Affiliations: Department of Pediatrics, Anesthesia and Surgery, Children's & Women's Health Centre, University of British Columbia, Vancouver, BC, Canada
Note: [] Corresponding author: Prof. A.J. Macnab, Critical Care Research Office, Room L317, Mail Box 80, Children's & Women's Health Centre of BC, 4480 Oak St., Vancouver, BC, Canada V6H 3V4, Tel.: +1 604 875 3524; Fax: +1 604 875 2728; E‐mail: amacnab@cw.bc.ca.
Abstract: During cardiac surgery, bypass pumps rely on pressure monitors to evaluate flow. We studied whether it would be possible to optimize pump flow by monitoring changes in cerebral cytochrome a,a3 using NIRS to maintain cyt redox status at its pre‐bypass level. Method: 18 healthy 7–45 kg swine were placed on bypass for repeated cycles of cooling and re‐warming from 36 to 15 to 36°C in 3°C steps. Between each cycle, the swine's bypass pump blood flow rate was adjusted to restore cytochrome redox status to its pre‐bypass value. Results: In all swine trials, the number of pump flow alterations imposed by NIRS monitoring ranged from 0 to 42, the average being 14 per trial. The best trial had 22 pump flow adjustments during which the range of cytochrome redox status change was 0.50±0.06 μmol l−1. The average trial had a range of cytochrome redox status change of 1.50±0.22 μmol l−1. Conclusion: NIRS‐driven alterations in pump flow rate to maintain pre‐bypass cytochrome redox status can be achieved successfully in the animal model.
Keywords: Spectrophotometry, nasopharyngeal, cytochrome, NIRO‐300, oxygenation status
Journal: Spectroscopy, vol. 17, no. 2-3, pp. 477-482, 2003
