Low pressure pneumoperitoneum during laparoscopic donornephrectomy: a pilot study

Living donor kidney donation is currently the most effective strategy to manage
the shortage of donor kidneys. In this way mortality of patients with end-stage
renal disease is reduced and the waitinglist for transplantation shortened.
Furthermore it is possible to transplant prior to initiation of dialysis. This
prevents other interventions (for example shunt surgery) required for dialysis.
The last years the number of kidneys from unrelated donors is increasing. The
willingness among friends or even anomynous individuals to donate is
increasing. Evidently the ethical basis for living donor kidney donation is
shifting. With a decreasing connection between donor and recipient, it becomes
less clear what the win is for the donor in daily life. In this context it is
essential that surgical techniques are optimised and that safety of the donor
is garantueed as much as possible. In previous studies it has been shown that
donor benefit from kidney donation using a laparoscopic technique. Compared
with a minimal invasive, open technique, laparoscopic kidney donation
correlates with a better quality of life, less pain, shorter hospitalization
and earlier return to work.
For further optimization of the technique of laparoscopic kidney donation, the
procedure could be performed using low pressure for the insufflation of
carbonic gas in the abdominal cavity (pneumoperitoneum). In the current
practive standard pressures between 12 and 14 mmHg are used, however from
literature it is known that laparoscopic operations can be performed in a safe
manner with pressures between 7 and 9 mmHg. In patients undergoing laparoscopic
operations, low pressure pneumoperitoneum reduces the incidence of referred
shoulder pain, postoperative painscores and the use of opiates. Furthermore
there are clear indications that conventional pressure pneumoperitoneum reduces
the perfusion of abdominal organs and could lead to a temporary reduction in
renal function.It is not known whether this has consequences for renal function
in the long-term. Since it is of great importance to reduce the risk for kidney
donors as much as possible, the technique of low pressure pneumoperitoneum
during laparoscopic donornephrectomy is simple, safe and low-cost.

Hypothesis: the use of low pressure pneumoperitoneum during laparoscopic
donornephrectomy leads to reduced postoperative painscores, opiate use,
improved quality of life, earlier return to work and preservation of renal
function of the remaing kidney in the donor.

The feasability of a randomized trial studying the advantageous effects of
low-pressure pneumoperitoneum during laparoscopic donornephrectomy will be
assessed.

A single-centre, double blind, randomized pilot-study wil be performed.
Randomization will occur after intubation and positioning of the patient on the
operating table by a research assistant. A computer generated randomizationlist
will be used. Twenty patients will be included and randomized in two groups;
conventional pressure versus low-pressure pnuemoperitoneum during laparoscopic
donornephrectomy. The technique (conventional or low-pressure) will not be
communicated to the patient until the last questionaires are completed 3 months
postoperative. Follow-up including urine samples, QST-measurements and quality
of life and return to work forms will done until 3 months after the operation.

Laparoscopic donornephrectomy will be performed in a standard manner. A
research assistant will set the pressure for inflation of the abdominal cavity
after placement of the first trocar at 7 or 14 mmHg depending on randomisation.
After placement of the first subcostal 5 mm trocar a infusion catheter
(sterile) is connected to this port. The infusion catheter (filled with air) is
connected to an IBP (invasive blood pressure) sensor wich is connected to the
artery catheter channel of the patientmonitor. Continuously measured
intra-abominal pressure is made invisible at the patientmonitor for the surgeon
and all personell present at the operating room. In case of a significant
bleeding during the operation (>100 ml blood loss) or in case of insufficient
exposure of the operating field limiting progress of the procedure (determined
by the surgeons; urologist and vascular surgeon), blinding is abrogated and the
pressure will be converted to standard (if applicable).

Burden:
In total 17 questionnaires should be completed (3x preoperative, 14x
postoperative). To take a blood sample and a fresh urine sample at
postoperative day 7 patients should visit the outpatient clinic once (1 week
after the operation) beside to the scheduled routine visits to the outpatient
clinic. Furthermore a specially trained research-nurse will perform 3 QST
measurements (pre-operative and postoperative at day 1 and 3) during hospital
stay in a quiet room at the nursing department. The fourth and last QST
measurement will be performed during a routine visit at the outpatient clinic
after 3 months.

Risks:
It is expected that lowering the pressure of the pneumoperitoneum has no effect
on: duration of the operation, blood loss, chance of conversion to an open
procedure (laparotomy) or rare complications (such as bowel injury). In the
existing literature none of the abovementioned adverse effects are found to
occur more frequent in those patients undergoing low-pressure pneumoperitoneum
procedures. To garantee the safety of the participants of this study as much as
possible, conversion to standard pressure (after unblinding) will be performed
in cases of a significant bleeding (>100 ml) or insufficient exposure of the
operating field. If an unexpected, severe (rare) complication occurs in one of
the participant (e.g. bowel- or pancreatic injury, re-intervention due to
bleeding) unblinding will be effectuated and a possible causal relationship
with low-pressure pneumoperitoneum will be assessed. If the team of researchers
(2 urologists, 2 nephrologists and 3 vascular surgeons) conclude that the
complication is possibly related to low-pressure pneumoperitoneum, then further
inclusion of patients will be stopped.