNav intracardiac echocardiographic and microTEE miniaturized transducers

BACKGROUND

Multiple barriers to transthoracic echocardiography are present in critically ill infants immediately after surgery. Transesophageal echocardiography (TEE) is sometimes needed to obtain specific important information that transthoracic echocardiography fails to demonstrate. Formerly, the investigators used the AcuNav intracardiac echocardiographic (ICE) intravascular ultrasound transducer (8 Fr, 2.5 mm, 64-element crystal array, multifrequency [5.5-10 MHz], single longitudinal plane, linear phased array [Siemens Medical Solutions USA, Inc., Mountain View, CA]). Recently, the investigators have also used the microTEE transducer (8-mm transducer tip, 5.2-mm shaft, multifrequency [3-8 MHz], multiplane phased array, 32-element probe [Philips Medical Systems, Andover, MA]). Both transducers have two-dimensional, M-mode, color Doppler, and pulsed-wave and continuous-wave Doppler capabilities. The aim of this study was to compare the efficacy, safety, ease of insertion, capabilities, utilization, and cost of the AcuNav ICE transducer versus those of the microTEE transducer.

METHODS

A retrospective review of all 50 postoperative critically ill infants who underwent TEE using the AcuNav and microTEE in the past 5 years was conducted. TEE was performed as ordered by the attending physician to answer a specific question not answered by transthoracic echocardiography.

RESULTS

In all cases, the clinical information sought was obtained. The AcuNav ICE transducer was safe, easy to insert through the transnasal route, and did not require paralysis; however, it had a limited number of echocardiographic views and had greater sterilization cost. The microTEE transducer had greater echocardiographic capabilities and lower sterilization cost; however, it was slightly more difficult to insert, had a few manageable complications, and required more sedation and paralysis.

CONCLUSIONS

TEE in this setting has increased because of demonstrated efficacy and safety. Both the AcuNav ICE and microTEE transducers are useful and effective in this critical clinical scenario.

Clinical application of a micro multiplane transoesophageal probe in congenital cardiac disease

AIM

To assess the quality of imaging modalities of a new micro multiplane transoesophageal echocardiogram probe.

METHOD

This is a prospective study of micro transoesophageal echocardiogram S8-3t probe used at a single institution between 15 December, 2009 and 15 March, 2010. The images were compared with standard paediatric or adult probes where possible. Assessors prospectively rated imaging quality - two dimensional, colour flow imaging, pulse wave, and continuous wave Doppler - with a subjective 4-point scale (1 = poor to 4 = excellent).

RESULTS

A total of 24 studies were performed on 23 patients, with a median weight = 11.7 kilograms (2.6-72 kilograms) and a median age of 3 years (0.16-60 years). Of the 23 patients, one neonate (2.8 kilograms) had transient bradycardia on probe insertion. Imaging in patients less than 10 kilograms was of full diagnostic value and new information was obtained in eight out of ten patients. Pulse wave and continuous wave Doppler was consistently good across all weight groups. There were high frame rates and good imaging quality to a depth of 4-6 centimetres in all studies. A comparison with a larger alternative probe was available for 12 studies (weight 11.9-72 kilograms). The median micro transoesophageal two-dimensional image quality score was 3 (2-4) and 4 (3-4) with the comparative probe. For the 10- to 30-kilogram group, image quality with the micro transoesophageal echocardiogram probe was judged as inferior to larger standard probes. Adult sized patients had good imaging of near the field, allowing guidance for percutaneous device closure of the atrial septum.

CONCLUSION

The micro multiplane transoesophageal echocardiogram probe provides imaging of diagnostic quality in neonates. In larger patients, it offers good imaging of near field structures. In the intermediate-sized child (10-30 kilograms), standard paediatric probes provide better imaging.

Transesophageal Echocardiography in Tetralogy of Fallot

Transesophageal echocardiography (TEE) plays an important role in the anatomical, functional, and hemodynamic assessment of patients with congenital heart disease (CHD). This imaging approach has been applied to both children and adults with a wide range of cardiovascular malformations. Extensive clinical experience documents significant contributions, particularly in the perioperative setting. In fact, in the current medical era, many consider this technology to be an essential adjunct to surgical and anesthetic management in CHD. This review focuses on the applications of TEE in patients with tetralogy of Fallot (TOF), the most common form of cyanotic heart disease. Emphasis is given to the perioperative use of this imaging modality and benefits derived during the prebypass and postbypass periods. Limitations and pitfalls relevant to the TEE assessment in patients with this anomaly are also addressed.

The added value of real-time three-dimensional echocardiography in the diagnosis of supravalvar mitral ring: case report and review of the literature

Supravalvular mitral stenosis is a rare condition characterized by an abnormal ridge, with one or two orifices, covering and obstructing the mitral valve. Preoperative identification of the supravalvular ring is the target for obtaining good surgical results. Two-dimensional echocardiogram and transesophageal echocardiography both failed in reaching this objective. In this case, we showed that three-dimensional echocardiogram is a new technique that provides additional and more accurate echocardiographic characterization of congenital supravalvular mitral stenosis.

Occlusion of the right subclavian artery after insertion of a transesophageal echocardiography probe in an adult with a vascular ring -A case report-

Intraoperative transesophageal echocardiography (TEE) has become an important monitoring device for patients undergoing cardiac or noncardiac surgery. Complications associated with TEE are unusual, but the potential for TEE probe compression of the posterior vascular structures has been reported in pediatric patients. We present here a case of occlusion of the right subclavian artery in an adult patient with a vascular ring after insertion of a TEE probe.

A new transesophageal probe for newborns

Current transesophageal probes are designed for adults and are used both in the operating theatre for monitoring as well as in the outpatient clinic for patients with specific indications, like obesity, artificial valves, etc. For newborns (<5 kg), transesophageal echocardiography (TEE) is not possible because the current probes are too big for introducing them into the esophagus. There is a clear need for a small probe in newborns that are scheduled for complicated cardiac surgery and catheterization. We present the design and realization of a small TEE phased array probe with a tube diameter of 5.2mm and head size of only 8.2-7 mm. The number of elements is 48 and the center frequency of the probe is 7.5 MHz. A separate clinical evaluation study was carried out in 42 patients (Scohy et al. 2007).

Ventilatory compromise in an infant with Tetralagy of fallot and right aortic arch after insertion of transesophageal echocardiography probe: A case report

Right aortic arch, a congenital malformation of the great vessels, can cause compression of trachea and/or esophagus. We experienced a case of ventilatory compromise in an infant with tetralogy of Fallot and right aortic arch immediately after insertion of transesophageal echocardiography probe during cardiac surgery. Although intraoperative transesophageal echocardiography can be safely performed in infants with congenital heart disease, it should be done with caution in patient with similar vascular malformation.

Optimal head position during transesophageal echocardiographic probe insertion for pediatric patients weighing up to 10 kg

No data exists for the optimal head position during transesophageal echocardiography (TEE) probe insertion in children. Turning the head to the side closes the ipsilateral pyriform sinus and dilates the contralateral pyriform sinus, theoretically making probe insertion safer and easier. In this study, 94 children (weight, <or=10 kg) undergoing TEE during heart surgery between March 2000 and August 2001 were studied. The head position was either midline or left. A scale was devised to grade the resistance during probe insertion: grade 1 (none), grade 2 (mild), grade 3 (moderate), grade 4 (severe), and grade 5 (inability to insert probe). Probe insertion was midline in 38 and left in 56 of the children. Mild or no resistance was encountered in 86% of the head left versus 63% of the head midline children (p = 0.002). Probe insertion was easier with the head left in three subgroups: I (weight, >5 kg), II (weight, 4-5 kg), and III (weight, <4 kg). The difference was statistically significant only for subgroup III (p = 0.0001). Insertion failed in four children with the head in the midline position but was successful when the head was turned leftward. Children undergoing TEE who weigh less than 10 kg should have the head positioned to the side rather than in the midline position during probe insertion. If insertion is unsuccessful or difficult with the head in the midline position, the authors recommend turning the head to the side and reattempting probe insertion.