Biomedical subjects

William Oh

Publications and source records attributed to William Oh.

27 records · Page 2Linked to original sources

PubMed2003

Association between peak serum bilirubin and neurodevelopmental outcomes in extremely low birth weight infants.

OBJECTIVE: To assess the association between peak total serum bilirubin (PSB) levels during the first 2 weeks of life and neurodevelopmental outcomes of extremely low birth weight (ELBW) infants at 18 to 22 months' postmenstrual age. METHODS: A retrospective analysis was conducted of a cohort of ELBW infants (401-1000 g) who survived to 14 days of age in the 12 participating centers of the National Institute of Child Health and Human Development Neonatal Research Network between January 1, 1994, and December 31, 1997. Demographic and clinical risk factors and PSB levels during the first 14 days were analyzed with reference to death or adverse neurodevelopmental outcomes at 18 to 22 months' postmenstrual age. The neurodevelopmental variables considered were Psychomotor Developmental Index (PDI) <70, Mental Developmental Index (MDI) <70, moderate or severe cerebral palsy (CP), hearing impairment (needs hearing aids), and a composite category designated as neurodevelopmental impairment (NDI). The NDI is defined as infants with any 1 or more of the following: PDI <70, MDI <70, moderate to severe CP, bilateral blindness, or bilateral hearing impairment requiring amplification. RESULTS: The subjects of this cohort analysis are infants who were admitted to the Network centers during calendar years 1994-1997 and survived beyond 14 days and had PSB recorded during the 14-day period. From this cohort, 3246 infants survived at discharge, 79 died after discharge, and 592 were lost to follow-up. Thus, 2575 of 3167 infants were seen in the follow-up clinics with a compliance rate of 81%. Logistic regression analysis showed that various demographic and clinical variables are associated with poor neurodevelopmental outcomes. After adjustment for these risk factor, significant association were found between PSB (mg/dL) and death or NDI (odds ratio: 1.068; 95% confidence interval [CI]: 1.03-1.11); PDI <70 (R = 1.057; 95% CI: 1.00-1.12), and hearing impairment requiring hearing aids (odds ratio: 1138; 95% CI: 1.00-1.30). There was no significant association between PSB (mg/dL) and CP, MDI <70, and NDI. CONCLUSIONS: PSB concentrations during the first 2 weeks of life are directly correlated with death or NDI, hearing impairment, and PDI <70 in ELBW infants. The statistical association based on retrospective analysis of observational data and relatively small effect size should be interpreted with caution. Furthermore, because of the possibility of compounding effects of variables on outcome, the potential benefits of moderate hyperbilirubinemia and the potential adverse effects of phototherapy, a randomized, controlled trial of aggressive and conservative phototherapy is needed to address this controversial issue.

Bilirubin↗

PubMed2002

Changes in pathogens causing early-onset sepsis in very-low-birth-weight infants.

BACKGROUND: It is uncertain whether the rates and causes of early-onset sepsis (that occurring within 72 hours after birth) among very-low-birth-weight infants have changed in recent years, since antibiotics have begun to be used more widely during labor and delivery. METHODS: We studied 5447 very-low-birth-weight infants (those weighing between 401 and 1500 g) born at centers of the Neonatal Research Network of the National Institute of Child Health and Human Development between 1998 and 2000 who had at least one blood culture in the first three days of life and compared them with 7606 very-low-birth-weight infants born at centers in the network between 1991 and 1993. RESULTS: Early-onset sepsis (as confirmed by positive blood cultures) was present in 84 infants in the more recent birth cohort (1.5 percent). As compared with the earlier birth cohort, there was a marked reduction in group B streptococcal sepsis (from 5.9 to 1.7 per 1000 live births of infants weighing 401 to 1500 g, P<0.001) and an increase in Escherichia coli sepsis (from 3.2 to 6.8 per 1000 live births, P=0.004); the overall rate of early-onset sepsis was not significantly changed. Most E. coli isolates from the recent birth cohort (85 percent) were resistant to ampicillin, and mothers of infants with ampicillin-resistant E. coli infections were more likely to have received intrapartum ampicillin than were those with ampicillin-sensitive strains (26 of 28 with sensitivity data vs. 1 of 5, P=0.01). Infants with early-onset sepsis were more likely to die than uninfected infants (37 percent vs. 13 percent, P<0.001), especially if they were infected with gram-negative organisms. CONCLUSIONS: Early-onset sepsis remains an uncommon but potentially lethal problem among very-low-birth-weight infants. The change in pathogens over time from predominantly gram-positive to predominantly gram-negative requires confirmation by ongoing surveillance.

Ampicillin↗

PubMed2002

Initial decline in hemoglobin during neoadjuvant hormonal therapy predicts for early prostate specific antigen failure following radiation and hormonal therapy for patients with intermediate and high-risk prostate cancer.

BACKGROUND: Declines in serum hemoglobin (Hgb) levels occur from the use of androgen suppression therapy (AST) in the treatment of prostate cancer patients. We studied whether time to prostate specific antigen (PSA) failure following external beam radiation therapy (RT) and AST could be predicted by the rate of decline in the Hgb level following the administration of neoadjuvant AST or by the Hgb level at presentation or at the start of RT. METHODS: The study cohort comprised 110 intermediate or high-risk prostate cancer patients who were managed using three-dimensional conformal RT (70 Gy) and 6 months of AST (2 months neoadjuvant, concurrent, and adjuvant). A Cox regression multivariable analysis was performed to evaluate the ability of the rate of decline of the Hgb from baseline to the start of RT, baseline PSA level, Gleason score, percent positive biopsies, and T-category to predict time to PSA failure. RESULTS: A decline in the Hgb level of 1 g/dL or more during the first month of AST was the only significant predictor of time to PSA failure (P = 0.02) on multivariable analysis. The relative risk of PSA failure (95% confidence interval) for patients with a decline in Hgb level during the first month (> or = 1 g/dL vs. < 1 g/dL) was 6.3 (2.4, 8.3) and the 3-year estimate of PSA outcome was 66% versus 82% (P = 0.04), respectively. There were no imbalances in the pretreatment prognostic factors or length of follow-up in each of these groups. CONCLUSION: A decline of 1 g/dL or more in Hgb level during the first month of neoadjuvant AST was a predictor of early PSA failure following RT and AST in intermediate and high-risk prostate cancer patients.

Aged↗

PubMed2002

Risk factors for early death among extremely low-birth-weight infants.

OBJECTIVE: The purposes of this study were to compare the clinical characteristics of extremely low birth-weight infants (501-1000 g birth weight) who die early (<12 hours of age) with those of infants who die >12 hours after birth and infants who survive to neonatal intensive care unit discharge and to develop a model of risk for early death. STUDY DESIGN: Perinatal data were prospectively collected on 5986 infants in the 12 participating centers of the National Institute of Child Health and Human Development Neonatal Research Network from March 1993 through December 1997. Maternal and neonatal characteristics of infants who died early were compared with infants who survived and infants who died beyond 12 hours of age. A model for risk for early death was developed by logistic regression analysis, with results expressed as odds ratio with 95% CI. RESULTS: Mothers of infants who died early were more likely to be delivered in an inborn setting and experience labor and were less likely to have hypertension or preeclampsia, to receive antenatal corticosteroids, or to be delivered by cesarean birth than mothers of infants who died >12 hours after birth or infants who survived. Infants who died early were more likely to have lower Apgar scores and lower gestational age/birth weight and were less likely to be intubated at birth and to receive mechanical ventilation and surfactant therapy than infants who died >12 hours after birth or infants who survived. Greater risk for early death versus survival to neonatal intensive care unit discharge was associated with the lack of surfactant administration (odds ratio, 8.6; 95% CI, 6.3-11.9), lack of delivery room intubation (odds ratio, 5.3; 95% CI, 3.5-8.1), lack of antenatal corticosteroid use (odds ratio, 2.3; 95% CI, 1.6-3.2), lower 1-minute Apgar score (odds ratio, 2.0; 95% CI, 1.8-2.2), male sex (odds ratio, 1.7; 95% CI, 1.3-2.3), multiple gestation (odds ratio, 1.7; 95% CI, 1.2-2.5), no tocolytics (odds ratio, 1.7; 95% CI, 1.2-2.3), lower gestational age per week (odds ratio, 1.4; 95% CI, 1.3-1.6), and lower birth weight per 50 g (95% CI, 1.2-1.4). CONCLUSION: Early death (<12 hours of age) among extremely low-birth-weight infants may reflect an assessment of non-viability by obstetricians and neonatologists.

Adrenal Cortex Hormones↗

PubMed2002

Neurodevelopmental outcome of premature infants after antenatal phenobarbital exposure.

OBJECTIVE: We previously demonstrated that antenatal phenobarbital does not decrease the risk of intracranial hemorrhage or early death in premature infants. The objective of the present study was to evaluate the impact of antenatal phenobarbital exposure on the neurodevelopmental outcome of premature infants born to women who were participating in the randomized clinical trial of antenatal phenobarbital exposure. STUDY DESIGN: Infants were evaluated at 18 to 22 months corrected age with a standard neurologic examination and the Bayley scales of infant development measuring the mental developmental index and the psychomotor developmental index. RESULTS: Of the 578 infants <34 weeks of gestational age who were born to women who were enrolled in the primary study, 7 infants died after discharge from the neonatal intensive care unit, and 135 infants were lost to follow-up. Infants who were lost to follow-up had a higher mean birth weight and gestational age and a lower maternal education, but the rates of intracranial hemorrhage were comparable to those infants who were evaluated. Among the infants who were evaluated (n = 436; 76%), the mean birth weight and gestational age, maternal education, and frequency and distribution of intracranial hemorrhage were similar in the antenatal phenobarbital exposed and placebo groups. Eighteen infants (8%) in the antenatal phenobarbital exposed group and 21 infants (11%) in the placebo group had cerebral palsy (P = not significant). There was no difference between the 2 groups in either the median Bayley II mental developmental index (85 in the antenatal phenobarbital and 86 in the placebo group) or the Psychomotor Developmental Index (91 in the antenatal phenobarbital and 91 in the placebo group). Infants with intracranial hemorrhage (23%) had significantly lower mental developmental index and psychomotor developmental index scores than infants with no intracranial hemorrhage, independent of antenatal phenobarbital exposure. In the total cohort of 436 infants, the presence of intracranial hemorrhage or periventricular leukomalacia was associated with lower mental developmental index and psychomotor developmental index scores; the presence of increasing birth weight, maternal education, and a complete course of antenatal steroids was associated with a higher mental developmental index score. CONCLUSION: Antenatal phenobarbital exposure did not favorably or adversely affect the neurodevelopmental outcome of premature infants at 18 to 22 months of age.

Anticonvulsants↗

PubMed2002

Diluted tincture of opium (DTO) and phenobarbital versus DTO alone for neonatal opiate withdrawal in term infants.

OBJECTIVE: The purpose of this study was to test the hypothesis that treatment of neonatal opiate withdrawal (NOW) in the term infant with diluted tincture of opium (DTO) and phenobarbital was superior to treatment with DTO alone. STUDY DESIGN: This was a partially randomized, controlled trial in which 20 term infants exposed to methadone and/or heroin in utero were studied. The severity of NOW was assessed by using the Finnegan scoring system. Infants were assigned to either DTO and placebo (n = 10) or DTO and phenobarbital (n = 10) when medication was required. The primary outcome variable was the duration of hospitalization. Severity of withdrawal and hospital cost were secondary outcome variables. RESULTS: There were no significant differences in the gestational age, growth variables, maternal methadone dose, or age at enrollment between the 2 groups. The duration of hospitalization was reduced by 48% (79-38 days) (P <.001) and hospital cost per patient reduced by $35,856 (P <.001) for the DTO and phenobarbital group. Furthermore, these infants spent less time with severe withdrawal (P <.04), more time with mild withdrawal (P <.03), and required a lower maximum daily DTO dose (P <.009) when compared with the DTO-only group. The average duration of outpatient phenobarbital use was 3.5 months. CONCLUSIONS: The combined use of DTO and phenobarbital resulted in a shorter duration of hospitalization, less severe withdrawal, and reduced hospital cost. This combination may be a preferred regimen for the treatment of NOW.

Analgesics, Opioid↗

PubMed2002

Minimal ventilation to prevent bronchopulmonary dysplasia in extremely-low-birth-weight infants.

OBJECTIVE: To determine whether minimal ventilation decreases death or bronchopulmonary dysplasia (BPD). STUDY DESIGN: Infants with birth weight 501 g to 1000 g and mechanically ventilated before 12 hours were randomly assigned to minimal ventilation (partial pressure of carbon dioxide [PCO(2)] target >52 mm Hg) or routine ventilation (PCO(2) target <48 mm Hg) and a tapered dexamethasone course or saline placebo for 10 days, using a 2 x 2 factorial design. The primary outcome was death or BPD at 36 weeks' postmenstrual age. RESULTS: After enrollment of 220 patients, the trial was halted because of unanticipated nonrespiratory adverse events related to dexamethasone therapy. The relative risk for death or BPD at 36 weeks in the minimal versus routine ventilation groups was 0.93 (95% CI, 0.77-1.12; P =.43). Ventilator support at 36 weeks was 1% in the minimal versus 16% in the routine group (P <.01). Major morbidities and long-term outcome were comparable in both treatment groups. CONCLUSIONS: With the sample size studied, minimal ventilation did not reduce the incidence of death or BPD. The reduced ventilator support at 36 weeks in the minimal ventilation group warrants further study of this intervention.

Anti-Inflammatory Agents↗

PubMed2002

Late-onset sepsis in very low birth weight neonates: the experience of the NICHD Neonatal Research Network.

OBJECTIVE: Late-onset sepsis (occurring after 3 days of age) is an important problem in very low birth weight (VLBW) infants. To determine the current incidence of late-onset sepsis, risk factors for disease, and the impact of late-onset sepsis on subsequent hospital course, we evaluated a cohort of 6956 VLBW (401-1500 g) neonates admitted to the clinical centers of the National Institute of Child Health and Human Development Neonatal Research Network over a 2-year period (1998-2000). METHODS: The National Institute of Child Health and Human Development Neonatal Research Network maintains a prospective registry of all VLBW neonates admitted to participating centers within 14 days of birth. Expanded infection surveillance was added in 1998. RESULTS: Of 6215 infants who survived beyond 3 days, 1313 (21%) had 1 or more episodes of blood culture-proven late-onset sepsis. The vast majority of infections (70%) were caused by Gram-positive organisms, with coagulase-negative staphylococci accounting for 48% of infections. Rate of infection was inversely related to birth weight and gestational age. Complications of prematurity associated with an increased rate of late-onset sepsis included patent ductus arteriosus, prolonged ventilation, prolonged intravascular access, bronchopulmonary dysplasia, and necrotizing enterocolitis. Infants who developed late-onset sepsis had a significantly prolonged hospital stay (mean length of stay: 79 vs 60 days). They were significantly more likely to die than those who were uninfected (18% vs 7%), especially if they were infected with Gram-negative organisms (36%) or fungi (32%). CONCLUSIONS: Late-onset sepsis remains an important risk factor for death among VLBW preterm infants and for prolonged hospital stay among VLBW survivors. Strategies to reduce late-onset sepsis and its medical, social, and economic toll need to be addressed urgently.

Anti-Infective Agents↗

PubMed2002

Whole-body hypothermia for neonatal encephalopathy: animal observations as a basis for a randomized, controlled pilot study in term infants.

OBJECTIVE: Modest reduction in brain temperature is a promising therapy to reduce brain damage after neonatal encephalopathy as a result of acute perinatal asphyxia. The efficacy of modest hypothermia may in part be dependent on the stability of the desired brain temperature. The objective of this study was 1) to evaluate in newborn animals a commercially available cooling system (Blanketrol II Hyperthermia-Hypothermia system) to control brain temperature during whole-body hypothermia and 2) to use the results of the animal experiments to perform a pilot study evaluating the feasibility of whole-body hypothermia as a neuroprotective therapy for newborns with encephalopathy at birth. METHODS: In the animal investigation, 3 miniature swine were instrumented and ventilated, and temperature probes were placed in the esophagus and the brain (1 cm and 2 cm beneath the parietal cortical surface and the dura). Body cooling was achieved using the automatic control mode (servo) of the cooling system. In the human investigation, 19 term infants with moderate or severe encephalopathy were randomized to either normothermia (n = 10) or hypothermia (n = 9) within 6 hours of birth. Whole-body hypothermia was achieved using the hyperthermia-hypothermia cooling system with servo control of esophageal temperature to 34.5 degrees C for 72 hours followed by slow rewarming. RESULTS: In the animal investigation, body cooling with the animal lying on a single blanket resulted in rapid cooling of the body within 90 minutes. Repetitive cyclical swings in esophageal temperature of 1.7 +/- 0.2 degrees C (mean +/- standard deviation) around the set point of 33.5 degrees C were reduced to 0.7 +/- 0.2 degrees C when a second, larger blanket was attached and suspended. Esophageal temperature was a good marker of deep brain temperature (esophageal to 2-cm brain difference: 0.1 +/- 0.3 degrees C). In the human investigation, the infants were randomized at 4.1 +/- 1.3 hours (mean +/- standard deviation) after birth. Age at randomization was similar in the 2 groups. Cooling was initiated at an average age of 5.3 hours. Target temperature of 34.5 degrees C was achieved within 30 minutes and remained constant throughout the intervention period. Heart rate decreased to 108 +/- 14 beats per minute (bpm) at 60 minutes and remained between 115 and 130 bpm for the duration of cooling compared with 130 to 145 bpm in the normothermia group. Blood pressure was similar in the 2 groups. No adverse events occurred during 72 hours of cooling. The mortality rate and frequency of persistent pulmonary hypertension, renal failure, hepatic dysfunction, and need for pressor support were similar in both groups. CONCLUSIONS: Animal studies showed that a simple modification of a commercially available cooling system (2 blankets attached, subject lying on 1 and the second hanging freely) results in stable core body and brain temperature when used in the automatic control mode. The pilot study in term infants with encephalopathy using this cooling system demonstrates feasibility of initiating whole-body hypothermia at <6 hours of age to a constant esophageal temperature using servo control and provides no evidence that hypothermia involved greater hazard than benefit.

Animals↗