ABSTRACT
Objective To explore the impact and protective mechanisms of head cooling on neural activity during passive hyperthermia.Methods Sixteen subjects were randomly exposed for 1 h to three different conditions: normal (25℃), hot (50℃) and head cooling (chamber:50℃,cold packs:5℃),after environment exposure, rs-fMRI were performed.Regional homogeneity(ReHo) datum at three different conditions were analyzed by REST2.0 to obtain brain areas with statistical difference.Brain voxel with statistical difference were selected as ROIs to ReHo values and were analyzed by One-Way ANOVA with SPSS18.0.Neural activity of brain areas with statistical difference were compared in any two groups by Post hoc.Results The brain regions showing differences among three groups included right orbital frontal cortex,left middle frontal gyrus,bilateral amygdala,left middle temporal gyrus,left hippocampus,bilateral parietal inferior, left precentral gyrus.Compared with normal group, ReHo increased in right orbital frontal cortex, and decreased in left precentral gyrus,left middle frontal gyrus,left parietal inferior,but no changed in bilateral amygdala,left middle temporal gyrus,left hippocampus,right parietal inferior in head cooling group.Compared with hot group,head cooling group showed increased ReHo in left middle temporal gyrus,left hippocampus,right parietal inferior,and decreased ReHo in bilateral amygdala,left parietal inferior,unchanged ReHo in right orbital frontal cortex, left precentral gyrus, left middle frontal gyrus.Conclusion The specified alterations of ReHo may reflect that the head cooling could partially eliminate the impact of passive hyperthermia, and is closely linked with emotional function.
ABSTRACT
Objective To explore the causal influences between activated regions in executive control network when participants were performing attention network test (ANT)under passive hyperthermia using Granger causality analysis.Methods Thirty male healthy participants which were randomly divided into control group (n=1 5)and experimental group (n=1 5)performed ANT task during two thermal conditions:hyperthermic condition (50℃)and normothermic condition (20℃)during functional magnetic reso-nance imaging.The data processing was performed using statistical parametric mapping 8 (SPM8).Granger causality analysis was performed on the resulted activated regions,as well as the correlations of the GC values with the reaction time in both groups.Results Between-group comparisons on Granger causality analysis revealed significantly enhanced influences of anterior cingulate gyrus and right inferior parietal lobule on dorsolateral prefrontal cortex,and bidirectional influences between dorsolateral prefrontal cortex and right superior parietal lobule,but decreased influence between right superior parietal lobule and right inferior parietal lobule.The correlation analysis showed significant correlation between GC value of right superior parietal lobule to dorsolateral prefrontal cortex and the reaction time in control group (r=-0.558,P =0.031),but yet there was no significant correlation in experimental group (r=0.355,P =0.257).Conclusion Heat stress affected the causal influences within the executive control network,which subse-quently disrupted the executive control performance during passive hyperthermia.
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Objective To explore the changes of different brain regions of the human beings during completion of spatial working memory tasks under hyperthermia condition with functional magnetic yesonance.Methods Twenty-eight right-handed healthy young male volunteers were divided into control group and hyperthermia group randomly,and working memory task using block design was performed during behavioral test and fMRI scanning on both conditions.Activation intensity and location of different brain areas were compared in control and hyperthermia group.Results The activations of frontal,parietal,occipital and insular lobe were seen in both of the control group and the hyperthermia group.Right lateralization was shown in control group during spatial working memory (Li=0.05 1).While,in hyperthermia group the effect of the right lateralization significantly was enhanced (Li=0.103). Moreover,activation of bilateral middle frontal gyrus and right parietal lobe were significantly enhanced.Conclusion It is found for the first time that the hyperthermia could affect bilateral middle frontal gyrus and right parietal lobe,and enhance the effect of right lateralization in the spatial working memory task.
ABSTRACT
To realize the measurement of the chest compression depth during the administration of manual cardiopulmonary resuscitation, two 3-axis digital accelerometers were applied for chest compression acceleration and environment acceleration acquisition, with one placed in the chest compression sensor pad, and the other placed in the back sensor pad. Then double integration was made for the acceleration-to-depth conversion with both of the accelerations after preprocessing. The method further included integration reset mechanism based on compression force, with the force point of a pre-determined threshold and the maximum force point as the starting point and the ending point of the integration, respectively. Moreover, a software compensation algorithm was implemented to further increase the accuracy of the depth estimation and reliability of the acceleration. The final performance of the compression depth estimation is within +/- 0.6 cm with 95% confidence of a total of 283 compressions. Accurate and real-time estimation of chest compression depth greatly facilitates the control of compression depth for the lifesaver during manual cardiopulmonary resuscitation.
Subject(s)
Humans , Acceleration , Cardiopulmonary Resuscitation , Methods , Heart Arrest , Therapeutics , Heart Massage , Methods , Reference Standards , Pressure , ThoraxABSTRACT
To have a thorough understanding of the CPR quality based on patients' various physiological states, the doctors must do something to simulate the chest compression physiological feedback parameters (CCPFP). The CCPFP simulation plays an important role in raising efficiency of CPR training and improving chest compression quality. In this study, the CCPFP, including cardiac output (CO), coronary perfusion pressure (CPP), partial pressure of End-tidal CO2 (PETCO2) and mean arterial relaxation pressure (MARP), was simulated using Charles F. Babbs' Model. Simulation results showed that the effect of compression depth upon CCPFP was important in the range of 2-6 cm, whereas compression rate had little effect on the CCPFP higher than 100/min; the thoracic factor is inversely proportional to the CCPFP with fixed compression depth and compression rate. The CCPFP simulation can be implemented at the various physiological statuses, and verified well with the animal experimental results and the clinical results.