The use of photoplethysmography and Doppler ultrasound to predict anastomotic viability after segmental intestinal ischaemia in dogs.

OBJECTIVE

To compare photoplethysmography and Doppler ultrasonography in the prediction of the viability of experimental jejunoileal anastomoses in the presence of arterial (n = 11), venous (n = 11), and mixed arterial and venous (n = 9) segmental ischaemia.

DESIGN

Experimental open study.

MATERIAL

31 Mongrel dogs.

INTERVENTIONS

Laparotomy, selective devascularisation, and anastomosis. In 20 of the experiments a bolus injection of papaverine was given into the superior mesenteric artery. Second laparotomy on day 15, or earlier if indicated.

OUTCOME MEASURES

Correlation between photoplethysmography, Doppler ultrasonography, and macroscopic and histological findings.

RESULTS

All non-viable anastomoses had photoplethysmographic wave amplitudes of less than 10% of the control value, with sensitivity and specificity of 100%. Venous volume and maximum venous outflow had a sensitivity of 72% and a specificity of 77%. Doppler ultrasonography had a sensitivity of 100%, but a specificity of only 67%. Papaverine had no effect on photoplethysmographic wave amplitude in these experiments.

CONCLUSION

Photoplethysmography is the preferred method of assessing intestinal viability in the presence of ischaemia.