LASER-DOPPLER FLUX AND TISSUE OXYGEN-TENSION AS INDICATORS OF COLONICPERFUSION IN PIGS

Objective: To evaluate laser Doppler flowmetry (LDF) and tissue oximet ry (TpO2) for intraoperative assessment of colonic perfusion in pigs. Material: Eight pigs weighing from 19-22 kg. Interventions: Relationsh ips of laser Doppler flux and TpO2 to mean arterial pressure (MAP) wer e measured in porcine sigmoid colon. The influence of different fracti onal inspired oxygen concentrations (FiO2) and the variability of the laser Doppler flux were evaluated. Results: Highly significant reprodu cible non-linear perfusion compared with pressure relations were found with both methods (r greater-than-or-equal-to 0.9, p < 0.0001). There was a rapid decrease when MAP fell below 90 mmHg. The dependency of T pO2 on FiO2 was omitted by using the ratio TpO2: PaO2. The coefficient of variation of repeated LDF recordings of 30 second duration with th e hand held probe was 0.11 (0.07-0.16) (median and 95% confidence inte rval). Three recordings gave a reproducible mean flux with an estimate d precision of 10% either way. Simultaneous recordings with sutured an d handheld probes correlated well (r greater-than-or-equal-to 0.9, p l ess-than-or-equal-to 0.01). Conclusion: Both methods yielded quantitat ive and reproducible intraoperative assessments of colonic perfusion, and are applicable for clinical use.