Clinical physiology and functional imaging
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Clin Physiol Funct Imaging · Mar 2011
ReviewCerebrovascular pathophysiology following mild traumatic brain injury.
Mild traumatic brain injury (mTBI) or sport-induced concussion has recently become a prominent concern not only in the athletic setting (i.e. sports venue) but also in the general population. The majority of research to date has aimed at understanding the neurological and neuropsychological outcomes of injury as well as return-to-play guidelines. Remaining relatively unexamined has been the pathophysiological aspect of mTBI. ⋯ In this review, we focus on the current research available from both human and experimental (animal) studies surrounding the pathophysiology of mTBI. First, the quest for a unified definition of mTBI, its historical development and implications for future research is discussed. Finally, the impact of mTBI on the control and regulation of cerebral blood flow, cerebrovascular reactivity, cerebral oxygenation and neuroautonomic cardiovascular regulation, all of which may be compromised with mTBI, is discussed.
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Clin Physiol Funct Imaging · Mar 2011
Comparative StudyDiurnal and position-induced variability of impedance cardiography measurements in healthy subjects.
Cardiovascular (CV) parameters and their measurements are subject to variation. In this study, we evaluated the reproducibility of impedance cardiography (ICG) measurements following orthostatic and diurnal challenges for a set of 22 CV parameters in ten randomly selected healthy nonpregnant women. A standard protocol was used to record a consecutive series of measurements for each parameter before and after three position changes. ⋯ Inter- and intrasession ICC for individual measurements varied between 0·02 and 1 for all parameters, however inter- and intrasession PCC for mean values was consistently >0·80 for stroke volume (SV), stroke index (SI), cardiac output (CO), acceleration and velocity index (ACI and VI), thoracic fluid content (TFC), TFC index (TFCI) and heart period duration (HPD). We conclude that in healthy subjects under standardised conditions, reproducibility of means of multiple ICG measurements is high for SV, SI, CO, ACI, VI, TFC, TFCI and HPD. From our data, we cannot draw conclusions on trends in diseased subjects.
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Clin Physiol Funct Imaging · Mar 2011
Randomized Controlled TrialThe effects of clonidine on arterial baroreflex sensitivity and cardiopulmonary baroreflex control of sympathetic nerve activity in patients with left ventricular dysfunction.
Clonidine is a potent sympatholytic drug with central neural effects. The aim of this study was to evaluate the effects of clonidine on arterial baroreflex sensitivity (BRS) and cardiopulmonary (CP) baroreflex control of muscle sympathetic nerve activity (MSNA) in patients with left ventricular (LV) dysfunction. ⋯ Clonidine enhanced BRS and CP baroreflex control of MSNA while reducing baseline sympathetic activity in patients with LV dysfunction.
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Clin Physiol Funct Imaging · Mar 2011
Assessments of skin and tongue microcirculation reveals major changes in porcine sepsis.
To examine the relation between central hemodynamics, clinical severity and microvascular findings in tongue and skin during sepsis. ⋯ Capillary bleedings may be used as an early indication of severe sepsis. Examination of skin and tongue microcirculations may be used to characterize severity of sepsis and possibly to assess effect of treatment.