AIM: To determine the possible existence of a hepatocardiovascular response and its regulatory mechanism in normal rats.METHODS: Systemic hemodynamic changes following intraportal injection of latex microspheres were ...AIM: To determine the possible existence of a hepatocardiovascular response and its regulatory mechanism in normal rats.METHODS: Systemic hemodynamic changes following intraportal injection of latex microspheres were studied in two modified rat models of hepatic circulation, in which the extrahepatic splanchnic circulation was excluded by evisceration and the liver was perfused by systemic blood via either the portal vein (model 1) or hepatic artery(model 2)in vivo.RFSULTS: In model 1, intraportal injection of two sized microspheres (15-μm and 8O-μm) induced a similar decrease in mean arterial pressure, while extrahepatic portal venous occlusion induced an immediate increase in mean arterial pressure. In model 2, microsphere injection again induced a significant reduction in mean arterial pressure, aortic blood flow and aortic resistance. There were no significant differences in these parameters between liver-innervated rats and liver-denervated rats.The degrees of microsphere-induced reduction in mean arterial pressure (-38.1±1.9% in liver-innervated rats and -35.4±2.1% in liver-denervated rats, respectively)were similar to those obtained by withdrawal of 2.0 mL of blood via the jugular vein (-33.3±2.1%) (P＞0.05).Injection of 2.0 mL Haemaccel in microsphere-treated rats, to compensate for the reduced effective circulating blood volume, led to a hyperdynamic state which, as compared with basal values and unlike control rats, was characterised by increased aortic blood flow (+21.6±3.3%),decreased aortic resistance (-38.1±3.5%) and reduced mean arterial pressure (-9.7±2.8%).CONCLUSION: A hepato-cardiovascular response exists in normal rats. It acts through a humoral mechanism leading to systemic vasodilatation, and may be involved in the hemodynamic disturbances associated with acute and chronic liver diseases.展开更多
Purpose: We investigated the effect of menstrual cycle on the cardiovascular responses during recovery period from exercise. 10 healthy women were participated in the early follicular phase (EP: low estrogen and low p...Purpose: We investigated the effect of menstrual cycle on the cardiovascular responses during recovery period from exercise. 10 healthy women were participated in the early follicular phase (EP: low estrogen and low progesterone: 1 - 4 days) and the late follicular phase (LP: high estrogen and low progesterone: 10 - 13 days) during menstrual cycle. Methods: All subjects completed a graded cycling exercise testing to determine the relative exercise intensity. All subjects were assessed systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), stroke volume (SV), cardiac output (CO), and total vascular conductance (TVC) at resting and during recovery period from moderated cycling exercise during EP and LP. Results: During EP, compared with LP, resting SBP and MAP were higher and TVC was lower (p p Conclusions: This study could be increased the peripheral vasoconstriction in low estrogen levels. And during early follicular phase with low estrogen level, it may maintain an increased blood pressure during recovery period following cycling. We suggest that the timing of the menstrual cycle should be considered when measuring blood pressure during clinical exercise testing.展开更多
Background Whole-body vibration(WBV) therapy has become a common treatment in rehabilitation of various patient populations. While it has been shown in healthy young adults that the oxygen consumption rate(VO_2)and he...Background Whole-body vibration(WBV) therapy has become a common treatment in rehabilitation of various patient populations. While it has been shown in healthy young adults that the oxygen consumption rate(VO_2)and heat rate(HR) are significantly increased when WBV is added to exercise. However, the cardiovascular response to WBV in patients with subacute stroke is unknown. The objective of this study was to determine the acute cardiovascular responses to WBV during the various exercises in different WBV conditions in patients with subacute stroke(onset less than 3 months). Methods A total of 54 subjects with subacute stroke performed six exercises while being exposed to 3 WBV conditions:(1) no WBV,(2) low WBV intensity [amplitude: 0.6 mm,frequency: 20 Hz, peak acceleration: 0.96 gravitational constant(G)], and(3) high WBV intensity(amplitude:0.44 mm, frequency: 30 Hz, peak acceleration: 1.61 G). The cardiovascular responses(HR and VO_2) were measured by a FitMateTMPro metabolic system during the 6 exercises. Two-way repeated measures ANOVA was used to compare the VO_2, and HR data across the different conditions. In addition, we calculated the rate pressure product(RPP) =(HR × systolic blood pressure)/100, for measuring the myocardial oxygen demand. Two-way ANOVA with repeated measures was used to compare the RPP data across the different test conditions. Results Exposure to WBV(high-and low-intensity protocols) significantly induced higher VO_2 by 0.35-1.07 mL·kg-1·min-1(P<0.001) and HR by 0.8-6.0 beats per minute(P<0.001) compared with the no WBV condition, regardless of the exercise performed. No significant difference in VO_2 and HR was found between the low-and high-intensity WBV protocols(P>0.05). For RPP, there was an overall significant effect between pre-and post-WBV(P<0.001). The main effect of WBV intensity(P=0.572), and intensity × time interaction effect(P=0.756), however,were not significant. Conclusions HR and VO_2 are increased significantly with addition of WBV training. The added low-and high-intensity WBV induce a similar increase in VO_2 and HR. RPP is similarly increased after exercise, regardless WBV is added or not[.S Chin J Cardiol 2019;20(1):15-24]展开更多
目的应用序贯法探讨丙泊酚或不同剂量瑞马唑仑对舒芬太尼抑制老年患者气管插管反应的半数有效剂量(50%effective dose,ED_(50))的影响。方法选择2022年10至12月在气管插管全身麻醉下接受择期手术的老年患者,美国麻醉医师协会(American S...目的应用序贯法探讨丙泊酚或不同剂量瑞马唑仑对舒芬太尼抑制老年患者气管插管反应的半数有效剂量(50%effective dose,ED_(50))的影响。方法选择2022年10至12月在气管插管全身麻醉下接受择期手术的老年患者,美国麻醉医师协会(American Society of Anesthesiologists,ASA)分级Ⅰ、Ⅱ级,年龄65~80岁,将患者采用随机数字表法分为4组:丙泊酚组(P组,诱导时给予丙泊酚2mg/kg)和瑞马唑仑组(R1、R2、R3组,诱导时分别静脉注射瑞马唑仑0.2、0.3、0.4mg/kg)。麻醉诱导时给予Dixon序贯法设定剂量的舒芬太尼后,静脉注射丙泊酚或相应剂量瑞马唑仑及顺式阿曲库铵0.15mg/kg,待4个成串刺激(train of four,TOF)计数为0时行气管插管。若气管插管反应阳性,则下一例患者舒芬太尼剂量提高1个浓度梯度,否则降低1个浓度梯度,各相邻浓度之间的比为1∶1.1,直至出现7个转折点终止研究。采用Probit回归分析计算舒芬太尼抑制老年患者气管插管反应ED_(50)和95%有效剂量(95%effective dose,ED_(95))以及相应的95%置信区间(confidenceinterval,CI)。记录所有患者低血压、心动过缓、注射痛等不良反应的发生情况。结果本研究共纳入老年患者113例,P、R1、R2、R3组分别24、28、30、31例。丙泊酚2mg/kg或0.2、0.3、0.4mg/kg瑞马唑仑时舒芬太尼抑制老年患者气管插管反应的ED_(50)和ED_(95)及相应95%CI分别为:P组ED_(50)为0.236μg/kg(95%CI:0.218~0.256),ED_(95)为0.266μg/kg(95%CI:0.250~0.398);R1组ED_(50)为0.284μg/kg(95%CI:0.265~0.309),ED_(95)为0.329μg/kg(95%CI:0.306~0.478);R2组ED_(50)为0.239μg/kg(95%CI:0.221~0.260),ED_(95)为0.282μg/kg(95%CI:0.261~0.415);R3组ED_(50)为0.198μg/kg(95%CI:0.182~0.211),ED_(95)为0.231μg/kg(95%CI:0.216~0.303)。与P组相比,R1、R2、R3组低血压、心动过缓、注射痛发生率较低(P<0.05)。R2组舒芬太尼ED_(50)与P组相类似,但低血压、注射痛发生率与P组相比较低。结论随着瑞马唑仑剂量的增加,舒芬太尼抑制老年患者气管插管反应的ED_(50)逐渐降低;在ED_(50)相近的情况下,瑞马唑仑相较于丙泊酚诱导的低血压、心动过缓、注射痛发生率更低,因而在老年患者气管插管全身麻醉中,使用瑞马唑仑诱导更具有优势。展开更多
Background: Hemodynamics is a practical and complicated theoretical problem. The aim of this paper is to analyze the characteristics of blood pressure in the cardiovascular system changing with the mechanical paramete...Background: Hemodynamics is a practical and complicated theoretical problem. The aim of this paper is to analyze the characteristics of blood pressure in the cardiovascular system changing with the mechanical parameters of blood vessels and the storage of some visceral organs. Method: The fluid network model was used for the study. The cardiovascular system was modeled as a system consisting of 20 segments of vessels. The main controlling parameters were determined first by using dimensional analysis. Then the responses of blood pressure of each segment of vessels were analyzed by changing the controlling parameters. Results: The parameters of the blood vessel of brain have the least influence on the pressures of other parts. The pressures of the system of blood vessels will decrease if some blood is stored in the liver or the abdominal vein system. Vice versa. The effects of regulation of blood on the variation of blood pressure are larger than the other controlling parameters. Conclusions: The controlling parameters of the abdominal aorta and ascending aorta affect greatly the blood pressure of each vessel.展开更多
基金Supported by the Medical Science and Technology Development Foundation of Health Department of Jiangsu Province, China. No.H200204
文摘AIM: To determine the possible existence of a hepatocardiovascular response and its regulatory mechanism in normal rats.METHODS: Systemic hemodynamic changes following intraportal injection of latex microspheres were studied in two modified rat models of hepatic circulation, in which the extrahepatic splanchnic circulation was excluded by evisceration and the liver was perfused by systemic blood via either the portal vein (model 1) or hepatic artery(model 2)in vivo.RFSULTS: In model 1, intraportal injection of two sized microspheres (15-μm and 8O-μm) induced a similar decrease in mean arterial pressure, while extrahepatic portal venous occlusion induced an immediate increase in mean arterial pressure. In model 2, microsphere injection again induced a significant reduction in mean arterial pressure, aortic blood flow and aortic resistance. There were no significant differences in these parameters between liver-innervated rats and liver-denervated rats.The degrees of microsphere-induced reduction in mean arterial pressure (-38.1±1.9% in liver-innervated rats and -35.4±2.1% in liver-denervated rats, respectively)were similar to those obtained by withdrawal of 2.0 mL of blood via the jugular vein (-33.3±2.1%) (P＞0.05).Injection of 2.0 mL Haemaccel in microsphere-treated rats, to compensate for the reduced effective circulating blood volume, led to a hyperdynamic state which, as compared with basal values and unlike control rats, was characterised by increased aortic blood flow (+21.6±3.3%),decreased aortic resistance (-38.1±3.5%) and reduced mean arterial pressure (-9.7±2.8%).CONCLUSION: A hepato-cardiovascular response exists in normal rats. It acts through a humoral mechanism leading to systemic vasodilatation, and may be involved in the hemodynamic disturbances associated with acute and chronic liver diseases.
文摘Purpose: We investigated the effect of menstrual cycle on the cardiovascular responses during recovery period from exercise. 10 healthy women were participated in the early follicular phase (EP: low estrogen and low progesterone: 1 - 4 days) and the late follicular phase (LP: high estrogen and low progesterone: 10 - 13 days) during menstrual cycle. Methods: All subjects completed a graded cycling exercise testing to determine the relative exercise intensity. All subjects were assessed systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), stroke volume (SV), cardiac output (CO), and total vascular conductance (TVC) at resting and during recovery period from moderated cycling exercise during EP and LP. Results: During EP, compared with LP, resting SBP and MAP were higher and TVC was lower (p p Conclusions: This study could be increased the peripheral vasoconstriction in low estrogen levels. And during early follicular phase with low estrogen level, it may maintain an increased blood pressure during recovery period following cycling. We suggest that the timing of the menstrual cycle should be considered when measuring blood pressure during clinical exercise testing.
基金supported by Medical Scientific Research Foundation of Guangdong Province of China(No.A2016537)
文摘Background Whole-body vibration(WBV) therapy has become a common treatment in rehabilitation of various patient populations. While it has been shown in healthy young adults that the oxygen consumption rate(VO_2)and heat rate(HR) are significantly increased when WBV is added to exercise. However, the cardiovascular response to WBV in patients with subacute stroke is unknown. The objective of this study was to determine the acute cardiovascular responses to WBV during the various exercises in different WBV conditions in patients with subacute stroke(onset less than 3 months). Methods A total of 54 subjects with subacute stroke performed six exercises while being exposed to 3 WBV conditions:(1) no WBV,(2) low WBV intensity [amplitude: 0.6 mm,frequency: 20 Hz, peak acceleration: 0.96 gravitational constant(G)], and(3) high WBV intensity(amplitude:0.44 mm, frequency: 30 Hz, peak acceleration: 1.61 G). The cardiovascular responses(HR and VO_2) were measured by a FitMateTMPro metabolic system during the 6 exercises. Two-way repeated measures ANOVA was used to compare the VO_2, and HR data across the different conditions. In addition, we calculated the rate pressure product(RPP) =(HR × systolic blood pressure)/100, for measuring the myocardial oxygen demand. Two-way ANOVA with repeated measures was used to compare the RPP data across the different test conditions. Results Exposure to WBV(high-and low-intensity protocols) significantly induced higher VO_2 by 0.35-1.07 mL·kg-1·min-1(P<0.001) and HR by 0.8-6.0 beats per minute(P<0.001) compared with the no WBV condition, regardless of the exercise performed. No significant difference in VO_2 and HR was found between the low-and high-intensity WBV protocols(P>0.05). For RPP, there was an overall significant effect between pre-and post-WBV(P<0.001). The main effect of WBV intensity(P=0.572), and intensity × time interaction effect(P=0.756), however,were not significant. Conclusions HR and VO_2 are increased significantly with addition of WBV training. The added low-and high-intensity WBV induce a similar increase in VO_2 and HR. RPP is similarly increased after exercise, regardless WBV is added or not[.S Chin J Cardiol 2019;20(1):15-24]
文摘目的应用序贯法探讨丙泊酚或不同剂量瑞马唑仑对舒芬太尼抑制老年患者气管插管反应的半数有效剂量(50%effective dose,ED_(50))的影响。方法选择2022年10至12月在气管插管全身麻醉下接受择期手术的老年患者,美国麻醉医师协会(American Society of Anesthesiologists,ASA)分级Ⅰ、Ⅱ级,年龄65~80岁,将患者采用随机数字表法分为4组:丙泊酚组(P组,诱导时给予丙泊酚2mg/kg)和瑞马唑仑组(R1、R2、R3组,诱导时分别静脉注射瑞马唑仑0.2、0.3、0.4mg/kg)。麻醉诱导时给予Dixon序贯法设定剂量的舒芬太尼后,静脉注射丙泊酚或相应剂量瑞马唑仑及顺式阿曲库铵0.15mg/kg,待4个成串刺激(train of four,TOF)计数为0时行气管插管。若气管插管反应阳性,则下一例患者舒芬太尼剂量提高1个浓度梯度,否则降低1个浓度梯度,各相邻浓度之间的比为1∶1.1,直至出现7个转折点终止研究。采用Probit回归分析计算舒芬太尼抑制老年患者气管插管反应ED_(50)和95%有效剂量(95%effective dose,ED_(95))以及相应的95%置信区间(confidenceinterval,CI)。记录所有患者低血压、心动过缓、注射痛等不良反应的发生情况。结果本研究共纳入老年患者113例,P、R1、R2、R3组分别24、28、30、31例。丙泊酚2mg/kg或0.2、0.3、0.4mg/kg瑞马唑仑时舒芬太尼抑制老年患者气管插管反应的ED_(50)和ED_(95)及相应95%CI分别为:P组ED_(50)为0.236μg/kg(95%CI:0.218~0.256),ED_(95)为0.266μg/kg(95%CI:0.250~0.398);R1组ED_(50)为0.284μg/kg(95%CI:0.265~0.309),ED_(95)为0.329μg/kg(95%CI:0.306~0.478);R2组ED_(50)为0.239μg/kg(95%CI:0.221~0.260),ED_(95)为0.282μg/kg(95%CI:0.261~0.415);R3组ED_(50)为0.198μg/kg(95%CI:0.182~0.211),ED_(95)为0.231μg/kg(95%CI:0.216~0.303)。与P组相比,R1、R2、R3组低血压、心动过缓、注射痛发生率较低(P<0.05)。R2组舒芬太尼ED_(50)与P组相类似,但低血压、注射痛发生率与P组相比较低。结论随着瑞马唑仑剂量的增加,舒芬太尼抑制老年患者气管插管反应的ED_(50)逐渐降低;在ED_(50)相近的情况下,瑞马唑仑相较于丙泊酚诱导的低血压、心动过缓、注射痛发生率更低,因而在老年患者气管插管全身麻醉中,使用瑞马唑仑诱导更具有优势。
文摘Background: Hemodynamics is a practical and complicated theoretical problem. The aim of this paper is to analyze the characteristics of blood pressure in the cardiovascular system changing with the mechanical parameters of blood vessels and the storage of some visceral organs. Method: The fluid network model was used for the study. The cardiovascular system was modeled as a system consisting of 20 segments of vessels. The main controlling parameters were determined first by using dimensional analysis. Then the responses of blood pressure of each segment of vessels were analyzed by changing the controlling parameters. Results: The parameters of the blood vessel of brain have the least influence on the pressures of other parts. The pressures of the system of blood vessels will decrease if some blood is stored in the liver or the abdominal vein system. Vice versa. The effects of regulation of blood on the variation of blood pressure are larger than the other controlling parameters. Conclusions: The controlling parameters of the abdominal aorta and ascending aorta affect greatly the blood pressure of each vessel.
