scholarly journals Heart Rate Variability in Children with Tricyclic Antidepressant Intoxication

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Ener Cagri Dinleyici ◽  
Zubeyir Kilic ◽  
Sabiha Sahin ◽  
Rabia Tutuncu-Toker ◽  
Makbule Eren ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Spectral Analysis ◽  
Intensive Care ◽  
Time Domain ◽  
Tricyclic Antidepressant ◽  
Noninvasive Testing ◽  
Testing Method ◽  
Starting Point ◽  
Hrv Analysis ◽  
The Time Domain

The aim of this study was to evaluate HRV in children requiring intensive care unit stays due to TCA poisoning between March 2009 and July 2010. In the time-domain nonspectral evaluation, the SDNN (P<0.001), SDNNi (P<0.05), RMSDD (P<0.01), and pNN50 (P<0.01) were found to be significantly lower in the TCA intoxication group. The spectral analysis of the data recorded during the first 5 minutes after intensive care unit admission showed that the values of the nLF (P<0.05) and the LF/HF ratio (P=0.001) were significantly higher in the TCA intoxication group, while the nHF (P=0.001) values were significantly lower. The frequency-domain spectral analysis of the data recorded during the last 5 minutes showed a lower nHF (P=0.001) in the TCA intoxication group than in the controls, and the LF/HF ratio was significantly higher (P<0.05) in the intoxication group. The LF/HF ratio was higher in the seven children with seizures (P<0.001). These findings provided us with a starting point for the value of HRV analysis in determining the risk of arrhythmia and convulsion in TCA poisoning patients. HRV can be used as a noninvasive testing method in determining the treatment and prognosis of TCA poisoning patients.

Spectral analysis of noise in the neonatal intensive care unit

2008 ◽  
Vol 75 (3) ◽  
Author(s):  
M. D. Livera ◽  
B. Priya ◽  
A. Ramesh ◽  
P. N. Suman Rao ◽  
V. Srilakshmi ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Spectral Analysis ◽  
Intensive Care ◽  
Neonatal Intensive Care Unit ◽  
Neonatal Intensive Care

scholarly journals Investigation of Dispersion-Relation-Preserving Scheme and Spectral Analysis Methods for Acoustic Waves

1997 ◽  
Vol 119 (2) ◽  
pp. 250-257 ◽  
Author(s):  
Florence O. Vanel ◽  
Oktay Baysal
Keyword(s):  
Spectral Analysis ◽  
Boundary Conditions ◽  
Time Domain ◽  
Acoustic Waves ◽  
Acoustic Wave Propagation ◽  
Analysis Methods ◽  
Time Domain Data ◽  
Disturbance Source ◽  
The Time Domain ◽  
Tukey Method

Important characteristics of acoustic wave propagation are encoded in their dispersion relations. Hence, a computational algorithm, which attempts to preserve these relations, was investigated. Considering the linearized, 2-D Euler equations, simulations were performed to validate this scheme and its boundary conditions. The results were found to agree favorably with the exact solutions. The boundary conditions were transparent to the outgoing waves, except when the disturbance source was close to a corner boundary. The time-domain data generated by such computations were often intractable until their spectra was analyzed. For this purpose, the relative merits of three spectral analysis methods were considered. For simple, periodic waves with steep-sloped spectra, the periodogram method produced better estimates than the Blackman-Tukey method, and the Hanning window was more effective when used with the former. For chaotic waves, however, the weighted-overlapped-segment-averaging and Blackman-Tukey methods were better than the periodogram method. Therefore, it was observed that the spectral representation of time-domain data was significantly dependent on the particular method employed.

scholarly journals Nursing Surge Capacity Strategies for Management of Critically Ill Adults with COVID-19

2020 ◽  
Vol 10 (1) ◽  
pp. 23-32
Author(s):  
Abbas Al Mutair ◽  
Anas Amr ◽  
Zainab Ambani ◽  
Khulud Al Salman ◽  
Deborah Schwebius
Keyword(s):  
Intensive Care Unit ◽  
Critical Care ◽  
Intensive Care ◽  
Critically Ill ◽  
Nursing Staff ◽  
Best Practice ◽  
Expert Panel ◽  
Evidence Based ◽  
Surge Capacity ◽  
Starting Point

Background: There is a vital need to develop strategies to improve nursing surge capacity for caring of patients with coronavirus (COVID-19) in critical care settings. COVID-19 has spread rapidly, affecting thousands of patients and hundreds of territories. Hospitals, through anticipation and planning, can serve patients and staff by developing strategies to cope with the complications that a surge of COVID-19 places on the provision of adequate intensive care unit (ICU) nursing staff—both in numbers and in training. Aims: The aim is to provide an evidence-based starting point from which to build expanding staffing models dealing with these additional demands. Design/Method: In order to address and develop nursing surge capacity strategies, a five-member expert panel was formed. Multiple questions directed towards nursing surge capacity strategies were posed by the assembled expert panel. Literature review was conducted through accessing various databases including MEDLINE, CINAHL, Cochrane Central, and EMBASE. All studies were appraised by at least two reviewers independently using the Joanna Briggs Institute JBI Critical Appraisal Tools. Results: The expert panel has issued strategies and recommendation statements. These proposals, supported by evidence-based resources in regard to nursing staff augmentation strategies, have had prior success when implemented during the COVID-19 pandemic. Conclusion: The proposed guidelines are intended to provide a basis for the provision of best practice nursing care during times of diminished intensive care unit (ICU) nursing staff capacity and resources due to a surge in critically ill patients. The recommendations and strategies issued are intended to specifically support critical care nurses incorporating COVID-19 patients. As new knowledge evidence becomes available, updates can be issued and strategies, guidelines and/or policies revised. Relevance to Clinical Practice: Through discussion and condensing research, healthcare professionals can create a starting point from which to synergistically develop strategies to combat crises that a pandemic like COVID-19 produces.

Over 8 years experience on severe acute poisoning requiring intensive care in Hong Kong, China

2010 ◽  
Vol 29 (9) ◽  
pp. 757-765 ◽  
Author(s):  
Sin-Man Lam ◽  
Arthur Chun-Wing Lau ◽  
Wing-Wa Yan
Keyword(s):  
Intensive Care Unit ◽  
Hong Kong ◽  
Intensive Care ◽  
Alcohol Intoxication ◽  
Acute Poisoning ◽  
Tricyclic Antidepressant ◽  
Psychiatric Ward ◽  
Intensive Care Admission ◽  
Lengths Of Stay ◽  
Overall Mortality

In order to obtain up-to-date information on the pattern of severe acute poisoning and the characteristics and outcomes of these patients, 265 consecutive patients admitted to an intensive care unit in Hong Kong for acute poisoning from January 2000 to May 2008 were studied retrospectively. Benzodiazepine (25.3%), alcohol (23%), tricyclic antidepressant (17.4%), and carbon monoxide (15.1%) were the four commonest poisons encountered. Impaired consciousness was common and intubation was required in 67.9% of admissions, with a median duration of mechanical ventilation of less than 1 day. The overall mortality was 3.0%. Among the 257 survivors, the median lengths of stay in the intensive care unit and acute hospital (excluding days spent in psychiatric ward and convalescent hospital) were less than 1 day and 3 days, respectively. Factors associated with a longer length of stay included age of 65 or older, presence of comorbidity, Acute Physiology and Chronic Health Evaluation II score of 25 or greater, and development of shock, rhabdomyolysis, and aspiration pneumonia, while alcohol intoxication was associated with a shorter stay. This is the largest study of its kind in the Chinese population and provided information on the pattern of severe acute poisoning requiring intensive care admission and the outcomes of the patients concerned.

scholarly journals The CFD Method-Based Research on Damaged Ship’s Flooding Process in Time-Domain

2019 ◽  
Vol 26 (1) ◽  
pp. 72-81
Author(s):  
Hu Li-Fen ◽  
Qi Huibo ◽  
Li Yuemeng ◽  
Li Wubin ◽  
Chen Shude
Keyword(s):  
Time Domain ◽  
Vof Method ◽  
Dynamic Mesh ◽  
Navier Stokes ◽  
Ship Motions ◽  
Starting Point ◽  
Cfd Method ◽  
The Time Domain ◽  
Dead Ship Condition ◽  
Damaged Ship

Abstract The flooding process is one of the main concerns of damaged ship stability. This paper combines the volume of fluid (VOF) method incorporated in the Navier-Stokes (NS) solver with dynamic mesh techniques to simulate the flooding of a damaged ship. The VOF method is used to capture the fluid interface, while the dynamic mesh techniques are applied to update the mesh as a result of transient ship motions. The time-domain flooding processes of a damaged barge and a rectangular cabin model are carried out based on the abovementioned method, and the computational results appear compatible with the experimental data. During the flooding process, the motion of the flooding flow at different stages is observed and compared with that observed in real conditions. The time-domain research of the flooding process is the starting point for subsequent establishment of damaged ship’s roll movement and capsizing the mechanism of dead ship condition in wave.

scholarly journals Analytic resolution of time-domain half-space Green's functions for internal loads by a displacement potential-Laplace-Hankel-Cagniard transform method

2020 ◽  
Vol 476 (2235) ◽  
pp. 20190610
Author(s):  
Ronald Y. S. Pak ◽  
Xiaoyong Bai
Keyword(s):  
Half Space ◽  
Time Domain ◽  
Surface Force ◽  
Point Load ◽  
Wave Group ◽  
Branch Points ◽  
Transform Method ◽  
Displacement Potential ◽  
Starting Point ◽  
The Time Domain

A refined yet compact analytical formulation is presented for the time-domain elastodynamic response of a three-dimensional half-space subject to an arbitrary internal or surface force distribution. By integrating Laplace and Hankel transforms into a method of displacement potentials and Cagniard's inversion concept, it is shown that the solution can be derived in a straightforward manner for the generalized classical wave propagation problem. For the canonical case of a buried point load with a step time function, the response is proved to be naturally reducible with the aid of a parametrized Bessel function integral representation to six wave-group integrals on finite contours in the complex plane that stay away from all branch points and the Rayleigh pole except possibly at the starting point of the contours. On the latter occasions, the possible singularities of the integrals can be rigorously extracted by an extended method of asymptotic decomposition, rendering the residual numerical computation a simple exercise. With the new solution format, the arrival time of each wave group is derivable by simple criteria on the contour. Typical results for the time-domain response for an internal point force as well as the degenerate case of a surface point source are included for comparison and illustrations.

scholarly journals Approximation and analysis of transient responses of a reverberation chamber by pulsed excitation

2020 ◽  
Vol 18 ◽  
pp. 53-73
Author(s):  
Konstantin Pasche ◽  
Fabian Ossevorth ◽  
Ralf T. Jacobs
Keyword(s):  
Spectral Analysis ◽  
Steady State ◽  
Time Constant ◽  
Time Domain ◽  
Linear Time ◽  
System Response ◽  
Transient Field ◽  
Reverberation Chamber ◽  
Transient Behaviour ◽  
The Time Domain

Abstract. Reverberation chambers show transient behaviour when excited with a pulsed signal. The field intensities can in this case be significantly higher than in steady state, which implies that a transient field can exceed predefined limits and render test results uncertain. Effects of excessive field intensities of short duration may get covered and not be observable in a statistical analysis of the field characteristics. In order to ensure that the signal reaches steady state, the duration of the pulse used to excite the chamber needs to be longer than the time constant of the chamber. Initial computations have shown that the pulse width should be about twice as long as the time constant of the chamber to ensure that steady state is reached. The signal is sampled in the time domain with a sampling frequency according to the Nyquist theorem. The bandwidth of the input signal is determined using spectral analysis. For a fixed stirrer position, the reverberation chamber, wires, connectors, and antennas can jointly be considered as a linear time-invariant system. In this article, a procedure will be presented to extract characteristic signal properties such as rise-time, transient overshoot and the mean value in steady state from the system response. The signal properties are determined by first computing the envelope of the sampled data using a Hilbert transform. Subsequent noise reduction is achieved applying a Savitzky–Golay filter. The point where steady state is reached is then computed from the slope of the envelope by utilising a cumulative histogram. The spectral analysis is not suitable to examine the transient behaviour and determine the time constants of the system. These constants are computed applying the method of Prony, which is based on the estimation of a number of parameters in a sum of exponential functions. An alternative to the Prony Method is the Time-Domain Vector-Fit method. In contrast to the first mentioned variant, it is now also possible to determine the transfer function of the overall RC system. Differences and advantages of the methods will be discussed.

A Fast ECG Diagnosis by Using Non-Uniform Spectral Analysis and the Artificial Neural Network

2021 ◽  
Vol 2 (3) ◽  
pp. 1-21
Author(s):  
Kun-chih (Jimmy) Chen ◽  
Po-Chen Chien ◽  
Zi-Jie Gao ◽  
Chi-Hsun Wu
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Spectral Analysis ◽  
Power Consumption ◽  
Time Domain ◽  
High Frequency ◽  
Heart Diseases ◽  
Ecg Signal ◽  
Computing Power ◽  
The Time Domain

The electrocardiogram (ECG) has been proven as an efficient diagnostic tool to monitor the electrical activity of the heart and has become a widely used clinical approach to diagnose heart diseases. In a practical way, the ECG signal can be decomposed into P, Q, R, S, and T waves. Based on the information of the features in these waves, such as the amplitude and the interval between each wave, many types of heart diseases can be detected by using the neural network (NN)-based ECG analysis approach. However, because of a large amount of computing to preprocess the raw ECG signal, it is time consuming to analyze the ECG signal in the time domain. In addition, the non-linear ECG signal analysis worsens the difficulty to diagnose the ECG signal. To solve the problem, we propose a fast ECG diagnosis approach based on spectral analysis and the artificial neural network. Compared with the conventional time-domain approaches, the proposed approach analyzes the ECG signal only in the frequency domain. However, because most of the noises in the raw ECG signal belong to high-frequency signals, it is necessary to acquire more features in the low-frequency spectrum and fewer features in the high-frequency spectrum. Hence, a non-uniform feature extraction approach is proposed in this article. According to less data preprocessing in the frequency domain than the one in the time domain, the proposed approach not only reduces the total diagnosis latency but also reduces the computing power consumption of the ECG diagnosis. To verify the proposed approach, the well-known MIT-BIH arrhythmia database is involved in this work. The experimental results show that the proposed approach can reduce ECG diagnosis latency by 47% to 52% compared with conventional ECG analysis methods under similar diagnostic accuracy of heart diseases. In addition, because of less data preprocessing, the proposed approach can achieve lower area overhead by 22% to 29% and lower computing power consumption by 29% to 34% compared with the related works, which is proper for applying this approach to portable medical devices.

Expansion of Indicial Function Approximations for 2-D Subsonic Compressible Aerodynamic Loads

2012 ◽  
Author(s):  
T. Farsadi ◽  
J. Javanshir
Keyword(s):  
Time Domain ◽  
Step Function ◽  
Aerodynamic Loads ◽  
Indicial Function ◽  
Starting Point ◽  
Function Approximations ◽  
The Time Domain ◽  
New Generation ◽  
Duhamel’S Integral ◽  
General Time

This article deals with the new generation of proper Mach dependent exponential approximations of the indicial aerodynamic functions toward the aeroelastic formulation of 2-D lifting surface in the subsonic compressible flow. The indicial lift response is a useful starting point in the development of a general time-domain unsteady aerodynamic theory. By definition, an indicial function is the response to a disturbance that is applied instantaneously at time zero and held constant thereafter; that is a disturbance given by a step function. If the indicial response is known, then the unsteady loads to arbitrary changes in angle of attack can be obtained through the superposition of indicial responses using Duhamel’s integral. The indicial functions have been used to modify the circulatory part of the lifting force and pitching moment in unsteady compressible aerodynamic models. The coefficients of the approximation are obtained with an indirect approach by relating numerical results obtained for oscillating airfoil in the frequency domain back into the time domain. compressible and supersonic flight speed regimes. Exponential approximations of the subsonic compressible indicial functions in the existing research works are available only in limited Mach numbers (M = 0.5, 0.6, 0.7, 0.8). In the present study, a novel exponential approximation is developed which represent the coefficients of approximations as functions of Mach number (0.5 < M < 0.8).

Sign in / Sign up

Export Citation Format

Share Document