PURPOSE: The purpose of this study was to investigate the effect of changes in partial pressure of arterial CO(2) (PaCO(2)) 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, CO(2) was added to inspired gas to change the inspired CO(2) tension. Measurements were performed with end-tidal CO(2) tension (ETCO(2)) maintained at 30, 40, 50, and 60 mmHg. RESULTS: Heart rate in both groups gradually decreased with increasing ETCO(2). In contrast, both systolic and diastolic arterial pressures gradually increased with increasing ETCO(2). Both CBF and BBF increased and MBF decreased with increasing ETCO(2). 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 PaCO(2) may induce a redistribution of oral tissue blood flow during both ISO and PROP anesthesia.
PURPOSE: The purpose of this study was to investigate the effect of changes in partial pressure of arterial CO(2) (PaCO(2)) 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, CO(2) was added to inspired gas to change the inspired CO(2) tension. Measurements were performed with end-tidal CO(2) tension (ETCO(2)) maintained at 30, 40, 50, and 60 mmHg. RESULTS: Heart rate in both groups gradually decreased with increasing ETCO(2). In contrast, both systolic and diastolic arterial pressures gradually increased with increasing ETCO(2). Both CBF and BBF increased and MBF decreased with increasing ETCO(2). 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 PaCO(2) may induce a redistribution of oral tissue blood flow during both ISO and PROP anesthesia.