Proper cannula positioning in single site veno-venous extracorporeal life support (vv-ELS) is cumbersome and necessitates image guidance to obtain a safe and stable position within the heart and the caval veins. Importantly, image-guided cannula positioning alone is not sufficient, as possible recirculation cannot be quantified. We present an ultrasound dilution technique allowing quantification of recirculation for optimizing vv-ELS. We suggest quantification of recirculation in addition to image guidance to provide optimal vv-ELS

AF Heijst van

Antoine P. Simons

CA Bermudez

D Clements

Dirk W. Donker

Erik P. J. Körver

J Javidar

J Walker

Jos G. Maessen

ME Dolch

NM Krivitski

P Ganslmeier

Patrick W. Weerwind

Yuri M. Ganushchak

English

PubMed

Crossref

Intensive Care Medicine

Quantification of recirculation as an adjuvant to transthoracic echocardiography for optimization of dual-lumen extracorporeal life support

Springer - Publisher Connector

Erik P. J. Ko¨rver
Yuri M. Ganushchak
Antoine P. Simons
Dirk W. Donker
Jos G. Maessen
Patrick W. Weerwind
Quantification of recirculation as an adjuvant
to transthoracic echocardiography
for optimization of dual-lumen extracorporeal
life support
Received: 3 November 2011
Accepted: 17 February 2012
Published online: 29 March 2012
 The Author(s) 2012. This article is
published with open access at
Springerlink.com
E. P. J. Ko¨rver ())  Y. M. Ganushchak 
A. P. Simons  J. G. Maessen 
P. W. Weerwind
Department of Cardiothoracic Surgery,
Maastricht University Medical Centre,
P. Debeyelaan 25, P.O. Box 5800,
6202 AZ Maastricht, The Netherlands
e-mail: erik.korver@mumc.nl
Tel.: ?31-43-3875070
Fax: ?31-43-3875075
D. W. Donker
Department of Cardiology,
Maastricht University Medical Centre,
Maastricht, The Netherlands
D. W. Donker
Department of Intensive Care Medicine,
Maastricht University Medical Centre,
Maastricht, The Netherlands
Abstract Purpose: Proper can-
nula positioning in single site veno-
venous extracorporeal life support
(vv-ELS) is cumbersome and neces-
sitates image guidance to obtain a
safe and stable position within the
heart and the caval veins. Impor-
tantly, image-guided cannula
positioning alone is not sufficient, as
possible recirculation cannot be
quantified. Methods and results:
We present an ultrasound dilution
technique allowing quantification of
recirculation for optimizing vv-ELS.
Conclusion: We suggest quantifica-
tion of recirculation in addition to
image guidance to provide optimal
vv-ELS.
Keywords Veno-venous
extracorporeal life support 
Recirculation  Echocardiography 
Dual-lumen cannula 
Ultrasound dilution
Introduction
Veno-venous extracorporeal life support (vv-ELS) has
increasingly been employed in adult patients with severe
respiratory insufficiency [1]. Historically, vv-ELS in adult
patients has required dual cannulation. A novel developed
bi-caval dual-lumen cannula (Avalon ELITETM, Avalon
Laboratories, LLC., CA, USA) for vv-ELS uses single
site venous cannulation via the right jugular vein [2]. The
cannula simultaneously drains blood from the superior
and the inferior caval vein. Oxygenated blood is returned
into the right atrium via the infusion port pointing towards
the tricuspid valve. This approach aims at reducing the
risk of insertion site bleeding, thrombosis, infection and
accidental dislodgement by facilitating implantation and
patient mobilization [3].
Support, however, can be negatively influenced by
recirculation as a result of improper cannula position [4].
Recirculation is defined as the fraction of the oxygenated
blood that exits the infusion port, and which is immedi-
ately drained back into the drainage ports. During dual-
lumen vv-ELS, cannula position can be verified using
transoesophageal echocardiography combined with fluo-
roscopy [2] or saline injection [5]. Recirculation and
resultant inadequate lung assist, however, may still occur.
To maintain optimal support, i.e. sufficient oxygenation
and decapneization, quantification of recirculation may be
crucial in correctly (re)positioning of the dual-lumen
cannula. Although it has been reported in experimental
and neonatal ELS using single site cannulation [6–8], to
the best of our knowledge, quantification of recirculation
during adult vv-ELS using single site cannulation has not
been reported in the literature so far.
We describe three cases to illustrate the benefits of a
technique for the quantification of recirculation as an
adjuvant to transthoracic echocardiography during vv-ELS.
Intensive Care Med (2012) 38:906–909
DOI 10.1007/s00134-012-2534-z PHYSIOLOGICAL AND TECHNICAL NOTES
Case presentations
The medical ethics committee of the Maastricht Univer-
sity Medical Centre approved the use of patient
recordings. The technique to quantify recirculation mea-
sures changes in fluid density, meaning that it detects the
dilution of blood with saline from changes in the average
cross-sectional velocity of an ultrasound beam that illu-
minates the blood flowing through the tubing of the
circuit. One ultrasonic probe is placed on the arterial inlet,
whereas a second probe is placed on the venous outlet line
of the dual-lumen cannula. In contrast to van Heijst et al.
[7] who applied ultrasound dilution using a 5-mL saline
bolus injection to quantify recirculation during vv-ELS,
we in our cases used a 10-mL saline bolus. The bolus is
injected into the outlet port of the oxygenator and is
subsequently detected by both probes as a dilution curve.
Voltage changes that correspond to the mean cross-sec-
tional ultrasound velocity across the tubing are
transmitted to the computer system. Software analysis
(Transonic Systems Inc., Ithaca, NY, USA) provides a
percentage of recirculation by dividing the area under the
curve measured by the venous probe by the corresponding
area detected by the arterial probe. Detection of changes
in ultrasound velocity occurs until fluid density is in
equilibrium.
Fig. 1 Transthoracic echocardiography (colour Doppler) shows:
a the dual-lumen cannula (31 Fr.) situated properly in the caval
veins (draining 4.3 L/min), with the outflow jet pointing at the
tricuspid valve and right ventricle. The distance between the distal
drainage port and the infusion port amounts to 9.4 cm (left). The
schematic representation shows the position of the dual-lumen
cannula (middle). Ultrasound dilution creates an arterial (A) and
venous (V) dilution curve, resulting in a level of recirculation that
amounts to 2 % (right). b An improperly situated dual-lumen
cannula (27 Fr.). The cannula is rotated and the infusion port is
located in the inferior caval vein near the hepatic vein (left). The
schematic representation shows the position of the dual-lumen
cannula (middle). Although ELS flow amounted to 4.7 L/min,
ultrasound dilution measures a recirculation level of 45 % (right).
c The bi-caval dual-lumen cannula (31 Fr.) correctly positioned. A
large blue coloured jet within the superior caval vein is directed
toward the proximal cannula drainage port and can be interpreted as
drainage flow. A red coloured jet shows blood leaving the cannula
infusion port and flowing directly toward the tricuspid valve (left).
The schematic representation shows the position of the dual-lumen
cannula (middle). Ultrasound dilution, however, detects a recircu-
lation level of 38 % at a flow rate of 5.3 L/min, revealing cannula
malposition (right). ICV inferior caval vein, SCV superior caval
vein, RA right atrium, RV right ventricle, HV hepatic vein, A area
under the curve measured by the arterial probe, V area under the
curve measured by the venous probe, U voltages in volts 9 100
907
In the first case, transthoracic echocardiography shows
a proper cannula position, confirmed by a recirculation
level of 2 % (Fig. 1a), thereby facilitating lung protective
mechanical ventilation (tidal volume 3.6 mL/kg predicted
body weight (PBW), positive end expiratory pressure
(PEEP) 12 cmH2O, plateau pressure 17 cmH2O and 50 %
oxygen fraction with an arterial saturation of 95 %).
The second case illustrates an improperly located
cannula, which was confirmed by a recirculation level of
45 % (Fig. 1b). Consequently, this resulted in an unde-
sirable increase of mechanical ventilatory support and
subsequently repositioning of the cannula was needed. To
maintain arterial saturation above 80 %, tidal volume was
increased from 4.7 to 6.0 mL/kg PBW, with an increase
of plateau pressure from 24 to 26 cmH2O and oxygen
fraction from 45 to 100 %; PEEP 10 cmH2O.
The final case highlights proper cannula positioning by
transthoracic echocardiography (Fig. 1c); however,
mechanical ventilatory support required tidal volume to be
increased from 4.7 to 6.0 mL/kg PBW to maintain arterial
saturation above 80 %. Recirculation was shown to be
38 %. Thus, echocardiography alone provided a false-
positive confirmation of a properly positioned dual-lumen
cannula. Repositioning of the cannula allowed for a
decrease of mechanical ventilatory support and return to full
protective lung ventilation, while increasing arterial satu-
ration to 94 %. Plateau pressure was diminished from 26 to
22 cmH2O and the oxygen fraction was halved, to 50 %;
PEEP 12 cmH2O.
Comments
Cannula migration can cause suboptimal vv-ELS, but
resultant recirculation may remain undetected using
echocardiography. Quantification of recirculation using
ultrasound dilution as an adjuvant to transthoracic echo-
cardiography proved to be a valuable tool to monitor
dual-lumen cannula position during vv-ELS.
Echocardiography at the bedside has been recom-
mended as the standard imaging technique for positioning
of the dual-lumen cannula for vv-ELS. Adding fluoros-
copy as an imaging modality [2], however, might affect
the echocardiographic image quality as a result of the
body mass index, i.e. in extreme obesity. Dolch et al. [5]
described a method using transoesophageal
echocardiography together with microbubbles present in
saline for cannula placement visualization. Ideally, image
guidance should simultaneously provide position valida-
tion and functional testing during dual-lumen cannula
placement. However, as we showed in case 3, despite the
confirmed correct cannula position by transthoracic
echocardiography, ultrasound dilution technique revealed
an inadequate lung support, having a recirculation of
38 % at a support flow rate of 5.3 L/min. In other words,
when, from the clinical point of view, support proves
sufficient, ultrasound imaging can fail in detecting mal-
position. Consequently, mechanical ventilatory support
was increased and cannula repositioning needed.
Recirculation is a dynamic event that is influenced by a
variety of factors, such as cannula and patient position,
volume status, pump flow rate, and cardiac output [4].
Commonly, the monitoring of recirculation during vv-ELS
is performed with the use of the accepted, but clinically
limited and time-consuming, saturation method [6]. On the
other hand, the ultrasound dilutional technique has been
described as an accurate quantification method for recir-
culation [6, 8, 9]. Nonetheless, the latter technique has not
gained widespread application during vv-ELS. We report
the clinical application of quantification of recirculation in
adult vv-ELS and, additionally, show the added value of this
quantification in serving as an adjunct to echocardiographic
imaging to improve extracorporeal lung support.
In conclusion, dilutional ultrasound provides a prac-
tical method to quantify and monitor recirculation during
dual-lumen extracorporeal lung support. Therefore, the
technique completes interventions that improve oxygen-
ation and decapneization.
Acknowledgments The authors would like to acknowledge Dr.
Nikolai Krivitski (Transonic Systems Inc., Ithaca, NY, USA) for
technical assistance and stimulating discussion. The support of Mr.
Serge Heines (ventilation practitioner, Department of Intensive
Care Medicine, Maastricht University Medical Centre, Maastricht,
the Netherlands) is highly appreciated.
Conflicts of interest The authors declare that there is no conflict
of interest. This research received no specific grant from any
funding agency in the public, commercial, or not-for-profit sectors.
Open Access This article is distributed under the terms of the Cre-
ative Commons Attribution License which permits any use,
distribution, and reproduction in any medium, provided the original
author(s) and the source are credited.
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909


Korver, Erik P. J.

Ganushchak, Yuri M.

Simons, Antoine P.

Donker, Dirk W.

Maessen, Jos G.

Weerwind, Patrick W.

NARCIS 

Ann Thorac Surg 90:991–995 9084. Pettignano R, Clark RH, Cornisch JD

Percutaneous cannulation for extracorporeal life support. Thorac Cardiov Surg 59:103–107 2. Javidar

Transesophageal echocardiographyguided technique for extracorporeal membrane oxygenation dual-lumen catheter placement.

Quantification of recirculation as an adjuvant to transthoracic echocardiography for optimization of dual-lumen extracorporeal life support

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