Thesis (Ph.D)--Stanford University, 1999. / Title from pdf t.p. (viewed April 3, 2002). "March 1999." "Adminitrivia V1/Prg/19990407"--Metadata.

Acute hypotensive episodes (AHE) is a critical event that can lead to irreversible organ damage and death in intensive care units (ICU). The goal of the 10 th annual PhysioNet/Computers in Cardiology Challenge is to predict which ICU patients will experience AHE within a forecast window of one hour. In tackling this problem, most of the previous studies extract their features for AHE prediction from the time history of MAP, diastolic ABP and systolic ABP. In contrast, by exploring the interaction within the cardiovascular system, this work employs frequency domain approach. Toward this goal, this work proposes two feature sets: degree of concentration and energy from the spectrogram of the ECG and ABP signals. The mulstiscale entropy of these features have also been studied. The effectiveness of these features is statically investigated by comparing their means between the AHE and non AHI patient groups.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references (leaves 405-423). Available also in a digital version from Dissertation Abstracts.

Background: With the increasing survival rate of early preterm infants and the extensive use of invasive health care procedures, the nosocomial infection rate is on the rise in the past decade in the neonatal intensive care unit (NICU). The patients in NICU are a unique and highly vulnerable population, including preterm infants and infants requiring surgery. Nosocomial infection (NI) is associated with the majority of infectious complications of infants, resulting in morbidity and mortality. Close surveillance, accurate measurement, and promotion of full awareness of the risk factors of infection are essential to nosocomial infection control. Previous research had pointed out some factors related to the NI in other countries, and further research is still much needed to reveal the incidence of NI and further analyze the risk factors in China. Objectives: The objectives of this study were to assess incidence and epidemiologic profile of nosocomial infection in NICU of China, and to identify the main risk factors of nosocomial infections. Methods: This was a retrospective cohort with a nested case control study. All data were collected from the database of the medical records of all the patients who were admitted to the Guangzhou Women and Children’s Medical Center (N=1653) during December 2009 to May 2012.Infection rate, infection density and central line-associated bloodstream infection rate were estimated. Stepwise regression model yielded adjusted odds ratio (OR) of potential risk factors for NI. Results: The infection rate in NICU during the study period was 6.2 episodes per 100 patients (6.0-6.4 episodes per 100 patients). Infection density was 4.2 episodes per 1000 patient-days each year (95%CI=3.4-5.0 episodes per 1000 patient-days). The infection rate of ventilation-related pneumonia was 3.4 episodes per 1000 Mechanical Ventilation (MV) days. (95%CI= 3.2-3.5 episodes per MV patient-days).Central line-associated bloodstream infection rate was 5.4 episodes per 1000 central line days (95%CI= 5.1-5.6episodes per central line days). Overall, infants with gestational age >32weeks, longer duration of receipt of parenteral nutrition and longer duration of receipt of probiotics were significantly less likely to have NI (adjusted ORs= 0.35, 0.94 and 0.88, respectively). Congenital malformation, multiple birth, receipt of vein or arterial catheter, receipt of surgical operation and gastric tube feeding were significantly more likely to have NI(adjusted ORs=4.43,3.24 and 3.88, respectively). And longer duration of using prophylactic antibiotic was significantly more likely to have NI (adjusted OR=1.13). Conclusion: Our study provided information to the prevention strategies of nosocomial infections and improvement of health care service.We described the nosocomial infection rate, infection density and device-related infection rate, seasonal distribution, the type of infection and the pathogens identified to reveal the profile of nosocomial infection of NICU in Guangzhou, China.Andwe identified the association between intrinsic factors of infants and health care procedures with NI. Multicenter prospective study can be conducted in the future to investigate the specific risk factors on different birth weight or gestational age in China. / published_or_final_version / Public Health / Master / Master of Public Health

Background: Most of the previous studies about risk factors associated with death in pediatric intensive care unit (PICU) were done in western countries and focused on physiological and laboratorial indexes. Some of them had inconsistent results. There were few studies about the epidemiologic profile of mortality and risk factors associated with death in the PICU in China. Compared with other countries, China has different health care policy, insurance system, population, culture, and socioeconomic situation that may affect disease outcomes differently. Some data showed that Chinese PICUs had higher mortality. It is important to know more about the possible factors associated with excess death in PICU in a Chinese setting. Objectives: The objectives of this study were to estimate mortality (incidence proportion of death) in pediatric intensive care unit (PICU) in a tertiary hospital and identify the main risk factors associated with death in PICU. Methods: This was a case-control study. We retrospectively investigated the clinical data of patients who were admitted to the PICU during January 2010 to December 2013 in a tertiary hospital in Guangzhou, China. All the dead cases in PICU during the studied period were chosen as cases, and the controls were randomly selected from the patients who were alive when they were discharged from the PICU during the same period. The incidence proportion of death was estimated, and then logistic regression model was carried out to explore the risk factors for death. Results: The overall mortality in this PICU was 6.5% (95% CI 5.6 % - 7.4%) during January 2010 to December 2013. The following factors were found to have significant association with higher risk for death: middle level socioeconomic status (OR 2.51, 95% 1.07 - 5.87) and low level socioeconomic status (OR 5.86, 95% CI 2.32 - 14.77) compared with the high level socioeconomic status; admission from pediatric emergency observation unit (OR 2.08, 95% CI 1.10 - 3.91) compared with admission from transfer system (i.e. other hospital); critical severity of disease (OR 2.62 , 95% CI 1.48 - 4.64), and seriously critical severity of disease (OR 8.41, 95% CI 3.26 - 21.67) compared with non-critical severity of disease ; existence of multiple organ dysfunction syndrome (OR 3.64, 95% CI 1.91- 6.91) compared with absence of multiple organ dysfunction syndrome; existence of comorbidity (OR 3.14, 95% CI 1.68 - 5.86) compared with absence of comorbidity; infectious disease (OR 2.42, 95% CI 1.07- 5.49), neoplasm (OR 4.53, 95% CI 1.63 - 12.62), neurological disease ( OR 4.21, 95% CI 1.85 - 9.59) and endocrine, immune and nutritional disease (OR 7.56, 95% CI 2.10 - 27.20 ) compared with respiratory disease . Conclusion: Our study was the first one to comprehensively investigate the risk factors for death in PICU of a tertiary hospital in China. We described profile of dead cases, estimated the mortality and investigated the risk factors associated with death in PICU. During January 2010 to December 2013 the mortality in the PICU was found to be 6.5%, and risk factors for higher mortality in PICU included lower level socioeconomic status, admission from the pediatric emergency observation unit, more severe conditions of disease, presence of comorbidity and multiple organ dysfunction syndrome, and disease categories of infectious diseases, neoplasm, neurological disease, and endocrine, immune and nutritional disease. Our study provided information for developing preventive strategy to reduce the mortality in PICU. / published_or_final_version / Public Health / Master / Master of Public Health

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