The effect of amniotic fluid aspiration on pulmonary function in the adult and newborn rabbit.

Aspiration of uncontaminated human amniotic fluid was investigated in adult and newborn rabbits and compared with three other experimental groups: 10% meconium solution, saline, and sham-injected controls. Fluids were injected into the trachea of adult animals (4 or 6 ml/kg body weight), newborn vaginally-delivered animals (a mean volume of 8 ml/kg), and cesarean-delivered animals before their first breath (a mean volume of 11 ml/kg). In adult animals aspirating amniotic fluid or saline, arterial PO2 measured over a 24-h period showed a mean difference between groups of less than 5% for both 4 and 6 ml/kg. Meconium aspiration produced a greater depression in PO2 than amniotic fluid aspiration (a mean difference of 16 and 31% for 4 and 6 ml/kg, respectively) and animals aspirating meconium showed a deteriorating trend over 24 h, whereas animals aspirating amniotic fluid improved. One of eight adult animals aspirating amniotic fluid died versus four of five aspirating meconium. All five animals aspirating saline 6 ml/kg survived. Lung weight and resting volume of adult animals aspirating amniotic fluid were not significantly different from animals aspirating saline or nothing. Lung pressure volume curves from adult animals aspirating amniotic fluid were nearly identical to controls. Histology showed significantly greater atelectasis in adult animals that received 6 ml/kg amniotic fluid than controls, but this was not different from saline. There was no association between the number of cells in amniotic fluid and arterial PO2 after aspiration or any other aspect of pulmonary function measured.(ABSTRACT TRUNCATED AT 250 WORDS)

Feeding practices of the very low-birth-weight infant within the first year.

Information summarized from early feeding practices of VLBW infants (1,500 gm. or less at birth) identified three prevalent practices which potentially could result in compromised nutrition for these babies: (1) Cereals were introduced at an early age. Feeding cereals before infants are developmentally ready may decrease formula intake or result in a forced feeding situation. (b) Two percent and skim milk were fed to approximately 50% of these infants within their first year of life. Feeding calorically dilute milk may reduce energy intake, as well as compromise the intake of essential fatty acids. (c) Whole cow's milk was introduced to some VLBW infants at an early age. The feeding of cow's milk to young infants without appropriate supplementation may predispose these infants to significant nutritional deficiencies and imbalances. Any one of these feeding practices could affect an infant's nutrient intake. If all three are encountered in the same baby, growth may be adversely affected. Whether increased attention to appropriate feeding practices during the first year of life would result in a more favorable growth outcome for VLBW infants is not known.

Growth outcome of the very low-birth-weight infant at one year.

Growth patterns of weight, length, and OFC complete through 12 months corrected age were determined for 122 VLBW infants who weighed 1,500 gm. or less and were 35 weeks or less gestational age at birth. Significant differences in growth were apparent when infants were grouped according to sex and appropriateness of intrauterine growth. When the mean values of each group were compared, the female AGA infants demonstrated growth at higher percentiles (NCHS term infant norms) for all three growth parameters (weight, length, and OFC). AGA male, SGA male, and SGA female infants all grew similarly, at lower percentiles for weight and length, when compared with the same norms. Growth in OFC was closest to term infant norms in all subgroups of infants. (formula; see text) Appropriateness of weight for length was determined for each of the infants at one year corrected age. The majority of the babies, regardless of subgroup, achieved weights and lengths greater than the 5th percentile and with normal weights for lengths. At 12 months corrected age, 30% remained below the 5th percentile in weight, 21% below the 5th percentile in length, and 14% below the 5th percentile in OFC. Eighteen infants (15%) demonstrated a disproportionately low weight for length (less than the 5th percentile).

Nutritional outcome of 207 very low-birth-weight infants in an intensive care unit.

Growth and feeding outcomes during the first weeks of life were prospectively evaluated in 207 critically ill, very low-birth-weight (VLBW) infants (birth weight less than 1,500 gm). Maximal weight loss occurrd by day 9, averaging 13 percent of birth weight, while birth weight was regained by day 18. Energy intake during initial weight gain (19 gm. per day) averaged 100 kcal per kilogram. Feeding and growth outcome were highly correlated (p of less than 0.001) with severity of illness but were not significantly related to sex, birth weight, or appropriateness of weight for gestational age.

Evaluation of a system for continuous neonatal blood pressure monitoring.

The purpose of this study was to determine the effects of varying infusion rates as well as different catheter sizes and types on the mean arterial pressure as measured by a system in which the pressure transducer is connected in series to the line of fluids being administered through the catheter. The results of this study show that, under most circumstances, errors in mean blood pressure measured by this system are minimal and clinically insignificant.

Effect of acute nonsurgical stress on fetal and maternal plasma glucose, glucagon and insulin concentration in sheep.

The purpose of this study was to investigate the effect of nonsurgical stress on plasma glucose, insulin and glucagon in the ewe and fetus. Plasma glucose, insulin and glucagon were measured before and after a 2 min period of verbal and physical startling of much greater magnitude than that to which we ewe is exposed during routine blood drawing. Studies were completed on 5 fed ewes, 5 fasted ewes and on 4 fetuses of fasted ewes. There were no significant differences after a startling compared to the control values. Thus, there appears no need to allow the ewe a prolonged period (more than 1-2 weeks) to become accustomed to handling by humans before chronic metabolic studies involving serum glucose, insulin and glucagon are undertaken.

Metabolic and hormonal response to chronic maternal fasting in the ewe.

The purpose of this study was to investigate the metabolic adaptations of the fetus during maternal starvation and to determine the changes of plasma insulin and glucagon concentrations in the fed state and during severe maternal fasting in the chronic fetal sheep preparation. Maternal fasting resulted in a decrease in maternal and fetal plasma glucose as well as a decrease in fetal plasma fructose. Fetal-maternal arterial urea concentration differences increased with maternal fasting, suggesting increased fetal amino acid catabolism. Both maternal anf fetal plasma insulin decreased parallel to the decrease in plasma glucose concentration. Maternal glucagon did not change significantly during fasting and with a short-term fast there was no change in fetal glucagon concentration. However, by 6 days of fasting, the fetal glucagon concentration tended to increase.

Improved survival of ventilated neonates with modern intensive care.

The records of 909 infants who required mechanical ventilation over a 42-month period were reviewed; 68.3% of the infants survived. The highest survival rate was in infants with persistent fetal circulation and hyaline membrane disease, and the lowest in infants with congenital anomalies and miscellaneous diseases. The survival rate for each year of the 3 1/2-year study increased from the previous year. There was also a dramatic increase in the survival rate in infants with a birth weight greater than 1,250 gm.

An analysis of tolazoline therapy in the critically-ill neonate.

There were 47 seriously-ill neonates with medical causes of respiratory distress and 10 infants with severe respiratory distress secondary to a congenital diaphragmatic hernia treated with tolazoline according to a strict protocol designed to manage persistent fetal circulation (PFC). Of the 47 infants, 28 (60%) had a positive response defined as an increase in the pO2 greater than or equal to 24 mm Hg within 4 hr of beginning the drug. Of 7 infants, 4 with congenital diaphragmatic hernia had a positive response. The mean increase in the pO2 for the 47 infants was statistically significant (p less than .05). Of the 47 infants with medical disorders, 27 survived (survival 57%), whereas only 2 of the 10 infants with congenital diaphragmatic hernia and severe persistent fetal circulation survived (survival 28%). Erythema (60%), hematest positive gastric aspirates (55%), thrombocytopenia (45%), hyponatremia (40%) and increased gastric aspirates (36%) were the most common adverse effects occurring during tolazoline infusion. Hypotension occurred in nine cases, but was transient. Of the 27 survivors, 20 with medical causes of persistent fetal circulation were evaluated at age 1 yr. Eighty percent of these infants studied were considered normal as defined by an MDI and PI of the Bayley Scales of greater than or equal to 70. These data suggest that tolazoline is a useful adjunct in the management of neonates with PFC. In addition, tolazoline was more effective in mechanically ventilated neonates treated with respiratory paralytic agents. Although tolazoline resulted in a significant improvement in the paO2 in 4 infants with congenital diaphragmatic hernia, it did not appear to improve mortality in these infants.

The use of metrizamide (amipaque) to visualise the gastrointestinal tract in children: a preliminary report.

Metrizamide (amipaque) has not been used previously as a diagnostic contrast agent in the gastrointestinal tract. Metrizamide is a water-soluble isotonic contrast material having many advantages over barium and existing hypertonic water-soluble agents. There are many clinical situations in children in which metrizamide should be the contrast agent of choice for investigating the gastrointestinal tract. Four neonates are presented in whom barium or gastrografin were absolutely contraindicated. In each case metrizamide gave excellent visualization of the gastrointestinal tract. It could be followed through be bowel giving excellent visualisation even up to 120 h after ingestion. No harmful effects were noted in the four cases studied.

Nasal deformities in neonates. Their occurrence in those treated with nasal continuous positive airway pressure and nasal endotracheal tubes.

Seventy-two infants were treated with nasal continuous positive airway pressure for one day to five weeks, and nasal deformities developed in none. One hundred thirty-six infants were treated with nasotracheal tubes and eight (6%) were found to have nasal deformities. There was a strong correlation between duration of intubation and birth weight and the presence of deformities. In no infant receiving ventilation therapy for less than six days did nasal deformities develop. The incidence of nasal deformities in infants weighing less than 1,000 g was 50%, whereas in infants heavier than 1,000 g it was 2.4%. No infant had clinical symptoms suggestive of subglottic stenosis during the first year of life. The data do not support the use of routine tracheostomy in newborn infants even after prolonged intubation.

Acute small animal preparation--suitable for fetal metabolic studies?

To determine the immediate effects of the "acute" experimental preparation, 11 near-term pregnant rabbits and 20 fetuses were studied. Blood samples were obtained from the maternal auricular artery, the fetal umbilical vein, and the fetal heart within 90 s of exposure of the uterus by laparotomy. Samples were assayed for pH, O2 and CO2 tension, O2 content, blood urea nitrogen, and plasma glucose. Results indicated that a pronounced fetal acidosis (primarily respiratory) had developed by the time samples were obtained. Further, fetal cardiac glucose levels were significantly elevated above umbilical vein concentrations in 7 of the 20 fetuses. In addition, maternal arterial O2 tension under light pentobarbital anesthesia was significantly less than that found in 35 unanesthetized does (52 vs. 79 Torr, P less than 0.01). All parameters measured varied over a wide range between animals. The results raise serious questions concerning the feasibility of performing and interpreting certain metabolic or cardiorespiratory studies in the acute small animal preparation.