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Biomedical subjects

G Cassady

Publications and source records attributed to G Cassady.

At least 19 recordsLinked to original sources
PubMed1991

Black-white differences in newborn anthropometric measurements.

The mean birth weight of black infants is consistently less than that of white infants. In 1518 low-income multiparous women, the mean difference in singleton births was 171 g, of which 38 g was partitioned to preterm births and another 35 g reflected lower gestational ages in term births. A series of regression analyses were used to determine the effect of black race on various newborn measurements in 1205 term newborns, adjusting for other known risk factors. In this model, black race accounted for a mean decrease of 148 g in weight and 0.52 cm in length. There were also significant decreases in mean head (0.44 cm), chest (0.66 cm), and abdominal (0.56 cm) circumferences. Arm and leg lengths were not different, but black arm circumferences (0.14 cm) were significantly larger. Triceps and thigh skin fold measurements were not statistically different, but black subscapular skin fold values were significantly smaller (0.17 mm). The ponderal index in blacks was significantly less than in whites. These data suggest that in this population, intrinsic and/or extrinsic factors associated with race account for most smaller black newborn measurements and for much of the racial difference in birth weight.

Alabama↗
PubMed1991

28-day survival rates of 6676 neonates with birth weights of 1250 grams or less.

Survival rates specific for birth weight, gestational age, sex, and race are described for 6676 inborn neonates who weighed less than 1251 g at birth and were born during 1986 through 1987. Overall 28-day survival increased with gestational age and birth weight, from 36.5% at 24 weeks' gestation to 89.9% at 29 weeks' gestation, or from 30.0% for neonates of 500 through 599 g birth weight to 91.3% for neonates of 1200 through 1250 g. The expected birth weight-specific survival advantage for female neonates and black neonates diminished when the data were controlled for gestational age, showing that certain previously reported survival advantages are based on lower birth weight for a given gestational age. Multivariate analysis showed that all tested variables were significant predictors for survival, in order of descending significance: gestational age and birth weight, sex, race, single birth, and small-for-gestational-age status. The powerful effect of gestational age on survival highlights the need for an accurate neonatal tool to assess the gestational age of very low birth weight neonates after birth.

Black or African American↗
PubMed1990

Hyperoxia potentiates Ureaplasma urealyticum pneumonia in newborn mice.

The effect of continuous exposure to 80% oxygen on newborn mice with Ureaplasma urealyticum pneumonia was determined. Mice were inoculated intranasally with either U. urealyticum or sterile broth and then housed in either 80% oxygen or room air (21% oxygen). The mice were sacrificed at either 7 or 14 days after inoculation. Significantly more mice in the U. urealyticum group housed in 80% O2 than in the room air-exposed group were culture positive 14 days after inoculation (P = 0.042), but no difference was found at 7 days. The presence of alveolar macrophages, neutrophils, and lymphocytes and alveolar wall thickness were determined. Overall, the group housed in 80% O2 and inoculated with U. urealyticum had severe pulmonary lesions at both time points, while the lesion severity in the room air-exposed group inoculated with U. urealyticum and the group housed in 80% O2 and inoculated with sterile broth was dependent on the time point. Mortality was significantly higher in the group housed in 80% O2 and inoculated with U. urealyticum than it was in all other groups (P less than 0.001). Our results indicate that hyperoxia causes the persistence of U. urealyticum in the lungs of newborn mice, acutely potentiates the inflammatory response, and turns an otherwise self-limited pneumonia into a lethal disease.

Animals↗
PubMed1990

Effects of position changes on transcutaneous carbon dioxide tension in neonates with respiratory distress.

Routine neonatal care includes frequent position changes. Recent research has concluded that positions other than supine may result in beneficial physiologic responses. Specifically, several studies suggest that neonates may ventilate more effectively in a prone rather than in a supine position. This study tested the hypothesis that transcutaneous carbon dioxide tension (TcPCO2) would be lower in the prone than in the supine position in neonates with respiratory distress. Fourteen ventilated infants were studied. TcPCO2 was measured and recorded in prone, supine, and right-side-lying positions for each subject. There were no statistically significant differences in mean TcPCO2 values between the three positions (F = .45; df 2,39; P = .64). The relationship between TcPCO2 and PaCO2 values was stable (r = .88) during the studies. The results indicate that changing a neonate's position does not significantly alter transcutaneous carbon dioxide tension.

Blood Gas Monitoring, Transcutaneous↗
PubMed1990

Control of infection due to Klebsiella pneumoniae in an intensive care nursery.

Because of an increased incidence of necrotizing enterocolitis (NEC) temporally related to Klebsiella pneumoniae colonization noted in several infants, a study was undertaken to identify the source and to eradicate the infection. Twenty infants in the neonatal intensive care unit (NICU) and 51 in the well-baby nursery were prospectively studied. Cultures were done on all infants. In addition, cultures were done on all employees and parents who regularly visited. Our results showed an increased incidence of infection during this period--8.3% as compared with 4.79% overall. Colonization with K pneumoniae was eradicated, at least temporarily, by establishing a cohort system in both the NICU and the well-baby nursery and by the administration of antibiotics to all infants in these nurseries. Colonized parents and employees were also treated. Follow-up cultures showed clearing of Klebsiella, and the cohort system was abolished. Serotyping of all affected infants later showed that different strains were present, making it unlikely that there was a common source for the Klebsiella. (Initially the source of infection had been thought to be a mother whose premature triplets were colonized. We feel that the eradication of this organism and the subsequent decline in NEC was enhanced by the combination of cohorting and handwashing. The selected use of antibiotics may have prevented an extension of the outbreak, but this could not be proven.

Alabama↗
PubMed1989

A randomized, controlled trial of very early prophylactic ligation of the ductus arteriosus in babies who weighed 1000 g or less at birth.

We speculated that prophylactic ligation of the ductus arteriosus would reduce mortality and morbidity in very-low-birth-weight infants. To test this hypothesis, we randomly assigned 84 babies who weighed 1000 g or less at birth and required supplemental oxygen either to receive standard treatment (n = 44) or to undergo prophylactic surgical ligation of the ductus arteriosus on the day of birth (n = 40). The ductus was ligated in babies in the control group only if the shunt was hemodynamically important. All the babies were followed for one year. The incidence of necrotizing enterocolitis was reduced in the group that underwent prophylactic ligation (3 of 40 [8 percent]) as compared with the control group (13 of 44 [30 percent]; P = 0.002). The frequency of death, bronchopulmonary dysplasia, retinopathy of prematurity, and intraventricular hemorrhage was similar in both groups. Because early enteral feeding may have increased the incidence of necrotizing enterocolitis, we analyzed separately the babies who were fed early. Among the infants who were fed within 14 days of birth, those who underwent prophylactic ligation had a lower incidence of necrotizing enterocolitis (1 of 11 [9 percent]) than those who did not (13 of 24 [54 percent]; P = 0.001). Within the control group, the infants who were fed within 14 days of birth and whose ductus was ligated for medical reasons within 5 days of birth had a lower incidence of necrotizing enterocolitis (2 of 10 [20 percent]) than those whose ductus was ligated later or not at all (11 of 14 [79 percent]; P = 0.004). We conclude that early surgical closure of the ductus arteriosus reduces the risk of necrotizing enterocolitis in infants of very low birth weight who require supplemental oxygen.

Bronchopulmonary Dysplasia↗
PubMed1989

Intraventricular haemorrhage and the renin-angiotensin-aldosterone system in very low birthweight infants.

Blood volume, plasma renin activity (PRA) and urine aldosterone excretion (UAE) were measured in ten very low birthweight infants who had a Grade 3 or 4 intraventricular haemorrhage (IVH) during the first 2 days after birth. Mean (range) birthweight was 950 (630-1500) g and gestational age was 27 (23-31) weeks. Nine infants were receiving assisted ventilation and one was breathing spontaneously. Eight IVH occurred on the first postnatal day and two on the second; seven were symptomatic and three asymptomatic. PRA was significantly higher than control values on Day 1 only; median 244 (range 91-654) ng/ml per h vs. 64 (4-259) ng/ml per h (P less than 0.01). Infants with symptomatic IVH in the preceding 8 h (n = 6) all had PRA greater than 300 ng/ml per h; none of these infants had received transfusions or volume expansion between IVH and PRA measurement. PRA was less than 100 ng/ml per h in the three infants with asymptomatic IVH and one infant with greater than 24 h interval between IVH and PRA measurement; three of these four had received transfusions prior to PRA measurement. UAE was not significantly different from control values on either Day 1 or Day 2. Blood volume at 22 +/- 3 h postnatal age ranged from 75 to 107 ml/kg. There was an inverse logarithmic correlation between PRA and blood volume (r = 0.883; P less than 0.005), with PRA values exceeding 300 ng/ml per h when blood volume was less than 90 ml/kg. UAE did not correlate with either PRA or blood volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
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

Capillary and venous bilirubin values. Are they really different?

We measured total serum bilirubin values in paired capillary and venous samples from 79 untreated jaundiced newborn infants (group 1) and in 29 infants who were receiving phototherapy (group 2). While bilirubin values from the two sites correlated significantly for both groups, capillary samples underestimated venous bilirubin values when the latter exceeded 170 mumol/L (10 mg/dL) (mean and 95% confidence limits: group 1, -15.1 mumol/L [-0.9 mg/dL] and -24.7 to -5.5 mumol/L [-1 to -0.3 mg/dL]; group 2, -10.3 mumol/L [-0.6 mg/dL] and -17.1 to -3.4 mumol/L [-1 to -0.2 mg/dL]). Furthermore, capillary samples underestimated venous bilirubin levels by more than 17 mumol/L (1 mg/dL) in eight of 16 group 1 patients and five of 18 group 2 patients when venous bilirubin values exceeded 170 mumol/L (10 mg/dL). Lower capillary values at higher bilirubin levels might be due to the influence of environmental light. As clinical treatment decisions may be made on the basis of differences in serum bilirubin level of about 17 mumol/L (1 mg/dL) and as capillary samples may underestimate venous bilirubin levels by a similar amount, it may be prudent to measure venous rather than capillary bilirubin levels when the total serum bilirubin level exceeds 170 mumol/L (10 mg/dL).

Bilirubin↗
PubMed1987

Low colloid osmotic pressure in very low birthweight infants receiving assisted ventilation.

Plasma colloid osmotic pressure (COP) was measured in three groups of very low birthweight infants. Babies in Group 1 (n = 8) were breathing spontaneously and had no respiratory disease. Those in Group 2 (n = 9) received assisted ventilation for hyaline membrane disease (HMD), and those in Group 3 (n = 7) received assisted ventilation for other reasons (five apnoea, two pneumonia). Both assisted ventilation groups had lower mean COP values than spontaneously breathing infants. Mean values (s.e.m.) for Groups 1, 2 and 3, respectively, were: 15.3 (0.6), 11.3 (0.4) and 11.9 mmHg (0.5) (P less than 0.001) on Day 1; and 15.2 (0.4), 12.9 (0.4) and 12.8 mmHg (0.3) (P less than 0.001) on Day 2. The increase from Day 1 to Day 2 was significant for those with HMD (P less than 0.05). Colloid osmotic pressure correlated with mean blood pressure (r = 0.51; P less than 0.001) but not with birthweight, gestation, crystalloid fluid intake or pH. The role of low COP in the pathogenesis of acute respiratory failure in infants with uncomplicated HMD is unclear, but such low COP may contribute to development of pulmonary oedema as a complication, particularly if the ductus arteriosus is still patent and the infants are given high volume intravenous fluids.

Blood Pressure↗
PubMed1986

Effect of application pressure and gestational age on transfontanel pressure in healthy neonates.

We developed and evaluated a transducer holder and calibrated, spring-loaded applicator for the Ladd intracranial pressure monitor. The transducer holder/applicator combination allows reproducibility of application pressure and assures coplanarity of the transducer and the skin of the anterior fontanel. Measured transfontanel pressure (TFP) increased with increasing application pressure. Mean TFP was 9.1 +/- (SD) 2.6 cm H2O with an application pressure of about 10 g/cm2 in a group of healthy preterm and term infants at 6 h postnatal age. Birth weight, gestational age and mode of delivery did not affect TFP, allowing use of a single normative value and set of confidence limits in all infants at 6 h of postnatal age.

Birth Weight↗
PubMed1986

The effect of assisted ventilation on creatinine clearance and hormonal control of electrolyte balance in very low birth weight infants.

Because renal function and electrolyte balance are commonly altered in premature infants, particularly those requiring ventilatory support, we studied the influence of assisted ventilation on renal electrolyte and water excretion in infants with birth weights less than 1501 g during the 2 days after birth. Twenty-two infants receiving assisted ventilation, either as intermittent mandatory ventilation or nasal continuous positive airway pressure, were compared with 21 spontaneously ventilating infants of similar birthweight and gestational age. Mean (and SEM) creatinine clearance was lower (p less than 0.05) in the assisted ventilation group on day 1 (2.9 +/- 0.4 versus 4.1 +/- 0.4 ml/min/1.73 m2) and on day 2 (4.1 +/- 1.0 versus 6.8 +/- 0.8 ml/min/1.73 m2, p = 0.05), and there was a correlation between creatinine clearance and mean blood pressure in both groups. Mean urine vasopressin was higher in the assisted ventilation group on the first day (360 +/- 86 versus 123 +/- 30 pg/mg creatinine; p less than 0.02) and correlated with higher urine osmolality. There were no differences in urine volume, in osmolar or free water clearances, or in the intake and urine excretion of sodium, potassium, and chloride. Plasma renin activity, urine aldosterone, and urine prostaglandin E2 were similar in both groups on both days. Neither the mode of assisted ventilation nor the cause of respiratory failure appeared to affect these results.

Creatinine↗