• Journal of the Optical Society of Korea
• /
• v.13 no.1
• /
• pp.166-170
• /
• 2009

NIRS (Near-infrared spectroscopy) is a relatively, new, non-invasive, and non-ionizing method of measuring hemodynamic responses in thick biological tissues such as the cerebral cortex. In this study, we measured the hemodynamic responses of the rat barrel cortex to whisker stimulation by using a frequency-domain NIRS system. We designed multiple optical probes comprising multi-mode optical fibers and manipulating arms, both of which can be easily applied to small animals. Various electrical stimulations were applied to rat whiskers at different voltage levels and stimulation frequencies. Our results show that the hemodynamic responses are highly dependent on the stimulation voltage level, and not so much on stimulation frequency. This paper suggests that NIRS technology is highly suitable for the study of small animal brains.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.7
• /
• pp.1049-1055
• /
• 2012

We measure the hemodynamic responses during the 4 kinds of tasks on the motor cortex in the right and left human brain by using near-infrared spectroscopy. The experimental results show that the change of concentration of oxy-hemoglobin is larger than that of deoxy-hemoglobin and the change of concentration of chromophores induced by finger and arm related task show more activations than that of leg.

• Proceedings of the Optical Society of Korea Conference
• /
• 2009.02a
• /
• pp.427-428
• /
• 2009

Optical imaging offers excellent spatio-temporal sensitivity that is unparalleled by any other perfusion based imaging techniques. We used in vivo optical recording of intrinsic signals (ORIS) to map neurovascular hemodynamics of perfusion, oximetry and membrane potential during epileptic events in rat and mouse neocortex. Studies of hemodynamic changes with ORIS alone were also performed in human. Laboratory studies in rodent epilepsy models have demonstrated a persistent increase in deoxygenated hemoglobin (Hbr) and a decrease in tissue oxygenation during interictal spikes and ictal events. This "epileptic dip", like the "initial dip" recorded during normal sensory processing, implies that the enormous rise in cerebral blood flow (CBF) is inadequate to meet the increased metabolic demands associated with synchronized epileptic activity. These findings are critically important to the interpretation of the perfusion-based imaging studies, such as fMRI. In addition, we visualized the effect of direct cortical electrical stimulation, an alterative epilepsy treatment. The optical data following direct cortical electrical stimulation showed that hemodynamic signals are sensitive to different electrical stimulation parameters. Furthermore, our recent data demonstrated that the application of unilateral electrical stimulation is able to elicit bilateral hemodynamic responses in rat neocortex.

• The Korean Journal of Pain
• /
• v.10 no.1
• /
• pp.58-63
• /
• 1997

Background : Endotracheal intubation is one of the methods most securely establishing airway. But accompanying hemodynamic responses are harmful to coronary or cerebral vascular disease patients. These hemodynamic responses are regarded as the results of sympathetic stimulation due to pharyngolaryngeal stimulation, and sympathetic blocking method-stellate ganglion block- may be obtundate these hemodynamic responses. Methods : 75 patients of ASA physical status I-II were selected. There were 40 patients normotensive (Group I), 35 patients hypertensive (Group II) Group I, steliate ganglion block was performed on 20 patients (Group I-S) the remainder had no procedure (Group I-O). Group II, 18 patients received SG3 (Group II-S), 17 patients had no procedure (Group II-O). SGB was performed with 1% lidocaine 8 ml on right stellate genglion after patient's consent. Blood pressure (IIP) and pulse rate(PR) were first measured in the pre-anesthesia room. Follow up BP and PR are checked immediately following SGB and every 5 minutes for subsequent 20 minutes, then after arrival at operatig room, then immediately after intubation and at 3, 5, 10, 15 and 20 minutes after incubation. Results : All group experienced significantly increased blood pressure and pulse rate upon arrival at the pre-anesthesetic and opeating rooms, as compared to when patients rates in the ward. After intubation and for subsequent 5 minutes, significant changes were measured. Patients then recovered to preblock value. In Group I, no statistical significance was recorded between subgroup I-S and I-O. However in Group II, there were significant differences between sub-group II-S and II-O. In evaluating pulse rate changes, there were no significant differences between Group I-S and I-O; nor II-S and II-O. Conclusion : The proper diagnosis of Stellate Ganglion Block had some measure of protective effect on hemodynamics following endotracheal intubation, especially in hypertensive patients.

• Journal of Dental Anesthesia and Pain Medicine
• /
• v.20 no.4
• /
• pp.195-202
• /
• 2020

Background: Nasotracheal intubation is the most commonly used method to secure the field of view when performing surgery on the oral cavity or neck. Like orotracheal intubation, nasotracheal intubation uses a laryngoscope. Hemodynamic change occurs due to the stimulation of the sympathetic nervous system. Recently, video laryngoscope with a camera attached to the end of the direct laryngoscope blade has been used to minimize this change. In this study, we investigated the optimal effect-site concentration (Ce) of remifentanil for minimizing hemodynamic responses during nasotracheal intubation with a video laryngoscope. Methods: Twenty-one patients, aged between 19 and 60 years old, scheduled for elective surgery were included in this study. Anesthesia was induced by slowly injecting propofol. At the same time, remifentanil infusion was initiated at 3.0 ng/ml via target-controlled infusion (TCI). When remifentanil attained the preset Ce, nasotracheal intubation was performed using a video laryngoscope. The patient's blood pressure and heart rate were checked pre-induction, right before and after intubation, and 1 min after intubation. Hemodynamic stability was defined as an increase in systolic blood pressure and heart rate by 20% before and after nasotracheal intubation. The response of each patient determined the Ce of remifentanil for the next patient at an interval of 0.3 ng/ml. Results: The Ce of remifentanil administered ranged from 2.4 to 3.6 ng/ml for the patients evaluated. The estimated optimal effective effect-site concentrations of remifentanil were 3.22 and 4.25 ng/ml, that were associated with a 50% and 95% probability of maintaining hemodynamic stability, respectively. Conclusion: Nasotracheal intubation using a video laryngoscope can be successfully performed in a hemodynamically stable state by using the optimal remifentanil effect-site concentration (Ce₅₀, 3.22 ng/ml; Ce₉₅, 4.25 ng/ml).

• Proceedings of the Korean Society of Veterinary Pathology Conference
• /
• 2000.09a
• /
• pp.19-19
• /
• 2000

Most renal diseases progress by consecutive cell responses such as hypertrophy, hyperplsia, proliferation, defferentiation, sclerosis, fibrosis and other cellular degenerative process. These cellular responses are mediated by the activation of various mitogens such as vasoconstrictors, growth factors, hormone, genotoxins and cytokines through mechanical, hemodynamic, immunological injury as well as metabolic abnormality. (omitted)

• Proceeding of EDISON Challenge
• /
• 2017.03a
• /
• pp.650-652
• /
• 2017

the aim of this study was to observe the combined effect of the CRT and LVAD on electromechanical cardiac behavior under LBBB and RBBB conditions computationally. We performed simulation by using advanced electromechanics model of failing ventricle combined with lumped model represents circulatory system, CRT and LVAD. We analyzed seven failing ventricle model including normal sinus rhythm, LBBB, LBBB coupled with CRT, LBBB coupled with CRT and LVAD, RBBB, RBBB coupled with CRT, and RBBB coupled with CRT and LVAD. We compared the effect from CRT and the effect from combined CRT and LVAD to both under LBBB and RBBB conditions. The results showed that the combined CRT and LVAD contributed a better hemodynamic compared to single CRT. This combined system synchronized the electrical activation greatly under LBBB and slightly under RBBB. It also shortened mechanical activation time which resulted short electromechanical delay. More importantly, the combined system produced better mechanical responses under both LBBB and RBBB conditions.

• Current Optics and Photonics
• /
• v.4 no.1
• /
• pp.57-62
• /
• 2020

The selection of anesthetic agent is important in preclinical studies, since each agent affects the systemic hemodynamics in different ways. For that reason, we hypothesized that different anesthetic agents will result in different vaginal hemodynamic response and temperature during sexual arousal, in an animal model. To validate the hypothesis, animal experiments were performed using female rats with two anesthetic agents widely used in preclinical studies: ketamine and isoflurane. Our previously developed near-infrared-spectroscopy-based probe was used to measure the changes of oxyhemoglobin (OHb), deoxyhemoglobin (RHb), and total hemoglobin (THb) concentrations along with temperature from the animal vaginal wall. As a control, saline was administered to both isoflurane- and ketamine-anesthetized animals, and did not show any significant changes in OHb, RHb, THb, or temperature. However, an administration of apomorphine (APO, 80 ㎍/kg) induced increases of OHb (63 ± 28 μM/DPF), RHb (35 ± 20 μM/DPF), and THb (98 ± 49 μM/DPF) in ketamine-anesthetized animals, while decreases of OHb (52 ± 76 μM/DPF) and THb (38 ± 30 μM/DPF) and an increase of RHb (28 ± 51 μM/DPF) were found in isoflurane-anesthetized animals. The vaginal temperature decreased from the baseline in both ketamine-(0.42℃) and isoflurane-(1.22℃)anesthetized animals. These results confirmed our hypothesis, and suggest that a preclinical study monitoring hemodynamic responses under anesthesia should employ an appropriate anesthetic agent for the study.

• Journal of Korea Entertainment Industry Association
• /
• v.13 no.2
• /
• pp.197-205
• /
• 2019

This study was to compare arterial stiffness and hemodynamic responses between male smokers and non-smokers. This study also investigates the influences of smoking before exercise on arterial stiffness and hemodynamic responses. 24 male subjects of age 20-29 without history of cardiorespiratory disease were divided into smokers and non-smokers. Smokers had more than 5 years of smoking experience. In order to evaluate the effects of pre-exercise smoking, smokers were tested twice, once with a cigarette before the exercise and the other once without one. Data was collected from bio-impedance analysis, SphygmoCor XCEL, graded exercise test, and fitness test. Main results of this study are as follows: First, there are differences between smokers and non-smokers in cardiorespiratory and hemodynamic response functions, as shown by maximal oxygen consumption, exercise duration, and heart rate. Second, the although the arterial stiffness between smokers and non-smokers showed statistically significant differences in the speed of the pulse wave velocity and augmentation index, smoker had a faster rate. It shows that smoking behavior has a negative impact on the cardiovascular system. Third, pre-exercise smoking behavior does have an impact on cardiorespiratory and hemodynamic response functions, as shown by exercise duration and heart rate. Lastly, arterial stiffness between smokers and non-smokers showed statistically not significant in the speed of the pulse wave velocity and augmentation index. However, the difference was not statistically significant. Brachial systolic pressure, a component of pulse wave analysis, on the other hand, was significantly dependent on pre-exercise smoking behavior. Subjects who participated in this study are college students in early 20s. Given their relatively short history of smoking, it is possible that their smoking habits are not severe enough to develop into cardiorespiratory or cardiovascular diseases. But Smokers showed lower levels of cardiopulmonary functions, as maximal oxygen consumption and exercise duration than nonsmokers.

• Journal of Trauma and Injury
• /
• v.27 no.4
• /
• pp.115-125
• /
• 2014

Purpose: Stable vital signs (SVSs) are thought to be the most important criteria for successful non-operative management (NOM) of blunt spleen injury (BSI). However, a consistent definition of SVSs has been lacking. We wanted to evaluate the diversity of the definitions of SVSs by using a nationwide survey. Methods: A questionnaire regarding the definition of SVSs was sent to the trauma surgeons working at the Department of Trauma Surgery and Emergency Medicine at a level-I trauma center between October 2011 and November 2011. Data were compared using analyses of the variance, t-tests, ${\chi}^2$ tests and logistic regressions. Results: Among 201 surgeons, 198 responded (98.2%). Of these 198 responses, 45 were incomplete, so only 153 (76.1%) were analyzed. In defining the SVSs, significant diversity existed on the subjects of type of blood pressure (BP), cut-off value for hypotension, technique for measuring BP, duration of hypotension, whether or not to use the heart rate (HR) as a determinant, cut-off value of hypotension when the patient had a comorbidity or when the patient was a child. Of the 153 surgeons whose responses were analyzed, 91.5% replied that they were confused when defining SVSs. Conclusion: Confusion exists regarding how to define SVSs. Most surveyed surgeons felt that a need existed to clarify both the definition of SVSs and the use of SVSs to determine hemodynamic stability for NOM.