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Biomedical subjects

D Vidyasagar

Publications and source records attributed to D Vidyasagar.

At least 19 recordsLinked to original sources
PubMed1991

Cardiopulmonary resuscitation of apparently stillborn infants: survival and long-term outcome.

To determine the outcome of apparently stillborn infants who received cardiopulmonary resuscitation, we studied the short- and long-term outcome of 93 infants who had an Apgar score of 0 at 1 minute of age and were resuscitated at birth. Sixty-two (66.6%) responded and left the delivery room alive; 26 (42%) of the 62 infants died in the neonatal period and 36 infants were discharged home; of the 36 infants, three subsequently died during infancy. Of the 33 survivors, ten were lost to follow-up after discharge. Developmental assessment of 23 of 33 long-term survivors revealed normal outcome in 14 (61.7%), abnormal results in 6 (26%), and suspect status in 3 (13%). Fifty-eight infants had an Apgar score of 0 at greater than or equal to 10 minutes of age and all except one died; the surviving infant has an abnormal developmental outcome. We conclude that 39% of apparently stillborn infants who were resuscitated survived beyond the neonatal period and that 61% of the 23 survivors who were available for developmental follow-up had normal development at the time of last examination. Survival was unlikely if there was no response after 10 minutes of resuscitation.

Apgar Score↗
PubMed1991

Improvement in oxygen tensions and pulmonary blood flow with intermittent distal aortic compression during normoxia, hypoxic hypoxia, and hyperoxia in neonatal piglets.

BACKGROUND AND METHODS: We investigated the hypothesis that, in a newborn piglet during normoxia, hypoxia, and hyperoxia, increasing aortic pressure transiently by intermittent short-duration aortic compression would affect left-to-right shunting of blood and thus increase pulmonary artery blood flow, pulmonary arterial PO2, and aortic PO2 proximal to the point of compression. We also investigated whether a balloon atrial septostomy, by providing an open channel for communication between the right- and left-sided circulations, would further improve pulmonary blood flow and aortic PO2. Studies were performed in eight 7- to 10-day-old newborn piglets in three phases (FIO2 of 0.21, 0.12, and 1.0) before and after balloon arterial septostomy in each piglet. Blood gas measurements and hemodynamic variables were recorded before and at the end of a 30-sec period of aortic compression. RESULTS: During aortic compression, all the animals demonstrated a 50 to 70 mm Hg increase in aortic pressure proximal to the compression. Before balloon septostomy, there were 21%, 41%, and 8% increases in aortic PO2 in the room air, hypoxic, and hyperoxic phases of the experiment, respectively. There were also statistically significant increments in pulmonary blood flow and arterial pressures. After balloon septostomy, there were 35%, 25%, and 21% increments in aortic PO2 during the room air, hypoxic, and hyperoxic phases of the experiment, respectively. However, there was no statistically significant further improvement in the effects of aortic compression on PO2 with septostomy compared with those effects before septostomy. CONCLUSIONS: Our results suggest that increasing systemic arterial pressures in order to forcibly affect left-to-right shunting of blood may be potentially beneficial in the management of hypoxia in situations where low pulmonary artery blood flow may be contributing to hypoxia, e.g., in persistent pulmonary hypertension of the newborn.

Animals↗
PubMed1991

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Animals↗
PubMed1990

Effect of exogenous surfactant on the development of bronchopulmonary dysplasia in a baboon hyaline membrane disease model.

To test the effect of exogenous surfactant on the evolution of histopathologic changes of bronchopulmonary dysplasia (BPD), we conducted a study in a premature baboon hyaline membrane disease model. One hundred mg/kg bovine surfactant sonicated in saline or 3 ml/kg saline placebo was instilled via the trachea at about 10 min of age. The clinical status and physiologic changes were monitored for 9 days, and pulmonary histopathology was evaluated after death. Compared to the control, the surfactant-treated animals showed a significant improvement in arterial/alveolar oxygen ratio and pulmonary compliance, facilitating rapid weaning from assisted ventilation. Lung histology revealed that pulmonary parenchyma expanded 70% to 95% without features of early BPD. Dysplastic maturation, air trapping, or cellular atypia was not seen. In contrast, lung histology in the control group revealed alveolar expansion less than or equal to 50%, basal cell hyperplasia in the bronchial and bronchiolar epithelium, dysplastic maturation with cellular atypia, extensive epithelial erosion, and type II cell hyperplasia, all features of early BPD. The results of this study suggest that in the premature baboon model, exogenous surfactant therapy improves pulmonary functional abnormalities and lessens the histologic features of BPD, perhaps because of rapid weaning and reduced barotrauma.

Animals↗
PubMed1990

Effect of single dose surfactant on pulmonary function.

Sequential changes in pulmonary mechanics in response to single dose exogenous surfactant instillation were studied in 15 preterm neonates who had hyaline membrane disease (HMD). The infants were part of a larger double-blind national study. Birth weight ranged from 0.88 to 1.55 kg, and gestational age was between 27 to 32 wk. There were six infants in the surfactant group and nine in the placebo group. Pulmonary mechanics were studied before and at 2, 24, 60, and 96 h after surfactant or sham instillation using a pneumotachometer and an esophageal balloon catheter. The variables studied were dynamic compliance (Cdyn), pulmonary resistance, work of breathing, tidal volume, and minute ventilation. Infants in the surfactant group showed an immediate and significant (p less than .05) improvement in gas exchange ratio, decreased mean airway pressure (9.7 +/- 0.9 to 7.9 +/- 0.4 cm H2O) and airway resistance (133 +/- 6.3 to 92 +/- 14.9 cm H2O/L.sec) (p less than .05). Changes in Cdyn were noted only at 24 h after surfactant instillation. In the control group, gradual improvement occurred after the initial deterioration. The findings suggest that the immediate improvement in oxygenation after surfactant instillation is the result of factors other than changes in lung compliance, such as improved ventilation/perfusion and better capillary stability with decreased leakage of fluid into alveoli.

Airway Resistance↗
PubMed1990

Chest radiographic course after exogenous surfactant therapy in baboons with respiratory distress syndrome.

Exogenous surfactant materials have been used under a variety of treatment protocols in cases of neonatal respiratory distress syndrome (RDS). To evaluate the differences in radiologic changes that follow either an early or late therapy with exogenous bovine surfactant, we reviewed 189 serially obtained chest radiographs from 48 premature baboons with RDS studied under different treatment regimen. Twenty-six animals were controls (100 chest films), and 22 received 100 mg/kg bovine surfactant instilled via the trachea in three study protocols (89 chest films). Surfactant was given within 10 min of birth in one group and at 2 h of age in the other. In 25/26 controls, radiologic evidence of severe RDS was seen by 2 h of age; these changes persisted in 15 animals at 24 h. By contrast, a rapid clearing of radiologic features of RDS was seen following surfactant instillation in all 22 (100%) animals within 4 h, but one (4.5%) of these 22 deteriorated at 9 h of age. Pulmonary interstitial emphysema (PIE) was seen in 9/26 (34.6%) and pneumothorax in 5/26 (19.2%) control animals, while 1/22 (4.5%) surfactant-treated animals developed PIE, and none had pneumothorax. The presence of a shunt via the patent ductus arteriosus did not affect radiographic findings in 20 animals studied by contrast injection. Therapy for patent ductus arteriosus (PDA) also had no substantial influence on the radiographic findings, or with regard to the pulmonary course. Radiographic clearing of RDS occurred approximately 18 to 20 h prior to the improvement in pulmonary compliance.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Use of a palatal stabilizing device in prevention of palatal grooves in premature infants.

A prospective, randomized study using an acrylic palatal stabilizing device (PSD) was conducted to evaluate the effectiveness of this device in preventing disruptions in palatal architecture. A total of 26 premature infants with birth weights of 540 to 1740 g, and intubated orally for a period varying from 7 to 109 days were randomized to control and experimental groups. All neonates in the control group developed palatal grooving ranging from 2 to 5 mm in depth, whereas those in the experimental group (with a PSD) showed no evidence of palatal grooving. We conclude that a PSD is an effective preventive device in premature orally intubated infants.

Dental Impression Technique↗
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↗
PubMed1989

Surfactant therapy and spontaneous diuresis.

The effect of artificial surfactant therapy on renal function and the onset of spontaneous diuresis was prospectively evaluated in 19 infants with hyaline membrane disease in a double-blind, controlled study. Twelve infants were in the surfactant group; seven infants received placebo (0.9% saline solution). There was no difference in the time of onset of spontaneous diuresis (as defined by output greater than or equal to 80% of intake). The glomerular filtration rate, determined by endogenous creatinine clearance, was also similar in the surfactant- and placebo-treated infants during the first 3 days of life. The fractional excretion of sodium was significantly higher in the placebo group at 24 hours and 36 hours. Infants in the placebo group had a higher negative sodium balance than those in the surfactant group. Ventilatory status improved significantly soon after surfactant treatment, as evidenced by improvement in the alveolar/arterial oxygen pressure ratio and by a lower mean airway pressure. These data suggest that ventilatory status can be improved without diuresis; the factors that regulate diuresis are multiple and not fully understood.

Blood Gas Analysis↗
PubMed1989

In vivo distribution of human milk leucocytes after ingestion by newborn baboons.

The in vivo distribution of enterally administered human milk leucocytes labelled with indium hydroxyquinoline (111In) was studied in premature baboons. The animals were killed at 72 hours of age and tissue samples examined for radioactivity. Maximum activity was found in the luminal contents, and activity in the liver and spleen was higher than in bone marrow, the site where free isotope is normally deposited. These findings suggest that some intact milk leucocytes may cross from the gastrointestinal tract into the neonatal circulation. Also the high activity in gastrointestinal tissue that had been washed several times indicates that leucocytes adhere to mucosa or lie intramurally. We speculate that the presence of leucocytes in the gastrointestinal tract 60 hours after a single breast feed can provide an important defence mechanism against infection.

Animals↗
PubMed1989

Treatment of patent ductus arteriosus after exogenous surfactant in baboons with hyaline membrane disease.

The effect of early treatment of patent ductus arteriosus (PDA) on the acute course of hyaline membrane disease was tested in a primate model, after intratracheal administration of 100 mg/kg exogenous bovine surfactant phospholipids at mean ages between 2.3-2.4 h. Twenty-two premature baboons were divided into four groups: seven animals were controls (group A); five were treated with surfactant but PDA was not intervened (group B); in five surfactant treatment was followed by three doses of 0.2 mg/kg intravenous indomethacin beginning at a mean age of 5.5 h (group C); and in five surfactant treatment was followed by a surgical ligation of PDA between 5-5.5 h of age. After surfactant instillation in groups B, C, and D, a prompt and sustained improvement was noted in a/APO2, mean airway pressure, ventilator efficiency index and pulmonary compliance. However, no consistent differences were found in the respiratory variables within the surfactant treated groups during the 72-h experiment: the respiratory course in the animals treated for PDA (groups C and D) was generally similar to the animals in which PDA was not treated (group B). In animals treated with surfactant and indomethacin (group C) the mean aortic blood pressure was maintained more optimally as compared to the other three groups. These findings suggest that although a significant early ductal shunting does occur after exogenous surfactant therapy in this animal model, the expected pulmonary deterioration does not occur, and an early abrupt interruption of PDA does not seem to provide additional advantage to the immediate course of hyaline membrane disease.

Animals↗
PubMed1989

Iatrogenic disorders in modern neonatology.

Rather than give a detailed listing of all the iatrogenic problems in modern neonatology, this article seeks to explain the process of iatrogenicity and separate those problems that are preventable from those that currently are unpreventable.

Humans↗
PubMed1989

Pulse oximetry in neonatal intensive care.

Pulse oximetry, a noninvasive technique of measuring oxygen saturation continuously, is being used increasingly in the intensive care setting. This article provides information regarding physiologic basis and practical aspects of clinical usage of pulse oximetry in the neonate, both in medical and surgical units.

Critical Care↗
PubMed1989

Electrolyte problems in neonatal surgical patients.

Surgical care itself, apart from the disorder for which it is given, results in catabolism and its attendant electrolyte disturbances in all patients. Research has focused primarily on adult surgical patients, and little is known about these electrolyte disturbances in newborn infants, especially preterm infants. This article presents what is known about this patient population.

Acid-Base Imbalance↗
PubMed1987

Double-blind controlled trial of single-dose treatment with bovine surfactant in severe hyaline membrane disease.

In a double-blind clinical trial the effects of a single dose of reconstituted bovine surfactant ('Surfactant TA') were assessed in 30 premature infants (birthweight 751-1750 g) with severe hyaline membrane disease. 17 infants had a sonicated saline suspension of 100 mg/kg surfactant phospholipid instilled into the trachea at 5.0 (SD 0.7) hours of age and 13 infants received saline by the same route at 4.3 (1.1) hours of age. In the surfactant-treated group there was early improvement in oxygenation and ventilation. Haemodynamically significant patent ductus arteriosus occurred more often in the surfactant group; pneumothorax and pulmonary interstitial emphysema occurred less often. The combined incidence of death and severe bronchopulmonary dysplasia was significantly lower in the surfactant group (3/17) than in the placebo group (9/13).

Animals↗
PubMed1987

Lipogenesis in the brown adipose tissue of the fetal baboon.

The ultrastructural and lipogenic capacity of the white and brown adipose tissue (WAT and BAT) of 10 baboon fetuses (gestational age, 138-183 days) were studied. The axillary, interscapular and pericardiac sites had at least 50% brown fat cells while the retroorbital site contained white adipocytes only. Both WAT and BAT incorporated 3H2O and 14C-glycerol into lipids at similar high rates. The activities of enzyme acetyl CoA carboxylase and glycerokinase were higher than those reported in human BAT and comparable to these reported in rodent BAT under unstimulated conditions. It is concluded that in the fetal baboon adipose tissue is capable of considerable de novo lipogenesis and that, despite the differences in microscopic appearance, WAT and BAT have similar lipogenic potentials with respect to the parameters measured.

Acetyl-CoA Carboxylase↗