An assessment of pulse transit time for detecting heavy blood loss during surgical operation

Copyright @ Wang et al.; Licensee Bentham Open. This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.The main contribution of this paper is the use of non-invasive measurements such as electrocardiogram (ECG) and photoplethysmographic (PPG) pulse oximetry waveforms to develop a new physiological signal analysis technique for detecting blood loss during surgical operation. Urological surgery cases were considered as the control group due to its generality, and cardiac surgery as experimental group since it involves blood loss and water supply. Results show that the control group has the tendency of a reduction of the pulse transient time (PTT), and this indicates an increment in the blood flow velocity changes from slow to fast. While for the experimental group, the PTT indicates high values during blood loss, and low values during water supply. Statistical analysis shows considerable differences (i.e., P <0.05) between both groups leading to the conclusion that PTT could be a good indicator for monitoring patients' blood loss during a surgical operation.The National Science Council (NSC) of Taiwan and the Centre for Dynamical Biomarkers and Translational Medicine, National Central University, Taiwan

Regression Based Comparative Study for Continuous BP Measurement Using Pulse Transit Time

Context: Blood Pressure (BP) measurement becomes a vital parameter now days due to the continuous increase in chronic heart diseases worldwide. Existing devices for BP measurement are less portable and also does not support continuous BP measurement. Many studies have been done on non-invasive BP measurement using electrocardiography (ECG) and photoplethysmograph (PPG) waveforms. These methods also clarify accurate results.Calculation of PTT and BP:This study relates BP measured using two PPGs with the existing methods which uses the ECG signals. The cuff and ECG signal can be replaced by PPG sensors as the results acquired using PPG signals gives high accuracy.Basic terms can be defined to relate BP followed by detection of P-base point and ends with the estimation for BP calculations.Proposed Methodology: The algorithm for the proposed technology can be defined and the work shows how the use of wavelet de-noised PPGs can replace the existing ECG based techniques to decrease the complexity of overall devices and also increases the precision level.Results and Discussion: Analysis of all the type of combinations can show the results that minimum error and maximum accuracy can be found when BP is estimated. Conclusion: PTT based on two PPG’s are best among all other methods including the utilization of second order non-linear regression technique

Smart bracelet for anxiety

This paper introduces a novel non-invasive wearable device that can infer whether people are suffering from anxiety or not. The device allows capturing physiological signals such as: electrodermal activity (EDA), skin temperature (ST), electrocardiography (ECG) and photoplethysmography (PPG), and provides an estimation of blood pressure -through the pulse transit time (PTT) technique- and breathing rate (BR) -by analyzing the heart rate variability-. The hardware also includes an SD card to store the signals for offline processing in laboratory tests

Southwest Research Institute assistance to NASA in biomedical areas of the technology

Significant applications of aerospace technology were achieved. These applications include: a miniaturized, noninvasive system to telemeter electrocardiographic signals of heart transplant patients during their recuperative period as graded situations are introduced; and economical vital signs monitor for use in nursing homes and rehabilitation hospitals to indicate the onset of respiratory arrest; an implantable telemetry system to indicate the onset of the rejection phenomenon in animals undergoing cardiac transplants; an exceptionally accurate current proportional temperature controller for pollution studies; an automatic, atraumatic blood pressure measurement device; materials for protecting burned areas in contact with joint bender splints; a detector to signal the passage of animals by a given point during ecology studies; and special cushioning for use with below-knee amputees to protect the integrity of the skin at the stump/prosthesis interface

Hypothalamic-pituitary-gonadal activity in paradoxical and psychophysiological insomnia

Background: Although insomnia is a sex-dimorphic disorder, there is limited knowledge about the association between sex hormones and insomnia. In the present study, the level of hypothalamus-pituitary-gonadal (HPG) axis activity was investigated in patients with insomnia by measuring serum levels of luteinizing hormone (LH), follicle stimulating hormone (FSH), 17α-Hydroxyprogesterone, testosterone, progesterone, estradiol, dehydroepiandrosterone sulfate, and sex hormone-binding globulin. Methods: Numbers of 19 patients; including 13 females (68.40) with paradox insomnia (32-53 years; 43.20 ± 6.40) and 17 patients; including 8 females (47.05) with psychophysiological insomnia (14-62 years; 38.40 ± 16.30) were recruited. Seventeen aged-matched normal sleeper consisted of 13 males (26-59 years; 40.70 ± 10) consisted of 13 males (76.50) were also recruited as control group. Insomnia was diagnosed by a sleep clinician according to the International Classification of Sleep Disorders-Second Edition criteria and an overnight polysomnography (PSG). A volume of 5 ml of venous blood samples were collected, prepared, and stored at 8 AM under standard condition. Serum levels of hormones were measured using enzyme-linked immunosorbent assay kits. Data were analyzed by Chi-square and ANCOVA. The associations between PSG and biochemical parameters were evaluated using multiple linear regression analysis. Results: There were no significant differences in all biochemical analyses between two insomnia subgroups (paradoxical and psychophysiological insomnia) and normal sleepers. Testosterone was positively related to maximum pulse transit time (PTT). Moreover, both LH and FSH were positively related to wake index and diastolic blood pressure. Conclusion: Although there were no significant differences in all HPG's hormones between groups, both LH and FSH were associated with wake index and diastolic blood pressure. Moreover, testosterone was positively related to PTT. © 2019 Journal of Medical Signals & Sensors