Changes in Partial Pressure of Arterial Carbon Dioxide Induces Redistribution of Oral Tissue Blood Flow in the Rabbit
Purpose
The purpose of this study was to investigate the effect of changes in partial pressure of arterial CO2 (PaCO2) on oral tissue blood flow.
Materials and Methods
Twenty male tracheotomized Japan white rabbits were anesthetized with isoflurane (ISO) or propofol (PROP) under mechanical ventilation. Observed variables included heart rate, blood pressure, common carotid artery blood flow (CBF), and tissue blood flow of the mandibular bone marrow (BBF), the masseter muscle (MBF), and the mandibular periosteum (PBF). After completion of experimental preparation, CO2 was added to inspired gas to change the inspired CO2 tension. Measurements were performed with end-tidal CO2 tension (ETCO2) maintained at 30, 40, 50, and 60 mmHg.
Results
Heart rate in both groups gradually decreased with increasing ETCO2. In contrast, both systolic and diastolic arterial pressures gradually increased with increasing ETCO2. Both CBF and BBF increased and MBF decreased with increasing ETCO2. PBF showed no change throughout the experiment. A positive relationship was observed between CBF and BBF; in contrast, a negative relationship was observed between CBF and MBF.
Conclusion
Changes in PaCO2 may induce a redistribution of oral tissue blood flow during both ISO and PROP anesthesia.
⁎Research Associate, Department of Dental Anesthesiology, Tokyo Dental College, Chiba, Japan
†Professor and Chairman, Department of Dental Anesthesiology, Tokyo Dental College, Chiba, Japan
‡Professor, Department of Dental Anesthesiology, Tokyo Dental College, Chiba, Japan
Address correspondence and reprint requests to Dr Handa: Department of Dental Anesthesiology, Tokyo Dental College, 1-2-2, Masago, Mihama-ku, Chiba 261-8502, Japan
Supported in part by a grant from the Ministry of Education, Culture, Sports, Science and Technology of Japan.
ABSTRACT