Objective To investigate the effect of acute hypervolemic hemodilufion (AHHD) on EC50 of propofol by target-controlled infusion (TCI) for loss of consciousness (LOC). Methods Sixty ASA Ⅰ or Ⅱ patients aged 18-64 yr scheduled for vertebral eolunm or total hip replacement surgery were randomly divided into 4 groups (n = 15 each) : group Ⅰ target plasma concentration of propofol (Tp) ;group Ⅱ target effect-site concentration of propofol (Te) ;group Ⅲ AHHD + Tp and group Ⅳ AHHD + Te. All the patients recoived iv infusion of lactated Ringer's solution 0.7 ml·kg-1 ·h-1 via peripheral vein for 30 min. At the same time 4% gelofusion 15 ml/kg was infused over 30 min via internal jugular vein in group Ⅲ and Ⅳ. At the end of gelofusine infusion TCI of propofol was started. The initial target concentration was set at 1.2 μg/ml. After the target concentration was steadily maintained for 30 s, the consciousness of the patients was evaluated by an anesthesiologist not involved in the study using OAA/S scale. The target concentration was increased in 0.3 μg/ml increment until the patients lost consciousness (OAA/S = 0). The target plasma concentration and effect-site concentration were then recorded. EC50 and 95% confidence interval (CI) of propofol for LOC were calculated by probit analysis. Results The ECho (95 % CI) of propofol for patients in group Tp, Te, AHHD + Tp and AHHD + Te (group Ⅰ-Ⅳ) were 3.74 (3.46-4.16), 2.32 (2.17-2.42), 4.12 (3.81-4.32) and 2.38 (2.14-2.56) μg/ml respectively. EC50 was significantly higher for loss of consciousness in AHHD + Tp group (group Ⅲ)than in Tpgroup (group Ⅰ), but there was no significant difference in EC50 between group Te and group AHHD + Te. Conclusion AHHD can increase the EC50 of target plasma concentration of propofol by TCI for LOC but has no effect on EC50 of target effect-site concentration.

Objective: To study the difference of airway volume among the adolescent subjects with various vertical skeletal patterns. Methods: CBCT records of 88 adolescents with normal sagittal facial pattern were collected and divided into 3 groups according to their FH-MP angle. The subjects of the 3 groups were matched in age and sex. Airway volume and cross-sectional areas were compared among the 3 groups with Dolphin software. Correlation analyses of the airway dimensions with the maxillofacial variables was carried out. Results: There were statistical differences among the 3 groups in volumes of velopharynx,glossopharynx and oropharynx, minimal cross-section area of oropharynx and cross-section area on EP plane,and all the measurements decreased from low angle to normal angle to high angle groups(P ＜ 0. 05). Cross-section areas of HP plane and SP plane in low angle group were significantly larger than that of the normal angle and high angle groups(P ＜ 0. 05). The oropharyngeal airway dimensions showed negative correlation with FMA,and positive correlation with Co-Po,Ar-Gn (except cross-section area of HP). Conclusion: The pharyngeal airway volumes among different vertical skeletal patterns in adolescents are different.