高龄病人异丙酚分步TCI时效应室浓度及BIS的变化

Changes in the effect compartment concentration and bispectral index during a step-by-step TCI of propofol in the elderly

目的 研究高龄病人异丙酚分步靶控输注(TCI)时效应室浓度变化的规律及其相应镇静程度和双频指数(BIS)的变化。方法10例年龄67～77岁病人,进行异丙酚分步TCI,靶浓度(Ct)由1μg/ml,分6步渐增加至4μg/ml。观察效应室浓度(Ce)、BIS和镇静警觉评分(OAA/S),并于Ct分别为1、2、3和4μg/ml时取桡动脉血测异丙酚浓度(Cb)。结果①Ce随Ct增加而增加,但较Ct明显滞后,Ce达到4μg/ml较Ct滞后时间为(14.4±0.5)min。②Cb均高于Ct。PE、MDPE和MDAPE分别为16.3％,9.7％和11.2％。③BIS与Ct和Ce均呈显著负相关(r=-0.878和-0.888,P<0.01)。OAA/S与BIS呈显著正相关(r=0.913,P<0.01),与Ct、Ce均呈显著负相关(r=-0.876和-0.893,P<0.01)。④意识和痛刺激反应消失时BIS值分别为64.6±10.6和43.6±8.1,Ce分别为(1.67±0.49)μg/ml和(2.78±0.46)μg/ml。结论 高龄病人 Ce变化较Ct明显滞后,高龄病人BIS监测可很好反映异丙酚麻醉的深度。

Objective To assess the changes in the effect compartment concentration (Ce) and bispectral index (BIS) during a step-by-step TCI of propofol in the elderly.Methods Ten ASA Ⅰ -Ⅱ patients (6 male, 4 female) aged 67-77yr and weighing 51-78kg, undergoing elective surgery were studied. Patients with severe cardiovascular disease were excluded. The patients were unpremedicated. Anesthesia was induced with propofol administered by a TCI system (Diprifusor) . The target concentration (Ct) of propofol was increased step-by-step from 1μg·ml-1 to 4μg·ml-1 in 6 steps. At each step Ct increased by 0.5μg·ml-1 and the interval between the two steps was 2min. The changes in Ce (calculated and displayed by Diprifusor) and BIS were recorded. Modified OAA/S sedation score were measured. Blood samples were taken from artery for determination of blood concentration of propofol (Cb) before TCI (T0 ) and when Ct was 1, 2, 3, and 4μg*******ml-1 (T1-4) in 5 randomly selected patients.Results (1) Ce consistently increased with the increase in Ct and there was a delay between Ct and Ce. When Ct was increased to 4μg*******ml-1, it took (14.4 ± 0.5) min to achieve the balance between Ct and Ce. (2) Cb of propofol was higher than Ct of propofol at each step. MDPE and MDAPE was 9.7% and 11.2% respectively. (3) There was a close correlation between BIS and Ct, Ce and OAA/S score( r = - 0.878, - 0.888 and 0.913 respectively , P< 0.01). (4) When the patients become unconscious, BIS was 64.6 ±10.6, Ct (2.27 ± 0. 53) μg·ml-1, Ce (1.67±0.49)μg·ml-1 and dose of propofol (1.04 ±0.29) mg·kg-1 . When the patients lost response to pain BIS was 46.6 ±8.1, Ct (3.54± 0.46) fig·ml-1, Ce (2.78 ± 0.46) μg·ml-1 and dose of propofol 1.73 ± 0.27mg·kg-1 .Conclusions Ce consistently increases with the increase in Ct and there is a delay. BIS can predict the depth of propofol anesthesia.