Deficits in local Oxygen Utilisation in Complex Regional Pain Syndrome Type I.

In patiënts with Complex Regionaal Pijn Syndroom type 1, who have been
operated, venous bloodgas sampling has been performed by prof Goris [1]. The
venous oxygen saturation seems very high (between 86-90%), in contrast with
literature.

We have sampled 25 venous bloodgasses of CRPS I patients. Control data for
venous oxygen saturation during operation were retrieved from the literature,
especially samples obtained during femoro-popliteal bypass grafting[2-4].
Unfortunately a healty control population is missing.

1. Goris RJA. Reflex Sympathetic Dystrophy: Model of a severe Regional
Inflammatoy Response Syndrome. World J Surg 1998;197-202.
2. Sonnenfeld T, Nowak J, Cronestrand R, Astrom H, Euler CV. LEg venous oxygen
saturation in the evaluation of intra-operative blood flow during arterial
reconstructive surgery. Scand J Clin Lab Invest 1979;39:577-584.
3. Keys A. The Oxygen saturation of the venous blood in normal human subjects.
J Appl Physiol 1938;13-21.
4. MacDonald MJ, Tarnopolsky MA, Green HJ, Hughson RL. Comparison of femoral
blood gases and muscle near-infrared spectroscopy at exercise onset in humans.
J Appl Physiol 1999;86:687-693.

Venous bloodgassampling of a control group of healty patients who will be
operated for elective surgery.

AFter informed consent: 16 patients, undergoing elective surgery, venous
bloodgas sampling will be performed during operation under general anesthesia.
Two cc of blood will be taken, after that the groin will be pressed for one
minute and a bandage is left in place for 4-6 hrs.

Based on literature [2-4] for control population standard deviations are found
between 3 to 16, with an average venous bloodgas saturation of 62 to 71%. We
expect that the average venous saturation in the new population will be up to
80% (i.e. upper limit 95%-BI is maximum of 80%), as such the average will be
statistical significant from the CRPS patiënts (saturation >=91%). If we expect
that the standarddeviatie in SvO2 at least 20% from the new control population
with an avaerage of 70%, we need at least 16 patients with a standard error of
the mean of at least 5%.

One time puncture in groin for bloodgas sampling, risk of infection and
hematoma.