Nexfin monitoring and laboratory testing in the per-and postoperative setting of major hepatectomy

In 2011, thirty-four major liver resections (resection *3 segments) were
performed in the AMC. The outcome of these hemihepatectomies has improved in
the last years because of better surgical techniques and postoperative care.
Nevertheless, there is a large amount of patients who will develop fluid
overload postoperatively.

The stress response to surgery causes anti-diuresis and oliguria. Fluid
administration seems to be a logical step in case of decreased diuresis.
However, after trying to control hypotension with fluid admission, a large
amount of patients develop fluid overload, with the following symptoms: weight
gain, delayed intestinal motility, pleural effusion, ascites and extended
hospital stay.
Therefore, this raises the question whether a decreased diuresis is a
consequence of hypovolemia, which can be controlled by intravenous fluid
administration.
To answer this question we need a more extensive device (in addition to
standard monitoring of blood pressure, heart rate and oxygen saturation) to
monitor the hemodynamic state of the patient per- and post-operatively. We will
use the Nexfin to retrieve supplemental parameters to get a better idea of the
cardiovascular state of the patient. The parameters will be cardiac output,
cardiac index and stroke volume.

The aim of this study is to retrieve extra measurements by Nexfin and
laboratory testing in the per- and postoperative period. Can the use of Nexfin
contribute in the generation of meaningful data to get an idea of the
hemodynamic state of the patient during and after surgery?

15 patients undergoing a major liver resection, will be monitored with the
Nexfin monitor per- and postoperatively. At admission, we will measure the
cardiac output, cardiac index and stroke volume to get a baseline value. During
the operation, every hour a 250 ml fluid challenge will indicate fluid
responsiveness, measured by Nexfin.
Postoperatively, patients will be measured by Nexfin two times a day. The urine
concentrations of sodium, potassium and creatine in a 24-hours urine sample
will be measured twice during hospital stay. Furthermore plasma samples of
aldosterone, renin and ADH will be taken pre and postoperatively. The patients
will receive the standard care. No intervention will be done based on the
Nexfin results.

The risks of participating in this trial are low. No extra interventions are
performed, only the Nexfin finger cuff is wrapped around the finger and no
complications of this finger cuff have been reported. The 24-hour urine
collections, plasma samples and nexfin baseline measurements before the
operation can be collected during the standard outpatient clinic visits.
The potential benefits of this study are substantial. The proposed study aims
to do this in a minimally invasive setting that will impose no significant
burden on patients participating in this study.