Use of photoplethysmography to determine gastrointestinal perfusion pressure: an experimental canine model.

OBJECTIVES

To develop an experimental model to assess the parietal perfusion pressure (PPP) of the digestive tract using photoplethysmography.

MATERIALS AND

METHODS

Twenty-two mongrel dogs were used. Progressive external compression was applied to the intestinal wall and the PPP was assessed with photoplethysmography. The study group was divided into two groups. In group 1 PPP was measured at the levels of the stomach, duodenum, jejunum and transverse colon. In group 2 PPP was measured after temporary occlusion of the truncal and marginal circulation of the jejunum to provide further variables.

RESULTS

The PPP decreased significantly for each successive distal section. Correlation coefficients and indices for PPP and mean arterial pressures were statistically significant (p < 0.005). Truncal occlusion provoked a drop in PPP whereas marginal occlusion scarcely modified the basal results.

CONCLUSIONS

Photoplethysmography, through measurements of the residual arterial wave amplitude, is a valid method of determining quantitatively the PPP of the digestive tract and could be useful in a clinical environment.