Nitric oxide metabolites as biomarkers for influenza-like acute respiratory infections presenting to the emergency room

Aims: Nitric oxide (NO) is increased in the respiratory tract in pulmonary infections. The aim was to determine whether nasal wash NO metabolites could serve as biomarkers of viral pathogen and disease severity in children with influenza-like illness (ILI) presenting to the emergency department (ED) during the 2009 influenza A H1N1 pandemic. Methods: Children ≤18 years old presenting to the ED with ILI were eligible. Nasal wash specimens were tested for NO metabolites, nitrate and nitrite, by HPLC and for respiratory viruses by real-time PCR. Results: Eighty-nine patients with ILI were prospectively enrolled during Oct-Dec, 2009. In the entire cohort, nasal wash nitrite was low to undetectable (interquartile range [IQR], 0 - 2 μM), while median nitrate was 3.4 μM (IQR 0-8.6). Rhinovirus (23%), respiratory syncytial virus (RSV) (20%), novel H1N1 (19%), and adenovirus (11%) were the most common viruses found. Children with RSV subtype B-associated ILI had higher nitrate compared to all other viruses combined (P=0.002). Conclusion: Concentration of NO-derived nitrate in nasal secretions in children in the ED is suggestive of viral pathogen causative for ILI, and thus might be of clinical utility. Predictive potential of this putative biomarker for ILI needs further evaluation in sicker patients in a prospective manner

Urinary nitrate might be an early biomarker for pediatric acute kidney injury in the emergency department

NO is involved in normal kidney function and perturbed in acute kidney injury (AKI). We hypothesized that urinary concentration of NO metabolites, nitrite, and nitrate would be lower in children with early AKI presenting to the emergency department (ED), when serum creatinine (SCr) was uninformative. Patients up to 19 y were recruited if they had a urinalysis and SCr obtained for routine care. Primary outcome, AKI, was defined by pediatric Risk, Injury, Failure, Loss of function, End-stage renal disease (pRIFLE) criteria. Urinary nitrite and nitrate were determined by HPLC. A total of 252 patients were enrolled, the majority (93%) of whom were without AKI. Although 18 (7%) had AKI by pRIFLE, 50% may not have had it identified by the SCr value alone at the time of visit. Median urinary nitrate was lower for injury versus risk (p = 0.03); this difference remained significant when the injury group was compared against the combined risk and no AKI groups (p = 0.01). Urinary nitrite was not significantly different between groups. Thus, low urinary nitrate is associated with AKI in the pediatric ED even when SCr is normal. Predictive potential of this putative urinary biomarker for AKI needs further evaluation in sicker patients

Consenting Postpartum Women for Use of Routinely Collected Biospecimens and/or Future Biospecimen Collection

The National Children’s Study (NCS) Harris County, Texas Study Center participated in the NCS Provider Based Sampling (PBS) substudy of the NCS Vanguard Phase pilot. As part of the hospital-based birth cohort component of the PBS substudy, we conducted a secondary data analysis to evaluate the proportion of postpartum women who consented to future biospecimen collection alone and to both future collection and use of residual birth biospecimens. In phase 1, 32 postpartum women at one hospital were asked to consent only to maternal future biospecimen collection. In phase 2, 40 other postpartum women from the same hospital were asked for an additional consent to use residual clinical biospecimens from the birth event that otherwise would be discarded, including cord blood and maternal blood and urine. Among 103 eligible women, a total of 72 participated. They were 28.3 ± 5.9 years old on average; 58 % were Hispanic; 63 % consented in English, and 37 % in Spanish; 39 % had some college education; 42 % were married; 60 % had an annual family income \u3c$30,000; and 51 % were employed. In phase 1, 59 % consented to future biospecimen collection, and in phase 2, 95 % consented to both future collection and use of at least one residual birth biospecimen, with a difference between phases of 36 % [95 % CI 17–54 %]. Demographic characteristics did not differ among those who did and did not consent. Postpartum women were significantly more likely to grant consent for use of future and residual hospital-obtained biospecimens than future biospecimen collection alone

Multilevel Provider-Based Sampling for Recruitment of Pregnant Women and Mother-Newborn Dyads

Objective: In 2010, the National Children’s Study launched 3 alternative recruitment methods to test possible improvements in efficiency compared with traditional household-based recruitment and participant enrollment. In 2012, a fourth method, provider-based sampling (PBS), tested a probability-based sampling of prenatal provider locations supplemented by a second cohort of neonates born at a convenience sample of maternity hospitals. Methods: From a sampling frame of 472 prenatal care provider locations and 59 maternity hospitals, 49 provider and 7 hospital locations within or just outside 3 counties participated in study recruitment. During first prenatal care visits or immediately postdelivery at these locations, face-to-face contact was used to screen and recruit eligible women. Results: Of 1450 screened women, 1270 were eligible. Consent rates at prenatal provider locations (62%–74% by county) were similar to those at birth locations (64%–77% by county). During 6 field months, 3 study centers enrolled a total prenatal cohort of 530 women (the majority in the first trimester) and during 2 months enrolled a birth cohort of an additional 320 mother-newborn dyads. As personnel became experienced in the field, the time required to enroll a woman in the prenatal cohort declined from up to 200 hours to 50 to 100 hours per woman recruited. Conclusions: We demonstrated that PBS was feasible and operationally efficient in recruiting a representative cohort of newborns from 3 diverse US counties. Our findings suggest that PBS is a practical approach to recruit large pregnancy and birth cohorts across the United States