Summary
Background
Transoesophageal echocardiography (TOE) is feasible in neonates using a miniaturized probe, but is not widely used because of low imaging quality.
Aims
To assess handling and imaging quality of a new release of a micro-TOE probe in children.
Methods
Thirty-eight consecutive children, enrolled during February and May 2013, underwent TOE with the Philips S8-3t probe. Insertion, handling and image quality were assessed.
Results
The 38 children (aged 7 days to 12 years; weight 3.1–27 kg) underwent 75 TOE (30 [40.0%] before cardiac surgery, 31 [41.3%] after cardiac surgery, 4 [5.3%] during a percutaneous procedure, 10 [13.3%] in the intensive care unit). Insertion of the micro-TOE probe was ‘very easy’ in 37/38 patients (97.4%). Handling was better in the lightest children ( P = 0.001). Image quality was mainly ‘good’ or ‘very good’, with no significant changes between preoperative and postoperative examinations or over time. Total scores (insertion, handling, image quality) were significantly better in the lightest children ( P = 0.02). Preoperative TOE did not provide additional information over transthoracic echocardiography. Postoperative TOE was useful to assess surgical results, but no residual lesions required extracorporeal circulation return. Micro-TOE was useful during the postoperative care of neonatal surgery with open breastbone to assess the surgical result and ventricular function. It was also useful to guide extracorporeal membrane oxygenation (ECMO) indication and withdrawal; and was a useful guide for percutaneous procedures.
Conclusion
Micro-multiplane TOE is safe and efficient for use in neonates and children. This minimally invasive tool increases the impact of TOE in paediatric cardiology.
Résumé
Contexte
L’échographie transœsophagienne (ETO) est réalisable chez le nourrisson à l’aide de sondes miniaturisées dédiées. Néanmoins, l’usage n’est pas répandu du fait d’une qualité d’image moyenne.
Objectif
Nous avons évalué la maniabilité et la qualité d’image de la nouvelle version de la sonde transœsophagienne micromultiplan S8-3t durant la pratique courante en cardiopédiatrie.
Méthodes
Trente-huit enfants ont été inclus consécutivement entre février et mai 2013 avec réalisation d’une ETO avec la sonde Philips S8-3t. La maniabilité et la qualité d’image ont été évaluées indépendamment par deux opérateurs.
Résultats
Soixante-quinze ETO avec la sonde micro S8-3t ont été réalisées chez les 38 enfants, âgés de 7 jours à 12 ans (3 – 27 kg). Les indications étaient requises par l’usage courant : au bloc opératoire avant ( n = 30, 40,0 %) ou après ( n = 31, 41,3 %) une chirurgie cardiaque, pour guider des procédures de cathétérisme interventionnelles ( n = 4, 5,3 %) et en réanimation pédiatrique ( n = 10, 13,3 %). L’insertion a été simple chez tous les patients sauf un (2,6 %). La maniabilité et la stabilité de la sonde étaient meilleures chez les enfants les plus légers ( p = 0,001). La qualité d’image était bonne et globalement meilleure chez les enfants de faible poids. Il n’a pas été constaté de détérioration de la qualité d’image entre avant et après la chirurgie cardiaque ni durant l’étude. L’ETO préopératoire n’a pas apporté d’informations complémentaires par rapport à l’échographie transthoracique préopératoire. L’ETO postopératoire a permis d’apprécier le résultat chirurgical mais aucune lésion n’a nécessité un retour en circulation extracorporelle. La sonde micro S8-3t s’est révélée très utile pour la gestion postopératoire de chirurgie cardiaque néonatale avec thorax ouvert et pour guider l’indication et le retrait d’assistance circulatoire transitoire. L’ETO micro s’est révélée utile pour le guidage de cathétérisme interventionnel pédiatrique.
Conclusion
L’ETO avec la sonde micro S8-3t est un examen utile, sûr et efficace au bloc opératoire de chirurgie cardiaque pédiatrique, en salle de cathétérisme et en réanimation pédiatrique. Cette sonde micro peu invasive augmente l’intérêt de l’ETO en cardiologie pédiatrique, particulièrement chez le nouveau-né et le nourrisson.
Background
Transoesophageal echocardiography (TOE) is a useful tool for the surgical or interventional treatment of congenital heart disease (CHD) in children and neonates . It is also useful for the assessment of cardiac function and haemodynamic status in the intensive care unit (ICU) . The first reports assessing TOE were published in the 1990s, but these were in older children and adults. Many surgeries for CHD are performed in neonates, raising difficulties of insertion and risk of complications (e.g. oropharyngeal and oesophageal traumas, arrhythmias and circulatory disturbance ) with mini-multiplane probes.
In 2007, a micro-multiplane probe was released for use in neonates. Handling was good, but image quality was low, possibly due to an overheating issue . In the current study, we tested a new release of the micro-multiplane probe and report our initial experience of clinical use. The primary objective was to assess the imaging quality of this new probe in current practice in children undergoing cardiac surgery, catheterizations and in the ICU. Secondary objectives were to assess safety and handling.
Methods
Patients
Between February and May 2013, consecutive children were enrolled prospectively from the paediatric cardiology unit of the children’s hospital of Toulouse. Children for whom a TOE was indicated for a medical purpose (cardiac surgery, an interventional procedure or in the ICU) during the study period were enrolled. Exclusion criteria were: lack of consent, accurate transthoracic echocardiographic images in the ICU obviating the need for a TOE examination and contraindications for TOE as stated in the recommendations from the Pediatric Council of the American Society of Echocardiography .
Informed verbal consent was obtained from each patient (when possible) and their legal representatives after full explanation of the procedure had been given. Written consent was not required according to French laws because the echography evaluation was part of the regular management of these children and was required for their medical condition. No additional examinations were performed solely for the purpose of the study. The study protocol was approved by the national commission for data processing and freedoms (N o 1673449v0: declared on 31st May 2013).
Micro-TOE S8-3t probe
The new release of the S8-3t probe (Philips Healthcare Medical Systems, Andover, MA, USA) was used in all cases. It has been available for clinical use since 2012. It has a tip length of 18.5 mm, a tip width of 7.5 mm, a tip height of 5.5 mm and a shaft diameter of 5.2 mm. The transducer array is mounted on a pulley, providing various angle views ranging from 0° to 180 from a median longitudinal cross-sectional view. The probe can anteflex up to 110° and retroflex up to 45°. The first enhancement is an improved mechanism for sensor rotation. New 7 × 7 steering cables are stronger, more flexible and less susceptible to failure with use. The second improvement is a new articulation knob that is easier to control. The probe allows two-dimensionnal colour imaging with pulsed and continuous Doppler in children weighing < 4.5 kg. The micro-multiplane TOE probe S8-3t was used with the iE33 ultrasound machine (Philips Medical Systems).
Micro-TOE probe insertion
The micro-TOE probe was systematically inserted after patient sedation and intubation, before surgery or catheterization. In the ICU, the micro-TOE was used in patients under mechanical ventilation when transthoracic echocardiography was not feasible (open breastbone). The previously lubricated probe was inserted blindly and delicately with a jaw thrust of the mandible or, if not feasible, under direct visualization by laryngoscopy. After the initial examination during CHD surgeries, the probe was advanced into the stomach and left in an unlocked position during the procedure. The ultrasound machine was turned off during surgery. During the weaning from extracorporeal circulation, the post-repair TOE examination was performed.
TOE image acquisition and scoring system
For congenital heart disease surgery, two TOE examinations were performed: one before surgery to confirm or modify the other preoperative examinations and one after surgery. Relevant modifications of the preoperative diagnosis from the TOE findings were to have been displayed and discussed with the surgical team.
Examinations were performed by one of two first operators (S. H. or M. P.). For each patient, the following recommended views were performed: mid oesophageal four chamber (0–20°), right ventricular outflow tract (60–90°), left outflow tract and aortic valve (short axis 30–60°, long axis 100–150°), mitral commissural (60–70°) and trans-gastric views . Off-line analysis was performed by a second operator (K.H.) to assess inter-rater agreement of the imaging quality scoring.
Ease of use (insertion and handling) was scored by the first operator. Imaging quality (two-dimensionnal echocardiography, colour Doppler, pulsed Doppler and continuous Doppler) was scored by the first and second operators. The scoring system is described in Table 1 . The total score was calculated for each child by the sum of the scores of the six criteria.
| Category | Criteria | Score | |||
|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | ||
| Ease of use | 1. Probe insertion | Very easy (insertion blindly or under laryngoscopy within 1 minute) | Easy (under laryngoscopy within 2 minutes) | Hard (insertion under laryngoscopy requiring > 2 minutes) | Not possible |
| 2. Handling (torque, probe stability, probe flexion) | Very good | Good | Bad | Very bad | |
| Image quality | 3. Two-dimensional echocardiography | Very good (good quality for all cardiac structures) | Good (satisfactory quality for cardiac structures of interest) | Bad (cardiac structures of interest difficult to analyse) | Very bad (no images) |
| 4. Colour Doppler | |||||
| 5. Pulsed Doppler | |||||
| 6. Continuous Doppler | |||||
Side effect evaluation
Particular attention was paid to haemodynamic parameters during probe insertion and TOE examination. After the TOE, the probe and oropharynx were inspected for any sign of blood or trauma. No specific medications, e.g. proton pump inhibitors, were routinely given.
Statistical analysis
Age and weight are expressed as median (range); qualitative data are expressed as number and percentage. For CHD surgeries, imaging quality between the preoperative and the postoperative examinations was compared. As we did not find any difference in scoring between repeated TOEs within the same child, we also performed a per-patient analysis. We investigated the impact of the weight (as a continuous variable) on the ratings for each of the six criteria using the non-parametric Kruskall-Wallis test. Patients were stratified in four groups according to quartiles of weight. Comparisons of ratings of the six criteria ( Table 1 ) between the four weight groups were performed using a non-parametric exact Fischer test. The total score was compared between the four groups using the Kruskall-Wallis test. Inter-rater agreement between the two operators was assessed using the kappa coefficient for quality of imaging (criteria 3–6 in Table 1 ). A P -value < 0.05 was considered statistically significant. Statistical analysis was performed using Stata8 (Statacorp, TE, USA).
Results
Patients
A total of 38 children (median [range] age 9.3 years [7 days–12 years]; weight 12 [3.1–27] kg) underwent 75 TOE examinations using the micro-TOE probe. TOE indications, along with numbers of TOEs per patient, are shown in Table 2 . Surgical procedures, mainly atrial or ventricular septal defect closures, are detailed in Table 2 . During the study, no diagnosis changed after preoperative TOE compared with preoperative transthoracic echocardiography.
| TOE examinations ( n = 75) | |
|---|---|
| TOE indications | |
| Before cardiac surgery to confirm lesions | 30 (40.0) |
| After cardiac surgery to assess the result | 31 (41.3) |
| To guide percutaneous procedures | 4 (5.3) |
| To assess cardiac function in the ICU | 10 (13.3) |
| Surgeries | |
| Atrial septal defect closure | 9 (12.0) |
| Ventricular septal defect closure | 8 (10.7) |
| Tetralogy of Fallot repair | 4 (5.3) |
| Right ventricular outflow tract reconstructions a | 2 (2.7) |
| Atrio-ventricular septal defect repair | 2 (2.7) |
| Total cavo-pulmonary derivation | 2 (2.7) |
| Other b | 4 (5.3) |
| Percutaneous procedures | |
| Atrial septal defect closure | 2 (2.7) |
| Balloon valvuloplasty of a severe mitral stenosis | 1 (1.3) |
| Percutaneous dilatation of severe aortic valve stenosis | 1 (1.3) |
| ICU | |
| Endocarditis | 1 (1.3) |
| Aetiological investigation of stroke | 2 (2.7) |
| Post-cardiac surgery due to poor quality transthoracic echocardiography | 7 (9.3) |
| Number of examinations per patient | |
| 1 | 7 (18.4) |
| 2 | 27 (71.1) |
| 3 | 3 (7.9) |
| 5 | 1 (2.6) |
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