Changes in the Cerebral Oxygen Environment during Psychosedation Sedation : Evaluation using a Near-Infrared Oxygenation Monitor

采用近红外氧监测仪(NIRO)，观察吸入一氧化二氮(I)和静脉注射刺激剂(咪达唑仑：MD-；0.03 mg/kg、0.05 mg/kg、0.07 mg/kg组，丙泊酚：PRF-；1~3 mg/kg/h组)(II)吸入镇静期间脑内氧环境的变化。1.两组患者的SBP、DBP、HR在整个实验过程中均无明显变化。混合气体吸入后，两组ETCO_2均以室内空气吸入方式逐渐升高，两组间差异有统计学意义。混合气体吸入后，TCPO_2呈逐渐下降的趋势，但两组间无显着性差异。N2O组吸入混合气体后室内空气吸入HBO_2明显下降，两组间差异也有统计学意义。在整个实验过程中，ΔCytaa3在两组…中都没有显著变化2.给药后ETCO_2和TCPCO_2逐渐升高。停药后ETCO_2和TCPCO_2开始迅速下降，10分钟后恢复到原来的水平。2.给药后SpO_2和TCPO_2逐渐降低。3.HBO_2从5分钟到17分钟逐渐升高，18分钟到38分钟逐渐降低。4.ΔCytaa3在整个实验过程中无明显变化。结论牙科临床在一氧化二氮吸入镇静和静脉镇静期间及之后，虽然血中氧含量下降，但维持了良好的脑内氧环境，提示动脉血氧分压不会因SpO_2和TcPO_2的变化而下降，但脑氧分压下降是由于吸入30%一氧化二氮后室内空气中HBO_2的显著下降所致。但目前认为脑组织缺氧不是由于Δ、Cytaa3的变化所致。较少

We investigated the change of the intracerebral oxygen environment during inhalation sedation with nitrous oxide(I) and intravenously injected with abirritants (Midazolam : MD- ; 0.03mg/kg,0.05mg/kg, 0.07mg/kg group, Propofol : PRF- ; 1〜3 mg/kg/hrgroup) (II) using a near-infrared oxygen monitor (NIRO).ResultsI. 1.In both groups, SBP, DBP and HR did not change significantly throughout the experiment.2. In both groups, ETCO_2 increased gradually and significantly by the room air inhalation after a mixed-gas inhalation and there was also a significant difference between the two groups.3. TCPO_2 showed a trend that decreases gradually by the room air inhalation after a mixed-gas inhalation but there was no significant difference between the tow groups.4. HbO_2 had a significant fall by room air inhalation after a mixed-gas inhalation in N2O group and there was also a significant difference between the two groups.5. Δ Cytaa3 did not change significantly throughout the experiment in both gro … More ups, and there was no significant difference between the two groups.II. 1. ETCO_2 and TCPCO_2 increased gradually under administration. After administration was halted, ETCO_2 and TCPCO_2began to decrease promptly and recovered to the original status after 10 minutes. 2. SpO_2 and TCPO_2 decreased gradually under administration. 3. HbO_2 increased gradually from 5 to 17 minutes and then decreased gradually from 18 to 38 minutes. 4. Δ Cytaa3 did not change significantly throughout the experiment.ConclusionIn conclusion, during and after nitrous oxide inhalation sedation and during and after intravenous sedation in clinical dentistry, although the oxygen content in blood fell, a satisfactory intracerebral oxygen environment was maintained.Therefore, the results of this study suggest that the partial pressure of oxygen in arterial blood will not fall from change of SpO_2 and TcPO_2, but cerebral partial pressure of oxygen falls due to the significant fall of HbO2 following inhalation of the room air after 30% of nitrous oxide inhalation. However it is believed that hypoxia of cerebral tissue does not occur from the change of Δ Cytaa3. Less