Biomedical subjects

Zhenguo Qiu

Publications and source records attributed to Zhenguo Qiu.

7 recordsLinked to original sources

PubMed2006

Neonatal intensive care unit characteristics affect the incidence of severe intraventricular hemorrhage.

OBJECTIVES: The incidence of intraventricular hemorrhage (IVH), adjusted for known risk factors, varies across neonatal intensive care units (NICU)s. The effect of NICU characteristics on this variation is unknown. The objective was to assess IVH attributable risks at both patient and NICU levels. STUDY DESIGN: Subjects were <33 weeks' gestation, <4 days old on admission in the Canadian Neonatal Network database (all infants admitted in 1996-97 to 17 NICUs). The variation in severe IVH rates was analyzed using Bayesian hierarchical modeling for patient level and NICU level factors. RESULTS: Of 3772 eligible subjects, the overall crude incidence rates of grade 3-4 IVH was 8.3% (NICU range 2.0-20.5%). Male gender, extreme preterm birth, low Apgar score, vaginal birth, outborn birth, and high admission severity of illness accounted for 30% of the severe IVH rate variation; admission day therapy-related variables (treatment of acidosis and hypotension) accounted for an additional 14%. NICU characteristics, independent of patient level risk factors, accounted for 31% of the variation. NICUs with high patient volume and high neonatologist/staff ratio had lower rates of severe IVH. CONCLUSIONS: The incidence of severe IVH is affected by NICU characteristics, suggesting important new strategies to reduce this important adverse outcome.

Acute Disease↗

PubMed2005

Variations in rates of nosocomial infection among Canadian neonatal intensive care units may be practice-related.

BACKGROUND: Nosocomial infection (NI), particularly with positive blood or cerebrospinal fluid bacterial cultures, is a major cause of morbidity in neonatal intensive care units (NICUs). Rates of NI appear to vary substantially between NICUs. The aim of this study was to determine risk factors for NI, as well as the risk-adjusted variations in NI rates among Canadian NICUs. METHODS: From January 1996 to October 1997, data on demographics, intervention, illness severity and NI rates were submitted from 17 Canadian NICUs. Infants admitted at < 4 days of age were included. NI was defined as a positive blood or cerebrospinal fluid culture after > 48 hrs in hospital. RESULTS: 765 (23.5%) of 3253 infants < 1500 g and 328 (2.5%) of 13228 infants > or = 1500 g developed at least one episode of NI. Over 95% of episodes were due to nosocomial bacteremia. Major morbidity was more common amongst those with NI versus those without. Mortality was more strongly associated with NI versus those without for infants > or = 1500 g, but not for infants < 1500 g. Multiple logistic regression analysis showed that for infants < 1500 g, risk factors for NI included gestation < 29 weeks, outborn status, increased acuity on day 1, mechanical ventilation and parenteral nutrition. When NICUs were compared for babies < 1500 g, the odds ratios for NI ranged from 0.2 (95% confidence interval [CI] 0.1 to 0.4) to 8.6 (95% CI 4.1 to 18.2) when compared to a reference site. This trend persisted after adjustment for risk factors, and was also found in larger babies. CONCLUSION: Rates of nosocomial infection in Canadian NICUs vary considerably, even after adjustment for known risk factors. The implication is that this variation is due to differences in clinical practices and therefore may be amenable to interventions that alter practice.

Bacteremia↗

PubMed2005

Chorioamnionitis with a fetal inflammatory response is associated with higher neonatal mortality, morbidity, and resource use than chorioamnionitis displaying a maternal inflammatory response only.

OBJECTIVE: This study was undertaken to evaluate whether the proximity of infection of the chorion/amnion and fetal vessels affects neonatal outcomes. STUDY DESIGN: We examined all (n=2012) infants admitted to the British Columbia's Children's Hospital Neonatal Intensive Care Unit, from January 1996 to October 1997. We included infants with a placental examination (n=1296), and stratified those with histologic chorioamnionitis into cases displaying a maternal inflammatory response only and cases also displaying a fetal inflammatory response (funisitis and/or fetal surface vessel angiitis). RESULTS: Histologic evidence of chorioamnionitis was present in 31% of placentas. Of those, 38% exhibited maternal inflammation only, whereas 62% also exhibited fetal inflammation. Neonatal mortality (9.2% vs 7.2%), morbidity, and resource use were significantly (P < .05) higher when fetal inflammation was present compared with when only maternal inflammation was present. CONCLUSION: Chorioamnionitis with a fetal inflammatory response is associated with higher neonatal mortality, morbidity, and resource use than when only a maternal inflammatory response is present.

Chorioamnionitis↗

PubMed2005

Improved outcomes of outborn preterm infants if admitted to perinatal centers versus freestanding pediatric hospitals.

OBJECTIVES: To examine whether admission hospital type (13 perinatal centers vs 4 freestanding pediatric hospitals) was associated with differences in risk and illness severity adjusted mortality and morbidity among outborn preterm infants. STUDY DESIGN: Records of singleton outborn infants < or =32 weeks' gestational age (n = 605) admitted to 17 tertiary level neonatal intensive care units participating in the Canadian Neonatal Network for the period 1996 to 1997 were examined. RESULTS: Outborn infants admitted to freestanding pediatric hospitals were at higher risk of death (adjusted odds ratio [AOR], 2.25; 95% confidence interval [CI], 1.20, 4.20), nosocomial infection (AOR, 2.48; 95% CI, 1.64, 3.73), and oxygen dependency at 28 days of age (AOR, 1.77; 95% CI, 1.14, 2.75) when compared with outborn infants admitted to perinatal centers. CONCLUSIONS: After adjustment for perinatal risks and admission illness severity, outborn infants had better outcomes if they were admitted to perinatal centers compared with freestanding pediatric hospitals.

Apgar Score↗

PubMed2005

SNAP-II predicts mortality among infants with congenital diaphragmatic hernia.

OBJECTIVE: Outcomes analysis in congenital diaphragmatic hernia (CDH) requires a validated risk-adjustment tool. The purpose of this study was to use the Canadian Neonatal Network (CNN) database to validate the Score for Neonatal Acute Physiology, Version II (SNAP-II) for prediction of mortality among CDH infants admitted to a neonatal intensive care unit (NICU), and to compare this to the predictive equation recently developed by the Congenital Diaphragmatic Hernia Study Group (CDHSG). STUDY DESIGN: Infants with CDH in the CNN database were identified. Bivariate and multivariable logistic regression models were used to identify risk factors predictive of mortality. Model predictive performance and calibration were assessed using the area under the receiver operator characteristic curve and the technique of Hosmer-Lemeshow, respectively, and compared with the CDHSG predictive equation. RESULTS: There were 88 patients with CDH among 19,507 admissions to CNN hospitals. The mortality rate among CDH patients surviving to NICU admission was 17%, and 12.5% received extracorporeal membrane oxygenation therapy. Gestational age and admission SNAP-II score predicted mortality. Model predictive performance and calibration were optimized with these variables combined. The CDHSG equation was equally predictive of mortality, but was only marginally calibrated. CONCLUSIONS: SNAP-II is highly predictive of mortality among patients with CDH, and can be used to risk-adjust these patients.

Cause of Death↗

PubMed2004

Variations in incidence of necrotizing enterocolitis in Canadian neonatal intensive care units.

OBJECTIVES: Necrotizing enterocolitis (NEC) is the most common acquired intestinal disease of neonates. Previous reports on incidence have generally examined small cohorts of extremely low-birth-weight infants and have not examined risk-adjusted variations among neonatal intensive care units (NICUs). The authors examined risk-adjusted variations in the incidence of NEC in a large group of Canadian NICUs and explored possible therapy-related risks. METHODS: The authors obtained data on 18,234 infants admitted to 17 tertiary level Canadian NICUs from January 1996 to October 1997. They used multivariate logistic regression analysis to examine the inter-NICU variation in incidence of NEC, with adjustment for population risk factors and admission illness severity, and explored therapy-related variables. RESULTS: The incidence of NEC was 6.6% (n = 238) among 3,628 infants with birth weight < or = 1,500 g (VLBW), and 0.7% (n = 98) among 14,606 infants with birth weight > 1,500 g (HBW). Multivariate logistic regression analysis showed that for VLBW infants, NEC was associated with lower gestational age and treatment for hypotension and patent ductus arteriosus. Among HBW infants, NEC was associated with lower gestational age, presence of congenital anomalies (cardiovascular, digestive, musculoskeletal, multiple systems) and need for assisted ventilation. There was no significant variation in the risk-adjusted incidence of NEC among NICUs, with the exception of one NICU reporting no cases of NEC. CONCLUSIONS: Risk factors for NEC were different in VLBW and HBW infants. There was no significant variation in the risk-adjusted incidence of NEC among Canadian NICUs, with one possible exception.

Birth Weight↗

PubMed2002

Bayesian hierarchical models for multi-level repeated ordinal data using WinBUGS.

Multi-level repeated ordinal data arise if ordinal outcomes are measured repeatedly in subclusters of a cluster or on subunits of an experimental unit. If both the regression coefficients and the correlation parameters are of interest, the Bayesian hierarchical models have proved to be a powerful tool for analysis with computation being performed by Markov Chain Monte Carlo (MCMC) methods. The hierarchical models extend the random effects models by including a (usually flat) prior on the regression coefficients and parameters in the distribution of the random effects. Because the MCMC can be implemented by the widely available BUGS or WinBUGS software packages, the computation burden of MCMC has been alleviated. However, thoughtfulness is essential in order to use this software effectively to analyze such data with complex structures. For example, we may have to reparameterize the model and standardize the covariates to accelerate the convergence of the MCMC, and then carefully monitor the convergence of the Markov chain. This article aims at resolving these issues in the application of the WinBUGS through the analysis of a real multi-level ordinal data. In addition, we extend the hierarchical model to include a wider class of distributions for the random effects. We propose to use the deviance information criterion (DIC) for model selection. We show that the WinBUGS software can readily implement such extensions and the DIC criterion.

Bayes Theorem↗