Bladder epithelial oxygen tension--a new means of monitoring regional perfusion? Preliminary study in a model of exsanguination/fluid repletion.

OBJECTIVE

To assess whether monitoring of bladder epithelial oxygen tension (BEOT) would provide an indication of regional (renal) organ perfusion in an exsanguination/fluid repletion animal model.

DESIGN

Prospective non-randomized laboratory study.

SETTING

Research laboratory.

INTERVENTIONS

Eight anaesthetised, spontaneously breathing Sprague-Dawley male rats weighing approximately 200 g were instrumented. They received 1-ml aliquots of fluid until no further haemodynamic improvement was seen, followed by removal of 1-ml aliquots of blood until renal blood flow fell by 50%. The animal was then resuscitated with repeated 1 to 2-ml aliquots of fluid until no further improvement was achieved and, finally, progressively exsanguinated to cardiovascular collapse.

MEASUREMENTS AND RESULTS

A continuous Clark-type oxygen electrode lying in contact with the inside wall of the bladder measured changes in BEOT during these exsanguination and fluid repletion manoeuvres. Changes in BEOT closely mirrored both systemic (blood pressure and aortic blood flow) and regional (renal blood flow) haemodynamic changes. A direct correlation existed between percentage change in BEOT and base deficit, and an indirect correlation was seen with arterial oxygen tension.

CONCLUSIONS

Measurement of BEOT may be a useful and relatively non-invasive means of monitoring regional organ perfusion. Further studies are warranted.