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Biomedical subjects

J M Hascoet

Publications and source records attributed to J M Hascoet.

At least 19 recordsLinked to original sources

The safety and efficacy of nitric oxide therapy in premature infants.

OBJECTIVES: To assess the safety-efficacy balance of low-dose inhaled nitric oxide (iNO) in hypoxemic premature infants because no sustained beneficial effect has been demonstrated clearly and there are concerns about side effects. STUDY DESIGN: Eight hundred and sixty infants <32 weeks were randomized at birth to receive 5 ppm iNO or placebo when they presented with hypoxemic respiratory failure (HRF) defined by a requirement for mechanical ventilation, fraction of inspired oxygen (FIO 2 ) >40%, and arterio-alveolar ratio in oxygen (aAO 2 ) <0.22. The primary end point was intact survival at 28 days of age. RESULTS: Sixty-one of 415 infants presented with HRF and were compared with 84 of 445 controls who presented with HRF. There was no difference in the primary end point (61.4% in infants [23% with HRF who were treated with iNO] vs 61.1% in controls [21.4% in controls with HRF]; P = .943). For the infants with HRF who were treated with iNO, there was no significant difference from controls for intraventricular hemorrhage (IVH) (6% vs 7%), necrotizing enterocolitis (8% vs 6 %), or patent ductus arteriosus (PDA) (34% vs 37%). Compared with nonhypoxemic infants, the risk of bronchopulmonary displasia (BPD) increased significantly in HRF controls (OR = 3.264 [CI 1.461-7.292]) but not in infants with HRF who were treated with iNO (OR = 1.626 [CI 0.633-4.178]). CONCLUSIONS: iNO appears to be safe in premature infants but did not lead to a significant improvement in intact survival on day 28.

Administration, Inhalation↗

Does smoking in pregnancy modify the impact of antenatal steroids on neonatal respiratory distress syndrome? Results of the Epipage study.

OBJECTIVES: To assess the relation between cigarette smoking during pregnancy and neonatal respiratory distress syndrome (RDS) in very preterm birth, and to analyse the differential effect of antenatal steroids on RDS among smokers and non-smokers. DESIGN: A population based cohort study (the French Epipage study). SETTING: Regionally defined births in France. METHODS: A total of 858 very preterm liveborn singletons (27-32 completed weeks of gestation) of the French Epipage study were included in this analysis. The odds ratio for RDS in relation to smoking in pregnancy was estimated using a logistic regression to control for gestational age. The odds ratio for RDS in relation to antenatal steroids was estimated taking into account an interaction between antenatal steroids and cigarette smoking, using multiple logistic regression to control for gestational age, birthweight ratio, main causes of preterm birth, mode of delivery, and sex. RESULTS: The odds ratio for RDS in relation to smoking in pregnancy adjusted for gestational age (aOR) was 0.59 (95% confidence interval (CI) 0.44 to 0.79). The aOR for RDS in relation to antenatal steroids was 0.31 (95% CI 0.19 to 0.49) in babies born to non-smokers and 0.63 (95% CI 0.38 to 1.05) in those born to smokers; the difference was significant (p = 0.04). CONCLUSIONS: Cigarette smoking during pregnancy is associated with a decrease in the risk of RDS in very preterm babies. Although antenatal steroids reduce the risk of RDS in babies born to both smokers and non-smokers, the reduction is smaller in those born to smokers.

Female↗

[Massive fetomaternal transfusion after induction of labor by oxytocin].

UNLABELLED: Severe fetomaternal transfusions are seldom, but may lead to neonatal morbidity or death. CASE REPORT: We report a case of lethal fetomaternal transfusion in which a failure to induce labour, at term, can be suspected. COMMENTS: We emphasize the need of a close monitoring of the fetal well-being in cases of failed induced labour at term.

Adult↗

[Early management of neonates with suspected congenital heart disease].

Congenital heart diseases may remain asymptomatic for days or weeks after birth. Early diagnosis of prenatally undiagnosed congenital heart diseases rests upon familial history of congenital heart disease and clinical signs such as cyanosis intrauterine growth retardation, tachypnea, excessive sweating, feeding difficulties, or abnormal cardiac auscultation. Hyperoxia test, blood gas determination, chest x-ray and electrocardiogram are the most useful complementary tests before the anatomical evaluation by the pediatric cardiologist. The initial medical management includes mechanical ventilation and oxygen supplementation, insertion of a good quality central or peripheral vascular line, correction of metabolic disorders, sedation, and prostaglandin administration in order to maintain the opening of the ductus arteriosus.

Diagnosis, Differential↗

[Perinatal corticotherapy: updates].

The beneficial effects of antenatal corticosteroid treatment are now well established. Likewise, a functional pulmonary improvement has been demonstrated when corticosteroids are used in neonates with chronic lung disease. However, several questions remain to be answered. This review of recent data suggest the need for an updated policy of treatment to improve prognosis. In our population, antenatal maturation has reached a level of 77% below 32 weeks gestation and is associated with a 50% reduction of the risk of severe respiratory distress syndrome. Antenatal steroids have been shown to be beneficial as soon as 23 weeks gestation, but the indication for treatment needs to be carefully evaluated since side effects appear to overcome benefits above 3 repeated courses of treatment. An optimal interval between each course can be set at 10 to 15 days according to the severity of premature labor and gestational age. Since several experimental and clinical studies suggest an increased risk of neurological disability with dexamethasone as compared with betamethasone, it seems consistent to favor the exclusive use of antenatal betamethasone as well as its postnatal choice when indicated. Postnatal use should be restricted to severe chronic lung disease and pulse therapy is now the optimal choice to reduce side effects.

Adrenal Cortex Hormones↗

A longitudinal study of fetal growth variability.

The aim of this study was to assess the variability in individual fetal growth rhythms in comparison to averaged standard curves obtained from cross-sectional data. Biparietal diameter (BDP), abdominal transverse diameter (ATD) and femur length (FL) were measured by ultrasonography in 24 normal subjects, and the variance in growth rates determined for four time intervals: 12-26, 26-34, 34-37 and 37-39 weeks gestation. BPD, ATD and FL growths were always linear until 26 weeks with low variances in growth rates. Growth rates decreased thereafter whereas related variances increased significantly with a great diversity in individual growth trajectories. This study questions the relevance of mathematically smoothed curves which lead to an erroneous impression of growth trajectory uniformity when ultrasonography does not seem to be able to predict accurately newborn biometrical characteristics by the end of gestation.

Abdomen↗

Risks and benefits of therapies for apnoea in premature infants.

Apnoea in infants can result from a wide range of causes, and requires thorough evaluation before deciding on appropriate treatment. Continuous monitoring of premature infants with apnoea is mandatory in order to define the pathophysiology and type of apnoea; selection of treatment involves careful assessment of aetiology, as well as efficacy and tolerability in each individual case. The objective of treatment is to prevent the deleterious consequences of apnoeas that last >20 seconds and/or are associated with bradycardia, cyanosis or pallor, and occur more often than once an hour over a 12-hour period. Apnoea management involves both pharmacological and nonpharmacological treatment. We suggest methylxanthines as first-line therapy for idiopathic apnoeas; evidence suggests that caffeine is better tolerated and as efficacious as theophylline (since it is particularly efficacious against the 'central' component of idiopathic apnoea of prematurity). If treatment fails, additional measures such as doxapram may be appropriate when hypoventilation is present, or nasal continuous positive airway pressure when upper airway instability or obstructive apnoeas are predominant. Apnoea prophylaxis is an additional reason to advocate prenatal maturation with betamethasone. Weaning from treatment is attempted 4 to 5 days after complete resolution of apnoea, beginning with the last treatment introduced. Monitoring should be maintained for 4 to 5 days to detect any relapse of recurrent and severe apnoeas, which would lead to the resumption of the most recently withdrawn treatment.

Apnea↗

Effects of hypoxia on carotid body dopamine content and release in developing rabbits.

Hypoxia induces dopamine (DA) release from the carotid body (CB), but the role of DA during hypoxia in the postnatal maturation of carotid chemosensory discharge remains controversial. The aim of this study was to evaluate changes in CB content and release of DA evoked by hypoxia at different stages of development in the rabbit. Five groups of rabbits aged < or = 24 h (n = 9), 5 days (n = 27), 15 days (n = 18), 25 days (n = 16), and > or = 1 yr (n = 11) were studied. CBs were surgically removed and immediately incubated at 37 degrees C for 1 h in a surviving medium equilibrated with 100% O2 or 8% O2 in N2. The content of DA in the CB ([DA]CB) and the DA released in the surviving medium ([DA]r) were measured by high-performance liquid chromatography. [DA]CB was significantly larger in adults than in all pup groups in both 100% O2 [385.5 +/- 74.1 (SE) pmol/CB in adults and 43.6 +/- 6.0 pmol/CB in pups; P < 0.01] and hypoxia (518.1 +/- 99.9 pmol/CB in adults and 24.7 +/- 3.2 pmol/CB in pups; P < 0.01), presumably because of the larger CB mass. [DA]r was significantly larger in hypoxia than in 100% O2 only in 25-day-old rabbits (19.8 +/- 4.2 and 3.6 +/- 1.1 pmol/h, respectively; P < 0.01) and in adults (183.9 +/- 57.7 and 7.9 +/- 1.7 pmol/h, respectively; P < 0.01). The average ratio of [DA]r in hypoxia to [DA]r in 100% O2 ranged from 1.3 to 2.2 in the three younger age groups and was 5.5 and 23.3 in 25-day-old and adult rabbits, respectively. We conclude that the release of DA evoked by hypoxia is weak at birth and develops during the first weeks of life in rabbits.

Aging↗

Neonatal necrotizing enterocolitis: a retrospective and multicentric review of 331 cases.

The authors retrospectively review 331 cases of necrotizing enterocolitis from 13 different departments of pediatric surgery; 184 cases were treated only medically at the acute stage (47 of whom developed intestinal stricture) and 147 cases were operated on at the acute stage. The different procedures of acute surgical intervention are reported and the results of two surgical procedures are compared. The first is a classical one comprising a laparotomy with exploration of the intestinal tract and resection of the necrotic segments followed by enterostomy above the resected area. The other procedure comprises a minimal laparotomy in the right lower quadrant with ileostomy above necrotic areas, without resection of necrotic segments associated with peritoneal drainage. The results are assessed using the postoperative mortality rate and the number of secondary intestinal strictures. Mortality during the first postoperative month occurred in 27.9% of cases, and intestinal strictures were noted in 31.3% of cases after acute surgical procedure.

Enterocolitis, Pseudomembranous↗

Effects of phenobarbital on cerebral blood flow during hypoxia.

Phenobarbital (PB), at anticonvulsant dosages, has been used in an attempt to reduce hypoxic brain injury in asphyxiated newborn infants. The effects of PB pretreatment on the cerebral blood flow (CBF) response in hypoxia were studied in 15 curarized and mechanically ventilated piglets: 7 animals were pretreated with 20 mg/kg of PB (group 1) and 8 served as untreated controls (group 2). Successive aliquots (25 ml) of carbon monoxide were introduced into a closed ventilator circuit and CBF (measured with radiolabelled microspheres), arterial blood pressure, blood gases, arterial pH and PaO2 were subsequently determined at different levels of hypoxia. The amount of hemoglobin available for oxygen transport (i.e. total Hb-HbCO) was used to express hypoxic aggression and decreased from grade I (> 2 mmol/l) to grade II (1-2 mmol/l) to grade III (< 1 mmol/l). In the control group, CBF increased during grade-I hypoxia and continuously remained above baseline values during grade-II and grade-III hypoxia. In pretreated animals, however, only grade-II hypoxia was associated with a significant increase in CBF above baseline. In addition during grade-III hypoxia, CBF decreased to the prehypoxic values despite a fall in cerebral oxygen delivery and cardiac index. These data suggest that PB should be used with caution to prevent brain damage in the asphyxiated newborn infants.

Animals↗

[Short and mid-term outcome of a cohort of 1157 newborn infants with respiratory distress syndrome].

BACKGROUND: Data concerning neonates with acute respiratory distress syndrome (RDS) are still scarce. The characteristics and follow-up of a French cohort which has participated in an international trial concerning the efficacy of artificial surfactant have been studied. POPULATION AND METHODS: One thousand one hundred and fifty-seven neonates admitted from October 1990 to December 1991 in 27 French intensive care units because of RDS due to hyaline membrane disease were included in the study, whatever their birthweight and gestational age (GA). RESULTS: Three hundred and sixteen neonates (27.3%) were born from twin or multiple pregnancies. Fourty-five (5.5%) of the mothers had been given corticosteroids for the week preceding delivery. 55.5% were delivered by cesarean section. Mean GA was 31.0 +/- 2.9 weeks and mean birth-weight was 1,603 +/- 625 g. Two hundred and sixty-six neonates (23%) were small for GA. Two hundred and twenty-three died after a mean survival of 4.2 days (63% before the end of the first week and 80% before the end of the third week). Fifty percent of these deaths were due to respiratory distress, 28% to severe brain disorders and 9% to infections. The bronchopulmonary dysplasia rate was 21.7%. Early ultrasound scan of the brain showed major injuries in 19.5% of cases; the second scan performed in 822 infants was normal in 84.3%. CONCLUSIONS: Taking into account GA, mortality and morbidity rates were similar to those of the other non-French participating centres.

Birth Weight↗

Low-frequency vs. high-frequency respiratory mechanics after methacholine challenge in artificially ventilated rabbits.

Respiratory system resistance (Rrs) and elastance (Ers) were estimated by two methods, before and after methacholine in six anesthetized, paralyzed, and artificially ventilated rabbits. Rrs and Ers were obtained (1) by multiple linear regression analysis of the relationship between tracheal pressure and tidal volume and flow [Rrs(mlr)], Ers(mlr), and (2) by analysis of the Fourier transforms of tracheal pressure and flow resulting from 4 to 30 Hz pseudorandom pressure oscillations delivered by an Infant Star respirator [Rrs(os), Ers(os)]. Rrs(os) was significantly lower than Rrs(mlr). For instance, Rrs(os) at 20 Hz [Rrs(os)20] was (mean +/- SD) 17.3 +/- 3.5 vs 21.4 +/- 3.6 cm H2O x L-1 x s (P < 0.01) for Rrs(mlr). Ers(os) was significantly higher than the respective value obtained by multiple linear regression (718.2 +/- 81.0 vs 403.7 +/- 43.0 cm H2O L-1; P < 0.01). After methacholine, the changes of respiratory mechanics were similar with both methods. Rrs(mlr) and Rrs(os)20 increased respectively by 131 +/- 45 and 134 +/- 76%, and Ers(mlr) and Ers(os) increased respectively by 63 +/- 7 and 54 +/- 13%. A significant correlation was observed between Rrs(mlr) and Rrs(os)20 (r = 0.97) and between Ers(mlr) and Ers(os) (r = 0.96). We conclude that positive response to methacholine may be detected by forced oscillation as well as by multiple linear regression. However, the identified physiological components of the lung response (alteration in lung viscoelastic properties, increased lung inhomogeneity or increased intrathoracic airway shunt) are likely to be different with each method.

Airway Resistance↗

Dual responses of carotid chemosensory afferents to dopamine in the newborn kitten.

The effects of dopamine and of dopamine D2 receptor blocker haloperidol on the activity of carotid chemoreceptors were studied in 24 anesthetized, paralyzed and artificially ventilated newborn kittens aged 0-17 days. Single or few fiber preparations of chemoreceptors were made from one carotid sinus nerve. The responses of the chemosensory afferents to intravenous injections of dopamine (5-50 micrograms.kg-1) were studied in kittens breathing air and 8% O2 in N2. The effects of haloperidol on the chemosensory activity in air or 100% O2 and on the chemosensory response to hypoxia were studied. Dopamine inhibited the chemosensory discharge in 25/44 studies in normoxia. Of the 9 studies performed in hypoxia, dopamine was excitatory in 5 or had no effect in 4 (P < 0.05 vs normoxia). Inhibition of the chemosensory discharge was observed in 24/37 studies performed in kittens aged more than 3 days and was predominantly excitatory in 6/7 studies in kittens aged 0-3 days (P < 0.01). One minute after haloperidol, the chemosensory discharge had increased significantly in all experiments. The biphasic pattern of chemosensory response to hypoxia (Marchal et al., Respir. Physiol. 87: 183-193, 1992) was not changed by haloperidol. The steady-state chemosensory activity was significantly increased after haloperidol, respectively from 3.9 +/- 0.7 impulses.sec-1 to 9.8 +/- 1.2 impulses.sec-1 in air, and from 13.1 +/- 1.4 impulses.sec-1 to 17.8 +/- 2.4 impulses.sec-1 in hypoxia (mean +/- SEM, P < 0.03). It is concluded that the dopaminergic mechanisms are active in the carotid body of the kitten, and the observed responses to dopamine and haloperidol are qualitatively similar to those reported in the adult cat.

Action Potentials↗