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J D Horbar

Publications and source records attributed to J D Horbar.

At least 37 records · Page 2Linked to original sources
PubMed1993

Decreasing mortality associated with the introduction of surfactant therapy: an observational study of neonates weighing 601 to 1300 grams at birth. The Members of the National Institute of Child Health and Human Development Neonatal Research Network.

OBJECTIVE: To determine whether the introduction of surfactant therapy was associated with decreased mortality for high-risk preterm neonates weighing 601 to 1300 g at birth. DESIGN: Before-after observational study. SETTING: Eight tertiary care neonatal intensive care units participating in the National Institute of Child Health and Human Development Neonatal Research Network. PATIENTS: The outcomes for neonates with birth weight 601 to 1300 g admitted in the 2 years before surfactants became available (n = 2780) were compared with those of neonates admitted in the year beginning 2 months after surfactants became available (n = 1413). MAIN OUTCOME MEASURES: The primary outcome measure was in-hospital mortality; secondary outcome measures included durations of assisted ventilation, length of hospitalization, and neonatal morbidity. RESULTS: Forty percent of neonates in the postsurfactant group received surfactant (range 28% to 69% at the centers). Mortality decreased from 27.8% before to 19.9% after surfactant therapy was introduced (Mantel-Haenszel chi 2 = 31.4, P = .001). The adjusted odds ratio for mortality after surfactants became available was 0.73 (95% confidence interval 0.55 to 0.95). The duration of assisted ventilation and length of hospitalization increased after surfactants were introduced (P = .0001 for both outcomes). CONCLUSION: Mortality for neonates weighing 601 to 1300 g decreased after surfactant therapy was introduced, suggesting that the efficacy of surfactants demonstrated in randomized controlled trials will translate into effectiveness in routine clinical care.

Female↗
PubMed1991

Radiographic findings associated with surfactant treatment.

Radiographs of the chest (CXR) were evaluated in 35 of 41 infants enrolled in a randomized controlled trial of modified bovine surfactant extract (Surfactant-TA Tokyo-Tanabe) treatment. Infants between birthweight 1000 and 1500 gm with respiratory distress syndrome requiring mechanical ventilation and an inspired oxygen concentration 0.4 or greater were randomly assigned to either a single intratracheal dose of saline or surfactant-TA prior to 8 hours of age. Radiographs obtained prior to treatment and 24 hours after treatment were reviewed by a radiologist (N.T.G.) without knowledge of treatment group. Evaluation consisted of a score including criteria for inflation of the lungs, density of the lungs, and extent of air bronchograms. Pneumothorax, pulmonary interstitial emphysema, and asymmetric parenchymal involvement were noted as well. No significant difference in CXR scores were noted in the two groups, before or after treatment. There was a greater incidence of pneumothorax and pulmonary interstitial emphysema in the control infants, which supports the role of surfactant in preventing barotrauma. Increased incidence of asymmetric parenchymal involvement was noted in the surfactant-treated infants. Further study of the possibility of drug maldistribution is warranted.

Female↗
PubMed1991

Very low birth weight outcomes of the National Institute of Child Health and Human Development Neonatal Network.

This report describes the neonatal outcomes of 1765 very low birth weight (less than 1500 g) infants delivered from November 1987 through October 1988 at the seven participating centers of the National Institute of Child Health and Human Development Neonatal Intensive Care Network. Survival was 34% at less than 751 g birth weight (range between centers 20% to 55%), 66% at 751 through 1000 g (range 42% to 75%), 87% at 1001 through 1250 g (range 84% to 91%), and 93% at 1251 through 1500 g (range 89% to 98%). By obstetric measures of gestation, survival was 23% at 23 weeks (range 0% to 33%), 34% at 24 weeks (range 10% to 57%), and 54% at 25 weeks (range 30% to 72%). Neonatal morbidity included respiratory distress (67%), symptomatic patent ductus arteriosus (25%), necrotizing enterocolitis (6%), septicemia (17%), meningitis (2%), urinary tract infection (4%), and intraventricular hemorrhage (45%, 18% grade III and IV). Morbidity increased with decreasing birth weight. Oxygen was administered for greater than or equal to 28 days to 79% of less than 751-g birth weight infants (range between centers 67% to 100%), 45% of 751- through 1000-g infants (range 20% to 68%), and 13% of 1001- through 1500-g infants (range 5% to 23%). Ventilator support for greater than or equal to 28 days was given to 68% of infants at less than 751 g, 29% at 751 through 1000 g, and 4% at greater than 1000 g. Hospital stay was 59 days for survivors vs 15 days for infants who died. Sixty-nine percent of survivors had subnormal (less than 10th percentile) weight at discharge. The data demonstrate important intercenter variation of current neonatal outcomes, as well as differences in philosophy of care and definition and prevalence of morbidity.

Gestational Age↗
PubMed1990

A European multicenter randomized controlled trial of single dose surfactant therapy for idiopathic respiratory distress syndrome.

We performed a multicenter prospective randomized controlled trial to determine the efficacy and safety of the surfactant preparation, Survanta (Abbott Laboratories, Chicago, USA), for 750-1750 g infants with idiopathic respiratory distress syndrome, (IRDS) receiving assisted ventilation with 40% or more oxygen. One hundred and six eligible infants from the eight participating centers were randomly assigned between March 1986 and June 1987 to receive either surfactant (100 mg phospholipid/kg, 4 ml/kg) or air (4 ml/kg) administered into the trachea within 8 h of birth (median time of treatment 6.2 h, range 3.2-9.1 h). The study was stopped before enrollment was completed at the request of the United States Food and Drug Administration when significant differences were observed in incidence of periventricular-intraventricular hemorrhage (PIH), between the surfactant treated and control infants. Surfactant treated infants had larger average increases in the arterial-alveolar oxygen ratio, (a/A ratio) (P less than 0.0001), and larger average decreases in FiO2 (P less than 0.0001) and mean airway pressure, (MAP) (P less than 0.017) than controls over the 48 h following treatment. The magnitude of the differences between the surfactant and control groups were 0.19 (SE = 0.03) for a/A ratio, -0.28 (SE = 0.04) for FiO2 and -1.7 cm H2O (SE = 0.70) for MAP. The clinical status on days 7 and 28 after treatment was classified using four predefined ordered categories: (1) no respiratory support; (2) supplemental O2 with or without continuous positive airway pressure (CPAP); (3) intermittent mandatory ventilation; and (4) death. There were no statistically significant differences in the status categories on days 7 or 28 between surfactant and control infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1989

A multicenter randomized, placebo-controlled trial of surfactant therapy for respiratory distress syndrome.

We carried out a multicenter randomized, placebo-controlled trial to evaluate the efficacy and safety of surfactant in the treatment of respiratory distress syndrome. The study population was made up of newborn infants weighing 750 to 1750 g who were receiving assisted ventilation with 40 percent or more oxygen. The eligible infants received a single dose of either surfactant (100 mg of phospholipid per kilogram of body weight [4 ml per kilogram]) or an air placebo (4 ml per kilogram), administered into the trachea within eight hours of birth by an investigator not involved in the clinical care of the infant. When compared with the infants who received the placebo (n = 81), the infants who were treated with surfactant (n = 78) had a 0.12 greater average increase in the ratio of arterial to alveolar oxygen tension (P less than 0.0001), a 0.20 greater average decrease in the fractional inspiratory oxygen concentration (P less than 0.0001), and a 0.26-kPa greater average decrease in the mean airway pressure (P less than 0.0001) during the 72 hours after treatment. Pneumothorax was less frequent among the infants treated with surfactant than in the control group (13 percent vs. 37 percent; P = 0.0005). There were no statistically significant differences between the groups in the proportion of infants in each of five ordered clinical-status categories on day 7 (P = 0.08) or day 28 (P = 0.75) after treatment. There were also no significant differences between the groups in the frequency of bronchopulmonary dysplasia, patent ductus arteriosus, necrotizing enterocolitis, or periventricular-intraventricular hemorrhage. In each group, 17 percent of the infants died by day 28. We conclude that treatment with the single-dose surfactant regimen used in this study reduces the severity of respiratory distress during the 72 hours after treatment and decreases the frequency of pneumothorax, but that it does not significantly improve clinical status later in the neonatal period and does not reduce neonatal mortality. Further study of different surfactant regimens and patient-selection criteria will be required to determine whether this initial improvement can be translated into reductions in mortality or serious morbidity.

Bronchopulmonary Dysplasia↗
PubMed1988

Variability in 28-day outcomes for very low birth weight infants: an analysis of 11 neonatal intensive care units.

A retrospective study of all infants weighing 701 to 1,500 g born at 11 neonatal intensive care centers during 1983 and 1984 was performed to determine whether two specific 28-day outcomes, survival and survival without the need for supplemental oxygen, varied among the centers. Survival without the need for supplemental oxygen was chosen as a reflection of infants surviving without chronic lung disease. There were 1,776 live-born infants delivered during the 2-year study period. Of these infants, 85% (1,512) survived 28 days, a range of 80% to 92% at the individual centers. A total of 60% (1,056) of the infants were alive without supplemental oxygen on day 28, a range of 51% to 70% at the individual centers. Multivariate analysis demonstrated that both survival on day 28 (chi 2 = 23.9, P less than .01) and survival without supplemental oxygen on day 28 (chi 2 = 44.2, P less than .0001) varied significantly among centers after the effects of birth weight, gender, and race were taken into account. Female gender, nonwhite race, and increased birth weight were factors associated with improved rates of survival and survival without supplemental oxygen. The magnitude of outcome variation among centers was estimated by using the logistic regression models to predict what the outcomes would be if each center were to treat a standardized population consisting of all 1,776 study infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Birth Weight↗
PubMed1987

Prediction of arterial blood pressure in the premature neonate using the oscillometric method.

The noninvasive oscillometric measurement of blood pressure (BP) in preterm neonates has become a common practice in intensive care nurseries. The method has gained acceptance primarily through its correlation with direct arterial measurement. In this study, the oscillometric method (using Dinamap 1846) was compared with direct intra-arterial BP monitoring in 15 preterm infants. The 95% prediction intervals for individual oscillometric measurements were wide, ranging from 17 mm Hg for the mean BP to 20 mm Hg for the systolic and diastolic BP. The oscillometric method also underestimated intra-arterial systolic and mean BP and overestimated diastolic BP. Caution must be used when oscillometrically measuring BP in premature neonates.

Blood Pressure Determination↗
PubMed1987

A calculator program for determining indices of neonatal respiratory distress syndrome severity.

The potential for treating and preventing neonatal respiratory distress syndrome (RDS) with exogenous surfactant has created renewed interest in quantitative measures and derived scores that can be used to assess disease severity. Many different indices of RDS severity have been suggested. They are useful as outcome measures in clinical trials and may assist in the early identification of infants at risk for severe complications. In this article, a program for the Hewlett-Packard 41CV programmable calculator is presented that calculates indices of RDS severity based on ventilator settings and arterial blood gas values.

Carbon Dioxide↗
PubMed1987

Episodic abnormalities in transcutaneous oxygen (TcPO2) recorded during neonatal intensive care.

An automated TcPO2 data system was tested and used to: 1) quantitate the frequency and duration of hypoxemic and hyperoxemic events experienced during the first three days after birth by 25 very low birth weight infants, and 2) determine whether hypoxemic events were associated with the occurrence of periventricular-intraventricular hemorrhage. During the first three days after birth, infants experienced a median of 41 episodes with a TcPO2 less than 40 torr having a cumulative duration of 37 minutes, and a median of 28 episodes with a TcPO2 greater than 100 torr having a cumulative duration of 14 minutes. Most episodes were less than 30 seconds in duration, but in some infants the duration was longer. There was no association between the occurrence of periventricular-intraventricular hemorrhage and either the frequency or cumulative duration of episodes with a TcPO2 less than 40 torr. A major problem with automated TcPO2 data systems is the inability of currently available systems to recognize inaccurate TcPO2 data. Twenty-four per cent of the summary TcPO2 monitoring data collected in this study was contaminated with unreliable TcPO2 values. Before automated TcPO2 data systems can be recommended for widespread research use or for medicolegal documentation, the problem of data contamination must be resolved.

Blood Gas Monitoring, Transcutaneous↗
PubMed1987

Randomized controlled trial of exogenous surfactant for the treatment of hyaline membrane disease.

We conducted a prospective, randomized, unblinded, controlled trial of exogenous bovine surfactant (surfactant TA) in premature infants requiring ventilator support for the treatment of severe hyaline membrane disease. Forty-one low birth weight infants with severe hyaline membrane disease were randomly assigned to saline or surfactant therapy and treated within eight hours of birth. Significant improvements in oxygenation (increased arterial/alveolar PO2) and respiratory support (decreased mean airway pressure) were seen in the group receiving surfactant within four hours after treatment. These improvements were maintained in the surfactant-treated infants, who also had fewer pneumothoraces and fewer number of days in environments of fractional inspiratory oxygen greater than 0.4 mm Hg. No problems were associated with administration of surfactant, and no acute side effects were detected. We conclude that exogenous surfactant, administered early in the course of severe hyaline membrane disease, is an effective therapy that can diminish the amount of respiratory support required during the first 48 hours of life.

Animals↗
PubMed1985

A computer simulation of medical decision strategy performance.

This study demonstrates a computer model which can be used to compare the effects of errors in probability and utility estimation on the performance of Bayesian and alternative medical decision strategies. The model task requires choosing one of three treatments for a patient with one of three diseases based on the patient's state with respect to five binary cues and estimates of the prior probabilities of disease, the conditional probabilities of the cues and the utilities of the treatments. A classic decision analytic strategy uses Bayes' formula to calculate posterior probabilities of disease and chooses treatments based on maximization of expected value. Alternative strategies use likelihood ratios to calculate disease scores for each patient state and choose the treatment with highest payoff for the disease with the highest score. Two strategies with different cutoffs for the ratios are compared with a random strategy and a classic decision analytic strategy. The simulation results show that the payoffs for all strategies except the random strategy decline with increasing estimation error. The decision analytic strategy has the highest mean payoff at all levels of error. The differences between this optical strategy and the alternatives, however, decrease as estimation error increases, and the frequency with which the strategies based on simple diagnostic scoring rules outperform the formal Bayesian strategy increases.

Bayes Theorem↗
PubMed1983

Obstetric events and risk of periventricular hemorrhage in premature infants.

The relationships between selected obstetric factors and the occurrence of periventricular-intraventricular hemorrhage (PIH) was studied in a group of 77 infants weighing 1,200 g or less at birth. The diagnosis of PIH was made using ultrasonography or at autopsy in 42 (55%) of these infants. Univariate associations between PIH and gestational age (less than 30 weeks), duration of labor (greater than or equal to six hours), and vaginal delivery were found. Multivariate analysis, however, did not substantiate an association between PIH and any single obstetric factor. Log-linear analysis of multiway frequency tables showed significant second-order associations of PIH with gestational age and presentation during delivery and with duration of labor and presentation. A model for the risk of PIH based on gestational age, presentation, and duration of labor was derived using stepwise logistic regression. This model correctly predicted PIH in 70% (55) of the infants. Although obstetric factors may have a role in the pathogenesis of PIH, the interactions among factors, rather than single factors alone, are important.

Cerebral Hemorrhage↗
PubMed1983

Revising ranked probabilities: a Bayesian approach to incomplete knowledge.

Incomplete knowledge refers to situations in which a decision maker can rank the probabilities of occurrence for events of interest, but cannot specify these probabilities exactly. In this paper a Monte Carlo approach is used to investigate how physicians can arrive at revised or posterior rankings of disease probability given only rank order information about both the patient's prior probabilities of disease and the conditional probabilities of specific clinical findings for each disease. Computer-generated estimates of the expected frequencies of the posterior rankings are presented for the cases of 2, 3, and 4 disease states. The application of probability revision under conditions of incomplete knowledge to therapeutic decision making is discussed.

Bayes Theorem↗
PubMed1982

Real-time ultrasonography: its use in diagnosis and management of neonatal hydrocephalus.

Real-time ultrasonography of the brain is useful in the examination of neonates with suspected hydrocephalus. Abnormalities of the cerebral ventricles can be identified and changes in ventricular size determined with repeated studies performed at the bedside. The response of hydrocephalus to medical and surgical intervention can be monitored. We studied cases of hydrocephalic infants with myelomeningocele, posterior fossa cyst, posthemorrhagic hydrocephalus, meningitis, and congenital intracranial teratoma. We also studied the role of ultrasonography in the diagnosis and follow-up of these cases.

Brain Neoplasms↗