Detection of hypovolemia in the elderly patient undergoing surgery

Elderly patients are vulnerable voor hypovolemia; they have a reduced fluid
intake resulting from an reduced sense of thirst, physiological diastolic
myocardial dysfunction and a reduced response to catecholamine. Added tot his,
there is frequent polypharmacy and multiple comorbiditeit. This makes elderly
patients strongly preload dependent when an increase in cardiac output is
needed. Hypovolemia leads to diminished preload causing failure of the cardiac
output. Hypovolemia can therefore lead to inadequate organ perfusion,
increasing the risk of postoperative complications such as delirium, surgical
site infection and acute kidney injury. While an hypovolemic state kan easily
be treated by means of optimizing circulatory volume.

There is currently limited evidence available on the occurrence of
perioperative hypovolemia in the elderly population, and whether this
hypovolemic state is related to postoperative complications in these patients.
More information regarding this relationship may be valuable in strategies
aiming for a reduction in postoperative complications in the elderly. In
particular, postoperative complications lead to long term morbidity, decrease
quality of live, increase costs and are the most important factor of patient
survival. In the present study we therefore aim to investigate how many elderly
patients suffer from hypovolemia in the perioperative period, and how this
relates to postoperative complications.

The primary aim of the study is to determine the incidence of perioperative
hypovolemia in the elderly patient scheduled for major surgery, and how this
relates to postoperative complications.

At four time points (preoperatively, postoperatively, after 24h and after 48h)
de volemic status will be assessed for the presence of hypovolemia.

Hypovolemia is defined as the presence of fluid responsiveness, measured as an
increase in stroke volume of 10% or more with the Nexfin, 1-5 minutes after
conducting a passive leg raise.

A passive leg raise is a maneuver in which the cardiac output measurement will
be performed first in sitting position, and then will be repeated after
lowering the head end of the bed en lifting the legs 30 degrees.

The Nexfin apparatus is a frequent used non invasive method to assess the
cardiac output with use of counterpulsations in a cuff placed around a finger.

One of the investigators will visit the ward and will use the inflatable blood
pressure cuff around the index finger of the right hand. The measurement will
be performed while sitting, and is continued for 5 minutes after lowering the
head end of the bed and raising the lower end of the bed. As the bed works
electronical the change in movement occurs slowly and will not cost any effort.
Overall discomfort associated with these tests is regarded to as minimal. There
are no benefits related with participation.