Changes in Partial Pressure of Arterial Carbon Dioxide Induces Redistribution of Oral Tissue Blood Flow in the Rabbit

Abstract

Mariko HANDA Changes in PaCO 2 induced redistribution of oral tissue blood flow in the rabbit Eur. J. Oral Sci.The purpose of this study was to investigate the effect of PaCO 2 changes on oral tissue blood flow. 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), tissue blood flow of the mandib ular bone marrow (BBF), of the masseter muscle (MBF), and of the mandibular periosteum (PBF). After completion of the experimental preparation, CO 2 was added to inspired gas to change inspired CO 2 tension. Measurements were performed when end-tidal CO 2 tension (ETCO 2 ) was maintained at 4, 5.3, 6.7 and 8 kPa.Heart rate in both groups gradually decreased as ETCO 2 increased. In contrast, both systolic and diastolic arterial pressures gradually increased as ETCO 2 increased. Both CBF and BBF increased, while MBF decreased as ETCO 2 increased. PBF showed no change throughout the experiment. Positive relationship was observed between CBF and BBF. In contrast, negative relationship was observed between CBF and MBF. These results suggested that changes in PaCO 2 may induce redistribution of oral tissue blood 3 flow during both ISO and PROP anesthesia.

Tissue Blood Flow During Remifentanil Infusion With Carbon Dioxide Loading

“…In addition, HR was decreased while SBP and DBP were increased. Although the present study was performed under sevoflurane anesthesia, the results were similar to those by Handa et al 7 Meanwhile, Koshika et al 9 reported that SBP, MAP, HR, TBF, BBF, MBF, UBF, and LBF were decreased when Remi was infused at 0.4 lg/kg/min under sevoflurane anesthesia at an ETCO 2 level of 35 to 40 mm Hg. In the present study, similar results were obtained at an ETCO 2 level of 40 mm Hg.…”

“…The DBP level was increased and HR was decreased along with ETCO 2 elevation during Remi infusion. Data are shown as mean 6 SD (n ¼ 8 Handa et al 7 reported that deliberate elevation of ETCO 2 under isoflurane anesthesia induced increases in CCBF and BBF and a decrease in MBF, although there was no change in mandibular periosteal blood flow. In addition, HR was decreased while SBP and DBP were increased.…”

“…5,6 Accordingly, we have researched another approach to control tissue blood flow in the oral region during general anesthesia. Handa et al 7 reported that hypercapnia increases common carotid artery blood flow (CCBF) and mandibular bone marrow tissue blood flow (BBF), while it decreases masseter muscle tissue blood flow (MBF). Kemmochi et al 8 reported that remifentanil (Remi) decreases CCBF and BBF without a substantial reduction of blood pressure.…”

Unilateral Stellate Ganglion Block Produces Bidirectional Changes in Tissue Oxygen Tension of the Mental Nerve in Rabbits

“…14,15 Stable muscle relaxation was achieved with 14 μg·kg -1 ·min -1 rocuronium bromide in rabbit experiments. 10,11,16 To expose bilateral mental nerves, skin incisions were performed without local anesthesia to prevent tissue blood flow change by lidocaine.…”

Relationship between Oral Tissue Blood Flow and Oxygen Tension in Rabbit

“…Consequently, several studies on control of oral tissue blood flow during anesthesia have been conducted [2][3][4][7][8][9][10]12,14,16,18) . Common methods for observation of tissue blood flow include hydrogen clearance tissue blood flowmetry 1) , microsphere injection technique 18,20) , thermal diffusion flowmetry 10) and laser Doppler flowmetry 25) .…”