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Biomedical subjects

G B Avery

Publications and source records attributed to G B Avery.

At least 19 recordsLinked to original sources
PubMed1998

Futility considerations in the neonatal intensive care unit.

The purpose of this article is to summarize and comment on the history of medical decision making in the neonatal intensive care nursery, emphasizing considerations of futility. Several epochs will be described, with shifting roles of health care providers, the infant's family, and proxies for society at large. Futility has been an issue in the intensive care of newborn infants throughout the last 35 years. Long before the Baby Doe regulations and the formation of ethics committees, neonatologists tried to determine which care measures were indicated. Given the frequency of severe malformations, birth asphyxia, and extreme prematurity, it has been a common event for the responsible physician to ask himself: will this treatment be beneficial or merely futile? As the therapeutic armamentarium became more powerful and complex, the choices from among a possible array of interventions became increasingly difficult. The autonomy of parents as decision makers was increasingly affirmed. In the 1980s, the federal government, the courts, and frequent malpractice suits set boundaries on medical decision making. In the 1990s, third party payors became increasingly assertive in limiting resource expenditure. These legal and societal mandates are frequently at variance with one another. Thus the issue of medical futility, as it applies to neonates in the United States, must be considered unresolved.

Decision Making↗
PubMed1988

Retinopathy of prematurity: progress report.

For the time being, risk of ROP seems inexorably linked to survival of extremely low birth weight prematures, whose embryonic retinas develop in an abnormal and fluctuating environment. Incidence and severity may be reduced by stabilizing ventilation, oxygenation, and perfusion, moderating light exposure, and providing normal levels of vitamin E. Progression of stage 3 retinopathy may sometimes be arrested by cryotherapy. In the future, antioxidants or other pharmacologic agents may be developed to provide a greater margin of safety. In the meantime, the eyes of prematures must be examined and those with ROP will need specialized ophthalmologic care.

Humans↗
PubMed1988

Retinopathy of prematurity: what causes it?

Retinopathy of prematurity continues to be a major cause of morbidity in surviving prematures despite attempts to regulate oxygen. Developing retinal vessels apparently can be disrupted by any of a considerable number of influences. By far the preeminent risk factor is extreme prematurity itself.

Humans↗
PubMed1987

Ethical dilemmas in the treatment of the extremely low birth weight infant.

Despite dramatically improved outcomes in prematures generally, the very smallest--those weighing below 750 grams--have a high mortality and a substantial morbidity among survivors. In addition, the cost and resource consumption required for care of these babies is large. Some survivors from this weight group appear to be entirely normal, however. Thus, there is a moral and ethical dilemma whether, for the sake of the potential intact survivors, the entire group should receive drastic life support. Today's neonatologist is caught in a crossfire of conflicting demands from families, referring physicians, federal and state regulations, hospital administrators, cost considerations, and personal ethical beliefs.

Ethics, Medical↗
PubMed1985

Effect of bright light in the hospital nursery on the incidence of retinopathy of prematurity.

The preterm infant is subjected to prolonged exposure to ambient nursery illumination at levels that have been found to produce retinal damage in animals. We prospectively investigated the effect of exposure to light in two intensive care nurseries by comparing the incidence of retinopathy of prematurity among 74 infants from the standard bright nursery environment (median light level, 60 foot-candles [ftc]) with the incidence among 154 infants of similar birth weight for whom the light levels were reduced (median, 25 ftc). There was a higher incidence of retinopathy of prematurity in the group of infants who had been exposed to the brighter nursery lights, particularly in those with birth weights below 1000 g (86 percent vs. 54 per cent, P less than 0.01 by chi-square test). We conclude that the high level of ambient illumination commonly found in the hospital nursery may be one factor contributing to retinopathy of prematurity and that safety standards with regard to current lighting practices should be reassessed.

Birth Weight↗
PubMed1985

Controlled trial of dexamethasone in respirator-dependent infants with bronchopulmonary dysplasia.

A randomized trial was conducted of dexamethasone therapy in infants with bronchopulmonary dysplasia who were dependent on respirators and were not progressing clinically despite conventional treatment. Babies were admitted to the study if they had a roentgenogram and clinical diagnosis of bronchopulmonary dysplasia, were 2 to 6 weeks in age, weighed less than 1,500 g, had made no progress in weaning for the preceding five days, and were free of sepsis, patent ductus arteriosus, and congenital heart disease, and had had no intravenous fat for at least 24 hours. After parental consent was obtained, infants were randomly assigned to control or treatment groups. The study hypothesis was that with steroid treatment, babies could be weaned from the respirator within 72 hours and would show a significant improvement in lung compliance within that time. Sequential analysis exceeded criterion (P less than .05) when seven consecutive untied pairs showed weaning with dexamethasone and failure to wean in control infants. Pulmonary compliance improved by 64% in the treated group and 5% in the control group (P less than .01). No significant intergroup differences were noted in mortality, length of hospital stay, sepsis, hypertension, hyperglycemia, or electrolyte abnormalities. Study design permits the conclusion that dexamethasone can produce substantial short-term improvement in lung function, often permitting rapid weaning from the respirator, but long-term efficacy and safety must be demonstrated by further investigations.

Bronchopulmonary Dysplasia↗
PubMed1984

Evaluation of a gastric tube with esophageal balloon for neonatal use.

A gastric tube with esophageal balloon was designed for neonatal use. The response of the balloon was evaluated. In vitro studies involved comparisons of pressure changes (delta P) in a flask, as measured directly, or as transferred via the balloon. Values for delta P ranged frm 5 cmH2O to 40 cmH2O, and frequencies from 10 to 1620 cycles per minute. The volume of air within the balloon was varied from 0.1 to 0.4 ml. At each combination of pressure, frequency and balloon volume, the balloon transmitted an accurate, if minimally lower delta P, than that imposed. In a rabbit, intraesophageal delta Ps measured via the balloon were compared with intrapleural delta Ps, measured via a chest tube. The frequency rates and delta Ps achieved were similar to those encountered in the clinical situation. The delta s measured via the balloon were frequently equal to or sometimes minimally lower than the actual pleural pressure changes. The prototype meets recommended dimensions for esophageal balloon use in the neonate and allows for accurate routine measurements for calculation of pulmonary function. The device is now available commercially.

Animals↗
PubMed1984

Nutrition for full-term and preterm infants. Meeting normal and exceptional needs.

Providing adequate nutrition for the healthy full-term newborn is relatively easy; breast milk or formula is sufficient for the first six months of life. Although the full-term infant's organ systems are relatively mature, the gastrointestinal tract is often stressed by the demands of rapid growth, and feeding difficulties, such as gastroesophageal reflux, colic, milk allergy, and constipation, may occur that necessitate special handling. The small preterm infant, however, has many urgent nutritional needs; management is usually complicated by the fact that the infant's immature organs may be unable to cope with enteral feedings. Thus, total parenteral nutrition is necessary, with extensive laboratory monitoring of metabolic functions and precise attention to detail to avoid a prolonged period of partial starvation.

Animals↗
PubMed1982

Congenital esophageal atresia: lipase activity is present in the esophageal pouch and stomach.

Lipolytic activity was studied in aspirates from the esophageal pouch and from the stomach of eight infants with congenital esophageal atresia. Lipolytic activity, tested with doubly labeled ([3H]glyceryl, [14C]fatty acid) long-chain triglyceride was present in esophageal and gastric aspirates. The activity in esophageal aspirates was in the range of 2.7-130 nmol/min/ml aspirate and that in gastric aspirates was in the range of 2.9-40.4 nmol/min/ml aspirate. The reaction products of lipolytic activity in esophageal and gastric aspirates were a mixture of mono- and diglycerides, glycerol, and free fatty acids. The lipolytic activity at the two sites--esophagus and stomach--varied with respect to pH optimum (5.0-7.6 and 6.0-6.5, respectively) and reaction products (glycerol 41.6 +/- 20% and 7.3 +/- 4.6%, respectively). These findings confirm the earlier observations that digestion of dietary fat is initiated in the stomach and suggest that the lipolytic activity present in gastric contents originates concomitantly from the oral-esophageal area as well as from the stomach. These studies do not exclude the possibility that the lipolytic activity in the stomach of infants with esophageal atresia could originate in regurgitated intestinal contents.

Esophageal Atresia↗
PubMed1982

Parenteral galactose therapy in the glucose-intolerant premature infant.

Blood galactose concentrations were measured in 55 neonates consuming at least 80 ml/kg/day of lactose-containing formula. The range of galactose concentration immediately after feeding was 0.8 to 4.2 mg/dl, with a mean of 1.5 +/- 0.2 mg/dl. Galactose concentration fell rapidly after feeding, and normal values for the population fell with a half-life of 45 minutes. Considering galactose as a potential intravenous nutrient, six glucose-intolerant premature infants were given galactose-containing solutions intravenously using a double-blind randomized crossover protocol. Infants were chosen who had sustained hyperglycemia (150 mg/dl) and glucosuria (2+ Clinitest) requiring glucose infusion at a rate below 7 mg/kg/minute for more than 24 hours. Compared to the control glucose period, intravenous alimentation with a solution containing carbohydrate as 50% glucose and 50% galactose resulted in a 65% increase in total carbohydrate infusion rate, normalization of the blood glucose concentration, and decreased glucosuria. Blood galactose concentration averaged 15 mg/dl, and no clinical or biochemical evidence of galactose toxicity was noted.

Blood Glucose↗