Full text of DOI:10.1007/BF03017907

CARDIOTHORACIC ANESTHESIA, RESPIRATION AND AIRWAY
1081
Transesophageal echocardiography in the manage-
ment of left atrio-femoral bypass during thora-
coabdominal aortic aneurysm repair: a case report
[L’échocardiographie transœsophagienne dans la conduite du pontage auriculo-fémoral pendant
la réparation d’un anévrysme de l’aorte thoraco-abdominale : une observation]
Ashraf Fayad MD FCARCSI, Corey Sawchuk MD FRCPC, Homer Yang MD FRCPC, Claudio Cina MD FRCSC
Purpose: To describe the utility of transesophageal echocardiogra-
phy (TEE) in a patient undergoing thoracoabdominal aneurysm
(TAA) surgery using left atrio-femoral bypass (LAFB).
men a permis l’ajustement du débit de la pompe de PAFG relative-
ment au remplissage du ventricule gauche et au remplacement de liq-
uide optimal afin de maintenir la perfusion du tronc supérieur et
inférieur.
Clinical features: A 57-yr-old female patient underwent repair of
type II TAA. As per institutional routine, LAFB technique was used.
Initial difficulty with the pump flow was encountered. TEE images
showed that the left atrial cannula was positioned against the left
atrial wall. The cannula position was adjusted and the pump flow
was established. During different stages of the surgery, TEE was
used to monitor the left ventricular cavity size and its function. This
allowed the adjustment of LAFB pump flow relative to left ventric-
ular filling and optimal fluid resuscitation in order to maintain both
upper and lower body perfusion.
Conclusion : L’ETO a permis de confirmer la position correcte de la
canule auriculaire gauche et de surveiller l’hémodynamique pendant le
PAFG.
NESTHETIC management of patients
requiring repair of the descending aorta is
challenging, secondary to the high frequen-
Conclusion: In this patient, TEE was useful to confirm the correct
position of the left atrial cannula and for hemodynamic manage-
ment during LAFB.
A
cy of coexisting disease and complexity of
intraoperative surgical management. Major anesthetic
considerations include the management of preexisting
medical problems, spinal cord and distal organ protec-
tion during aortic cross clamping, single lung ventila-
tion, bleeding, coagulopathy, and postoperative pain
management.
Type II Crawford thoracoabdominal aneurysm
(TAA) involves most of the descending and abdomi-
nal aorta.1 Surgical repair can involve the use of an
extra-corporeal circuit. In our institution, left atrio-
femoral bypass (LAFB) technique has been used in 73
patients since October 1997.
Figure 1 shows the components of the LAFB cir-
cuit. Details of LAFB, anesthesia, transfusion practice
and cooling technique for renal preservation in TAA
surgery have been reported elsewhere.2,3
Objectif : Décrire l’utilité de l’échocardiographie transœsophagienne
(ETO) chez une femme subissant la réparation d’un anévrysme thora-
co-abdominal (ATA) par pontage auriculo-fémoral gauche (PAFG).
Éléments cliniques : Une femme de 57 ans devait subir la répara-
tion d’un ATA de type II. Suivant la pratique courante de l’institution,
une technique de PAFG a été utilisée. Une première difficulté s’est
présentée avec le débit de la pompe. Les images de l’ETO ont montré
que la canule auriculaire gauche était placée sur la paroi auriculaire
gauche. La canule a été replacée et le débit de la pompe a été établi.
À différentes étapes de l’intervention, l’ETO a été utilisée pour sur-
veiller la taille de la cavité ventriculaire gauche et sa fonction. Cet exa-
Cardiac output is directly affected by the left ven-
tricle end diastolic volume (LVEDV). Estimation of
From the Department of Anesthesia, McMaster University, Hamilton Health Sciences, Hamilton, Ontario, Canada.
Address correspondence to: Dr. Ashraf Fayad, Department of Anesthesia, McMaster University, Hamilton Health Sciences, 1200 Main
Street West, Hamilton, Ontario L8N 3Z5, Canada. Phone: 905-521-2100; Fax: 905-523-1224; E-mail: fayad@attcanada.ca
Accepted for publication April 8, 2002.
Revision accepted August 9, 2002.
CAN J ANESTH 2002 / 49: 10 / pp 1081–1083

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CANADIAN JOURNAL OF ANESTHESIA
left ventricular volume using transesophageal echocar-
diography (TEE) can be obtained either from mea-
surements of cavity area or from volumetric models.4
End diastolic cross-sectional left ventricle area, typical-
ly in the short-axis view at the midpapillary level, is
commonly viewed as a surrogate of volume status.5,6
In this report we describe the utilization of TEE to
confirm position of the left atrial cannula in LAFB. In
addition, monitoring of the left ventricular volume
assisted hemodynamic management and adjustment of
the LAFB pump flow rate.
Case report
FIGURE 1 Venous cannula through the upper pulmonary vein,
connected to the left ventricle assistance device (LVAD), left ven-
tricle (LV), right ventricle (RV), left atrium (LA)
A 57-yr-old female (54 kg) presented for type II TAA
repair. Her main complaint was persistent backache
and dysphagia. Past medical history revealed hyper-
tension, hyperlipidemia and peripheral vascular dis-
ease. Current medications included acetyl-salicylic
acid and ramipril. Physical examination and laborato-
ry tests were normal except for mild chronic obstruc-
tive lung disease. Prior to induction, cerebral spinal
fluid drainage was achieved through a lumbar catheter
inserted at the L3–4 interspace and a thoracic epidur-
al was inserted at the T8–9 level. Invasive monitoring
included both radial and right femoral arterial lines,
and a pulmonary artery catheter. Following the induc-
tion of general anesthesia with propofol, sufentanil,
midazolam and pancuronium, the trachea was intu-
bated with an oral cuffed endotracheal tube (size 7.5)
and a left bronchial blocker was inserted. Correct
positions of the tube and of the blocker were con-
firmed using fibreoptic bronchoscopy.
Surgery was carried out with the patient in the right
decubitus position. Surgical exposure was achieved
through a posterolateral thoracoabdominal incision
and excision of the fifth rib. The left atrium was can-
nulated through the left upper pulmonary vein using
a 26-Fr aortic cannula. The left femoral artery was
exposed and cannulated with a 24-Fr femoral cannula.
The circuit was completed using an electromagnetic
centrifugal pump. (Biomedicus® BP-80 electromag-
netic centrifugal pump with heat exchanger and a
Medtronic Carmeda®-coated 3/8’’ diameter tubing
pack; Medtronic Inc., USA).
With initiation of LAFB, difficulty with the pump
flow was encountered. The pump was stopped and the
circuit was examined for its integrity. A request for
TEE was made to verify the position of the left atrial
cannula and assist with hemodynamic management.
Echocardiographic images of the left upper pul-
monary vein and the left atrium were obtained. The
cannula was visualized and noted to be lying against
the left atrial wall, and during atrial contractions, com-
FIGURE 2 The cannula is seen in the left atrium (LA).
plete occlusion of the cannula occurred. The cannula’s
position was adjusted, and its correct position con-
firmed by TEE (Figure 2). The LAFB was re-initiated
and the TEE image (colour flow Doppler) showed
free flow through the cannula. Four video clips
marked as initially, trying to advance, advanced and
flow may be consulted at cja-jca.org.
During the remainder of the case, TEE was used to
monitor left atrial and left ventricular cavity size dur-
ing different stages of the procedure. Initially, LAFB
flow rate was 500 mL·min–1. TEE images, however,
suggested underfilling of the left ventricle. Albumin
5% 500 mL and 2l of Ringer’s lactate were adminis-
tered. Mean arterial pressure was maintained between

Fayad et al.: TEE AND ATRIO-FEMORAL BYPASS
1083
65–75 mmHg. During aortic cross clamping, LAFB
flow was increased to over 3 L·min–1, but subsequent-
ly adjusted to between 2.5–3.5 L·min–1, based on the
TEE visualization of left ventricular cavity size.
In summary, TEE was used to confirm correct posi-
tioning of the left atrial cannula. The hazards of can-
nula malposition include poor flow rates to the distal
organs during TAA repair, and left atrium trauma or
rupture. TEE was useful to monitor the left ventricu-
lar volume and to adjust the LAFB flow rate. In this
case, TEE proved to be a useful adjunct for the man-
agement of LAFB during TAA repair.
Discussion
In this patient, TEE played a key role in confirming
the correct position of the left atrial cannula and in
monitoring left ventricular volume status.
TAA surgery carries high mortality and morbidity
rates but, over the last ten years, the mortality rate has
decreased to about 10%.7, A The use of LAFB has been
reported to decrease the incidence of neurologic
deficits and renal failure.8,9, B
TAA repair can be performed by clamping the
proximal aorta and suturing expeditiously. This
approach relies on surgical speed to limit ischemia.
Another approach utilizes the shunting of blood
through a conduit inserted between proximal and dis-
tal aorta in an attempt to maintain spinal cord, renal,
and lower extremity perfusion. A third approach uti-
lizes extracorporeal circulation. This involves clamp-
ing the aorta and circulating blood to the lower body
via femoral-femoral bypass or LAFB.10,11
In this patient, the LAFB technique was used. Flow
rates generated to the lower part of the body during
LAFB are dependent upon left atial volume, cardiac
output and distal vascular resistance. Native cardiac
output maintains perfusion to the upper body. The
LAFB flow rate determines the amount of blood
diverted and the left atrial volume or pressure may no
longer reflect the LVEDV. Consequently, pulmonary
arterial occlusion pressure may no longer reflect
LVEDV. If the LAFB flow rate is high and significant
volume is diverted from the left atrium, LVEDV may
be compromised, as may perfusion to the upper body.
During surgery, significant blood loss and third space
fluid shifts also occur. The need to distinguish hypov-
olemia from a LAFB-induced LV underfilling as the
cause for upper body hypotension becomes a clinical
challenge. Intraoperative TEE is unique in its ability
to provide continuous monitoring of left ventricular
function and filling. In fact TEE currently is the only
monitor capable of monitoring the size of the left ven-
tricular cavity (LVEDV) in this situation.
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