Cerebral blood flow and heart rate variability in chronic fatigue syndrome : a randomized cross-over study

Background: Pain, fatigue, and concentration difficulties are typical features of chronic fatigue syndrome (CFS). The exact underlying mechanisms of these symptoms are still unknown, but available evidence suggests an important role for impaired pain modulation. As evidence also suggests that pain modulation is related to cardiovascular mechanisms, it seems logical to investigate whether cerebral blood flow (CBF) and heart rate variability (HRV) are altered in these patients. Objectives: We aimed to investigate the role of the cardiovascular system in pain modulation and symptoms of CFS; the response of CBF and HRV to physical stress and their relation to the change in temporal summation (TS) of pressure pain and self-reported symptoms was evaluated. Study Design: A controlled, randomized cross-over trial. Setting: University Hospital Brussels. Methods: Twenty CFS patients and 20 sedentary healthy controls were included in this study. In both of the groups, the change in TS of pressure pain, CBF (using transcranial Doppler), and HRV (using finger plethysmography) was examined during physical and emotional stress (to control for potential bias), as well as their association mutually and with self-reported symptoms of pain, fatigue, and concentrations difficulties. Results: There was no significant interaction or group (F-values ranging from .100 to 1.862, P-values ranging from .754 to .181) effect in CBF or HRV parameters. HRV and CBF did change during physical exercise, but the changes did not differ between patients and controls. While pain scores during TS at the trapezius site reduced in the control group after the physical exercise protocol (P=.037), they did not change in the CFS group (P=.108), suggesting impaired pain modulation. There were no significant correlations between CBF, HRV, TS, and self-reported symptoms (all P-values of correlation analyses > .01). Limitations: Although effect sizes were medium to large, the study sample was relatively low. Also, the mild nature of the exercise bout is discussable. Nonetheless, this mild exercise was able to provoke endogenous pain modulation in the control group, which endorsed a proper execution of the cycling exercise. Moreover, mild exercises are more applicable to daily physical activities in CFS patients than vigorous exercises. Conclusion: These results seem to refute the previously suggested alterations of CBF/HRV in CFS patients. These cardiovascular parameters appear not to explain pain before, during, and following exercise

Feasibility of AmbulanCe-Based Telemedicine (FACT) Study:Safety, Feasibility and Reliability of Third Generation Ambulance Telemedicine

Telemedicine is currently mainly applied as an in-hospital service, but this technology also holds potential to improve emergency care in the prehospital arena. We report on the safety, feasibility and reliability of in-ambulance teleconsultation using a telemedicine system of the third generation.A routine ambulance was equipped with a system for real-time bidirectional audio-video communication, automated transmission of vital parameters, glycemia and electronic patient identification. All patients ( ≥ 18 years) transported during emergency missions by a Prehospital Intervention Team of the Universitair Ziekenhuis Brussel were eligible for inclusion. To guarantee mobility and to facilitate 24/7 availability, the teleconsultants used lightweight laptop computers to access a dedicated telemedicine platform, which also provided functionalities for neurological assessment, electronic reporting and prehospital notification of the in-hospital team. Key registrations included any safety issue, mobile connectivity, communication of patient information, audiovisual quality, user-friendliness and accuracy of the prehospital diagnosis.Prehospital teleconsultation was obtained in 41 out of 43 cases (95.3%). The success rates for communication of blood pressure, heart rate, blood oxygen saturation, glycemia, and electronic patient identification were 78.7%, 84.8%, 80.6%, 64.0%, and 84.2%. A preliminary prehospital diagnosis was formulated in 90.2%, with satisfactory agreement with final in-hospital diagnoses. Communication of a prehospital report to the in-hospital team was successful in 94.7% and prenotification of the in-hospital team via SMS in 90.2%. Failures resulted mainly from limited mobile connectivity and to a lesser extent from software, hardware or human error. The user acceptance was high.Ambulance-based telemedicine of the third generation is safe, feasible and reliable but further research and development, especially with regard to high speed broadband access, is needed before this approach can be implemented in daily practice

Development and Pilot Testing of 24/7 In-Ambulance Telemedicine for Acute Stroke:Prehospital Stroke Study at the Universitair Ziekenhuis Brussel-Project

Background: In-ambulance telemedicine is a recently developed and a promising approach to improve emergency care. We implemented the first ever 24/7 in-ambulance telemedicine service for acute stroke. We report on our experiences with the development and pilot testing of the Prehospital Stroke Study at the Universitair Ziekenhuis Brussel (PreSSUB) to facilitate a wider spread of the knowledge regarding this technique. Methods: Successful execution of the project involved the development and validation of a novel stroke scale, design and creation of specific hardware and software solutions, execution of field tests for mobile internet connectivity, design of new care processes and information flows, recurrent training of all professional caregivers involved in acute stroke management, extensive testing on healthy volunteers, organisation of a 24/7 teleconsultation service by trained stroke experts and 24/7 technical support, and resolution of several legal issues. Results: In all, it took 41 months of research and development to confirm the safety, technical feasibility, reliability, and user acceptance of the PreSSUB approach. Stroke-specific key information can be collected safely and reliably before and during ambulance transportation and can adequately be communicated with the inhospital team awaiting the patient. Conclusion: This paper portrays the key steps required and the lessons learned for successful implementation of a 24/7 expert telemedicine service supporting patients with acute stroke during ambulance transportation to the hospital. (C) 2016 S. Karger AG, Base

Heart rate variability and baroreceptor sensitivity in acute stroke:a systematic review

BackgroundAutonomic nervous system dysfunction is common after acute stroke and is associated with elevated risk of cardiac arrhythmia and mortality. Heart rate variability and baroreceptor sensitivity have been investigated as parameters of autonomic nervous system dysfunction for the prediction of stroke outcome. SummaryWe performed a systematic literature review on heart rate variability and baroreceptor sensitivity as parameters for autonomic nervous function in acute stroke. Twenty-two studies were included. Associations between heart rate variability or baroreceptor sensitivity and stroke severity, early and late complications, dependency and mortality were reported. However, interpretability of most studies and extrapolation to general stroke population are limited due to many confounding factors such as varying methodology, small sample sizes, survival selection, and exclusion of patients with frequently occurring comorbidities in stroke. Key issues, such as the effect of thrombolytic therapy on autonomic function, autonomic nervous system dysfunction in the hyperacute phase of stroke, and correlation with the risk of recurrent stroke have not been investigated. Also, nonlinear techniques have remained largely unexplored in this domain, in spite of their advantage to provide more solid evaluation in the occurrence of arrhythmia. Key messagesCardiac autonomic dysfunction, represented by reduced heart rate variability or impaired baroreceptor sensitivity, is associated with stroke severity, early and late complications, dependency, and mortality. Large-scale prospective studies applying internationally accepted standards of measures for analysis of heart rate variability and baroreceptor sensitivity are needed in patients with acute stroke

Feasibility, Reliability and Predictive Value Of In-Ambulance Heart Rate Variability Registration

Background Heart rate variability (HRV) is a parameter of autonomic nervous system function. A decrease of HRV has been associated with disease severity, risk of complications and prognosis in several conditions. Objective We aim to investigate the feasibility and the reliability of in-ambulance HRV registration during emergency interventions, and to evaluate the association between prehospital HRV parameters, patient characteristics, vital parameters and short-term outcome. Methods We conducted a prospective study using a non-invasive 2-lead ECG registration device in 55 patients transported by the paramedic intervention team of the Universitair Ziekenhuis Brussel. HRV assessment included time domain parameters, frequency domain parameters, nonlinear analysis, and time-frequency analysis. The correlation between HRV parameters and patient and outcome characteristics was analyzed and compared to controls. Results Artifact and ectopic detection rates were higher in patients during ambulance transportation compared to controls in resting conditions, yet technical reasons precluding in-ambulance HRV analysis occurred in only 9.6% of cases. HRV acquisition was possible without safety issues or interference with routine emergency care. Reliability of the results was considered sufficient for Sample entropy (SampEn), good for the ratio of low frequency and high frequency components (LF/HF ratio) in the frequency and the time frequency domain, and excellent for the triangular interpolation of the NN interval histogram (TINN), and for the short-term scaling exponent of the detrended fluctuation analysis (DFA alpha 1). HRV indices were significantly reduced inpatients with unfavorable outcome compared to patients with favorable outcome and controls. Multivariate analysis identified lower DFA alpha 1 as an independent predictor of unfavorable outcome (OR, 0.155; 95% CI 0.024-0.966; p = 0.049). Conclusion In-ambulance HRV registration is technically and operationally feasible and produces reliable results for parameters in the time, frequency, nonlinear and time frequency domain. Especially non-linear HRV analysis during emergency ambulance transportation may be a promising approach to predict patient outcome

Validation assessment of risk tools to predict outcome after thrombolytic therapy for acute ischemic stroke

Objective: We evaluated the reliability of eight clinical prediction models for symptomatic intracerebral hemorrhage (sICH) and long-term functional outcome in stroke patients treated with thrombolytics according to clinical practice. Methods: In a cohort of 169 patients, 60 patients (35.5%) received IV rtPA according to the European license criteria. The remaining patients received off-label IV rtPA and/or were treated with intra-arterial thrombolysis. We used receiver operator characteristic curves to analyze the discriminative capacity of the MSS score, the HAT score, the SITS SICH score, the SEDAN score and the GRASPS score for sICH according to the NINDS and the ECASSII criteria. Similarly, the discriminative capacity of the s-TPI, the iScore and the DRAGON score were assessed for the modified Rankin Scale (mRS) score at 3 months poststroke. An area under the curve (c-statistic) >0.8 was considered to reflect good discriminative capacity. The reliability of the best performing prediction model was further examined with calibration curves. Separate analyses were performed for patients meeting the European license criteria for IV rtPA and patients outside these criteria. Results: For prediction of sICH c-statistics were 0.66-0.86 and the MMS yielded the best results. For functional outcome c-statistics ranged from 0.72 to 0.86 with s-TPI as best performer. The s-TPI had the lowest absolute error on the calibration curve for predicting excellent outcome (mRS 0-1) and catastrophic outcome (mRS 5-6). Conclusions: All eight clinical models for outcome prediction after thrombolysis for acute ischemic stroke showed fair predictive value in patients treated according daily practice. The s-TPI had the best discriminatory ability and was well calibrated in our study population. (C) 2014 Elsevier B.V. All rights reserved