Changes In Peripheral Circulation Research Articles

Neuroinflammation as the Underlying Mechanism of Postoperative Cognitive Dysfunction and Therapeutic Strategies.

Postoperative cognitive dysfunction (POCD) is a common neurological complication following surgery and general anesthesia, especially in elderly patients. Severe cases delay patient discharge, affect the patient’s quality of life after surgery, and are heavy burdens to society. In addition, as the population ages, surgery is increasingly used for older patients and those with higher prevalences of complications. This trend presents a huge challenge to the current healthcare system. Although studies on POCD are ongoing, the underlying pathogenesis is still unclear due to conflicting results and lack of evidence. According to existing studies, the occurrence and development of POCD are related to multiple factors. Among them, the pathogenesis of neuroinflammation in POCD has become a focus of research in recent years, and many clinical and preclinical studies have confirmed the correlation between neuroinflammation and POCD. In this article, we reviewed how central nervous system inflammation occurred, and how it could lead to POCD with changes in peripheral circulation and the pathological pathways between peripheral circulation and the central nervous system (CNS). Furthermore, we proposed some potential therapeutic targets, diagnosis and treatment strategies at the cellular and molecular levels, and clinical applications. The goal of this article was to provide a better perspective for understanding the occurrence of POCD, its development, and preventive strategies to help manage these vulnerable geriatric patients.

Optimization of extracorporeal membrane oxygenation therapy using near-infrared spectroscopy to assess changes in peripheral circulation: A pilot study.

Near-infrared spectroscopy (NIRS) has been proposed as a noninvasive modality for detecting complications in patients undergoing extracorporeal membrane oxygenation (ECMO), and it can simultaneously reveal the global circulatory status of these patients. We optimized ECMO therapy on the basis of real-time peripheral NIRS probing. Three patients underwent venoarterial (VA) ECMO and one patient underwent venovenous (VV) ECMO. All patients received peripheral ECMO cannulation with routine distal perfusion catheter placement. We designed an experimental protocol to adjust ECMO blood flow over 1 hour. Hemodynamic responses were measured using NIRS devices attached to the calf at approximately 60% of the distance from the ankle to the knee. HbO2 levels change substantially with adjustments in ECMO flow, and they are more sensitive than HHb levels and the tissue saturation index (TSI) are. NIRS for optimizing ECMO therapy may be reliable for monitoring global circulatory status.

A systematic review of studies investigating the effects of controlled whole-body vibration intervention on peripheral circulation.

The findings of the published studies investigating the changes in peripheral circulation induced by exposure to whole-body vibration (WBV) are not consensual or conclusive. Also, those studies did not consider the role of vibration magnitude on the peripheral circulatory responses making the interpretation of the observed findings difficult. We aimed to review the published literature investigating the effects of controlled WBV intervention on peripheral circulation by characterizing the relevant exposure conditions including vibration magnitudes, and ascertain the specific patterns of responses in peripheral circulation of the lower extremity from such exposure. A computerized search was performed in PubMed and Scopus using selected key search terms, and the relevant data were extracted. The vibration magnitude in the included studies frequently exceeded the limit specified in the International Standard ISO 2631-1 (1997) for such exposure. As observed, exposure to WBV with frequencies≤30Hz caused an improvement in peripheral blood flow (BF) and/or skin temperature (ST) of the lower extremity. In contrast, the responses in BF and ST from exposure to WBV of higher frequencies (31Hz-50Hz) produced conflicting results. The findings of this review indicate that WBV exposure with relatively lower frequency and magnitude can be safely and effectively used to induce improvements in peripheral circulation. For this purpose, the limits recommended by the ISO 2631-1 (1997) should be considered till safe and effective vibration-related parameters are established.

Peculiarities of microcirculation in periodont tissues in children of key age groups sufficient type 1 diabetes. Part II

Relevance. Morpho-functional changes in peripheral circulation established in type 1 diabetes mellitus correlate with changes in central hemodynamics, allowing the use of microcirculation indicators as diagnostic and prognostic criteria for assessing the degree of functional vascular disorders. Identifcation of microcirculation features of the blood by the method of laser Doppler flowmetry in children with different experience of type 1 diabetes in key age categories.Materials and methods. The study included 67 children with type 1 diabetes mellitus aged 12-15 years with an experience of the disease from six months to ten years. The comparison group consisted of 38 healthy children. The state of the microvasculature was assessed by laser Doppler flowmetry using a laser analyzer for capillary blood flow LAKK-OP.Results. In children with an experience of type 1 diabetes of less than two years, microcirculation disorders in periodontal tissues correspond to the hyperemic form, accompanied by increased perfusion, a decrease in the amplitude of low-frequency oscillations, increased heart rate, high blood flling, and blood flow bypass. For children with an endocrinopathy experience of more than three years, microcirculation disorders correspond to a stagnant form, combined with a decrease in perfusion due to stagnation of blood in the venular link, endothelial domination with suppression of neurogenic and cardiac fluctuations, low efciency and redistribution of blood flow in favor of the nutritive link.Conclusions. With the increase in experience, the degree of compensation of type 1 diabetes, the progression of diabetic microangiopathy, it is advisable to designate two stages of development of microcirculatory disorders. Early – compensatory with active adaptation, including neurogenic and endothelial regulation mechanisms. Late – decompensation with passive adaptation, supporting the effectiveness of microcirculation due to myogenic control of regulation, shunting and increasing the rate of blood outflow.

Restoration of sinus rhythm does not improve peripheral blood flow in hemodynamically stable patients with atrial fibrillation

Background. Atrial fibrillation (AFib) is the most common atrial tachyarrhythmia with multiple negative hemodynamic consequences. Although there have been many studies on the effects of AFib on cardiac function, very few have focused on changes in peripheral circulation during arrhythmia. Therefore, the aim of the present study was to determine the effect of the reversal of AFib to sinus rhythm (SR) on peripheral blood flow. Material and methods. The forearm blood flow was determined by strain gauge plethysmography (EC 5R, Hokanson, Bellevue, USA) in hemodynamically stable 41 patients aged 63 ± 12 years with paroxysmal or persistent AFib. Venous capacity (VC), venous outflow (VO) and V 0.5–2.0 index, arterial inflow (AI) and fast blood flow (FBF) were measured. 24 patients underwent successful cardioversion. The assessment of peripheral blood flow, BP and HR was performed during arrhythmia and then replicated within 7 day period after restoring of SR. Results. At baseline, plethysmographic parameters, heart rate, systolic and diastolic BP did not differ significantly for patients who underwent successful cardioversion vs. in those who failed to restore SR. Conversion of AFib to SR did not change values of indices characterizing both venous and arterial vessels, values of systolic and diastolic blood pressure, whereas heart rate was significantly reduced. Conclusions. Restoration of sinus rhythm does not improve peripheral blood flow in hemodynamically stable patients with AFib in short term observation.

Peculiarities of microcirculation in peridont tissues in children of key age groups sufficient type 1 diabetes. Part I

The relevance of the research topic.Morpho-functional changes in peripheral circulation established in type 1 diabetes mellitus correlate with changes in central hemodynamics, allowing the use of microcirculation indicators as diagnostic and prognostic criteria for assessing the degree of functional vascular disorders.Purpose– identifcation of microcirculation features of the blood by the method of laser Doppler flowmetry in children with different experience of type 1 diabetes in key age categories.Methods.The study included 67 children with type 1 diabetes mellitus aged 12-15 years with an experience of the disease from six months to ten years. The comparison group consisted of 38 healthy children. The state of the microvasculature was assessed by laser Doppler flowmetry using a laser analyzer for capillary blood flow LAKK-OP.Results.In children with an experience of type 1 diabetes of less than two years, microcirculation disorders in periodontal tissues correspond to the hyperemic form, accompanied by increased perfusion, a decrease in the amplitude of low-frequency oscillations, increased heart rate, high blood flling, and blood flow bypass. For children with an endocrinopathy experience of more than three years, microcirculation disorders correspond to a stagnant form, combined with a decrease in perfusion due to stagnation of blood in the venular link, endothelial domination with suppression of neurogenic and cardiac fluctuations, low effciency and redistribution of blood flow in favor of the nutritive link.Summary.With the increase in experience, the degree of compensation of type 1 diabetes, the progression of diabetic microangiopathy, it is advisable to designate two stages of development of microcirculatory disorders. Early - compensatory with active adaptation, including neurogenic and endothelial regulation mechanisms. Late - decompensation with passive adaptation, supporting the effectiveness of microcirculation due to myogenic control of regulation, shunting and increasing the rate of blood outflow.

Can Blood Flow be Used to Monitor Changes in Peripheral Vascular Function That Occur in Response to Segmental Vibration Exposure?

Laser Doppler blood flow measurements have been used for diagnosis or detection of peripheral vascular dysfunction. This study used a rat tail model of vibration-induced vascular injury to determine how laser Doppler measurements were affected by acute and repeated exposures to vibration, and to identify changes in the Doppler signal that were associated with the exposure. Blood flow was measured immediately after a single exposure to vibration, or before vibration exposure on days 1, 5, 10, 15, and 20 of a 20 days exposure. After a single exposure to vibration, average tail blood flow was reduced. With 20 days of exposure, there was a reduction in the amplitude of the arterial pulse on days 10 to 20 in vibrated rats and days 15 to 20 in control rats. More detailed statistical analyses of laser Doppler data may be needed to identify early changes in peripheral circulation after exposure to vibration.

ОПТИКО-ЕЛЕКТРОННІ ТЕХНОЛОГІЇ ОЦІНЮВАННЯ ЗМІНИ ПЕРИФЕРІЙНОГО КРОВООБІГУ ПРИ ФОТОННОМУ ВПЛИВІ ДЛЯ КОМПЛЕКСНОГО ЛІКУВАННЯ ХРОНІЧНИХ УСКЛАДНЕНЬ ЦУКРОВОГО ДІАБЕТУ

The paper deals with the prospect of using the photoplethysmographic method for the evaluation of microcirculatory changes in peripheral circulation to study the processes that occur during photonic physiotherapy exposure for the complex treatment of chronic complications of diabetes. It is shown that photonic radiation helps to increase the elasticity of the walls of blood vessels, the elasticity of erythrocytes, oxygen transport function of the blood, the activity of cell membranes, the acceleration of processes of tissue regeneration, the reduction of lipid oxidation, the normalization of rheologic indices. After procedures of phototherapy in patients, the syndrome of thermoamputation disappeared, swelling of the legs decreased, as well as significantly decreased pain in the legs, numbness took place, leg cramps stopped. It is shown that photonic radiation of the Barva apparatus leads to anti-inflammatory, desensitizing, analgesic, antispasmodic, and anti-edema actions, which was confirmed in this study in the treatment of patients with complications of diabetes. To control the level of peripheral circulation, a photoplethysmographic method was used, which, compared to other known methods of blood circulation research, has certain advantages, because it allows to conduct studies in both transient and reflected light. It allows to obtain useful information about vascular activity, vascular response to specific substances, as well as to study blood circulation in isolated vessels of different caliber (veins, arteries, etc.). In addition, the photosensor does not cause compression of vessels of biological tissue, that is, does not cause impaired blood circulation. Thus, it is obvious that the most promising direction of registration of physiological parameters is the use of non-invasive methods of diagnosis, among which the wide development has received optical methods of registration and transformation of biomedical information and allows to study microcirculation in human tissues without impaired circulation in the study area, which is essential for medical practice.

Monitoring of the physical exam in sepsis.

Monitoring of mental status and peripheral circulatory changes can be accomplished noninvasively in patients in the ICU. Emphasis on physical examination in conditions such as sepsis have gained increased attention as these evaluations can often serve as a surrogate marker for short-term treatment efficacy of therapeutic interventions. Sepsis associated encephalopathy and mental status changes correlate with worse prognosis in patients. Evaluation of peripheral circulation has been shown to be a convenient, easily accessible, and accurate marker for prognosis in patients with septic shock. The purpose of this article is to emphasize the main findings according to recent literature into the monitoring of physical examination changes in patients with sepsis. Several recent studies have expanded our knowledge about the pathophysiology of mental status changes and the clinical assessment of peripheral circulation in patients with sepsis. Sepsis-associated encephalopathy is associated with an increased rate of morbidity and mortality in an intensive care setting. Increased capillary refill time (CRT) and persistent skin mottling are strongly predictive of mortality, whereas temperature gradients can reveal vasoconstriction and more severe organ dysfunction. Monitoring of physical examination changes is a significant and critical intervention in patients with sepsis. Utilizing repeated neurologic evaluations, and assessing CRT, mottling score, and skin temperature gradients should be emphasized as important noninvasive diagnostic tools. The significance of these methods can be incorporated during the utilization of therapeutic strategies in resuscitation protocols in patients with sepsis.

The Effects of Controlled Physical Training on Peripheral Circulation Following Interventional Treatment of Coronary Artery Disease.

Controlled physical training induces specific changes in the peripheral circulatory system and can lead to positive changes in the vascular perfusion of the lower extremities. The aim of the study was to evaluate changes in peripheral circulation in the calf in patients with acute coronary disease (ACD) undergoing controlled physical training. Impedance plethysmography was used to monitor peripheral circulation during the training. A total of 90 patients were divided into three study groups. Group 1 (n = 30) participated in a two-week cardiac rehabilitation program consisting of interval training on a cycle ergometer and exercise to improve the participants' general physical condition. Group 2 (n = 30) went through the same cardiac rehabilitation program for four weeks. The control group (n = 30) was assigned breathing exercises, active free exercises of the peripheral joints and different muscle groups, and relaxation exercises. All the patients underwent impedance plethysmography tests before and after the training sessions. In Group 1, the systolic slope (PSlope) increased by 2%, pulse wave amplitude (PAmpl) increased by 4.2%, crest time (CT) increased by 1.5% and propagation time (PT) decreased by 1.2% (p > 0.05). In Group 2, the PSlope and PAmpl increased by 19% and 17% respectively, while the CT and PT decreased by 8% and 6.5% respectively (p < 0.05). In the control group, only the CT decreased, by 5% (p < 0.05). The study confirmed that cardiac rehabilitation improves blood flow in lower limb vessels in patients with ACD. The results depend on the duration and the type of physical training. Impedance plethysmography allows for precise and repeatable monitoring of local blood flow.

Does dexmedetomidine have a cardiac protective effect during non-cardiac surgery? A randomised controlled trial.

This study was designed to determine the effects of dexmedetomidine on perioperative myocardial injury by observing peripheral circulatory changes in response to tracheal intubation and extubation, myocardial enzyme levels, myocardial ischaemia improvements, cardiovascular adverse events and cytokines in patients with coronary heart disease (CHD) undergoing non-cardiac surgery. This study was a prospective, randomized, double-blind trial. Eighty patients having CHD were scheduled for elective hip-replacement surgery and randomly allocated to receive a loading dose of 1 μg/kg dexmedetomidine followed by a 0.2 μg/kg per h infusion (Dex group; n = 40) or normal saline (control group; n = 40). Systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, rate-pressure product and changes in ST-T segment on the electrocardiogram were recorded every 5 min during surgery. Serum creatine kinase-MB (CK-MB), cardiac troponin I (cTnI), glycogen phosphorylase BB (GP-BB), interleukin (IL)-6 and tumour necrosis factor (TNF)-α protein levels were determined preoperatively, at the end of surgery and 12 and 24 h after surgery. The improvement rate of myocardial ischaemia was higher in the Dex than control group (87.5% vs 32.5%, respectively; P < 0.05). In addition, the Dex group had lower serum CK-MB, IL-6, cTnI and GP-BB concentrations than the control group (P < 0.05). There was no significance difference in TNF-α between the two groups (P > 0.05). Dexmedetomidine can reduce myocardial injury and cytokine levels in patients with CHD undergoing non-cardiac surgery.

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The relation of near-infrared spectroscopy with changes in peripheral circulation in critically ill patients*

We conducted this observational study to investigate tissue oxygen saturation during a vascular occlusion test in relationship with the condition of peripheral circulation and outcome in critically ill patients. Prospective observational study. Multidisciplinary intensive care unit in a university hospital. Seventy-three critically ill adult patients admitted to the intensive care unit. None. Patients were followed every 24 hrs until day 3 after intensive care admission. Near-infrared spectroscopy was used to measure thenar tissue oxygen saturation, tissue oxygen saturation deoxygenation rate, and tissue oxygen saturation recovery rate after the vascular occlusion test. Measurements included heart rate, mean arterial pressure, forearm-to-fingertip skin-temperature gradient, and physical examination of peripheral perfusion with capillary refill time. Patients were stratified according to the condition of peripheral circulation (abnormal: forearm-to-fingertip skin-temperature gradient ≥4 and capillary refill time >4.5 secs). The outcome was defined based on the daily Sequential Organ Failure Assessment score and blood lactate levels. Upon intensive care unit admission, 35 (47.9%) patients had abnormal peripheral perfusion (forearm-to-fingertip skin-temperature gradient >4 or capillary refill time >4.5 secs). With the exception of the tissue oxygen saturation deoxygenation rate, tissue oxygen saturation baseline and tissue oxygen saturation recovery rate were statistically lower in patients who exhibited abnormal peripheral perfusion than in those with normal peripheral perfusion: 72 ± 9 vs. 81 ± 9; p = .001 and 1.9 ± 0.7 vs. 3.2 ± 0.9; p = .001, respectively. When a mixed-model analysis was performed over time for estimate (s) calculation, adjusted to the condition of disease, we did not find a significant clinical effect between vascular occlusion test-derived tissue oxygen saturation measurements (as response variables) and mean systemic hemodynamic variables (as independent variables): tissue oxygen saturation vs. heart rate: s (95% confidence interval) = 0.007 (-0.08; 0.09); tissue oxygen saturation vs. mean arterial pressure: s (95% confidence interval) = -0.02 (-0.12; 0.08); tissue oxygen saturation deoxygenation rate vs. heart rate: s (95% confidence interval) = 0.002 (-0.0004; 0.006); tissue oxygen saturation deoxygenation rate vs. mean arterial pressure: s (95% confidence interval) - 0.0007 (-0.003; 0.004); tissue oxygen saturation recovery rate vs. heart rate: s (95% confidence interval) = -0.009 (-0.02; -0.0015); tissue oxygen saturation recovery rate vs. mean arterial pressure: s (95% confidence interval) = 0.01 (0.002; 0.018). However, there was a strong association between tissue oxygen saturation baseline and tissue oxygen saturation recovery rate with abnormal peripheral perfusion: tissue oxygen saturation vs. abnormal peripheral perfusion: s (95% confidence interval) = -10.1 (-13.9; -6.2); tissue oxygen saturation recovery rate vs. abnormal peripheral perfusion: s (95% confidence interval) =-10.1 (-13.9; -6.2); tissue oxygen saturation recovery rate vs. abnormal peripheral perfusion: s (95% confidence interval) = -1.1 (-1.4; -0.81). Poor outcome was more closely related to abnormalities in peripheral perfusion than to tissue oxygen saturation-derived parameters. We found that the condition of peripheral circulation in critically ill patients strongly influences tissue oxygen saturation resting values and the tissue oxygen saturation reoxygenation rate but not the tissue oxygen saturation deoxygenation rate. In addition, changes in near-infrared spectroscopy-derived variables were independent of condition of disease and were not accompanied by any major differences in systemic hemodynamic variables.

Effects of transdermal estrogen administration on peripheral vascular responsiveness in menopausal women

This study was designed to evaluate the peripheral vascular responses to acute estrogen replacement. According to a cross-over, double-blind study design, we randomized nine healthy postmenopausal women (time lapse from menopause to >1 year; mean age±SD 45.4±11.7 years) to treatment with transdermal patches of estradiol-17β or matched placebo. The estrogen patch was rated to assure a plasma concentration of substance of more than 100 pg/ml after 8–10 hours of treatment. Forearm blood flow (ml/100 ml/minute), local vascular resistance (mmHg/ml/100 ml/minute), venous volume (ml/100 ml), and venous compliance (ml/100 ml/mmHg) were measured in supine resting subjects by the straingauge venous occlusion plethysmography. Plasma concentration of norepinephrine (pg/ml) was quantified by HPLC-ED. Estradiol-17β produced increase in forearm blood flow and decrease in local vascular resistance. The drug reduced circulating norepinephrine concentrations. There were no significant changes in mean arterial pressure or heart rate. Venous volume and venous compliance were both enhanced by estrogen administration. The peripheral circulatory changes are attributed to a direct activity of estradiol-17β on arterial and venous wall and may in part reflect a modulation of estrogen on peripheral sympathetic tone.

Effects of peripheral vasodilation induced by regional anaesthesia blocks on resting tissue oxygenation values

Near-infrared spectroscopy is a technique for continuous, noninvasive, bedside monitoring of tissue oxygenation (StO2). The nature of the relationship between the kinetics of StO2 and changes in peripheral circulation has not been investigated. After successful regional anaesthesia blocks, local vasodilation and increased local blood flow occur as a result of blockade of sympathetic nerve fibers. We therefore studied the effects of peripheral vasodilation induced by regional anaesthesia blocks on resting StO2 values.

Effects of single low-temperature sauna bathing in patients with severe motor and intellectual disabilities

We have previously reported that thermal vasodilation following warm-water bathing and low-temperature sauna bathing (LTSB) at 60 degrees C for 15 min improves the cardiac function in patients with congestive heart failure. Through a comparative before-and-after study, we studied the hemodynamic and clinical effects of single exposure to LTSB in cerebral palsy (CP) patients who usually suffer from chilled extremities and low cardiac output. The study population comprised 16 patients ranging between 19 and 53 years with severe motor and intellectual disabilities. Noninvasive methods were used to estimate the systemic and peripheral circulatory changes before and after LTSB. Using blood flow velocity analysis, the pulsatile and resistive indexes of the peripheral arteries of the patients' lower limbs were calculated. Following LTSB, the patients' deep body temperature increased significantly by 1 degrees C. Their heart rates increased and blood pressure decreased slightly. The total peripheral resistance decreased by 11%, and the cardiac output increased by 14%. There was significant improvement in the parameters that are indicative of the peripheral circulatory status, including the skin blood flow, blood flow velocity, pulsatile index, and resistive index. Numbness and chronic myalgia of the extremities decreased. There were no adverse side effects. Thus, it can be concluded that LTSB improves the peripheral circulation in CP patients.

Vascular reactivity at different sites in preeclampsia-is there a correlation?

ObjectivePreeclampsia (PET) is associated with a disordered circulatory changes in the brain and the peripheral circulation as evidenced by changes in brachial artery Flow Mediated Vascular Dilation (FMVD) and estimated Cerebral Perfusion Pressure (eCPP). This study investigates whether the peripheral circulatory changes correlate with changes in the central cerebral circulation.Study design20 normotensive, 10 PET patients were assessed. Transcranial Doppler monitoring of the middle cerebral artery in the mother was performed and we recorded Mean and Diastolic Blood Presure and Mean and Diastolic Middle Cerebral Blood Flow Velocity (MCBFV). We calculated the eCPP according to the following equation eCPP = Vmean/(Vmean-Vdiastolic) × (BPmean – BPdiastolic). Following this FMVD of the brachial artery was measured post cuff release. We assessed the maximum brachial artery dilatation in each patient. The means were compared between the groups using student t tests and Correlation coefficient between FMVD and eCPP was measured in each of the 2 groups.ResultseCPP was significantly higher in the PET vs. the normotensive group (91.4±15.7 vs 56.9±11.5) P<.001). FMVD was significantly lower in the PET than the normotensive group (5.0±2.7 vs 8.2±2.9)(P<.022). There was poor correlation between FMVD and eCPP in the 2 groups. PET (R=.546), Normotensive (R=.498)ConclusionPreeclampsia is a multisystem disorder of generalized vasculopathy with multiple organ systems being affected. This study identifies that the peripheral vascular bed (FMVD) and cerebral circulation (eCPP) undergo significant changes in preeclampsia but these changes are independent components of the disease process. Vascular dysfunction occurring in one organ system cannot be used to predict dysfunction in another organ system. ObjectivePreeclampsia (PET) is associated with a disordered circulatory changes in the brain and the peripheral circulation as evidenced by changes in brachial artery Flow Mediated Vascular Dilation (FMVD) and estimated Cerebral Perfusion Pressure (eCPP). This study investigates whether the peripheral circulatory changes correlate with changes in the central cerebral circulation. Preeclampsia (PET) is associated with a disordered circulatory changes in the brain and the peripheral circulation as evidenced by changes in brachial artery Flow Mediated Vascular Dilation (FMVD) and estimated Cerebral Perfusion Pressure (eCPP). This study investigates whether the peripheral circulatory changes correlate with changes in the central cerebral circulation. Study design20 normotensive, 10 PET patients were assessed. Transcranial Doppler monitoring of the middle cerebral artery in the mother was performed and we recorded Mean and Diastolic Blood Presure and Mean and Diastolic Middle Cerebral Blood Flow Velocity (MCBFV). We calculated the eCPP according to the following equation eCPP = Vmean/(Vmean-Vdiastolic) × (BPmean – BPdiastolic). Following this FMVD of the brachial artery was measured post cuff release. We assessed the maximum brachial artery dilatation in each patient. The means were compared between the groups using student t tests and Correlation coefficient between FMVD and eCPP was measured in each of the 2 groups. 20 normotensive, 10 PET patients were assessed. Transcranial Doppler monitoring of the middle cerebral artery in the mother was performed and we recorded Mean and Diastolic Blood Presure and Mean and Diastolic Middle Cerebral Blood Flow Velocity (MCBFV). We calculated the eCPP according to the following equation eCPP = Vmean/(Vmean-Vdiastolic) × (BPmean – BPdiastolic). Following this FMVD of the brachial artery was measured post cuff release. We assessed the maximum brachial artery dilatation in each patient. The means were compared between the groups using student t tests and Correlation coefficient between FMVD and eCPP was measured in each of the 2 groups. ResultseCPP was significantly higher in the PET vs. the normotensive group (91.4±15.7 vs 56.9±11.5) P<.001). FMVD was significantly lower in the PET than the normotensive group (5.0±2.7 vs 8.2±2.9)(P<.022). There was poor correlation between FMVD and eCPP in the 2 groups. PET (R=.546), Normotensive (R=.498) eCPP was significantly higher in the PET vs. the normotensive group (91.4±15.7 vs 56.9±11.5) P<.001). FMVD was significantly lower in the PET than the normotensive group (5.0±2.7 vs 8.2±2.9)(P<.022). There was poor correlation between FMVD and eCPP in the 2 groups. PET (R=.546), Normotensive (R=.498) ConclusionPreeclampsia is a multisystem disorder of generalized vasculopathy with multiple organ systems being affected. This study identifies that the peripheral vascular bed (FMVD) and cerebral circulation (eCPP) undergo significant changes in preeclampsia but these changes are independent components of the disease process. Vascular dysfunction occurring in one organ system cannot be used to predict dysfunction in another organ system. Preeclampsia is a multisystem disorder of generalized vasculopathy with multiple organ systems being affected. This study identifies that the peripheral vascular bed (FMVD) and cerebral circulation (eCPP) undergo significant changes in preeclampsia but these changes are independent components of the disease process. Vascular dysfunction occurring in one organ system cannot be used to predict dysfunction in another organ system.

Effect of a short period of abstinence from smoking on rewarming patterns of the hands following local cooling

The purpose of the study was to examine the effect of a 12 h period of abstinence from smoking in young and old habitual smokers, on skin rewarming patterns of a hand following local cooling. This was done by comparing changes in peripheral circulation, measured indirectly by monitoring changes in skin surface temperatures of the hand with both infrared (IR) thermography and thermocouples before, during and after immersing the right hand for 2 min in water at 10 degrees C. Included in the study were young male non-smokers (n = 14) and smokers (n = 13), and elderly non-smokers (n = 12) and smokers (n = 14). The results showed no statistically significant difference between young non-smokers and smokers when comparing their response to the local cold challenge. The elderly smokers had a significantly higher hand skin temperature prior to cooling (34.0 +/- 0.2 degrees C) and after 80% rewarming (32.1 +/- 0.2 degrees C) (i.e. when the skin temperature in the "cooled" hand has regained 80% of the cold induced drop in temperature), compared to elderly non-smokers (33.3 +/- 0.2 and 31.3 +/- 0.2 degrees C, respectively). The elderly smoking subjects also had a faster recovery after cooling (9.7 +/- 0.8 min) than the elderly non-smoking subjects (16.7 +/- 2.6 min). A follow-up study with seven elderly smokers, who had smoked as usual until 2 h before the experiment, showed responses lying between the non-smokers and smokers who had had a longer period of abstinence (12 h) from smoking. In conclusion, we have demonstrated using IR-thermal imaging that elderly subjects who have smoked for many years have slightly warmer hand skin temperature when they abstain from smoking. Even a period of abstinence from smoking of a few hours can affect the way in which elderly subjects respond to a local cold challenge, recovering more rapidly then their non-smoking counterparts.

Effect of central hypothyroidism on Doppler-derived myocardial performance index

Background Myocardial performance index (MPI) has been used to assess global ventricular function in different types of cardiac disease. Thyroid hormones influence cardiac performance directly and indirectly by changes in peripheral circulation. The aim of this study was to evaluate the possible effect of central hypothyroidism (CH) on MPI. Methods The study included 28 control subjects and 7 patients with CH without cardiac disease. MPI was defined as the sum of isovolumetric contraction time (ICT) and isovolumetric relaxation time divided by ejection time. Patients were submitted to hormonal therapy with thyroxin and the study was repeated after 35 to 42 days. Results MPI was significantly higher in patients with CH (0.54 ± 0.08) than in control subjects (0.40 ± 0.05) ( P = .002). The increase in MPI was caused by the prolongation of ICT without a significant variation of isovolumetric relaxation time and ejection time. After hormonal therapy there was a significant reduction of MPI (0.54 ± 0.08 vs 0.42 ± 0.07; P = .028) and ICT. Conclusion MPI was increased in patients with untreated CH. The increase was related to prolongation of ICT and reverted by hormonal therapy.

Effect of thyroid hormones on cardiac function, geometry, and oxidative metabolism assessed noninvasively by positron emission tomography and magnetic resonance imaging.

Thyroid hormones influence cardiac performance directly and indirectly via changes in peripheral circulation. Little, however, is known about the effect on myocardial oxidative metabolism and its relation to cardiac function and geometry. Patients with a history of thyroidectomy for thyroid cancer present a unique model to investigate the cardiac effects of hypothyroidism. Ten patients without heart disease were investigated in the hypothyroid state and again 4-6 weeks later under euthyroid conditions. Myocardial oxidative metabolism was measured by positron emission tomography with [11C]acetate and the clearance constant k(mono). Cine magnetic resonance imaging was applied to determine left ventricular geometry. A stroke work index (SWI = stroke volume x systolic blood pressure/ventricular mass) was calculated. Then, to estimate myocardial efficiency, a work metabolic index [WMI = SWI x heart rate/k(mono)] was obtained. Compared to hormone replacement, systemic vascular resistance and left ventricular mass were significantly higher in hypothyroidism. Ejection fraction and SWI were significantly lower. Despite an additional reduction of k(mono), the WMI was significantly lower, too. In summary, cardiac oxygen consumption is reduced in hypothyroidism. This reduction is associated with increased peripheral resistance and reduced contractility. Estimates of cardiac work are more severely suppressed than those of oxidative metabolism, suggesting decreased efficiency. These findings may provide an explanation for development or worsening of heart failure in hypothyroid patients with preexisting heart disease.