Changes in partial pressure of arterial carbon dioxide induces redistribution of oral tissue blood flow in the rabbit.
OBJECTIVE
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.


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.


CONCLUSIONS
Changes in PaCO(2) may induce a redistribution of oral tissue blood flow during both ISO and PROP anesthesia.
Handa
Mariko
M
Research Associate, Department of Dental Anesthesiology, Tokyo Dental College, Chiba, Japan. mhanda@tdc.ac.jp
Ichinohe
Tatsuya
T
Kaneko
Yuzuru
Y
D000222:Adaptation, Physiological; D018686:Anesthetics, Intravenous / Q000494:pharmacology; D000818:Animals; D001784:Blood Gas Analysis; D001794:Blood Pressure; D001853:Bone Marrow / Q000098:blood supply*; D002245:Carbon Dioxide / Q000097:blood*; D006339:Heart Rate; D007530:Isoflurane / Q000494:pharmacology; D008297:Male; D008334:Mandible / Q000098:blood supply*; D008406:Masseter Muscle / Q000098:blood supply*; D010313:Partial Pressure; D010521:Periosteum / Q000098:blood supply*; D015742:Propofol / Q000494:pharmacology; D011817:Rabbits; D012039:Regional Blood Flow; D018709:Statistics, Nonparametric
D018686:Anesthetics, Intravenous; D002245:Carbon Dioxide; D007530:Isoflurane; D015742:Propofol