Background: Premature very low birthweight (VLBW) infants are born with an underdeveloped parasympathetic nervous system (PNS) which may limit their ability to respond adequately to feeding and may limit their capacit...Background: Premature very low birthweight (VLBW) infants are born with an underdeveloped parasympathetic nervous system (PNS) which may limit their ability to respond adequately to feeding and may limit their capacities for extrauterine growth and development. Objectives: To describe the patterns of autonomic response to feeding and identify relationships between change in heart period variability measures over time with selected infant characteristics. Methods: Individual growth curve analysis techniques were used to describe the patterns of change over time in sympathetic and parasympathetic tone as measured by low and high frequency heart period power. Results: Sixteen mechanically ventilated VLBW infants with a mean corrected gestational age of 30.4 weeks participated in the study. The low frequency (LF) power slope was - 17.67 (P=0.0002) and the high frequency (HF) power slope was - 0.92 (0.0003). There was a significant relationship between HF slope and birth gestational age (r=- 0.49, P=0.05). Conclusions: HF power, representing primarily parasympathetic activity, did not increase with enteral feeding as anticipated. LF power, an indicator of sympathetic tone, decreased during and after feeding suggesting the anticipated effect of inhibition of the sympathetic nervous system in response to the gut stimulus. Critically ill VLBW infants possess an overriding sympathetic response, but may not have adequate PNS tone development.展开更多
This study was designed to explore the relationships of early diabetic microangiopathy to alterations of cardiac sympathetic tone and myocardial blood flow(MBF)regulation in subjects with stable type 1 diabetes. In di...This study was designed to explore the relationships of early diabetic microangiopathy to alterations of cardiac sympathetic tone and myocardial blood flow(MBF)regulation in subjects with stable type 1 diabetes. In diabetes, augmented cardiac sympathetic tone and abnormal MBF regulation may predispose to myocardial injury and enhanced cardiac risk. Subject groups comprised healthy controls(C)(n=10), healthy diabetic subjects(DC)(n=12), and diabetic subjects with very early diabetic microangiopathy(DMA+)(n=16). [ 11C]meta-hydroxyephedrine([11C]HED)and positron emission tomography(PET)were used to explore left ventricular(LV)sympathetic integrity and [13N]ammonia-PET to assess MBF regulation in response to cold pressor testing(CPT)and adenosine infusion. Deficits of LV [ 11C]HED retention were extensive and global in the DMA+subjects(36±31%vs. 1±1%in DC subjects; p< 0.01)despite preserved autonomic reflex tests. On CPT, plasma norepinephrine excursions were two-fold greater than in C and DC subjects(p< 0.05), and basal LV blood flow decreased(-12%, p< 0.05)in DMA+but not in C or DC subjects(+45%and +51%, respectively). On adenosine infusion, compared with C subjects, MBF reserve decreased by-45%(p< 0.05)in DMA+subjects. Diastolic dysfunctionwas detected by two-dimensional echocardiography in 5 of 8 and 0 of 8 consecutively tested DMA+and DC subjects, respectively. Augmented cardiac sympathetic tone and responsiveness and impaired myocardial perfusion may contribute to myocardial injury in diabetes.展开更多
目的：末梢灌注指数（tip perfusion index TPI）是将指（趾）脉搏血氧饱和度探头采集的容积波形用数学方法经计算机处理后转化成数字为0-100的指数，本研究通过体位改变探讨TPI用于监测交感张力变化的价值。方法：随机选择健康自愿者5...目的：末梢灌注指数（tip perfusion index TPI）是将指（趾）脉搏血氧饱和度探头采集的容积波形用数学方法经计算机处理后转化成数字为0-100的指数，本研究通过体位改变探讨TPI用于监测交感张力变化的价值。方法：随机选择健康自愿者50例，依次行坐，蹲，站，躺，坐体位改变，每间隔2秒记录一次SpO2，HR和TPI，每种体位改变后记录30秒；计算体位改变前后HR和TPI的最大变化值（△HR和△TPI）和相应时间（T△HR和T△TPI）。以△HR或△TPI的变化幅度>5%定为HR或TPI反映交感张力变化阳性。结果：体位改变时HR反映交感张力交感张力变化阳性。结果：体位改变时HR反映交感张力变化的灵敏度为84.5%,TPI为98%，△TPI的变化幅度明显大于△HR的变化幅度（P<0.05)。而T△TPI和T△HR（P<0.05)。△HR和△TPI之间呈负相关（r=-0.721，p<0.01)；△HR和T△HR之间及△TPI和T△TPI之间呈正相关（r=0.437和0.0414，p<0.01)。结论：TPI与HR变化均可反映交感张力的变化，而且TPI比HR更迅速，灵敏。展开更多
目的探讨新生儿黄疸对心率变异性的影响及其临床意义。方法应用美国威豪公司CompaxXMHolter分析系统检测12例轻-中度黄疸新生儿、8例重度黄疸新生儿治疗前后和12例正常新生儿的心率变异性。结果轻-中度黄疸患儿即显示有HRV的增高,表现为...目的探讨新生儿黄疸对心率变异性的影响及其临床意义。方法应用美国威豪公司CompaxXMHolter分析系统检测12例轻-中度黄疸新生儿、8例重度黄疸新生儿治疗前后和12例正常新生儿的心率变异性。结果轻-中度黄疸患儿即显示有HRV的增高,表现为SNDD、SNDD index、RMSSD、5min total power、HF的升高(P<0.05),而重度黄疸HRV则下降,表现为SNDD、5min total power下降(P<0.05)。经治疗后重度黄疸的HRV增加,表现为交感神经张力的增加,但仍低于对照组(P<0.05)。结论新生儿黄疸可影响心脏自主神经功能,表现为交感神经张力增加。心率变异性判断新生儿黄疸预后的可靠指标。其中SNDDindex、5min total power两项指标反应黄疸新生儿的交感神经张力更敏感。展开更多
文摘Background: Premature very low birthweight (VLBW) infants are born with an underdeveloped parasympathetic nervous system (PNS) which may limit their ability to respond adequately to feeding and may limit their capacities for extrauterine growth and development. Objectives: To describe the patterns of autonomic response to feeding and identify relationships between change in heart period variability measures over time with selected infant characteristics. Methods: Individual growth curve analysis techniques were used to describe the patterns of change over time in sympathetic and parasympathetic tone as measured by low and high frequency heart period power. Results: Sixteen mechanically ventilated VLBW infants with a mean corrected gestational age of 30.4 weeks participated in the study. The low frequency (LF) power slope was - 17.67 (P=0.0002) and the high frequency (HF) power slope was - 0.92 (0.0003). There was a significant relationship between HF slope and birth gestational age (r=- 0.49, P=0.05). Conclusions: HF power, representing primarily parasympathetic activity, did not increase with enteral feeding as anticipated. LF power, an indicator of sympathetic tone, decreased during and after feeding suggesting the anticipated effect of inhibition of the sympathetic nervous system in response to the gut stimulus. Critically ill VLBW infants possess an overriding sympathetic response, but may not have adequate PNS tone development.
文摘This study was designed to explore the relationships of early diabetic microangiopathy to alterations of cardiac sympathetic tone and myocardial blood flow(MBF)regulation in subjects with stable type 1 diabetes. In diabetes, augmented cardiac sympathetic tone and abnormal MBF regulation may predispose to myocardial injury and enhanced cardiac risk. Subject groups comprised healthy controls(C)(n=10), healthy diabetic subjects(DC)(n=12), and diabetic subjects with very early diabetic microangiopathy(DMA+)(n=16). [ 11C]meta-hydroxyephedrine([11C]HED)and positron emission tomography(PET)were used to explore left ventricular(LV)sympathetic integrity and [13N]ammonia-PET to assess MBF regulation in response to cold pressor testing(CPT)and adenosine infusion. Deficits of LV [ 11C]HED retention were extensive and global in the DMA+subjects(36±31%vs. 1±1%in DC subjects; p< 0.01)despite preserved autonomic reflex tests. On CPT, plasma norepinephrine excursions were two-fold greater than in C and DC subjects(p< 0.05), and basal LV blood flow decreased(-12%, p< 0.05)in DMA+but not in C or DC subjects(+45%and +51%, respectively). On adenosine infusion, compared with C subjects, MBF reserve decreased by-45%(p< 0.05)in DMA+subjects. Diastolic dysfunctionwas detected by two-dimensional echocardiography in 5 of 8 and 0 of 8 consecutively tested DMA+and DC subjects, respectively. Augmented cardiac sympathetic tone and responsiveness and impaired myocardial perfusion may contribute to myocardial injury in diabetes.
文摘目的：末梢灌注指数（tip perfusion index TPI）是将指（趾）脉搏血氧饱和度探头采集的容积波形用数学方法经计算机处理后转化成数字为0-100的指数，本研究通过体位改变探讨TPI用于监测交感张力变化的价值。方法：随机选择健康自愿者50例，依次行坐，蹲，站，躺，坐体位改变，每间隔2秒记录一次SpO2，HR和TPI，每种体位改变后记录30秒；计算体位改变前后HR和TPI的最大变化值（△HR和△TPI）和相应时间（T△HR和T△TPI）。以△HR或△TPI的变化幅度>5%定为HR或TPI反映交感张力变化阳性。结果：体位改变时HR反映交感张力交感张力变化阳性。结果：体位改变时HR反映交感张力变化的灵敏度为84.5%,TPI为98%，△TPI的变化幅度明显大于△HR的变化幅度（P<0.05)。而T△TPI和T△HR（P<0.05)。△HR和△TPI之间呈负相关（r=-0.721，p<0.01)；△HR和T△HR之间及△TPI和T△TPI之间呈正相关（r=0.437和0.0414，p<0.01)。结论：TPI与HR变化均可反映交感张力的变化，而且TPI比HR更迅速，灵敏。
文摘目的探讨新生儿黄疸对心率变异性的影响及其临床意义。方法应用美国威豪公司CompaxXMHolter分析系统检测12例轻-中度黄疸新生儿、8例重度黄疸新生儿治疗前后和12例正常新生儿的心率变异性。结果轻-中度黄疸患儿即显示有HRV的增高,表现为SNDD、SNDD index、RMSSD、5min total power、HF的升高(P<0.05),而重度黄疸HRV则下降,表现为SNDD、5min total power下降(P<0.05)。经治疗后重度黄疸的HRV增加,表现为交感神经张力的增加,但仍低于对照组(P<0.05)。结论新生儿黄疸可影响心脏自主神经功能,表现为交感神经张力增加。心率变异性判断新生儿黄疸预后的可靠指标。其中SNDDindex、5min total power两项指标反应黄疸新生儿的交感神经张力更敏感。
