Peri-operative Anesthetic Innovations
During Pediatric Cardiac Surgery
Thierry V. Scohy
ISBN 978 94 6169 101 9
Cover design: Sarah, Sofi a and Luca Scohy
Copyright 2011 T.V. Scohy
All rights reserved. No part of this thesis may be reproduced, distributed, stored in a
retrieval system or transmitted in any form or by any means, without permission of the
author, or when appropriate, of the publishers of the publications.
Peri-operative Anesthetic Innovations
During Pediatric Cardiac Surgery
Peri-operatieve anesthetische vernieuwingen
ter verkrijging van de graad van doctor aan de
Erasmus Universiteit Rotterdam
op gezag van de
rector magnifi cus
Prof.dr. H.G. Schmidt
en volgens besluit van het College voor Promoties.
De openbare verdediging zal plaatsvinden op
vrijdag 28 oktober 2011 om 11:30 uur
Thierry Vincent Scohy
geboren te Lier, België
Prof.dr. A.J.J.C. Bogers
Prof.dr. J. Klein
Prof.dr.ir. N. de Jong
Prof.dr. P.J. de Feyter
Prof.dr. P. Wouters
Dr. D.A.M.P.J. Gommers
Dr. J. Hofl and
Het verschijnen van dit proefschrift werd mede mogelijk gemaakt door de steun van de
TABLE OF CONTENTS
A new transesophageal probe for newborns.
Scohy TV, Matte G, van Neer PL, van der Steen AF, McGhie J, Bogers A,
de Jong N.
Ultrasound Med Biol. 2009;35:1686-9.
Intraoperative evaluation of micromultiplane transesophageal
echocardiographic probe in surgery for congenital heart disease.
Scohy TV, Gommers D, Jan ten Harkel AD, Deryck Y, McGhie J, Bogers AJ.
Eur J Echocardiogr. 2007;8: 241-6.
Image quality using a micromultiplane transesophageal
echocardiographic probe in older children during cardiac surgery.
Scohy TV, Gommers D, Schepp MN, McGhie J, de Jong N, Bogers AJ.
Eur J Anaesthesiol. 2009;26:445-7.
Intraoperative transesophageal echocardiography is benefi cial for
hemodynamic stabilization during left ventricular assist device
implantation in children.
Scohy TV, Gommers D, Maat AP, Dejong PL, Bogers AJ, Hofl and J.
Paediatr Anaesth. 2009;19:390-5.
Rapid method for intraoperative assessment of aortic coarctation using
Scohy TV, du Plessis F, McGhie J, de Jong PL, Bogers AJ.
Eur J Echocardiogr. 2009;10:922-5.
Measurement of end-expiratory lung volume in intubated children
without interruption of mechanical ventilation.
Bikker IG, Scohy TV, Ad J J C Bogers, Bakker J, Gommers D.
Intensive Care Med. 2009;35:1749-53.
Alveolar recruitment strategy and PEEP improve oxygenation, dynamic
compliance of respiratory system and end-expiratory lung volume in
pediatric patients undergoing cardiac surgery for congenital heart
Scohy TV, Bikker IG, Hofl and J, de Jong PL, Bogers AJ, Gommers D.
Paediatr Anaesth. 2009;19:1207-12.
Intraoperative Glycemic Control without Insulin Infusion during Pediatric
Cardiac Surgery for Congenital Heart Disease.
Scohy TV, Golab HD, Egal M, Takkenberg JJM, Bogers AJJC.
Paediatr Anaesth. 2011 Apr 4. (Epub ahead of print)
List of publications
Ge neral introduction
General Introduction 9
CONGENITAL HEART DISEASE: A SHORT NOTE OF HISTORY
Congenital heart disease (CHD) refers to a series of birth defects that aff ect the heart and
thoracic vessels, aff ecting 6 to 8 out of 1,000 babies being born. In 40% of these children
no treatment is indicated because of minimal eff ect on hemodynamics and outcome.
In 60% treatment will be required; about half of them will require urgent surgery after
birth, while the other half will probably require surgery or medication at some point
during childhood. Due to advances in heart surgery, 85% of children with congenital
heart disease will survive into adulthood (1).
Although CHD has been recognized for centuries, therapeutic options were not avail-
able until the 20th century (2). Until the late 1930s little advances were made in cardiac
surgery due to a lack of refi nement in anesthesia and problems related to now routine
perioperative support techniques, such as blood transfusion and mechanical ventilation
(3). After the fi rst successful ligation of a patent ductus arteriosus in 1938 (4), a lot of
new operations found their origin. In 1949 perioperative mortality, approached 14.5%
(5). In the 1950s extracorporeal circulation made its entry. The introduction of new an-
esthetic drugs and the use of prostaglandins to maintain ductal patency and pulmonary
blood fl ow was one of the most important advances of the 1970s (6). In the late 1970s
cardioplegia solutions were introduced. During the 1980s sufentanil and midazolam
off ered alternatives to potent volatile anesthetics, although hospital mortality was
still 6% (7). From the 1990s miniaturizing components of the cardiopulmonary bypass
circuit reduced priming volumes, producing less coagulation factor dilution and further
improvement in patient outcome.
During the past two decades, mortality after surgery for congenital cardiac disease has
decreased dramatically and is now reported to be 4% in the European Association for
Cardio-thoracic Surgery and the Society of Thoracic Surgeons Congenital Heart Surgery
Database (8), the focus of clinical research and eff orts to improve quality has now shifted
to that of the minimization of morbidity (9).
ASPECTS OF QUALITY
Although quality management is a major strategic issue in health care organizations,
there is little agreement on the precise defi nition and content of quality and quality
management (10). Most often concepts and tools regard organizational quality and
originate from industry. For instance, the Netherlands implemented into the govern-
mental medical safety design policy, a report from a Royal Dutch Shell director, “In this
organisation you work safely, otherwise you don’t work here at all”, plays a key-role (11).
10 General Introduction
The Orde van Medische Specialisten (organisation for medical specialists in the Neth-
erlands) reports that professional medical practice quality is seen as interplay between
product-quality, process-quality, and structure-quality (12). Product-quality has aspects
of Good Clinical Practice like: effi ciency, expertise, making adequate indications for
medical care, capability, safety and carefulness. Process-quality has aspects of attitude
like: respectful treatment, willingness to give adequate information, trustful relation-
ship, cooperation and accountability. Structure-quality has aspects of organisational
management like: continuity of care, availability of care, functionalism and integrated
From the point of view of the medical professional, however, quality directly relates
to the delivery of medical care. One should approach each patient asking not only “How
can I provide the best care in this case?” but also “How can I improve the care I provide?”.
This opens the way to innovative care.
Although, effi cacy and cost-eff ectiveness are important aspects, innovative care may
at some point introduce less effi ciency and may initially seem to increase costs. When
however the medical professional results improve, a new reality for the organization is
According to Deming a quality improvement cycle consists of planning, doing, check-
ing and acting (13). This fi ts elegantly for improving patient care i.e. for application of
This thesis concerns aspects of innovative care and quality improvement in the opera-
tive treatment of pediatric patients with congenital heart disease.
LATEST IMPROVEMENTS OF TRANSESOPHAGEAL ECHOCARDIOGRAPHY (TEE)
AND ITS APPLICATION IN CLINICAL PRACTICE OF CHILDREN WITH CHD
Until 1990, intraoperative evaluation of infants and children undergoing congenital
heart surgery was not feasible with TEE because probe sizes were too large (14). The de-
velopment of miniaturized single- and bi-plane probes demonstrated that TEE could be
performed safely in the pediatric population (15). A multiplane TEE probe which obtains
images in several planes is an obvious advantage, certainly considering the complexity
of the intracardiac defects. Until 2007, the use of mini-multiplane TEE probe (10.7 – 8.0
mm diameter tip with a 7.4 mm diameter shaft) was still limited to children above the
weight of 5 kg (16).
In Chapter 1 we describe the physical characteristics and the acoustic properties of
the Oldelft microMulti TEE probe (8.2 – 7 mm diameter tip with a 5.2 mm diameter shaft),
a new technology that was developed at the Thoraxcentre to study neonates and small
General Introduction 11
In Chapter 2 we evaluated the clinical and diagnostic ability of this new technology
in 42 neonates and infants (as small as 2.5 kg) undergoing cardiac surgery to provide
data on safety and feasibility. Chapter 3 describes the limitations, loss of image quality
in larger children (>25 kg) of the Oldelft micromultiplane TEE probe.
In Chapter 4 we highlight an aspect of clinical necessity of intraoperative TEE. Mechani-
cal circulatory support with a left ventricle assist device (LVAD) is used in an increasing
number of children for treatment of advanced heart failure as bridge to transplant. In
adult patient care, intra-operative TEE plays a key-role in evaluating LVAD cannula posi-
tioning, haemodynamic stabilisation and the eff ect of device settings on right and left
heart function. No data were available and no studies defi ned the role of intra-operative
TEE for haemodynamic stabilisation during LVAD implantation in children. Therefore,
we studied the utility of intra-operative TEE in pediatric patients undergoing centrifugal
Aortic coarctation should be considered as a complex cardiovascular syndrome
(17,18,19). There is controversy about the accurate assessment of the haemodynamic
signifi cance of blood fl ow obstruction caused by re-stenosis after aortic coarctation
repair, for as the arm-leg blood pressure diff erence may not necessarily represent the
haemodynamic signifi cance of re-stenosis (20). Although an exact assessment of the
aortic anatomy is required for an optimal surgical repair, no feasible intra-operative
visualisation of a possible residual stenosis of the aorta exists. Till today, a brachial-ankle
blood pressure diff erence of > 20 mmHg (18) or > 30 mmHg (21) is the only intra-opera-
tive indication for residual stenosis. Therefore, we decided to assess the feasibility of 3D
echocardiography by assessing intra-operative morphological details of aortic coarcta-
tion and its repair in children. By this way three-dimensional echocardiography made its
very fi rst clinical entrance in pediatric cardiac anesthesia and surgery (Chapter 5).
Chapters 4 and 5 show how innovation improves medical professional result and
becomes a new reality.
END-EXPIRATORY LUNG VOLUME AND MECHANICAL VENTILATION
With regard to reducing morbidity after congenital heart surgery, pulmonary complica-
tions and central airway problems are a frequent cause for delayed recovery following
cardiac surgery in infants and small children (22).
Ventilation can profoundly alter cardiovascular function via complex processes (9),
due to the location of lungs and heart in the thoracic cavity. These processes refl ect the
interaction between many factors like: Ventricular function, Circulating blood volume,
Distribution of the fl ow of blood, Autonomic tone, Volume of air in the lungs, or pulmo-
nary volume, and Intrathoracic pressure (23).
12 General Introduction
Changes in pulmonary volume alter autonomic tone and pulmonary vascular resis-
tance, and at high pulmonary volumes compress the heart. Hyperinfl ation increases
pulmonary vascular resistance and the pressure in the pulmonary arteries, impeding
right ventricular ejection. Decreases in pulmonary volume induce alveolar collapse and
hypoxia, stimulating an increased pulmonary vasomotor tone by the process of hypoxic
pulmonary vasoconstriction. Maneuvers of alveolar recruitment, positive end-expiratory
pressure, and continuous positive airway pressure may reverse hypoxic pulmonary va-
soconstriction and reduce the pressure in the pulmonary arteries (9).
General anaesthesia is known to promote lung volume reduction, which prompts
atelectasis, lung compliance and arterial oxygenation (24). In children, decreased
lung volume is of special importance because of the lower elastic retraction forces
and a lower relaxation volume, which makes them more prone to airway collapse (25).
Monitoring end-expiratory lung volume (EELV) is a valuable tool to optimise respiratory
settings that could be of importance in mechanically ventilated pediatric patients (26).
We evaluated the feasibility and precision of an ICU ventilator with an inbuilt nitrogen
wash-out/wash-in technique in mechanically ventilated pediatric patients. In Chapter 6
the results of EELV measurements in pediatric post-operative cardiac surgery patients
are given. Optimising alveolar recruitment by alveolar recruitment strategy (ARS) and
maintaining lung volume with adequate positive end-expiratory pressure (PEEP) would
allow preventing ventilator-induced lung injury (VILI). In Chapter 7 we describe the ef-
fect of ARS and PEEP on variables like oxygenation and compliance of the respiratory
system in paediatric patients undergoing cardiac surgery for CHD. Here again we see
how innovation improves medical professional result and can become a new reality in
common clinical practice.
INTRAOPERATIVE GLYCEMIC CONTROL DURING PEDIATRIC CARDIAC
Several studies report that the occurrence of hyperglycemia in the postoperative period
is associated with increased morbidity and mortality rates in children after cardiac sur-
gery for congenital heart disease (27-30). However, an association with intraoperative
management or complexity of congenital heart disease has not yet been assessed.
Lately there is concern that glycemic control in the peri-operative period, aiming
at avoiding hyperglycemia while maintaining a strict euglycemic target, could place
patients at risk for hypoglycemia and hereby enhance the risk for adverse outcome (27,
In the light of this controversy we report on our pediatric cardiac anesthesiological
management and the blood glucose levels during open cardiac surgery for congenital
General Introduction 13
heart disease in Chapter 8. Amongst other items, this chapter refl ects the aspects of
quality management in a research setting: Plan (clinical research planning), Do (collect
data), Check (data analysis) and Act (implementation).
AIM OF THE THESIS
The aim of this thesis is to study actual aspects of perioperative care in pediatric cardiac
surgery by applying innovative techniques and concepts in order to improve the quality
Quality of care in pediatric cardiac anesthesia is clearly an evolving work in progress.
Good surgical team behaviour (34), process improvements, structural improvements,
and increases in expertise have diminished overall mortality rates.
14 General Introduction
1. Mulder BJM, Gewillig M, Pieper PG, Meijboom FJ, Witsenburg M, Hamer JPM. Aangeboren hartz-
iekten. In: van der Wall EE, van de Werf F, Zijlstra F. Cardiologie, 2nd edition, Houten, Bohn Stafl eu
van Loghum, 2008: pp 391-421.
2. Lake CL, Booker PD: Pediatric Cardiac Anesthesia; 4th edition, Louisville, Kentucky, Lippincott
Williams and Wilkins, 2005: pp 1-5.
3. Waldhausen JA: The early history of congenital heart surgery: closed heart operations. Ann Thorac
Surg 1997, 64: 1533-1539.
4. Gross RE, Hubbard JP: Landmark article Feb 25, 1939: Surgical ligation of a patent ductus arte-
riosus: report of fi rst successful case. By Robert E. Gross and John P. Hubbard. JAMA 1984, 251:
5. McQuiston WO: Anesthetic problems in cardiac surgery in children. Anesthesiology 1949, 10: 590-
6. Olley PM, Coceani F, Bodach E: E-type prostaglandins: a new emergency therapy for certain
cyanotic congenital heart malformations. Circulation 1976, 53: 728-731.
7. Hickey PR, Hansen DD, Norwood WI, Castaneda AR: Anesthetic complications in surgery for
congenital heart disease. Anesth Analg 1984, 63: 657-664.
8. Jacobs JP, Jacobs ML, Maruszewski B, Lacour-Gayet FG, Clarke DR, Tchervenkov CI et al.: Current
status of the European Association for Cardio-Thoracic Surgery and the Society of Thoracic Sur-
geons Congenital Heart Surgery Database. Ann Thorac Surg 2005, 80: 2278-2283.
9. Cooper DS, Jacobs JP, Chai PJ, Jaggers J, Barach P, Beekman RH et al.: Pulmonary complications
associated with the treatment of patients with congenital cardiac disease: consensus defi nitions
from the Multi-Societal Database Committee for Pediatric and Congenital Heart Disease. Cardiol
Young 2008, 18 Suppl 2: 215-221.
10. Van den Heuvel J. The eff ectiveness of ISO 9001 and Six Sigma in healthcare. Rotterdam, Beau-
mont Quality Publications 2006: p12.
11. Willems R. Hier werk je veilig, of je werkt hier niet. Eindrapportage Shell Nederland – November
12. http:orde.artsennet.nl/kwaliteit/organisatie kwaliteitsbeleid/Defi nitie-kwaliteit.htm.
13. Postal SN. Using the Deming quality improvement method to manage medical record depart-
ment product lines. Top Health Rec Manage 1990: 10(4);34-40.
14. Muhiudeen R, I, Miller-Hance WC, Silverman NH: Intraoperative transesophageal echocardiogra-
phy for pediatric patients with congenital heart disease. Anesth Analg 1998, 87: 1058-1076.
15. Yumoto M, Katsuya H: Transesophageal echocardiography for cardiac surgery in children. J
Cardiothorac Vasc Anesth 2002, 16: 587-591.
16. Sloth E, Hasenkam JM, Sorensen KE, Pedersen J, Olsen KH, Hansen OK et al.: Pediatric multiplane
transesophageal echocardiography in congenital heart disease: new possibilities with a miniatur-
ized probe. J Am Soc Echocardiogr 1996, 9: 622-628.
General Introduction 15
17. Marx GR. ‘Repaired’ aortic coarctation in adults: not a ‘simple’ congenital heart defect. J Am Coll
Cardiol 2000; 35: 1003-6.
18. Hager A, Kanz S, Kammerer H, Schreiber C, Hess J. Coarctation long-term assessment (COALA):
signifi cance of arterial hypertension in a cohort of 404 patients up to 27 years after surgical repair
of isolated coarctation of the aorta, even in the absence of restenosis and prosthetic material. J
Thorac Cardiovasc Surg 2007; 134: 738-45.
19. Hager A, Schreiber C, Nutzl S, Hess J. Mortality and restenosis rate of surgical coarctation repair in
infancy: a study of 191 patients. Cardiology 2009; 112: 36-41.
20. Araoz PA, Reddy GP, Tarnhoff H, Roge CL, Higgins CB. MR fi ndings of collateral circulation are
more accurate measures of hemodynamic signifi cance than arm-leg blood pressure gradient
after repair of coarctation of the aorta. J Magn Reson Imaging 2003; 17: 177-83.
21. Deanfi eld J, Thaulow E, Warnes C, et al. Management of grown up congenital heart disease. Eur
Heart J 2003; 24: 1035-84.
22. Bandla HP, Hopkins RL, Beckerman RC, Gozal D: Pulmonary risk factors compromising postopera-
tive recovery after surgical repair for congenital heart disease. Chest 1999, 116: 740-747.
23. Kocis KC, Meliones JN: Cardiopulmonary interactions in children with congenital heart disease:
physiology and clinical correlates. Prog Pediatr Cardiol 2000, 11: 203-210.
24. Hedenstierna G, Edmark L. The eff ects of anesthesia and muscle paralysis on the respiratory
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25. Mansell A, Bryan C, Levison H. Airway closure in children. J Appl Physiol 1972; 33: 711-4.
26. Hedenstierna G. The recording of FRC – Is it of importancce and can it be made simple? Intensive
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27. Wintergerst KA, Buckingham B, Gandrud L, Wong BJ, Kache S, Wilson DM: Association of hypogly-
cemia, hyperglycemia, and glucose variability with morbidity and death in the pediatric intensive
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28. Polito A, Thiagarajan RR, Laussen PC, Gauvreau K, Agus MS, Scheurer MA et al.: Association
between intraoperative and early postoperative glucose levels and adverse outcomes after
complex congenital heart surgery. Circulation 2008, 118: 2235-2242.
29. Vlasselaers D, Milants I, Desmet L, Wouters PJ, Vanhorebeek I, van den Heuvel I, et al.: Intensive
insulin therapy for patients in paediatric intensive care: a prospective, randomised controlled
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30. Yates AR, Dyke PC, Taeed R, Hoff man TM, Hayes J, Feltes TF et al.: Hyperglycemia is a marker for
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cose control in critically ill patients. N Engl J Med 2009, 360: 1283-1297.
16 General Introduction
33. Floyd TF, Horak J: Con: Tight perioperative glycemic control. J Cardiothorac Vasc Anesth 2009, 23:
34. Manser T. Teamwork and patient safety in dynamic domains of healthcare: a review of literature.
Acta Anaesthesiol Scand 2009, 53: 143-151.
Ch apter 1
A new transesophageal
probe for new borns
Scohy TV, Matte G, van Neer PL, van de Steen AF, McGhie J, Bogers AJ, de Jong N.
Ultrasound Med Biol. 2009 Oct;35(10):1686-9.
18 Chapter 1
Current transesophageal probes are designed for adults and are used both in the oper-
ating theatre for monitoring as well as in the outpatient clinic for patient with specifi c
indications, like obesitas, artifi cial valves etc. For newborns (< 5 Kg) TEE imaging is not
possible because the current probes are too big for introducing them in 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 5.2 mm and head size of only 8.2 - 7 mm. The number of elements is 48
and the centre frequency of the probe 7.5 MHz. A separate clinical evaluation study was
carried out on 42 patients (Scohy et al. 2007).
Chapter 1 19
The clinical application of transesophageal echocardiography (TEE) technology contin-
ues to progress, with various indications and diagnostic uses (Milani et al. 2003). The
most common indications for TEE in pediatric patients with congenital heart disease
(CHD) are for assessment during cardiac surgery and interventional cardiac catheteriza-
tion procedures (Ayres et al. 2005). Another indication for TEE in pediatric patients is in
situations in which the transthoracic technology is diagnostically inadequate because of
poor quality or limited echocardiographic windows, which is frequently encountered in
patients receiving mechanical ventilation, and other critically ill patients in an intensive
care unit. Other indications for TEE are pediatric patients with intracardiac conduits or
patients with suspicion of CHD, but where transthoracic echocardiography is nondi-
agnostic (Ayres et al. 2005). Until 1990, TEE evaluation in infants and children was not
possible because probes were too large (Muhiudeen et al. 1998). The development of
miniaturized single- and biplane probes (from 3.3 to 9 mm diameter) generated a num-
ber of studies, which demonstrated that TEE can be performed safely in the pediatric
population (Bruce et al. 2002; Andropoulus et al. 2000; Yumoto et al. 2002). A multiplane
TEE probe is an obvious advantage, certainly considering the complexity of the intra-
cardiac defects in neonates (Shiota et al.1999; Tardif et al. 1994; Yvorchuk et al. 1995).
Until recently, a safe investigation with the multiplane technique was limited to children
of $5 kg (Sloth 1996). Recently, we demonstrated that a new Oldelft micromultiplane
TEE probe (8.2 to 7-mm tip diameter, 5.2-mm shaft diameter) connected to a Philips
iE33 ultrasound system (Philips, Andover, MA, USA) provided excellent intraoperative
TEE assessment in neonates as small as 2.5 kg without major complications (Scohy et al.
2007). In this study, we describe the physical characteristics and the acoustic properties
of the Oldelft/Philips micromultiplane TEE probe.
MEASUREMENTS AND METHODS
The TEE transducer consists of 48 elements. The element width is 70 mm and the kerf 30
μm. The center 32 elements measure 7.5 mm in the elevation, whereas eight elements
at both ends of the transducer are tapered from 7.5 to 3.75 mm (size of element 1 and
48), resulting in an octagonal shape. The transducer center frequency is 7.5 MHz, which
is higher than the standard 5-MHz frequency of an adult TEE probe. The probe was con-
nected to a Philips IE33 scanner for the clinical evaluation and to a dedicated phased ar-
ray system (Lecoeur E´ lectronique, Chuelles, France) for acoustic in vitro measurements.
A photograph of the transducer is shown in Fig. 1.
20 Chapter 1
Figure 1: Photograph of the new probe (micro-multi) together with 2 commercially available TEE probes.
Top: Adult probe. Middle: mini multiplane probe. Bottom: micro multiplane probe.
The probe was connected to an experimental phased array system (Lecoeur E´ lectro-
nique), enabling optimal control in transmission. The acoustic fi eld was measured with a
calibrated hydrophone of 0.2-mm diameter (Precision Acoustics, Teddington Middlesex,
UK), of which the position was controlled by a computer-controlled X-Y-Z system (6K4,
Parker Hannifi n Corporation, Rohnert Park, CA, USA). For beam profi le measurements,
the scanner operated in a single-line mode steering at 0° and focused at an axial dis-
tance of 2 cm. The profi les were measured using a transmit pulse of two periods and a
center frequency of 7.5 MHz. The generated peak pressure at the focal point was kept
low (240 kPa).
Simulations were done using Field II (Jensen and Svendsen 1992; Jensen 1996). For the
simulations, the same settings were used as for the measurements (lateral focus at 2 cm,
elevation focus at 6 cm, steering 0 degrees, acoustic pressure 240 kPascal).
Figure 2 shows the beam profi les in lateral and elevation at a distance of 2 cm. The lateral
and elevation –3 dB beamwidths (one way) were, respectively, 0.5 mm and 1 mm. The
dotted line in the fi gure denotes the result of the simulation, which is in agreement
with the measurements. Figure 3 shows the acoustic pulse in focus (left) and the cor-
responding frequency spectrum (right). The maximum in the frequency spectrum is at
7.5 MHz, as seen in the fi gure. By considering this value as the center frequency, the
relative bandwidth at –6 dB is 53%.
Chapter 1 21
Figure 2: Lateral (right) and elevation (left) beam profi le at an axial distance of 2 cm
Figure 3: Acoustic pulse (left) and corresponding frequency spectrum at an axial distance of 2 cm.
Figures 4, 5 and 6 have been acquired as part of a routine intraoperative TEE examination
in a 1-week-old neonate weighing 2.6 kg, with transposition of the great arteries, and
who was scheduled for arterial switch procedure. Institutional review board approval/
consent was waived. Figure 4 shows the aorta and the pulmonary artery before the
arterial switch procedure for transposition of the great arteries; this image could only
be visualized in a 113_ multiplane angle. In Fig. 5 we measured the velocity of the septal
site of the mitral valve annulus with pulsed-wave tissue Doppler imaging, which can be
used to evaluate left ventricular function. Figure 6 shows the post-repair patency of the
coronary artery after implantation in the aorta with color Doppler. We also distinguish
the bifurcation of the mainstem into the left anterior descending and the circumfl ex
22 Chapter 1
Figure 4: Aorta and Pulmonary artery in Transposition of the Great Arteries in a 2.6 kg neonate in a
multiplane angle of 113°.
Figure 5: Pulsed-wave Tissue Doppler Imaging at the septal site of mitral valve annulus in a 2.6 kg
Figure 6: Color Doppler of the mainstem coronary artery re-implantation in the aorta.
Chapter 1 23
We present the design and realization of a small TEE phased array probe with a tube
diameter of 5.2 mm. The image quality of the probe is good and the probe has a clear
diagnostic value for neonates.
24 Chapter 1
Andropoulus DB, Stayer SA, Bent ST, Campos CJ, Fraser CD. The eff ects of transesophageal echocar-
diography on hemodynamic variables in small infants undergoing cardiac surgery. J Cardiothorac Vasc
Ayres NA, Miller-Hance W, Fyfe DA, Stevenson JG, Sahn DJ, Young LT, Minich LL, Kimball TR, Geva T, Smith
FC, Rychik J. Indications and guidelines for performance of transesophageal echocardiography in the
patient with pediatric acquired or congenital heart disease. J Am Soc Echocardiogr 2005;1:91–98.
Bruce CJ, O’Leary P, Hagler DJ, Seward JB, Cabalka AK. Miniaturized transesophageal echocardiography
in newborn infants. J Am Soc Echocardiogr 2002;15:791–797.
Jensen JA. Field: A program for simulating ultrasound systems. 10th Nordic-Baltic Conference on Biomedi-
cal Imaging. Med Biol Eng Comp 1996b;4(Suppl 1):351–353.
Jensen JA, Svendsen NB. Calculation of pressure fi elds from arbitrarily shaped, apodized and excited
ultrasound transducers. IEEE Trans Ultrason Ferroelec Freq Contr 1992;39:262–267.
Milani RV, Lavie CJ, Gilliland YE, Cassidy MM, Bernal JA. Overview of transesophageal echocardiography
for the chest physician. Chest 2003;124:1081–1089.
Muhiudeen RI, Miller-Hance WC, Silverman NH. Intraoperative transesophageal echocardiography for
pediatric patients with congenital heart disease. Anesth Analg 1998;87:1058–1076.
Scohy TV, Gommers DA, ten Harkel AD, Deryck Y, McGhie J, Bogers AJ. Intraoperative evaluation of mi-
cromultiplane transesophageal echocardiographic probe in surgery for congenital heart disease. Eur J
Shanewise JS, Cheung AT, Aronson S, Stewart WJ, Weiss RL, Mark JB, Savage RM, Sears-Rogan P, Mathew
JP, Quin˜ones MA, Cahalan MK, Savino JS. ASE/SCA guidelines for performing a comprehensive intraop-
erative multiplane transesophageal echocardiography examination: Recommendations of the American
Society of Echocardiography and the Society of Cardiovascular Anesthesiologists Task Force for Certifi ca-
tion in Perioperative Transesophageal Echocardiography. Anesth Analg 1999;89:870–884.
Shiota T, Lewandowski R, Piel JE, Smith LS, Lancee C, Djoa K, Bom N, Cobanoglu A, Rice MJ, Sahn DJ.
Micromultiplane transesophageal echocardiographic probe for intraoperative study of congenital heart
disease in neonates, infants, children, and adults.Am J Card 1999;83: 292–295.
Sloth E, Hasenkam JM, Sørensen KE, Pedersen J, Olsen KH, Hansen OK, Egeblad H. Pediatric multiplane
transesophageal echocardiography in congenital heart disease: New possibilities with a miniaturized
probe. J Am Soc Echocardiogr 1996;9:622–628.
Tardif JC, Schwartz SL, Vannan MA, Cao QL, Pandian NG. Clinical usefulness of multiplane transesopha-
geal echocardiography: Comparison to biplanar imaging. Am Heart J 1994;128:156–166.
Yumoto M, Katsuya H. Transesophageal echocardiography for cardiac surgery in children. J Cardiothorac
Vasc Anesth 2002;16:587–591.
Yvorchuk KY, Sochowski RA, Chan KL. A prospective comparison of the multiplane probe with the biplane
probe in structure visualization and Doppler examination during transesophageal echocardiography. J
Am Soc Echocardiogr 1995;8:111–120.
Ch apter 2
Intraoperative evaluation of
echocardiographic probe in surgery
for congenital heart disease
Scohy TV, Gommers D, ten Harkel DJ, Deryck Y, McGhie J, Bogers AJ.
Eur J Echocardiogr. 2007 Aug;8(4):241-6.
26 Chapter 2
Introduction: In the last years, transesophageal transducers for multiplane Doppler
echocardiography have demonstrated their superior imaging performance in pediatric
patients undergoing cardiac surgery. To date, the size of these probes has limited their
use in neonates and small children. New technologies allowing to perform TEE in smaller
patients are therefore promising.
Methods: We report our clinical experience with the Oldelft microMultiplane TEE probe
(8.2 -7 mm diameter tip with a 5.2 mm diameter shaft) specifi cally meant for use in
Results: Forty-two patients were examined intra-operatively using the microMulti
TEE harmonic transducer. Patients examined ranged in age from 4 days to 6 years and
ranged in weight from 2.5 to 23.8 kg. In two patients we had to adapt ventilatory set-
tings because of increased airway resistance after probe insertion. In 3 patients surgical
re-intervention was performed due to TEE assessment immediately after weaning from
bypass. In two patients signifi cant obstruction of the right ventricular outfl ow tract was
still present after Fallot correction, and one patient had an additional muscular ventricu-
lar septal defect still present after VSD closure.
Conclusions: The MicroMulti TEE harmonic transducer provided excellent diagnostic
intra-operative TEE in neonates and small children without major complications, special
attention should be taken for ventilatory parameters in neonates less than 3 kg.
Chapter 2 27
The role of transesophageal echocardiography (TEE) during surgery for congenital
cardiac disease to defi ne complex anatomical structures, functional abnormalities, and
to monitor hemodynamics is well established (1,2). Until 1990, intraoperative evalua-
tion of infants and children undergoing congenital heart surgery was not feasible with
TEE because probe sizes were too large (1). It is not surprising that inability to pass the
TEE probe and complications as esophageal trauma, airway compromise, and aortic
compression occur predominantly in smaller children (3). The subsequent development
of miniaturized single- and bi-plane probes (from 9 mm down to 3.3 mm diameter) has
generated a number of studies, which have demonstrated that TEE can be performed
safely in the pediatric population (4,5,6). However, the use of a mini multiplane TEE probe
(10.7 – 8.0 mm diameter tip with a 7.4 mm diameter shaft) is still limited to children
above the weight of 5 kg (7). A multiplane TEE probe for neonates and small children,
which obtains images in several planes, is an obvious advantage, certainly considering
the complexity of the intracardiac defects (8,9,10). In this study we evaluated the clinical
and diagnostic ability of the Oldelft microMulti TEE probe (8.2 – 7 mm diameter tip with
a 5.2 mm diameter shaft) in neonates and infants undergoing cardiac surgery to provide
data on safety and visibility.
Forty-two consecutive neonates and infants undergoing surgery for congenital cardiac
defects at the ErasmusMC Thoraxcentrum were included. All patients undergo routinely
TEE during cardiac surgery. Since the availability of the Oldelft microMultiplane TEE
probe the weight limit has dropped to 2.5 kg.
Before induction of anesthesia, all patients were monitored with a fi ve-lead, two-
channel electrocardiogram, non-invasive blood pressure measurement, and pulse oxim-
etry. After the insertion of a peripheral venous line, general anesthesia was induced with
midazolam 0.2 mg/kg, sufentanil 2 mcg/kg and pancuronium 0.15 mg/kg. Patients were
nasotracheally intubated and pressure controlled ventilated (PCV) using a Siemens 900C
ventilator. Anesthesia was maintained with midazolam 0.1 mg/kg/h and sufentanil 1 mcg/
kg/h. Invasive monitoring via a femoral arterial line and an internal jugular central venous
catheter was performed, and a Foley bladder catheter and rectal temperature probe were
inserted. The lubricated Oldelft MicroMultiplane TEE probe was inserted blindly with or
without a jaw thrust of the mandible or under direct laryngoscopic view. During inser-
tion of the TEE probe special attention was payed to tidal volume and dampening of the
arterial waveform (3). TEE examinations were performed using Philips iE 33 ultrasound
28 Chapter 2
system (Philips, Andover, MA. USA) equipped with 2D, pulsed, continuous, and color Dop-
pler capabilities. All TEE examinations were conducted by the same anaesthesiologist in
presence of a second anaesthesiologist who was responsible for the care of the patient.
The microMulti TEE Transducer is a miniature, phased array ultrasound (center frequency
7.5 MHz / bandwidth > 40% / 48 elements / 0.1mm pitch) multiplane TEE probe, devel-
oped for neonates and small children. The microMultiplane TEE transducer consists of
an octagonal 48-element array, 5.0 mm elevation , 4.77 mm lateral aperture, rotatable
through 180° mounted on the distal end of a gastroscope. The microMulti TEE Transducer
uses a fl exible shaft with a thickness of max 5.2 mm, with a length of 70 cm, with a bend-
ing neck capable of articulating in the anterior and posterior directions (120° +/- 10°
upward anterior, 90° +/- 10° backward posterior). The bending neck has a diameter of 5.6
mm and a length of 40 mm. The bead on the transition to the shaft has a diameter of 6.2
mm. The tip is 8.2 mm wide, 7.0 mm thick and has a length of 24.0 mm. Figure 1 shows
a comparison of an adult, the mini multiplane and the micro multiplane TEE probe tips.
Complete TEE examination took place before cardiopulmonary bypass(CPB). After the
initial examination, the probe was advanced into the stomach and left in an unlocked
position during the procedure; the ultrasound emission was turned off during bypass.
The TEE assessment of the surgical repair occurred immediately after weaning from CPB.
Figure 1: Adult, miniMulti and microMulti TEE probe.
Demographic data are summarized in Table 1. Patients examined ranged in age from 4
days to 6 years and ranged in weight from 2.5 to 23.8 kg. Table 1 also lists the diagnostic
information concerning patients who were evaluated before, during and after surgery.
Chapter 2 29
Table 1: Patients Characteristics
TGA / PDA / ASD
PDA / PA
TAPVC / PDA / DORV / TGA
DORV / TGA / PS / PDA
VSD / ASD
VSD / ASD
CoA / VSD / ASD
residual VSD after TOF
Coa / VSD
residual VSD after TOF
Multiple muscular VSDs
DORV / TGA / PS
VSD / PS / ODB
TGA / PA / DORV / MBT
Sinus Venosus Defect
HLHS / TGA / Cor triatriatrum
/ obstruction left LV
ASD / PS
ASD / ODB
Sinus Venosus Defect
Reop TOF / DCRV
CoA / VSD
TR + TS of prosthetic valve
Atrioseptectomy, closure PDA, central shunt
Reimplant Pulm Ven, atrioseptectomie,VP shunt
Correction + transannular patch
Single stage repair
Correction + transannular patch
Correction + transannular patch
Correction + transannular patch
Correction + transannular patch
PCPC, closure MBT
atrioseptectomy, deobstruction left LV
Correction + transannular patch
AS=aortic stenosis; ASD=atrial septal defect; ALCAPA=abnormal left coronary artery from the pulmonary
artery; CAVSD=complete atrioventricular septal defect; CoA=aortic coarctation; DORV=double outlet
right ventricle; HLHS=hypoplastic left heart syndrome; LCA=left coronary artery; PA=pulmonary atresia;
PDA=patent ductus arteriosus; PS=pulmonary stenosis; PV=pulmonary veins; TAPVC= total anomalous
pulmonary venous connection; TGA=transposition great arteries; TR=tricuspid regurgitation; TS=tricuspid
stenosis; TOF=tetralogy of Fallot; VSD=ventricular septal defect; VPshunt=ventricular pulmonary shunt.
30 Chapter 2
None of the patients was excluded beforehand. There were two patients with com-
plications related to introduction of the probe or its use during the surgical procedure.
Patient 1 had an increased airway resistance with increased air leak after introduction
of the microMulti TEE probe, the problem was solved by increasing PEEP level from 4 to
6 cm H2O and increasing peak inspiratory pressure from 10 to 14 cm H2O above PEEP.
Patient 6 had increased airway resistance after introducing the probe, withdrawal of the
nasal endotracheal tube for 0.5 cm, and PEEP increase from 4 to 8 cm H2O and peak
pressure increase from 10 to 18 cm H2O solved the problem. In both patients we noticed
no further diffi culties during TEE examination.
In three patients surgical re-intervention during the continued procedure was decided
after intra-operative TEE assessment of the initial repair. Case 21 and 31 had signifi cant
RVOT obstruction (continuous-wave Doppler velocities of 4.0 m/s) after correction ,
therefore widening of the RVOT (CW velocities 1.4 m/s and 2.0 m/s ) was performed.
Case 14 showed an additional muscular VSD after VSD correction, which was closed
subsequently. This reintervention rate is comparable to the 5-10% as reported earlier in
pediatric cardiac surgery after TEE assessment.
In two of the larger patients (case 40 and 42, body weight 20 and 24 kg) we had poor
TEE has become the standard of care in many institutions performing pediatric cardiac
surgery, to evaluate the surgical repair after weaning from cardiopulmonary bypass. The
cardiac performance can be assessed and possible residual lesions can be immediately
corrected (11). As surgical techniques have improved, greater numbers of neonatal and
small patients are referred for repair of complex intracardiac defects. TEE is frequently
used in this population. Due to the relatively large size and rigid nature of TEE probes,
airway complications, inadvertent extubation, and insertion failures have been reported
to occur predominantly in smaller patients (3). Until recently a safe investigation with
multiplane technique in neonates and infants was limited to children of 5 kg or more (7).
The Oldelft MicroMultiplane TEE probe provided excellent diagnostic intra-operative
TEE in neonates and small children without major complications, this probe allows
multiplane imaging in neonates and smaller children and provides additional and clear
information, with less manipulation than would be required for biplane visualization.
This is illustrated in Figures 2-7. In Figure 2 we measured a fl ow velocity of 4 m/s with
continuous wave (CW) doppler in the pulmonary artery after surgical repair, with the
simplifi ed modifi cation of the Bernoulli equation (ΔP = 4 x ΔV2 ) the estimated instanta-
neous systolic gradient would be 64 mmHg. Figure 3 shows an overriding aorta and VSD
Chapter 2 31
in TOF. Figure 4 shows the RVOT and the pulmonary artery. In Figure 5 we measured the
velocity time integral (VTI) with CW Doppler in a transgastric long-axis view of the aortic
valve. Figure 6 shows color Doppler fl ow in the left coronary artery (LCA) and fi gure 7
shows a transgastric long-axis view of the aortic valve.
In this study we were able to acquire useful images in children down to a weight of
2.5 kg, however in two of the larger children (case 40 and 42) we noticed poor quality
images. Although in two children ventilatory problems occur they could be resolved by
changing ventilatory settings.
Figure 2: Continuous Wave fl ow velocity measurement in pulmonary artery in a multiplane angle of 102°
Figure 3: Ventricular Septal Defect and overriding aorta in Tetralogy of Fallot in a multiplane angle of 108°
32 Chapter 2
Figure 4: Pulmonary artery in a multiplane angle of 48°.
Figure 5: CW Doppler VTI measurement through a normal aortic valve in a transgastric long-axis view;
multiplane angle 101°.
Figure 6: Color Doppler fl ow in Left Coronary Artery in a multiplane angle 14°
Chapter 2 33
Figure 7: Transgastric long-axis view of the aortic valve in a multiplane angle 105°.
In conclusion the Oldelft microMultiplane TEE probe examinations provided excellent
diagnostic intraoperative TEE assessment in neonates as small as 2.5 kg without major
complications. In larger children (>20kg) however we noticed poor image quality, fur-
ther investigation will have to confi rm this.
Immediate TEE assessment of the surgical repair after weaning from bypass may pre-
vent unplanned reoperations in the early and late post operative period. In the smallest
infants attention should be payed to ventilatory settings during and after introduction
of the microMulti TEE probe. Furthermore intra-operative TEE assessment also provided
additional information concerning cardiac performance. This information assisted in
taking the appropriate decisions for optimal pharmacologic treatment during weaning
of bypass. Intraoperative TEE monitoring is recommended in all cases.
34 Chapter 2
1. Muhiudeen RI, Miller-Hance WC, Silverman NH, Intraoperative transesophageal echocardiogra-
phy for pediatric patients with congenital heart disease. Anesth Analg 1998; 87: 1058-1076.
2. Ayres NA, Miller-Hance WC, Fyfe DA, Stevenson JG, Sahn DJ, Young LC et al, Indications and
guidelines for performance of transesophageal echocardiography in the patient with acquired
or congenital heart disease: A report from the Task Force of the Pediatric Council of the American
Society of Echocardiogrophy. J Am Soc Echocardiogr 2005: 18: 91-98.
3. Stevenson JG, Incidence of complications in Pediatric Transesophageal Echocardiography: Expe-
rience in 1650 Cases. J Am Soc Echocardiogr 1999:12: 527-532.
4. Bruce CJ, O’Leary P, Hagler DJ, Seward JB, Cabalka AK, Miniaturized transesophageal echocar-
diography in newborn infants. J Am Soc Echocardiogr 2002; 15: 791-797.
5. Andropoulus DB, Stayer SA, Bent ST , Campos CJ, Fraser CD, The eff ects of transesophageal
echocardiography on hemodynamic variables in small infants undergoing cardiac surgery. J
Cardiothorac Vasc Anesth. 2000: 14(2):133-5.
6. Yumoto M, Katsuya H, Transesophageal echocardiography for cardiac surgery in children. J
Cardiothorac Vasc Anesth. 2002: 16(5): 587-591.
7. Sloth E, Hasenkam JM, Sorensen KE, Pendersen J, Olsen KH, Hansen OK et al, Pediatric multiplane
transesophageal echocardiography in congenital heart disease: new possibilities with a minitu-
rized probe. J Am Soc Echocardiogr 1996: 9(5):622-8.
8. Shiota T, Lewandowski R, Piel JE, Smit LS, Lancée C, Djoa KB et al, Micromultiplane transesopha-
geal echocardiographic probe for intraoperative study of congenital heart disease in neonates,
infants, children, and adults. Am J Card 1999: 83: 292-295.
9. Tardif JC, Schwartz SL, Vannan MA, Cao QL, Pandian NG, Clinical usefulness of multiplane trans-
esophageal echocardiography: comparison to biplanar imaging. Am Heart J 1994:128(1):156-66.
10. Yvorchuk KY, Sochowski RA, Chan KL, A prospective comparison of the multiplane probe with
the biplane probe in structure visualization and Doppler examination during transesophageal
echocardiography. J Am Soc Echocardiogr 1995:8(2):111-20.
11. Ungerleider RM, Greeley WJ, Skeikh KH, Philips J, Pearce FB, Kem FH et al, Routine use of intra-
operative epicardial echocardiography and Doppler color-fl ow imaging to guide and evaluate
repair of congenital heart lesions: A prospective study. J Thorac Cardiovasc Surg 1990: 100: 297-
Ch apter 3
Image quality using a micromultiplane
transesophageal echocardiographic probe
in older children during cardiac surgery
Scohy TV, Gommers D, Schepp MN, McGhie J, de Jong N, Bogers AJ.
Eur J Anaesthesiol. 2009 May;26(5):445-7.
Chapter 3 37
Transesophageal echocardiography (TEE) is a standard procedure both for the intraop-
erative evaluation and monitoring of adult and paediatric patients undergoing cardiac
surgery (1-5). Cardiac performance can be assessed and residual lesions are immediately
corrected (3), thus avoiding re-operations and reducing morbidity, mortality, and costs
(1). We recently showed that the micromultiplane TEE probe (8.2 – 7 mm diameter,
24mm length tip, with a 5.2 mm diameter shaft ; Oldelft, Delft, The Netherlands) allows
diagnostic intra-operative TEE assessment of children and neonates as small as 2.5 kg
without major complications (3). However, in two heavier children (> 20kg), we noticed
poor quality images. TEE is a semi-invasive procedure and although complications are
rare (local trauma to the oropharynx and the oesophagus), the use of the smallest probe
available with acceptable image quality should be preferred (4). The purpose of the cur-
rent study is to defi ne the upper weight of patients in which the micromultiplane TEE
probe provides diagnostic images.
All patients weighing less than 50 kg and above 15 kg undergoing cardiac surgery at
the Thoraxcentre of the Erasmus MC Rotterdam between January 2006 and December
2007 were included. All patients at our centre routinely undergo TEE examination during
cardiac surgery. Institutional Review Approval/Consent was waived. Before induction of
anaesthesia, all patients are monitored with a fi ve-lead, two-channel electrocardiogram,
non-invasive blood pressure measurement, and pulse oximetry. After the insertion of
a peripheral venous line, general anaesthesia was induced with midazolam 0.2 mg/kg,
sufentanil 2 mcg/kg and pancuronium 0.15 mg/kg.
Patients were tracheally intubated and pressure controlled ventilated (PCV) using a
Siemens 900C ventilator (Siemens, Lund, Sweden). Anaesthesia was maintained with
midazolam 0.1 mg/kg per hour and sufentanil 1 mcg/kg per hour. Invasive monitoring
via a radial arterial line and an internal jugular central venous catheter was performed,
and a Foley bladder catheter with an integrated temperature probe was inserted. After
putting a Latex free micro paediatric ultrasound transducer probe cover (Palmedic,
Lichtenvoorde, The Netherlands) the micromultiplane TEE probe was inserted blindly
with or without a jaw thrust of the mandible or under direct laryngoscopic view. All TEE
examinations were performed using Philips iE 33 ultrasound system (Philips, Andover,
Massachusetts, USA) equipped with 2D, pulsed, continuous, and color Doppler capabili-
ties. All TEE examinations were conducted and digitally recorded by the same cardiac
anaesthesiologist in presence of a second anaesthesiologist who was responsible for
the care of the patient. Afterwards an experienced echocardiographer and cardiac
anaesthesiologist reviewed and scored all images separately. Images were divided in
38 Chapter 3
mid-oesophageal (MOE) and transgastric (TG) views. All images were evaluated as fol-
lowing: 1 = “Excellent“, 2 = “Good”, 3 = “Poor” and 4 = “Not interpretable”.
Table 1: Patient characteristics and evaluation.
age diagnosissurgical procedureMOE
1 154 TOF DCRVValvulo + infundibulotomy1111
2 153 ASD closure1111
3 157 cardiomyopathylevitronix LVAD1111
4 154 ASD closure1111
5 174 SVD closure1111
6 176 ASDclosure1111
7 17.14 ASDclosure1111
9 17.74 VSD,RVH,DCRVresection fi bromusculair
11 206CoA, VSD repair1212
12 216 ASD reop closure1212
13246 TI, TSTVR1212
14258 VSD closure2212
15 268TI, TS, Endocarditis TVR2323
16 27 10 SVD closure2323
17 339 CoA Repair3444
1937 11 VSDclosure4444
20 5013 DCRVMembrane resection4444
ASD, aortic stenosis; CoA, aortic coartation; DCRV, double chambered right ventricle; DSAS, dynamic
subaortic stenosis; HTX, transplantation of the heart; LVAD, left ventricle assist device; MOE, mid-
oesophageal; RVH, right ventricular hypertrophy; SVD, sinus venosus defect; TOF, tetralogy of fallot; TG,
transgastric; TR, tricuspid regurgitation; TS, tricuspid stenosis; TVR, tricuspid valve replacement; VSD,
ventricle septum defect; *Image Quality Score: 1=excellent; 2=good image quality; 3=Poor image quality;
4=“Not interpretable” image quality. MOE=mid-oesophageal, TG=transgastric.
The micromultiplane TEE probe was developed at the Thoraxcentre to study neonates
and small children and consists of a rotational phased array ultrasound multiplane
transducer (center frequency ~7.5 MHz / bandwidth >40% / 48 elements / 0.1 mm pitch),
mounted at the tip of a fl exible gastroscope. The transducer is an octagonal 48-element
array, 5.0 mm elevation, 4.7 mm lateral aperture, rotatable through 180°. The gastro-
scope has a thickness of max 5.2 mm, a length of 70 cm and a bending neck capable
of articulating in the anterior and posterior directions (120° ± 10° upward anterior,
Chapter 3 39
90° ± 10° backward posterior). The bending neck has a diameter of 5.6 mm and a length
of 40 mm. The bead on the transition to the shaft has a diameter of 6.2 mm. The tip is
8.2 mm wide, 7.0 mm thick and has a length of 24.0 mm (Figure 1) (6).
Figure 1: An adult multiplane, minimultiplane and a micromultiplane TEE probe are shown.
The demographic, diagnostic and evaluation data are summarized in Table 1. The pa-
tients ranged in age from 3 to 13 years and in weight from 15 kg to 50 kg. The images
up to a body weight of 20 kg were evaluated “excellent” in all views. From a body weight
of 20 to 25 kg images were evaluated “excellent” in the MOE views and “good” in the TG
views, from 25 to 27 kg images were considered “good” at the MOE level and “poor” at
the TG level. In the patients weighing 33 kg and more all images were assessed “poor”
and we had to use an adult TEE probe, providing excellent image quality.
TEE is a semi-invasive procedure for cardiac imaging and although complications are
rare the smallest probe providing diagnostic images should be used. It is not surprising
that inability to insert the TEE probe, oesophageal trauma, airway compromise, and
aortic compression occur predominantly with thicker TEE probes (7).
There are several reasons why there is an upper weight limit for the micromultiplane
TEE probe. First, because the centre frequency of the micromultiplane TEE transducer is
7.5 MHz, which gives an optimal image to a depth of 6–7 cm (8). This explains why the
image quality in the far fi eld becomes “poor”, in heavier patients.
Second, during TEE examination of heavier patients (>25 kg) it was impossible to acquire
deep TG longaxis and TG longaxis views. This can be explained by the shorter bending
neck (length of only 40 mm) of the micromultiplane TEE probe, as compared to that of
an adult TEE probe, which is approximately 80 mm long (Figure 1). This makes it impos-
sible to reach the apex of the left ventricle.
40 Chapter 3
A third explanation for the quality getting less within heavier patients is the fact that the
micromultiplane-phased array has less elements as compared to the standard adult TEE
probe (48 vs. 64). This results in a lower resolution and consequently a lower image qual-
ity (4). Finally a small probe within larger patients may have less-than-optimal acoustic
coupling with the heart (4).
In conclusion; the micromultiplane TEE probe provides image of “excellent” and “good”
quality in patients up to a weight of 25 kg. In patients above 25 kg, an adult TEE probe,
providing excellent image quality, can be used.
Chapter 3 41
1. Rice MJ, McDonald RW, Li X, Shen I, Ungerleider RM and Sahn DJ. New Technologies and Method-
ologies for Intraoperative, Perioperative, and Intraprocedural Monitoring of Surgical and Catheter
Interventions for Congenital Heart Disease. Echocardiography 2002;19(8):725-734.
2. Ayres NA, Miller-Hance W, Fyfe DA, Stevenson JG, Sahn DJ, Young LT et al. Indications and
guidelines for performance of transesophageal echocardiography in the patient with pediatric
acquired or congenital heart disease: a report from the Task Force of the Pediatric Council of the
American Society of Echocardiography. J Am Soc Echocardiogr. 2005;18(1):91-8.
3. Scohy TV, Gommers D, ten Harkel ADJ, Deryck Y, McGhie J and Bogers AJJC. Intraoperative evalu-
ation of micromultiplane transesophageal echocardiography probe in surgery for congenital
heart disease. Eur J Echocardiography 2007;8:241-246.
4. Reynolds HR, Spevack DM, Shah A, Applebaum RM, Kanchuger M, Tunick PA and Kronzon I.
Comparison of Image Quality Between a Narrow Caliber Transesophageal Echocardiographic
Probe and the Standard Size Probe during intraoperative evaluation. J Am Soc of Echocardiogr
5. Balmer C, Barron D, Wright JG, Giovanni JV, Miller P, Dhillon R et al. Experience with intraoperative
ultrasound in paediatric cardiac surgery. Cardiol Young 2006;16:455-462.
6. Product specifi cation, Oldelft Ultrasound, The Netherlands).
7. Muhiudeen RI, Miller-Hance WC, Silverman NH. Intraoperative transesophageal echocardiogra-
phy for pediatric patients with congenital heart disease. Anesth Analg 1998;87:1058-76.
8. David J. Sahn. Editorial comment. Eur J Echocardiography 2007;8(4):237-238.
Ch apter 4
echocardiography is benefi cial
for haemodynamic stabilisation
during left ventricular assist device
implantation in children
Scohy TV, Gommers D, Maat AP, Dejong PL, Bogers AJ, Hofl and J.
Paediatr Anaesth. 2009 Apr;19(4):390-5.
44 Chapter 4
Background: Mechanical circulatory support, with a Left Ventricular Assist Device (LVAD)
is used in an increasing number of children for treatment of advanced heart failure as
bridge-to-transplant. To date no data are available and no studies have defi ned the role
of intraoperative transesophageal echocardiography (TEE) for haemodynamic stabilisa-
tion during Centrimag Levitronix centrifugal pump implantation in children.
Methods: Children with therapy resistant heart failure, undergoing LVAD implantation
using Berlin Heart Excor pediatric cannula connected to a Levitronix Centrifumag pump,
are intraoperatively monitored using an Oldelft micromultiplane TEE. Intraoperative TEE
is specially used to monitor right ventricular (RV) and left ventricular (LV) function, cor-
rect position of the cannulas and response to pharmacological treatment.
Results: In 5 consecutive patients RV function was assessed by TEE after starting LVAD
Levitronix centrifugal pump. Initial RV failure presents with RV dilation and LV collapse.
After titration of vasopressor and inotropic agents, RV contractility improved and
thereby the fi lling of the LV. In one child, despite those measures the RV showed no im-
provement by TEE and a Levitronix right ventricular assist device (RVAD) to support the
RV function was implanted as well. All patients could haemodynamically be stabilised
before transport to the Intensive Care Unit.
Conclusion: The complex interaction of the right- and left ventricular function and cor-
rect positioning of the cannula, during LVAD implantation in children with end-stage
cardiac failure is improved by simultaneous visualisation of cardiac performance of both
ventricles and cannula positioning by means of intraoperative multiplane TEE.
Intraoperative TEE is benefi cial for haemodynamic stabilisation and evaluation of can-
nula positioning during LVAD implantation in children.
Chapter 4 45
Mechanical circulatory support, with a LVAD is used in an increasing number of children
for treatment of advanced heart failure as bridge-to-transplant. To date no data are
available and no studies have defi ned the role of intraoperative TEE for haemodynamic
stabilisation during LVAD implantation in children. Intraoperative TEE plays a fundamen-
tal role in evaluating LVAD cannula positioning, haemodynamic stabilisation and the
eff ect of device settings on right and left heart function.
This manuscript describes the utility of intraoperative TEE in pediatric patients under-
going centrifugal LVAD placement.
At the Erasmus MC Thorax centre all pediatric patients undergo routinely TEE during
cardiac surgery. Institutional Review Approval/consent was waived. Thus children with
therapy resistant heart failure, undergoing Berlin Heart Excor pediatric cannula implan-
tation connected to a Levitronix Centrifumag pump (Levitronix, Zurich, Switzerland), are
all intraoperatively monitored by TEE.
A LVAD centrifugal pump assists the left ventricle (LV) by drainage of blood from the
LV apex and pushes the blood via a pump into the ascending aorta. For drainage an
infl ow cannula is connected to the LV apex and the LVAD and for delivery an outfl ow
cannula is placed into the ascending aorta (Fig 1).
Figure 1: LVAD (from Berlin Heart)
46 Chapter 4
Before induction of anaesthesia, all children are monitored with a fi ve-lead, two-channel
electrocardiogram, non-invasive blood pressure measurement, and pulse oximetry. After
the insertion of a peripheral venous line, general anaesthesia is induced with midazolam
0.2 mg/kg, sufentanil 2 mcg/kg and pancuronium 0.15 mg/kg.
Patients are tracheally intubated and pressure controlled ventilated (PCV) using a
Siemens 900C ventilator (Siemens, Lund, Sweden). Anaesthesia is maintained with
midazolam 0.1 mg/kg/h and sufentanil 1 mcg/kg/h. Invasive monitoring is performed
via a cannula into a radial artery and a central venous catheter placed into an internal
jugular vein. A Foley bladder catheter with an integrated temperature probe is inserted
also into all patients.
All TEE examinations are performed with an Oldelft micromultiplane TEE transducer
(Oldelft, Delft, The Netherlands) (1) covered with a Latex free micro paediatric ultra-
sound probe cover (Palmedic, Lichtenvoorde, The Netherlands) connected to a Philips
iE33 ultrasound system (Philips, Andover, MA, USA).
Before the procedure starts, cardiac output (CO) is calculated according the body
surface (CO = 2.4 l/min/m2) in order to give us a target cardiac output for the optimal
output settings of the LVAD centrifugal pump (cardiac index cannot be measured with
the pump). The body surface area (BSA) is calculated according to the Dubois formula:
BSA (m2) = 0.20247 x Height (m) 0.725 x Weight (kg) 0.425 (2).
The Erasmus MC Rotterdam intraoperative TEE examination protocol for LVAD implan-
tations consists of a general echocardiographic examination and the specifi c pre-LVAD
and post-LVAD considerations. Pre-LVAD recommended views are Mid Oesophageal
(MOE) 4-chamber view for evaluation of LV and right ventricular (RV) function, Tricuspid
insuffi ciency (TI), Mitral valve stenosis (MS) and Right-Left (RL) shunts (atrial and ven-
tricular). MOE Aortic Valve (AV) Long-Axis (LA) view to evaluate Aortic Insuffi ciency (AI)
and ventricular RL shunt. The MOE RV infl ow – outfl ow view is used to evaluate Pulmonic
insuffi ciency (PI) in case of RVAD. Post-LVAD recommended views are MOE 4-chamber
view for evaluation of de-airing, RL shunting, infl ow cannula fl ow pattern (pulsed wave
(PW), continuous wave (CW) and colour Doppler) and alignment in LV, LV unloading,
RV function. In the MOE AV LA view we evaluate AI and outfl ow cannula fl ow pattern
(PW, CW and colour Doppler). Evaluation of ascending and descending aorta for aortic
dissection is also done (3).
After going on cardiopulmonary bypass (CPB) infl ow cannula is inserted in the LV apex
and the outfl ow cannula is connected to the ascending aorta. Before weaning from CPB
all patients received dobutamine 4 mcg/kg/min IV. After stopping CPB, Levitronix pump
was started by increasing the rotations/min under echocardiographic guidance in MOE
4 chamber view. The Levitronix pump rotations/min were increased until calculated CO
was reached. We desided not to place a left atrial pressure catheter. If during this process
RV dilated and LV collapsed, CPB was restarted and additional medication to support RV
Chapter 4 47
was started according to our protocol for additional RV support. This protocol consists in
dobutamine, enoximone and inhaled nitric oxide (NO). The whole process was repeated
until Levitronix pump output reached the calculated CO.
Five consecutive children with therapy resistant heart failure undergoing LVAD implan-
tation were studied. Patient characteristics are shown in Table 1. All patients received do-
butamine 4 mcg/kg/min iv before weaning from CPB and starting of the LVAD centrifugal
pump. In the fi rst attempt of weaning from CPB and starting LVAD, RV failure was seen
in all patients by dilation of the RV and collapse of the LV (Fig 2) when LVAD output was
set above half of the calculated CO. After going back on CPB, echographic evaluation of
cannula positioning, starting inhaled nitric oxide (NO) and titration of vasopressor and
inotropic agents (Table 1) RV contractility improved, emptying of the RV improved and
thereby the fi lling of the LV. On the second attempt of weaning from CPB with starting
LVAD centrifugal pump in patients 1, three to fi ve a haemodynamic stable condition was
achieved. Pump settings and some haemodynamic data are given in Table 2.
In patient 2, weaning from CPB was also not successful after starting the LVAD cen-
trifugal pump. TEE examination showed collapse of the LV and dilatation of the RV.
Therefore, dobutamine 7.5 mcg/kg/min iv, enoximone 0.2 mg/kg iv bolus injection,
noradrenalin 0.1 mcg/kg/min iv and inhaled nitric oxide 20 ppm was started to improve
RV function. Despite these inotropic agents the maximal RV output was just 0.5 L/min
(LVAD pump output just before RV dilation and LV collapse), being less than 30% of
the calculated necessary value (1.7 L/min). Therefore, we decided to implant a RVAD for
support of the RV function. After this biventricular assist device (BiVAD) implantation
weaning from CPB was successful. The patient showed a mean arterial pressure (MAP)
of 80 mmHg, iv noradrenalin could be stopped and nitro-glycerine 1 mcg/kg/min iv was
started (Table 2).
Table 1: Patients characteristics
NrAge Weight (kg) Diagnosis and time
cause other diseases
1 11m9 DCM 5 wvirale Sick Euthyroid syndrome
2 7y 15DCM 8 m idiopathic Asthma
3 10y 23DCM 16 m idiopathic
412 m8 DCM idiopathic
5 4y11 DCM 2 y idiopathiccongenital hypothyroid
PDA: catheter closure
48 Chapter 4
Table 2: Pump settings when successfully weaning from CPB
weaning of CPB
m/s outfl ow
1 Dobu 9 mcg/kg/
0,8 l/min70 mmHg -- 12
pH 7,40 1.0 l/min 1.8
NA 0,6 mcg/kg/
Inhaled NO 15
2 Dobu 7,5 mcg/
2,2 l/min80 mmHg 2,0 l/min 16
pH 7.41 1.7 l/min 1.6
Inhaled NO 20
3 Dobu 10 mcg/
1,6 l/min60 mmHg-- 15
pH 7,352.2 l/min 1.4
NA 0,08 mcg/kg/
Inhaled NO 15
4 Dobu 3 mcg/kg/
1,0 l/min70 mmHg --12
pH 7,411.0 l/min1
NA 0.02 mcg/kg/
Inhaled NO 20
5 Dobu 5 mcg/kg/
1.6 l/min60 mmHg--10
pH 7,38 1.3 l/min1.2
Inhaled NO 10
Chapter 4 49
In all patients cannula were orientated correctly. Flow into the apical cannula was lami-
nar and unidirectional by means of colour, PW (Fig 3) and CW Doppler. The MOE AV LA
view (Fig 3) was used to assess the positioning of the outfl ow cannula, by means of color,
PW and CW Doppler. PW Doppler fl ow velocities are given in Table 2.
None of the patients had RL shunt with concomitant systemic desaturation (4). Also
none of them had AI or MS, which could have worsened the emptying of the LV and the
latter also limiting fi lling of the LV. We observed no air entering from the sewing ring
around the apex cannula when the Levitronix pump kept pumping after LV collapse (4).
All patients maintained a haemodynamically stable condition during transport to the
Intensive Care Unit. Four patients remained haemodynamically stabilised with the Levi-
tronix pump and could later on be switched to a defi nitive Berlin Heart Excor ventricle
between two and six days. Unfortunately patient 2 died after six days due to intractable
pulmonary haemorrhage in severely damaged lungs.
Figure 2: MOE 4-chamber view of dilated RV, collapsed LV and outfl ow cannula in the LV apex.
Figure 3: PW Doppler of the infl ow cannula in the LV apex.
50 Chapter 4 Download full-text
In our center a Levitronix Centrimag pump is used as an intermediate LVAD device for
haemodynamic stabilisation in children with therapy resistant heart failure. The Berlin
Heart Excor LV infl ow cannula is implanted in the left ventricular apex while a Berlin
Heart Excor outfl ow cannula is anastomosed with the ascending aorta. Both cannulae
are connected to a LVAD centrifugal pump, which provides continuous fl ow. The use
of a LVAD centrifugal pump, connected to Berlin Heart Excor cannulae, is reported as
an attractive combination as bridge to bridge, for three main reasons. First for fi nancial
reasons: for a pediatric LVAD programme a range of diff erent sized Berlin Heart systems
should be readily available on the shelf, the initial investment is easily between € 350
000 and € 400 000, on the other hand by connecting the cannulae of the Berlin Heart
Excor System to a Levitronix pump only the cannulae and one size of Levitronix pump
have to be available minimising the investment (5).
The switch from Levitronix to the Berlin Heart Excor System (stop-clamp-disconnect-
connect-start) took less then one minute. Secondly as bridge to decision for severely
sick patients (5) and fi nally because of reduced bleeding complications: we start anti-
coagulation when bleeding is less then 1 ml/kg/min for three hours with heparin to
target activated clotting time (ACT) level (140-160 sec), while in the Deutches Herz-
centrum in Berlin heparin is started 8-12 hours post-operative. When a patient is still
bleeding, surgical intervention is considered (6). Besides the hemorrhage from the right
lung, which we considered as an intrinsic pulmonary problem, we did not face bleeding
problems during six days of support.
In all patients we were able to evaluate de-airing of the LV, in- and outfl ow cannula
orientation, pharmacological support of RV function and LVAD settings, guided by in-
TEE is benefi cial for the assessment of ventricular preload and function (7,8). In Table 2
right atrial pressures (RAP) are listed when weaning from CPB was successful. The varia-
tion in RAP makes it diffi cult to use a predefi ned RAP as a target for optimal preload.
We chose not to use Left Atrial Pressure (LAP) catheter. Although LAP can be useful,
we prefer echocardiography (Trans Thoracic Echocardiography at ICU) because of the
additional information concerning cannulae positioning and because of the avoidance
of the small bleeding risk when removing LAP catheter.
RV function is a critical factor in LVAD function because adequate LVAD support must
be warrented by adequate transpulmonary blood fl ow (9). Because the ventricles are
in-series the output of one ventricle is the input of the other (9), maximal RV output
could be measured with the LVAD Levitronix pump and TEE. When the LVAD Levitronix
pump output was set too high the RV dilated because right ventricular function then
was unable to drain the venous return and subsequently LV collapsed, because of the