Renal Oxygenation (rSO 2 ) Population Parameter Estimates in Premature Infants Routinely Monitored With Near-Infrared Spectroscopy.

BACKGROUND: Currently, reference ranges for renal oxygenation measured by near-infrared spectroscopy (NIRS) in preterm infants beyond the first days of life are lacking, especially those born prior to 29 weeks' gestation. Population estimates of renal oxygenation (rSO 2 ) levels among preterm infants over time have yet to be established, leading to reluctance in clinical application. PURPOSE: To characterize the distribution and estimate population parameters for renal oxygenation measured by NIRS during the first 14 days of life among preterm infants. METHODS: We prospectively observed rSO 2 trends of 37 infants before 34 weeks' gestation and 1800-g or less birth weight for the first 14 days of life. Analyses included distribution fit tests, ordinary least squares (OLS) regression, and t tests. RESULTS: Average daily rSO 2 variation steadily increased with 42% difference through the first 14 days of life. For all infants, renal rSO 2 means peaked during the first 3 days of life and plateaued around 7 days. Daily rSO 2 slopes were significantly lower among males and infants 29 weeks' or less gestation. IMPLICATIONS FOR PRACTICE: Renal rSO 2 during the first 14 days of life reflects normal extrauterine transition reaching stabilization around 7 days of life. Gestational age, birth weight, and gender may predict the early trajectory of rSO 2 patterns. Population estimates provide parameters for renal rSO 2 that may indicate early-onset tissue hypoxia when acute or significant drops from baseline occur. IMPLICATIONS FOR RESEARCH: We present a framework to guide future research using renal NIRS technology in preterm infants to determine deviations from expected trends that may precede renal injury.

Influence of Quiet Time on the Auditory Environment of Infants in the NICU.

OBJECTIVE: To determine the influence of quiet time on the auditory environment of infants in the NICU and to compare the effect of quiet time by room type, bed type, and infant clinical acuity. DESIGN: Cross-sectional, descriptive comparison study. PARTICIPANTS: Sixty-six infants born at less than 38 weeks gestation who were between 32 and 40 weeks postmenstrual age. SETTING: The auditory environments of infants in two level 3 NICUs within a pediatric hospital system in the Southeastern United States. Each NICU implemented quiet time for 4 hours per day. METHODS: We assessed the auditory environment of the participants using Language Environmental Analysis technology. We used paired t tests to assess differences in the auditory environment during quiet versus nonquiet time and to compare the effect of quiet time by room type, bed type, and clinical acuity. RESULTS: During quiet time, the auditory environment of participants had 13% more silence, 17% fewer electronic sounds, 25% less speech, and 30% fewer words than during nonquiet time. We observed greater differences in quiet time versus nonquiet time for infants in open bays and incubators and infants who had greater acuity. CONCLUSION: Our results support the implementation of quiet time to increase silence and reduce exposure to electronic sounds for infants in the NICU. Additional research is necessary to further examine the effect of quiet time on the auditory environment of infants in the NICU with consideration of environmental and clinical variables.

Renal Oxygenation Measured by Near-Infrared Spectroscopy in Neonates.

BACKGROUND: Acute kidney injury (AKI) affects approximately 30% of infants admitted to the neonatal intensive care unit (NICU), and increases mortality risk by 50%. Current diagnostic criteria (serum creatinine rise with oliguria) cannot detect early-onset AKI, as up to 50% of nephron damage may occur by the time these abnormalities present. Once AKI is established, clinical management is often ineffective; therefore, prevention is key. Near-infrared spectroscopy (NIRS) offers a feasible, noninvasive approach to continuously monitor renal oxygenation trends over time, serving as a surrogate marker for renal perfusion. PURPOSE: To provide an overview of NIRS principles for measuring renal oxygenation, and to describe current evidence of how this technology is being used among infants admitted to the NICU relative to the prediction and identification of AKI. METHODS: A comprehensive search of PubMed and CINHAL focused on renal NIRS studies in NICU preterm and term infants was conducted. RESULTS: Findings from 34 studies were included. In term infants, reduced renal oxygenation correlated to invasive SvO2 monitoring, predicted survivability and AKI. In preterm infants, reduced renal oxygenation was associated with AKI in one study, yet contrasting findings were reported in those with patent ductus arteriosus, including those who received prostaglandin inhibitors. Normative data in all infants were sparse. IMPLICATIONS FOR PRACTICE: Renal NIRS may offer a noninvasive measurement of kidney hypoperfusion that may precede conventional diagnostic measures. IMPLICATIONS FOR RESEARCH: Normative data are lacking, the threshold for renal ischemia is not defined, and consensus guiding clinical treatment based on NIRS data is nonexistent.

Predictors of Parental Presence in the Neonatal Intensive Care Unit.

BACKGROUND: Parental presence in the neonatal intensive care unit (NICU) may affect preterm infants' developmental outcomes. However, few studies have described predictors of parental presence in the NICU. PURPOSE: To identify sociodemographic, clinical, environmental, and maternal psychological factors that predict parent presence in the NICU. METHODS: Using a prospective cohort design, 66 preterm infants between 32 and 40 weeks' corrected gestational age were recruited at 2 level III NICUs in the United States. Data for length of parental presence were collected for 48 consecutive hours from daily visitation logs and medical records. A general linear model was estimated to identify significant predictors of parental presence. RESULTS: Parental presence varied considerably, with a mean percentage of visitation time of 32.40%. The number of children at home (P = .003), presence of neurological comorbidity (P < .001), room type (P < .001), surgical history (P < .001), and perceived stressfulness of the NICU (P = .03) each had large main effects on parental presence, and room type and surgical history (P = .004) had a large interaction effect on parental presence. These predictors accounted for 65.8% of the variance in parental presence. IMPLICATIONS FOR RESEARCH: Future research aimed at understanding predictors of parent presence is essential for developing interventions and designing NICUs that support parental presence. IMPLICATIONS FOR PRACTICE: Understanding factors that contribute to parental presence may help healthcare providers identify infants at risk for low parental presence and thus be able to provide greater support to these infants and their families. As a result, this may help improve outcomes and attachment.

Exploring the Mechanism of the Clinical Encounter on Depressive Symptoms in Young Adults: A Path Analysis.

Elucidating mechanisms of how high quality clinical encounters with providers may alleviate depressive symptoms in young adults are critical to reduce psychological morbidity and disability. Guided by Street's Model of Health Communication (SMHC), this study explores the predictive relationships of the clinical encounter, which includes communication functions (patient-provider communication and patient self-appraisal of communication skills with provider) and proximal outcomes (patient activation; PA) to improve health outcomes (depressive symptoms) in young adults. This study of young adults (n = 60) employed path analysis to examine the overall model fit and direct and indirect effects of each variable on depressive symptoms. The final SMHC had excellent model fit (X2 = 2.26, p =.32, TLI =.99, CFI = 1.00, RMSEA =.05). Patient-provider communication and self-appraised communication skills with providers had indirect effects on depressive symptoms and a direct effect on PA; PA had a direct effect on depressive symptoms (R2 =.30, p <.01). Findings elucidate potential novel targets, amenable to behavioral intervention, to improve depressive symptoms within the clinical encounter, and provide a foundation for hypothesis-driven model testing among young adults with depressive symptoms.

Does neighborhood deprivation modify the effect of preterm birth on children's first grade academic performance?

Children's cognitive development and academic performance are linked to both fetal and early childhood factors, including preterm birth and family socioeconomic status. We evaluated whether the relationship between preterm birth (PTB) and first grade standardized test performance among Georgia public school students was modified by neighborhood deprivation in early childhood. The Georgia Birth to School cohort followed 327,698 children born in Georgia from 1998 to 2002 through to end-of-year first grade standardized tests. Binomial and log-binomial generalized estimating equations were used to estimate risk differences and risk ratios for the associations of both PTB and the Neighborhood Deprivation Index for the census tract in which each child's mother resided at the time of birth with test failure (versus passing). The presence of additive and multiplicative interaction was assessed. PTB was strongly associated with test failure, with increasing risk for earlier gestational ages. There was positive additive interaction between PTB and neighborhood deprivation. The main effect of PTB versus term birth increased risk of mathematics failure: 15.9% (95%CI: 13.3-18.5%) for early, 5.0% (95% CI: 4.1-5.9%) for moderate, and 1.3% (95%CI: 0.9-1.7%) for late preterm. Each 1 standard deviation increase in neighborhood deprivation was associated with 0.6% increased risk of mathematics failure. For children exposed to both PTB and higher neighborhood deprivation, test failure was 4.8%, 1.5%, and 0.8% greater than the sum of two main effects for early, moderate, and late PTB, respectively. Results were similar, but slightly attenuated, for reading and English/language arts. Our results suggest that PTB and neighborhood deprivation additively interact to produce greater risk among doubly exposed children than would be predicted from the sum of the effects of the two exposures. Understanding socioeconomic disparities in the effect of PTB on academic outcomes at school entry is important for targeting of early childhood interventions.

Perinatal origins of first-grade academic failure: role of prematurity and maternal factors.

OBJECTIVE: We examined the relationships among gestational age at birth, maternal characteristics, and standardized test performance in Georgia first-grade students. METHODS: Live births to Georgia-resident mothers aged 11 to 53 years from 1998 through 2003 were deterministically linked with standardized test results for first-grade attendees of Georgia public schools from 2005 through 2009. Logistic models were used to estimate the odds of failure of the 3 components of the first-grade Criterion-Referenced Competency Test (CRCT). RESULTS: The strongest risk factor for failure of each of the 3 components of the first-grade CRCT was level of maternal education. Child race/ethnicity and maternal age at birth were also associated with first-grade CRCT failure irrespective of the severity of preterm birth, but these factors were more important among children born moderately preterm than for those born on the margins of the prematurity distribution. Adjusting for maternal and child characteristics, there was an increased odds of failure of each component of the CRCT for children born late preterm versus term, including for math (adjusted odds ratio [aOR]: 1.17, 95% confidence interval [CI]: 1.13-1.22), reading (aOR: 1.13, 95% CI: 1.08-1.18), and English/language arts, for which there was an important interaction with being born small for gestational age (aOR: 1.17, 95% CI: 1.07-1.29). CONCLUSIONS: Preterm birth and low maternal education increase children's risk of failure of first-grade standardized tests. Promoting women's academic achievement and reduce rates of preterm birth may be important to achieving gains in elementary school performance.

Urinary concentrations of dialkylphosphate metabolites of organophosphorus pesticides: National Health and Nutrition Examination Survey 1999-2004.

Organophosphorus (OP) insecticides were among the first pesticides that EPA reevaluated as part of the Food Quality Protection Act of 1996. Our goal was to assess exposure to OP insecticides in the U.S. general population over a six-year period. We analyzed 7,456 urine samples collected as part of three two-year cycles of the National Health and Nutrition Examination Survey (NHANES) from 1999-2004. We measured six dialkylphosphate metabolites of OP pesticides to assess OP pesticide exposure. In NHANES 2003-2004, dimethylthiophosphate was detected most frequently with median and 95th percentile concentrations of 2.03 and 35.3 µg/L, respectively. Adolescents were two to three times more likely to have diethylphosphate concentrations above the 95th percentile estimate of 15.5 µg/L than adults and senior adults. Conversely, for dimethyldithiophosphate, senior adults were 3.8 times and 1.8 times more likely to be above the 95th percentile than adults and adolescents, respectively, while adults were 2.1 times more likely to be above the 95th percentile than the adolescents. Our data indicate that the most vulnerable segments of our population-children and older adults-have higher exposures to OP pesticides than other population segments. However, according to DAP urinary metabolite data, exposures to OP pesticides have declined during the last six years at both the median and 95th percentile levels.

Metal exposures in an inner-city neonatal population.

OBJECTIVES: We measured concentrations of lead (Pb), manganese (Mn), chromium (Cr), and copper (Cu) in umbilical cord whole blood and examined sources of environmental Pb exposures in a predominantly African-American population. METHODS: Between April and July 2006, we collected reproductive histories, questionnaires, and blood samples from 102 women, aged 16-45 years, who delivered at a Memphis, TN hospital. RESULTS: The prevalence of preeclampsia and low birth weight infancy in the study population was 11% and 10%, respectively. Twenty-eight percent of mothers reported living near a potential Pb-contaminated area, while 43% lived in a residence built before 1978. Geometric mean (GM) concentrations for umbilical cord blood in the study population were 1.3, 3.5, 9.0, and 52.0 microg/dL for Pb, Mn, Cr, and Cu, respectively. Six neonates had cord blood Pb (CBL) concentrations above 10 microg/dL, while 20 had CBL concentrations > or =2 microg/dL. GM umbilical CBL levels were higher in neonates born to women living near a potential Pb-contaminated area (2.2 vs. 1.1 microg/dL) and those with friends, family or household members exposed to lead products (1.6 vs. 1.1 microg/dL). Some evidence of an exposure-response relationship was also detected between all four metal concentrations and an increasing number of maternal lead exposures. After adjustment for confounding, proximity to a Pb-contaminated area was the strongest environmental determinant of CBL levels among neonates with CBL concentrations of > or =2 microg/dL (odds ratio=5.1; 95% CI=1.6, 16.7). CONCLUSIONS: Metal concentrations were elevated in this population, and CBL levels were associated with proximity to Pb-contaminated areas.

Urinary concentrations of metabolites of pyrethroid insecticides in the general U.S. population: National Health and Nutrition Examination Survey 1999-2002.

BACKGROUND: Pyrethroid insecticides are the most commonly used residential insecticides in the United States. OBJECTIVES: Our objective was to assess human exposure via biomonitoring to pyrethroid insecticides in a representative sample of the general U.S. population >or= 6 years of age. METHODS: By using isotope-dilution high-performance liquid chromatography/electrospray chemical ionization/tandem mass spectrometry, we measured five urinary metabolites of pyrethroid insecticides in 5,046 samples collected as a part of the 1999-2002 National Health and Nutrition Examination Survey (NHANES). Univariate, multivariate, and Pearson correlation analyses were performed using SUDAAN and SAS software, incorporating the appropriate sample weights into the analyses. Multivariate analyses included age, sex, race/ethnicity, creatinine, fasting status, and urine collection time as covariates. RESULTS: We detected 3-phenoxybenzoic acid (3PBA), a metabolite common to many pyrethroid insecticides, in more than 70% of the samples. The least-squares geometric mean (LSGM) concentration (corrected for covariates) of 3PBA and the frequency of detection increased from 1999-2000 (0.292 ng/mL) to 2001-2002 (0.318 ng/mL) but not significantly. Non-Hispanic blacks had significantly higher LSGM 3PBA concentrations than did non-Hispanic whites and Mexican Americans in the 2001-2002 survey period and in the combined 4-year survey periods but not in the 1999-2000 survey period. Children had significantly higher LSGM concentrations of 3PBA than did adolescents in both NHANES periods and than adults in NHANES 1999-2000. Cis- and trans-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid were highly correlated with each other and with 3PBA, suggesting that urinary 3PBA was derived primarily from exposure to permethrin, cypermethrin, or their degradates. CONCLUSIONS: Pyrethroid insecticide exposure in the U.S. population is widespread, and the presence of its metabolites in the urine of U.S. residents indicates that children may have higher exposures than adolescents and adults.

Inclusion of non-viable neonates in the birth record and its impact on infant mortality rates in Shelby County, Tennessee, USA.

Rates of infant death are one of the most common indicators of a population's overall health status. Infant mortality rates (IMRs) are used to make broad inferences about the quality of health care, effects of health policies and even environmental quality. The purpose of our study was threefold: i) to examine the characteristics of births in the area in relation to gestational age and birthweight; ii) to estimate infant mortality using variable gestational age and/or birthweight criteria for live birth, and iii) to calculate proportional mortality ratios for each cause of death using variable gestational age and/or birthweight criteria for live birth. We conducted a retrospective analysis of all Shelby County resident-linked birth and infant death certificates during the years 1999 to 2004. Descriptive test statistics were used to examine infant mortality rates in relation to specific maternal and infant risk factors. Through careful examination of 1999-2004 resident-linked birth and infant death data sets, we observed a disproportionate number of non-viable live births (≤20 weeks gestation or ≤350 grams) in Shelby County. Issuance of birth certificates to these non-viable neonates is a factor that contributes to an inflated IMR. Our study demonstrates the complexity and the appropriateness of comparing infant mortality rates in smaller geographic units, given the unique characteristics of live births in Shelby County. The disproportionate number of pre-viable infants born in Shelby County greatly obfuscates neonatal mortality and de-emphasizes the importance of post-neonatal mortality.

Urinary paranitrophenol, a metabolite of methyl parathion, in Thai farmer and child populations.

Human exposure to methyl parathion can be assessed by measuring the concentration of its metabolite paranitrophenol (PNP) in urine. Our biologic monitoring study in Chiang Mai, Thailand, measured PNP and dialkylphosphate metabolites (i.e., dimethylphosphate [DMP] and dimethylthiophosphate [DMTP]) of methyl parathion in urine samples collected from 136 farmers (age 20 to 65 years) and 306 school children (age 10 to 15 years) in 2006. Participants came from two topographically different areas: one was colder and mountainous, whereas the other was alluvial with climate fluctuations depending on the monsoon season. Both children and farmers were recruited from each area. Despite methyl parathion's prohibited use in agriculture in 2004, we detected PNP in >90% of all samples analyzed. We applied a nonparametric correlation test (PNP vs. DMP and DMTP) to determine whether the PNP found in most of the samples tested resulted from exposures to methyl parathion. DMP (Spearman's rho = 0.601 [p = 0.001] for farmers and Spearman's rho = 0.263 [p <0.001] for children) and DMTP (Spearman's rho = 0.296 [p = 0.003] for farmers and Spearman's rho = 0.304 [p<0.001] for children) were positively correlated with PNP, suggesting a common source for the three analytes, presumably methyl parathion or related environmental degradates. Although we found a modest correlation between the metabolites, our findings suggest that despite the prohibition, at least a portion (approximately 25% to 60%) of the PNP detected among farmers and children in Thailand may be attributed to exposure from continued methyl parathion use.

Interpretation of biomonitoring data in clinical medicine and the exposure sciences.

Biomonitoring has become a fundamental tool in both exposure science and clinical medicine. Despite significant analytical advances, the clinical use of environmental biomarkers remains in its infancy. Clinical use of environmental biomarkers poses some complex scientific and ethical challenges. The purpose of this paper is compare how the clinical and exposure sciences differ with respect to their interpretation and use of biological data. Additionally, the clinical use of environmental biomonitoring data is discussed. A case study is used to illustrate the complexities of conducting biomonitoring research on highly vulnerable populations in a clinical setting.

Emergency preparedness among people living near US army chemical weapons sites after September 11, 2001.

We examined trust in the army and perceptions of emergency preparedness among residents living near the Anniston, Ala, and Richmond, Ky, US Army chemical weapons stockpile sites shortly after September 11, 2001. Residents (n = 655) living near the 2 sites who participated in a cross-sectional population were relatively unprepared in the event of a chemical emergency. The events of September 11 gave rise to concerns regarding the security of stored chemical weapons and the sites' vulnerability to terrorist attacks. Although residents expressed trust in the army to manage chemical weapons safely, only a few expressed a desire to actively participate in site decisions. Compliance with procedures during emergencies could be seriously limited, putting residents in these sites at higher levels of risk of exposure to chemical hazards than nonresidents.

Empirical Bayes estimation of the prevalence of uninsured individuals by county in the state of Tennessee and analyses of predictive factors.

Lawmakers at the state level require good estimates of those without health insurance in the areas they serve to inform policy decisions. These estimates are often built on inadequate data from smaller geographic areas, such as counties. The Small Area Estimates Branch of the U.S. Census Bureau developed a method to generate stable estimates at the county level using data from the Annual Social and Economic Supplement to the Current Population Survey and several other sources. Using data collected in the state of Tennessee, this article presents a less complicated and arguably less expensive alternative to that method, while providing comparable results. Limitations of both methods and suggestions for future research are discussed.

Assessing the impact of the local environment on birth outcomes: a case for HLM.

Hierarchical linear Models (HLM) is a useful way to analyze the relationships between community level environmental data, individual risk factors, and birth outcomes. With HLM we can determine the effects of potentially remediable environmental conditions (e.g., air pollution) after controlling for individual characteristics such as health factors and socioeconomic factors. Methodological limitations of ecological studies of birth outcomes and a detailed analysis of the varying models that predict birth weight will be discussed. Ambient concentrations of criterion air pollutants (e.g., lead and sulfur dioxide) demonstrated a sizeable negative effect on birth weight; while the economic characteristics of the mother's residential census tract (ex. poverty level) also negatively influenced birth weight.

Comparison of spatial scan statistic and spatial filtering in estimating low birth weight clusters.

BACKGROUND: The purpose of this study is to examine the spatial and population (e.g., socio-economic) characteristics of low birthweight using two different cluster estimation techniques. We compared the results of Kulldorff's Spatial Scan Statistic with the results of Rushton's Spatial filtering technique across increasing sizes of spatial filters (circle). We were able to demonstrate that varying approaches exist to explore spatial variation in patterns of low birth weight. RESULTS: Spatial filtering results did not show any particular area that was not statistically significant based on SaTScan. The high rates, which remain as the filter size increases to 0.4, 0.5 to 0.6 miles, respectively, indicate that these differences are less likely due to chance. The maternal characteristics of births within clusters differed considerably between the two methods. Progressively larger Spatial filters removed local spatial variability, which eventually produced an approximate uniform pattern of low birth weight. CONCLUSION: SaTScan and Spatial filtering cluster estimation methods produced noticeably different results from the same individual level birth data. SaTScan clusters are likely to differ from Spatial filtering clusters in terms of population characteristics and geographic area within clusters. Using the two methods in conjunction could provide more detail about the population and spatial features contained with each type of cluster.

Pterygium surgery with mitomycin and tarsorrhaphy.

PURPOSE: To determine if a pterygium surgical procedure consisting of minimal conjunctival removal, excision of the hypertrophic subconjunctival fibrovascular tissue, application of mitomycin 0.25 mg/mL for 1 minute combined with temporary nasal tarsorrhaphy, and use of postoperative dexamethasone/antibiotic drops achieves the following: safely simplifies pterygium removal, controls the early side effects of mitomycin, reduces the rate of recurrence, and lessens the need for conjunctival transplantation. METHODS: Twenty eyes in 19 patients underwent the procedure with use of mitomycin; 15 eyes had primary and 5 had recurrent pterygia. These were compared with a previous group of 28 eyes in 26 patients that underwent pterygium/tarsorrhaphy surgery without use of mitomycin; 20 eyes had primary and 8 had recurrent pterygia. Postoperatively, all eyes in both groups were treated with dexamethasone/antibiotic drops. RESULTS: In the mitomycin group, with an average follow-up of 12.1 months, 19 eyes healed uneventfully; there have been no recurrences. The nonmitomycin group, with an average follow-up of 42.6 months, has had nine recurrences (32%); four required a second procedure. Recurrence was significantly lower in the mitomycin group (P = .006). Conjunctival healing, as reflected in the time from surgery until tarsorrhaphy opening, was significantly delayed in the mitomycin group, 36.7 versus 17 days (P = .001). The delay in conjunctival healing may explain the complications associated with the use of mitomycin in pterygium surgery. CONCLUSION: Minimal conjunctival removal, extensive fibrovascular tissue excision, 1-minute application of mitomycin 0.25 mg/mL, temporary nasal tarsorrhaphy, and frequent application of dexamethasone/antibiotic drops postoperatively provided a safe and successful approach to pterygium management in this series.

Do Mexican Americans perceive environmental issues differently than Caucasians: a study of cross-ethnic variation in perceptions related to water in Tucson.

Little is known about the environmental perceptions of our nation's Mexican and Mexican American population, especially in the area of water quality. We examined these perceptions to determine the extent to which Caucasians and Mexican Americans living in the Tucson, Arizona, metropolitan area differ in their perceptions of water quality-related risk, inequity, trust, and participation in civic activities. Ethnic variations in perceptions toward inequity, trust, and public participation were observed even when socioeconomic variation between Caucasians and Mexican Americans was controlled. However, significant ethnic variations in perceptions of water quality-related risks were observed only when socioeconomic variation was not controlled. Implications of these findings to environmental justice efforts in Mexican American communities are discussed.