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Biomedical subjects

A Erenberg

Publications and source records attributed to A Erenberg.

At least 19 recordsLinked to original sources

Imaging evaluation of breast-feeding and bottle-feeding systems.

OBJECTIVE: To compare infant sucking and swallowing patterns during feeding with a new artificial nipple and during breast-feeding. METHODS: Fifteen healthy, term infants were fed successfully for 1 week with use of the new tricut nipple; then each infant's oral cavity was examined during feeding by using real-time ultrasonography. Measurements of nipple length and compression were made, together with observations concerning the integrity of the seal formed by the infant's mouth around the nipple. These data were compared with similar data from previous studies of 16 breast-fed infants. RESULTS: Although no artificial feeding system exactly simulates breast-feeding, the new tricut nipple was sucked in a manner similar to the way the human nipple is sucked and delivered milk posteriorly to the foramen cecum region of the tongue, just as the breast does. CONCLUSION: Although further studies are necessary, to evaluate other characteristics of the new tricut nipple, the measurements from this investigation are useful additions to the ultrasound data these investigators have accumulated on various artificial feeding systems. These data may also prove helpful in determining the most appropriate nipples for infants with various feeding disorders.

Bottle Feeding

Safety and efficacy of sufentanil therapy in the ventilated infant.

This pilot study examined the safety and efficacy of sufentanil in the ventilated neonate. Informed parental consent for study participation was obtained for eight infants who were admitted to the neonatal intensive care unit and required analgesic/sedative therapy as part of their medical management to support mechanical ventilation. An intravenous loading dose (0.2 microgram/kg) was administered over 20 minutes, followed by a continuous infusion (0.05 microgram/kg/hour). Whole blood samples were collected prior to onset of sufentanil therapy, immediately following the loading dose, and 24 hours after the start of the continuous sufentanil infusion for analysis of beta-endorphin and sufentanil serum content. Heart rate, respiratory rate, and blood pressure were recorded as a routine part of medical management. The ventilatory efficiency index (VEI) and ventilation index (VI) were calculated before and after sufentanil therapy. Four male and four female infants were admitted to this study; the mean gestational age was 37 weeks, and weight was 2,970 gm. Sufentanil therapy appeared to be well tolerated, as evidenced by a lack of nursing observations noting changes in heart rate or mean arterial pressure. VEI values increased in four subjects, and VI values decreased in six subjects. Overall, the mean increase in VEI was 19 percent; the decrease in VI was 27 percent. The beta-endorphin serum content decreased in all subjects, and nurses did not report any signs of patient discomfort. Serum sufentanil content was undetectable. Sufentanil appears to be a suitable agent to provide analgesia/sedation in the neonatal patient under the experimental conditions of this study.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure

Influence of infusion pumps on the pharmacologic response to nitroprusside.

OBJECTIVE: To compare the relationship between variability in nitroprusside delivery from five infusion pumps and the resulting variability in mean arterial pressure (MAP). DESIGN: Randomized, crossover study design. SETTING: A pediatric ICU in a university hospital. PATIENTS: Informed parental consent was obtained for six patients who were hemodynamically stable and receiving a continuous nitroprusside infusion for a clinical application. Subjects ranged in age from 11 months to 9 yr. INTERVENTIONS: All of the subjects were administered nitroprusside using selected infusion pumps, which included Abbott (Micro), 3M/AVI (210), IMED (965), IVAC (565), and Kendall McGaw (MicroRate). MEASUREMENTS AND MAIN RESULTS: After an initial equilibration interval for each device, MAP was measured and recorded at 10-sec intervals for greater than or equal to 90-min intervals using a computerized data collection technique. Variation in nitroprusside administration (flow continuity) for each infusion pump was determined in vitro using a computerized gravimetric technique. Variation in both MAP and flow continuity was mathematically expressed as the coefficient of variance (CV) of the measured values for each of the respective infusion pumps. For the Abbott, IMED, 3M/AVI, IVAC, and Kendall McGaw, infusion pumps, mean +/- SD continuity CV values were 85 +/- 31%, 39 +/- 26%, 19 +/- 8%, 17 +/- 3%, and 12 +/- 3%, respectively, and MAP CV values were 18 +/- 21%, 15 +/- 11%, 8 +/- 2%, and 16 +/- 10%, respectively. CONCLUSIONS: An apparent direct relationship between MAP variability and flow continuity was observed. We speculate that variation in effect of potent short-acting drugs may, in part, be due to infusion pump operation.

Blood Pressure

Pulmonary mechanics in healthy term neonates: variability in measurements obtained with a computerized system.

Using a commercially available computer-based analysis of ventilation and esophageal pressure (PeDs), we studied 11 healthy term neonates with serial pulmonary mechanics measurements during the first 3 days of life to determine the intrasubject variability of repeated measurements. Three consecutive pulmonary function tests were obtained before and after repositioning of the esophageal catheter, for a total of six measurements per day in each subject. The daily coefficient of variation for these 11 subjects ranged from 6% to 32% for respiratory rate; 6% to 27% for tidal volume; 3% to 28% for specific dynamic compliance, and 11% to 69% for pulmonary resistance. Repositioning the esophageal catheter did not produce significant differences in measurements of pulmonary mechanics (p greater than 0.05). We conclude that within a given subject, the maximum variability (mean + 2 SD) was 28% for specific dynamic compliance and 56% for pulmonary resistance. These intrasubject variability limits are important when one is interpreting pulmonary mechanics measurements in neonates before and after specific treatment, such as bronchodilators, diuretics, surfactant, or steroids.

Airway Resistance

Decreased flow accuracy from volumetric infusion pumps.

Accurate flow from infusion pumps should be maintained when exposed to a variety of clinical conditions. The intent of this study was to evaluate in vitro flow rate accuracy of three infusion pumps subjected to the influences of variable back-pressure, solution viscosity, and infusion rates. A factorial study design was selected to determine the influence of three flow rates (5, 10, and 20 ml/h), three back-pressures (100, 200, and 300 mm Hg), and two solution viscosities (5%, 25% dextrose in water) on flow rate accuracy from three infusion pumps (Abbott 4P, IVAC 560, and Travenol 6200) using a standard gravimetric technique. Mean +/- SD accuracy values were -9.4 +/- 6.4% (range -29.1 to -0.7), 0.5 +/- 2.2% (range -4.2 to 6.3), and -0.5 +/- 4.7% (range -8.5 to 9.9) of the desired rate for the Abbott, IVAC, and Travenol devices, respectively. Back-pressure was the only factor to influence significantly flow accuracy for the Abbott device (r = .81). All factors significantly influenced accuracy for the Travenol device (r = .55). No factor influenced accuracy for the IVAC infusion pump. Both the IVAC 560 and Travenol 6200 have acceptable flow accuracy values within the range of study factors examined. The Abbott 4P had significant decreases in flow accuracy in response to increasing back-pressure.

Calibration

Imaging evaluation of the human nipple during breast-feeding.

A new real-time ultrasound technique was employed to document in vivo the anatomic characteristics of the human nipple during breast-feeding. The study quantifies human nipple deformation and provides a description of the mechanics of normal sucking derived from 16 normal infants aged 60 to 120 days. This in vivo imaging technique has great potential value in the study of feeding dysfunction.

Adult

Flow rate variability from electronic infusion devices.

During continuous drug administration to pediatric patients, unfavorable pharmacologic effects have occurred. These effects were attributed to variations in flow from electronic infusion devices (EIDs). The intent of this investigation was to evaluate the influence of microrate (0.1 to 99.9 ml/h) EID on the accuracy, continuity, and pattern of flow of continuously effused fluid. Using a factorial study design, iv fluid was effused through iv delivery systems using combinations of five microrate EIDs, three iv flow rates, and three sample-collection intervals. Serial weights were measured at the appropriate sample-collection time using a computerized gravimetric technique to determine accuracy, continuity, and pattern of flow. All the EIDs produced accurate flow within 5% of the desired rate of 5 and 10 ml/h. At 1 ml/h, the actual iv flow rate ranged from 65.1% to 91% of the desired rate. Each of the respective EIDs produced various levels of flow continuity; each flow pattern characterized the mechanism of pump operation for each device. Thus, alteration in response (e.g., increased toxicity or decreased efficacy) to a continuous drug infusion must not be attributed exclusively to the drug or clinical condition of the patient. Serious consideration should also be given to the method of drug delivery and, in particular, the continuity of flow that results from a particular EID.

Child

Changes in arterial blood gases following cardiac asystole during fetal life.

A case of suspected fetal cardiac asystole with normal umbilical cord blood gas values is reported. Possible explanations of this apparent discrepancy were examined by measuring sequential changes in fetal arterial acid-base and blood gas values after induced cardiac asystole in chronically instrumented fetal lambs at 132-141 days' gestation. Arterial pH values did not decrease from baseline for at least ten minutes. Elevation of pCO2 values were observed at 30 minutes. Arterial pO2 and HCO3 values remained unchanged for at least 30 minutes. Therefore, we conclude that sudden fetal cardiac asystole occurring within ten minutes of delivery may be one reason why umbilical cord acid-base and blood gas values do not correlate with Apgar scores.

Acid-Base Equilibrium

In utero bladder diversion--problems with patient selection.

Based upon the concept that an obstruction-maldevelopment sequence is reversible after diversion, it has been suggested that the fetus with a bladder outlet obstruction is a potential candidate for in utero intervention. We report an infant who had both renal and pulmonary dysplasia at birth despite a technically successful diversion at 22 weeks' gestation. The poor outcome suggests that the organ damage either occurs so early that it precludes corrective surgery, or that the maldevelopment is not the result of obstruction, but rather a primary mesodermal defect.

Abdomen

Evaluation of an extension set for intermittent intravenous drug delivery to infants.

An intravenous administration set designed for delivery of drug doses to pediatric patients was tested in vitro for the effect of fluid density and flow rate on drug delivery, and delivery of drug by this extension set was compared in vivo with delivery by other methods. Gentamicin (as the sulfate salt) and penicillin G potassium were used to represent low-density and high-density drugs, respectively; a 1-mL solution of each drug, labeled with carbon 14, was tested with each of two primary infusion solutions: 0.45% sodium chloride injection and 10% dextrose injection. The drug dose was injected via a port into a piston-containing chamber from which an equivalent amount of the primary fluid was displaced. Serial samples collected from the end of the filter-containing extension set were analyzed for drug concentration using a liquid scintillation technique. In 12 infants receiving i.v. gentamicin, this delivery method was compared in a randomized crossover trial with delivery by a syringe pump and by i.v. push. Each delivery system was used on one of three consecutive days, and serum gentamicin concentrations were measured by enzyme-multiplied immunoassay. The time required for in vitro delivery of the dose was dependent on flow rate. Density of the drug solution or the primary i.v. fluid did not significantly affect drug delivery. Serum gentamicin concentrations were not significantly different for the three delivery methods, but variability of drug delivery was greatest with the pediatric extension set. This pediatric extension set provides accurate and reliable drug delivery at primary infusion flow rates slower than 10 mL/hr when the drug dosage volume is 2-3 mL or less.

Evaluation Studies as Topic

Palatal groove formation in neonates and infants with orotracheal tubes.

Long-term use of orotracheal tubes has been associated with palatal groove formation, acquired cleft palate, and defective primary dentition. To determine the incidence of palatal groove formation, maxillary impressions were made of 63 neonates and infants who required orotracheal intubation for one to 62 days. A palatal groove was present in 47.6% of these neonates and infants. The incidence of palatal groove formation increased with a longer use of tubes, being 87.5% in those neonates and infants requiring tubes for more than two weeks.

Body Weight

Appliance for stabilizing orogastric and orotracheal tubes in infants.

The long-term use of orotracheal tubes in infants has been associated with airway damage, palatal groove formation, acquired cleft palate, and defective primary dentition. Nasotracheal intubation is associated with trauma to the nasal septum and deformities of the nares. Because the infant is an obligatory nose-breather, nasogastric feeding tubes obstruct the nares and cause mucosal edema. We have developed an intraoral appliance designed to stabilize orogastric feeding and orotracheal tubes, and prevent obstruction to the nares and trauma to the palate and alveolar ridge.

Enteral Nutrition

Postnatal increase in airway surfactant in the premature rabbit exposed in utero to betamethasone.

In utero exposure to betamethasone on days 26 and 27 of gestation resulted in a significant increase in lung lavage phospholipid after 24 h of air breathing in rabbit pups delivered at 29 days of gestation. At 6 h of age, the proportion of type II epithelial cells in betamethasone-exposed newborns was nearly twice the saline-exposed control value. Phospholipid composition and pressure:volume analysis of compliance were both unaffected by betamethasone treatment. The betamethasone-associated increase in airway phospholipid content was observed only in female pups. These data support the conclusion that antenatal betamethasone treatment elicits an increase in airway phospholipid which is dependent on breathing and confined to the female newborn.

Animals