Calibration affects central blood pressure (BP) estimation accuracy. Factors influencing the accuracy of noninvasive central BP measurement, type of calibration method implemented (systolic/diastolic BP or mean/diastolic BP), and type of BP measurement device used (devices using the transfer function method, directly measurement from the carotid artery, and the transfer function-like method), were investigated. Fifty participants (aged 62.4 ± 8.9 years) without overt heart diseases were recruited. Invasive aortic and radial BP was measured. Simultaneously, noninvasive central BP was measured using three types of devices. The mean invasive aortic BP was 127 ± 19/95 ± 14 mmHg. Noninvasive central BP tended to be slightly lower than invasive BP, though without statistical significance. The type of calibration method did not significantly influence the noninvasive cSBP measurements (p ≥ 0.24). Results from cuff-based devices were significantly lower than invasive measurements (p = 0.04). Multiple regression analyses showed that gender was significantly correlated with the accuracy of noninvasive cSBP measurement. In conclusion, noninvasive cSBP measurements are comparable to invasive measurements but might underestimate true cSBP. The type of device may affect the accuracy of measurement. Either of the two calibration methods is acceptable.

Background: Invasive blood pressure (IBP) measurement is common in the intensive care unit, although its association with in-hospital mortality in critically ill patients with hypertension is poorly understood. Methods and Results: A total of 11,732 critically ill patients with hypertension from the eICU-Collaborative Research Database (eICU-CRD) were enrolled. Patients were divided into 2 groups according to whether they received IBP. The primary outcome in this study was in-hospital mortality. Propensity score matching (PSM) and inverse probability of treatment weighing (IPTW) models were used to balance the confounding covariates. Multivariable logistic regression was used to evaluate the association between IBP measurement and hospital mortality. The IBP group had a higher in-hospital mortality rate than the no IBP group in the primary cohort [238 (8.7%) vs. 581 (6.5%), p < 0.001]. In the PSM cohort, the IBP group had a lower in-hospital mortality rate than the no IBP group [187 (8.0%) vs. 241 (10.3%), p = 0.006]. IBP measurement was associated with lower in-hospital mortality in the PSM cohort (odds ratio, 0.73, 95% confidence interval, 0.59-0.92) and in the IPTW cohort (odds ratio, 0.81, 95% confidence interval, 0.67-0.99). Sensitivity analyses showed similar results in the subgroups with high body mass index and no sepsis. Conclusions: In conclusion, IBP measurement was associated with lower in-hospital mortality in critically ill patients with hypertension, highlighting the importance of IBP measurement in the intensive care unit.

Objective: To analyze the mechanism of invasive blood pressure change in radial artery caused by arm elevation by observing pressure, velocity and diameter of radial artery. Methods: Twenty-six hemodynamically stable hepatobiliary surgery patients admitted to the intensive care unit from June to December 2018 after general anesthesia in Tsinghua Changgung Hospital were selected. When the arm was raised, the invasive blood pressure was recorded, and the inner diameter and blood flow velocity of the radial artery were measured by Doppler ultrasound. The data following a normal distribution were compared with paired t test. Results: After arm elevation for 30 s, systolic blood pressure of radial artery decreased and diastolic blood pressure increased significantly((107±16) mmHg vs (120±17) mmHg, (75±6) mmHg vs (71±9) mmHg, t=25.0, -12.6, both P<0.05), but there was no significant difference in mean arterial pressure ((87±10) mmHg vs (87±11) mmHg, t=1.1, P>0.05). The peak velocity, end-diastolic velocity and resistance index of the radial artery increased significantly, and the transverse and longitudinal inner diameters of the radial artery decreased significantly after the arm was elevated for 30 s (t=-63.4, -14.6, -22.5, 31.4, 25.3, all P<0.01). Conclusions: Kinetic pressure compensation and vascular resistance compensation may be the main mechanism of radial artery pressure change when the arm is elevated. Arm elevation can be used as a vascular resistance response test clinically.
目的： 通过观测桡动脉压力、流速、直径等指标，分析抬高上肢导致桡动脉有创血压改变的流体力学机制。 方法： 选择2018年6至12月期间入住清华长庚医院重症监护病房（ICU）的血流动力学稳定的肝胆外科全身麻醉手术后患者26例。分别在抬高上肢前和抬高上肢时，记录有创血压数值，并以多普勒超声测量桡动脉置管处的动脉血管内径和血流速。符合正态分布的数据比较采用配对t检验。 结果： 与抬高上肢前相比，抬高上肢30 s后桡动脉收缩压下降、舒张压上升，分别为（107±16) mmHg比（120±17) mmHg和（75±6) mmHg比（71±9) mmHg，差异均有统计学意义（t=25.0、-12.6，均P<0.05)，但平均动脉压变化差异无统计学意义[(87±10) mmHg比（87±11) mmHg，t=1.1，P>0.05]。与抬高上肢前相比，抬高上肢30 s后桡动脉收缩期峰流速、舒张期末流速和阻力指数均显著增加，而桡动脉横径与纵径则显著减小，前后比较差异均有统计学意义（t=-63.4、-14.6、-22.5、31.4、25.3，均P<0.01)。 结论： 动压代偿和血管阻力代偿可能是抬高上肢时桡动脉压力改变的主要机制，抬高上肢可以作为血管阻力反应性试验在临床应用。.

OBJECTIVE: To explore the thoracic ascending aortic （TAA） pathophysiological characteristics of heterozygous mutant Myh11 R247C/+ mice under the norepinephrine-induced hypertension mode.
METHODS: Female heterozygous mutant Myh11 R247C/+ and wild type Myh11 +/+ mice were selected as experimental group (HET group) and control group (WT group)，respectively. The hypertensive model was induced by intraperitoneal injection of norepinephrine (NE)，and TAA diameter and invasive blood pressure (Bp) data were collected dynamically in real time using high-frequency ultrasound imaging and invasive arterial blood pressure monitoring technique，so as to indirectly analyze TAA compliance of two groups of mice. At the same time，the incidences of hemothorax and TAA rupture were further analyzed by autopsy and histology.
RESULTS: After injection of NE，heterozygous mice did not show a higher Bp increase percentage in systole or diastole comparing with wildtype mice. However，heterozygous mice exhibited 17% and 32% higher TAA diameter dilation percentage than wildtype ones in systole and diastole respectively. Two heterozygous mice had TAA dissection and rupture，and the incidence of hemothorax in heterozygous mice (3/5) was higher than that in wildtype (0/5).
CONCLUSIONS: It was very likely that the altered TAA wall compliance of mutant Myh11 R247C/+ mice had led to a higher TAA dilation degree than that in wildtype，and even could be the potential reason of TAA dissection and rupture.

Objective: To investigate the difference of invasive and noninvasive blood pressure in systolic, diastolic and mean blood pressure (SBP, DBP and MAP) levels in critically ill patients. Methods: A total of 197 critically ill patients were enrolled in the intensive care unit of Peking Union Medical College Hospital in this prospective observative study. There were 113 males and 84 females with a mean age of (59±17) years. With Pearson correlation and Bland-Altman analysis, the difference and agreement of invasive and noninvasive blood pressure in SBP, DBP and MAP levels were investigated. Results: Invasive blood pressure monitoring was significantly correlated with noninvasive blood pressure (the correlation coefficients of SBP, DBP and MAP was 0.908, 0.861 and 0.888, respectively, all P<0.001). The mean bias and 95% confidence interval (CI) in SBP(invasive)-SBP(noninvasive), DBP(invasive)-DBP(noninvasive), MAP(invasive)-MAP(noninvasive) respectively was as following: SBP (14.5±11.9) mmHg (-8.8-37.8 mmHg); DBP (1.0±7.2) mmHg(-13.2-15.2 mmHg); MAP (10.5±8.3) mmHg (-5.9-26.8 mmHg). Moreover, there was a significant positive correlation between the bias of SBP(invasive)-SBP(noninvasive) and the value of SBP; when the SBP(invasive)≥143 mmHg was used to predict a value of bias≥20 mmHg, the sensitivity was 72.4% and specificity was 81.3%, and the area under the receiver operating characteristic curve was 0.808 (95% CI: 0.745-0.870). Conclusions: There is a good agreement between invasive and noninvasive blood pressure in critically ill patients, the bias of invasive-noninvasive blood pressure measurement is positively correlated to the value of blood pressure.
目的： 比较重症患者有创血压和无创血压监测在收缩压(SBP)、舒张压(DBP)和平均动脉压(MAP)三个水平的一致性和差异。 方法： 前瞻性纳入2016年6月至2017年1月北京协和医院重症医学科已建立有创动脉血压监测的197例患者[男113例，女84例，平均年龄(59±17)岁]，同时进行有创血压与无创血压的测量，应用Pearson相关、Bland－Altman等方法分析有创和无创血压的相关性、一致性和区别等。 结果： Pearson相关性分析提示有创与无创血压呈显著正相关(SBP(有创)－SBP(无创)、DBP(有创)－DBP(无创)、MAP(有创)－MAP(无创)间相关系数R分别为0.908、0.861、0.888，均P<0.001)。Bland－Altman一致性分析显示，SBP(有创)－SBP(无创)、DBP(有创)－DBP(无创)、MAP(有创)－MAP(无创)的平均偏差以及95%可信区间(CI)分别为(14.5±11.9) mmHg(－8.8～37.8 mmHg)、(1.0±7.2) mmHg(－13.2～15.2 mmHg)和(10.5±8.3) mmHg(－5.9～26.8 mmHg)。有创与无创血压测量的偏差大小与血压数值高低呈显著正相关，当SBP(有创)≥143 mmHg时，预测SBP(有创)－SBP(无创)偏差值≥20 mmHg的敏感性为72.4%，特异性为81.3%，受试者工作特征曲线下面积为0.808(95% CI：0.745～0.870)。 结论： 重症患者有创血压和无创血压之间具有较好的一致性，两者偏差的大小与血压数值高低呈显著正相关。.

We aimed to compare simultaneous invasive and non-invasive blood pressure (IBP and NIBP) measurements in young, middle and old age using the data from the Multiparameter Intelligent Monitoring in Intensive Care II (MIMIC II) database. In total, 23,679 blood pressure measurements were extracted from 742 patients, divided into three groups of young, middle and old age. IBP-NIBP differences in systolic/diastolic blood pressure (SBP/DBP) were 0.1 ± 16.5 mmHg/11.0 ± 12.2 mmHg in young age, -2.9 ± 19.8 mmHg/6.9 ± 17.5 mmHg in middle age and -3.2 ± 29.3 mmHg/8.5 ± 19.8 mmHg in old age. The mean and standard deviation (SD) of invasive systolic blood pressure (ISBP)-non-invasive systolic blood pressure (NISBP) differences increased from young to middle then to old age, and the SD of invasive diastolic blood pressure (IDBP)-non-invasive diastolic blood pressure (NIDBP) differences also increased with age. In young, middle and old age, the correlation coefficients were 0.86, 0.79 and 0.53, respectively, between ISBP and NISBP, and 0.78, 0.78 and 0.41 between IDBP and NIDBP. In conclusion, IBP showed good correlation with NIBP in each age category. The agreement between IBP and NIBP measurements was influenced by age category.