593 research outputs found

    Mechanical Ventilation in Chest Trauma

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    Pulmonary tuberous sclerosis

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    Pulmonary involvement in tuberous sclerosis is very rare and seems to be associated with a more benign course. We present a 21-year-old woman with bilateral angiomyolipoma. She developed spontaneous pneumothorax which was successfully managed by tube thoracostomy. No recurrence of pneumothorax has been observed up to the present (4 years follow-up). ©2009 NRITLD, National Research Institute of Tuberculosis and Lung Disease

    Correlation of End-Tidal Carbon Dioxide with Arterial Carbon Dioxide in Mechanically Ventilated Patients

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    Background:: Patients undergone mechanical ventilation need rapid and reliable evaluation of their respiratory status. Monitoring of End-tidal carbon dioxide (ETCO2) as a surrogate, noninvasive measurement of arterial carbon dioxide (PaCO2) is one of the methods used for this purpose in intubated patients. Objectives:: The aim of the present trial was to study the relationship between end-tidal CO2 tensions with PaCO2 measurements in mechanically ventilated patients. Materials and Methods:: End-tidal carbon dioxide levels were recorded at the time of arterial blood gas sampling. Patients who were undergoing one of the mechanical ventilation methods such as: synchronized mandatory mechanical ventilation (SIMV), continuous positive airway pressure (CPAP) and T-Tube were enrolled in this study. The difference between ETCO2 and PaCO2 was tested with a paired t-test. The correlation of end-tidal carbon dioxide to (ETCO2) CO2 was obtained in all patients. Results:: A total of 219 arterial blood gases were obtained from 87 patients (mean age, 71.7 ± 15.1 years). Statistical analysis demonstrated a good correlation between the mean of ETCO2 and PaCO2 in each of the modes of SIMV, CPAP and T-Tube; SIMV (42.5 ± 17.3 and 45.8 ± 17.1; r = 0.893, P < 0.0001), CPAP (37 ± 9.7 and 39.4 ± 10.1; r = 0.841, P < 0.0001) and T-Tube (36.1 ± 9.9 and 39.4 ± 11; r = 0.923, P < 0.0001), respectively. Conclusions:: End-tidal CO2 measurement provides an accurate estimation of PaCO2 in mechanically ventilated patients. Its use may reduce the need for invasive monitoring and/or repeated arterial blood gas analyses

    Solid state image sensor research, phase I

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    Solid state image sensor in infrared and visible region

    Method and apparatus for cold gas reinjection in through-flow and reverse-flow wave rotors

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    A method and apparatus for cold gas reinjection in through-flow and reverse-flow wave rotors having a plurality of channels formed around a periphery thereof. A first port injects a supply of cool air into the channels. A second port allows the supply of cool air to exit the channels and flow to a combustor. A third port injects a supply of hot gas from the combustor into the channels. A fourth port allows the supply of hot gas to exit the channels and flow to a turbine. A diverting port and a reinjection port are connected to the second and third ports, respectively. The diverting port diverts a portion of the cool air exiting through the second port as reinjection air. The diverting port is fluidly connected to the reinjection port which reinjects the reinjection air back into the channels. The reinjection air evacuates the channels of the hot gas resident therein and cools the channel walls, a pair of end walls of the rotor, ducts communicating with the rotor and subsequent downstream components. In a second embodiment, the second port receives all of the cool air exiting the channels and the diverting port diverts a portion of the cool air just prior to the cool air flowing to the combustor

    Modified Through-Flow Wave-Rotor Cycle with Combustor-Bypass Ducts

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    A wave-rotor cycle is described that avoids the inherent problem of combustor exhaust gas recirculation (EGR) found in four-port, through-flow (uniflow) pressure-gain wave-rotor cycles currently under consideration for topping gas-turbine engines. The recirculated hot gas is eliminated by the judicious placement of a bypass duct that transfers gas from one end of the rotor to the other. The resulting cycle, when analyzed numerically, yields a mean absolute temperature for the rotor that is 18% below the already impressive value (approximately the turbine inlet temperature) predicted for the conventional four-port cycle. The absolute temperature of the gas leading to the combustor is also reduced from the conventional design by 17%. The overall design-point pressure ratio of this new bypass cycle is approximately the same as the conventional cycle. This paper will describe the EGR problem and the bypass-cycle solution, including relevant wave diagrams. Performance estimates of design and off-design operation of a specific wave rotor will be presented. The results were obtained using a one-dimensional numerical simulation and design code

    A numerical investigation of premixed combustion in wave rotors

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    Wave rotor cycles which utilize premixed combustion processes within the passages are examined numerically using a one-dimensional CFD-based simulation. Internal-combustion wave rotors are envisioned for use as pressure-gain combustors in gas turbine engines. The simulation methodology is described, including a presentation of the assumed governing equations for the flow and reaction in the channels, the numerical integration method used, and the modeling of external components such as recirculation ducts. A number of cycle simulations are then presented which illustrate both turbulent-deflagration and detonation modes of combustion. Estimates of performance and rotor wall temperatures for the various cycles are made, and the advantages and disadvantages of each are discussed

    A Modified Through-Flow Wave Rotor Cycle with Combustor Bypass Ducts

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    A wave rotor cycle is described which avoids the inherent problem of combustor exhaust gas recirculation (EGR) found in four-port, through-flow wave rotor cycles currently under consideration for topping gas turbine engines. The recirculated hot gas is eliminated by the judicious placement of a bypass duct which transfers gas from one end of the rotor to the other. The resulting cycle, when analyzed numerically, yields an absolute mean rotor temperature 18% below the already impressive value of the conventional four-port cycle (approximately the turbine inlet temperature). The absolute temperature of the gas leading to the combustor is also reduced from the conventional four-port design by 22%. The overall design point pressure ratio of this new bypass cycle is approximately the same as the conventional four-port cycle. This paper will describe the EGR problem and the bypass cycle solution including relevant wave diagrams. Performance estimates of design and off-design operation of a specific wave rotor will be presented. The results were obtained using a one-dimensional numerical simulation and design code

    Return to work after trauma: A survival analysis

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    Purpose To evaluate the return to work (RTW) rate, time and predictors among trauma patients using survival analysis. Methods This cohort study was conducted with a three-month follow-up on 300 trauma patients hospitalized in Shahid Beheshti Hospital, Kashan, Iran in 2014. The data were collected through conducting interviews and referring to patients' medical records during their hospital stay and follow-up information at one & three months after discharge from hospital. Final analysis was conducted on the data retrieved from 273 patients. Data were analyzed by chi-square test, Mann–Whitney U test and survival analysis method. Results The rate of RTW at the end of the first and the third follow-up months was respectively 21.6% and 61.2%. Survival analysis showed that the RTW time (Time between admission to first return to work) was significantly longer among patients with illiteracy, drug abuse, hospitalization history in the intensive care unit, low socioeconomic status, non-insurance coverage, longer hospital stay, multiple and severe injuries as well as severe disability. Conclusion Our findings indicated that trauma has profound effects on the rate and time of RTW. Besides disability, many personal and clinical factors can affect the outcome of RTW

    Measurement of Disability and Its Predictors Among Trauma Patients: A Follow-up Study

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    Background: Globally more than a billion people, 15% of the population, lives with disability and most of disabilities are caused by injuries. Objectives: The aim of this study was to describe the prevalence of disability and its predictors at 1 and 3 months post-injury in Kashan City during 2014 - 2015. Patients and Methods: In this longitudinal follow-up study, 400 injured patients 15 - 65 years referred to Shahid Beheshti hospital in Kashan and hospitalized more than 24 hours were assessed for disability status with the WHODAS II 12-item instrument at 1 and 3-months post-injury. Patients based on their disability scores were divided into 5 groups: none, mild, moderate, severe and very severe. Work status was assessed at the 3-month follow-up with one question “Are you back at work following your injury”. Also, demographic characteristics and information about injury were gathered by a checklist. Data were analyzed using chi-square, Mann-Whitney U, Kruskal Wallis, Pearson correlation coefficient and logistic regression by SPSS software. The significance level was set at P < 0.05. Results: The mean disability scores at 1 and 3 months post-injury was 30.3 (9.2) and 18.8 (8.3), respectively and there was a statistical significant difference between disability status at 1 and 3 months after trauma (P < 0.0001). The rates of return to work in 262 employed patients at 1 and 3 months after injury were 29% and 55.4%, respectively. The disability score showed a statistically significant correlation with Injury Severity Score (ISS) (P < 0.0001), work return (P = 0.033), intensive care unit transfer (P < 0.0001), trauma type (P = 0.001) and age (P = 0.004). Also, age, ISS, duration of hospital stay and injury to extremities were predictors of disability. Conclusions: More than half of the patients were disabled after 3 months of trauma. Elderly patients, patient with severe trauma, and long hospitalization and patients with extremity injuries were high risk for disability
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