The effect of an intraoperative, goal-directed volume protocol in abdominal surgery within an accelerated recovery program after surgery
(Enhanced Recovery Program After Surgery- = ERAS-Program).

Purpose of the study

The advent of the oesophageal doppler now gives the opportunity of measuring
cardiac output on a minimally invasive basis in the perioperative and intensive
care environment.
Up until now fluid administration has been guided by the optimisation of blood
pressure, indirect preload parameters such as CVP and markers of adequate
tissue perfusion such as urine production and lactate.

Since the blood pressure correlates poorly with cardiovascular flow, and
because parameters such as CVP, urine output and lactate only change with
severe fluid deficits this results in widely different amounts of intravenous
fluids being administered.
It has been shown that excessive intravenous fluids adversely affect patients
postoperatively in terms of impaired intestinal function and a higher risk of
pulmonary complications [1].
On the other hand there are indications that an extremely restrictive volume
regimen can also impair intestinal function and affect the well-being of the
patient [2].

Using the oesophageal doppler one can treat the patient for the first time not
only by applying a restrictive or liberal volume strategy but instead by
optimising stroke volume using measurements acquired by minimally invasive
means. Studies which have compared goal-directed volume administration with a
liberal strategy have shown its superiority in many different surgical fields.
This applies to traumatology, abdominal surgery and cardiac surgery. A table of
the completed studies can be found in reference 1.

In abdominal surgery where expected blood loss was > 500ml a reduction in
length of hospital stay and postoperative duration of paralytic ileus has been
achieved by the use of a protocol with the oesophageal doppler. This study
included urological, gynaecological and abdominal operations [3].
Wakeling et al. have succeeded in reducing the incidence of ileus and length of
hospital stay using a goal-directed volume mangement strategy guided by
oesophageal Doppler, too [4]. Noblett et al. performed the first trial in which
the *liberal* group ended up getting the same amount of fluid as the
goal-directed group showing the same results as Wakeling et al. [5].

The ERAS-Program aims to achieve a multi-modal improvement of peri-operative
evidence-based treatment algorithms in order to accelerate patient recovery and
minimise peri-operative problems [Wind, Polle, Br J Surg, 2006]. Thus far
patient studies related to the ERAS project or the Fast-Track concept have
shown a faster post-operative recovery but with similar or reduced morbidity to
patients not taking part in the program. Patient safety is the main objective
of the program. For this reason an international database has been setup to
facilitate the process of quality control [7].

Part of the ERAS program is the optimisation of pre- and postoperative fluid
management by avoiding extensive preoperative bowel irrigation. Patients can
drink up until 2 hours pre-operatively but postoperatively intravenous fluid
administration is discontinued and an early resumption of oral intake is aimed
for.

Up to this point all studies using the oesohageal doppler were single-center
studies and were neither part of the ERAS program, nor integrated into a
well-defined treatment pathway. At present there is no multi-center study which
shows the superiority of a *goal-directed* versus a *liberal* fluid protocol
within an ERAS framework.

The goal of this study is to prove that there is a benefit in terms of
post-operative outcome not only because of the multi-modal improvements in
peri-operative fluid management through the ERAS program, but also by the use
of a goal-directed fluid protocol.

Multicenter doubbelblind randomized trial.

group 1: standard volume therapie

group 2: doppler guided volume therapie

Evaluation and consideration of the forseeable risks and disadvantages to the
the study participants in contrast to the expected benefit for them and future
patients. (Risk-benefit evaluation)

The risks of using the oesophageal doppler probe are seen as minimal. According
to Deltex Medical the probe has thus far been used approximately 800,000 times
and there has only once been a suspicion of an oesophageal injury. Previous
studies have no indication of doppler-associated complications. By avoiding
nasal insertion of the probe one avoids the risk of epistaxis and for the
purposes of this study oral insertion of the probe will be used.

Against these minimal risks stand the findings of previous studies using the
oesophageal doppler which have demonstrated a reduced rate of complications as
well as a reduced length of ICU and hospital stay.

Ascertaining whether these desirable effects of Doppler guided volume therapy
offer similar advantages to patients in the ERAS program over a liberal volume
strategy, is a goal of this study.

The small risk of probe placement is justified by the significant potential
benefit.

Expected therapeutic benefit for the study participants (individual benefit
for a single patient):

It has been shown in volume therapy studies in other patient populations that
those guided by Doppler had an earlier stabilisation of their clinical
condition and suffered a lower rate of complications, thereby allowing them
earlier to be discharged home.

This proven effect in other populations is also the benefit expected to be seen
in the Doppler guided group of this trial.