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Biomedical subjects

J C Le Guennec

Publications and source records attributed to J C Le Guennec.

15 recordsLinked to original sources
PubMed1993

Spectrum of oxygen dependency in surviving infants weighing 600 to 1000 grams: decreased incidence of severe chronic lung disease.

Incidence and factors predisposing to chronic lung disease (CLD) were studied in a group of 110 infants still alive at the age of 1 year (69.2%) of an initial group of 159 infants born with a birthweight between 600 and 1000 gm from 1983 to 1988. Low peak inspiratory pressure (PIP), high initial ventilatory rates, slow weaning from respirator and partial arterial oxygen pressure and carbon dioxide pressure values in the range of 40 to 55 torr were used. Oxygen dependency had a bimodal distribution with a high number of infants needing oxygen supplement on day 1 (75.9%) and on day 28 (69.1%) compared with 40.3% on day 7, and 37.7% by 8 weeks. When postconceptional age was taken into consideration, 27% of the infants received oxygen supplement at 36 weeks, 10% at 40 weeks, and 3.6% at 44 weeks. Predisposing factors for oxygen dependency at 28 days were low gestational age, respiratory distress syndrome, intermittent positive pressure ventilation (IPPV), air leak, patent ductus arteriosus and oxygen need at 3 and 7 days of life. Conversely, intrauterine growth retardation was found to be the best factor protecting against CLD. Only 7.6% of infants with a gestational age of 30 weeks or more were still oxygen dependent at 36 weeks postconception versus 38.7% and 28% in the group of 24 to 25 weeks and 26 to 27 weeks, respectively. Of the infants 78.1% were intubated and required IPPV; 44.1% were weaned by 4 weeks, 82.5% by 8 weeks, 93% by 12 weeks, and 100% by 15 weeks of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Birth Weight↗
PubMed1991

Effects of indomethacin on prostaglandin E2 and thromboxane B2 contents of tracheal lavage fluids in premature infants.

A prospective longitudinal study was conducted in 14 premature infants intubated and receiving ventilatory support from birth, in order to evaluate the levels of prostaglandins E2 (PGE2) and thromboxane B2 (TxB2) in the tracheal lavage fluids (TLF) after treatment with indomethacin. Eight were treated with indomethacin, a cyclooxygenase inhibitor, for patient ductus arteriosus and the others served as controls. Infants who received indomethacin during the first postnatal week had significantly lower levels of eicosanoids in TLF during the first week. Our results suggest that levels of eicosanoids in TLF of premature infants are related to an inflammatory reaction and may serve as an index of the infant's overall clinical condition.

Body Fluids↗
PubMed1990

Somatic growth in infants receiving prolonged caffeine therapy.

We have evaluated the longitudinal growth of 28 premature infants who had been treated by prolonged caffeine therapy (mean: 23.8 weeks). Routine follow-up included at least 5 physical examinations with measurement of length, weight and head circumference at the beginning of caffeine therapy, at mid therapy, at the end of the therapy and at 3 and 6 months after therapy. The distribution of the infants on the growth curves according to weight, length and head circumference showed a regular increase in growth parameters. Analysis of variance was highly significant at p less than 0.0001. We conclude that long term caffeine treatment does not adversely influence growth parameters, at least during early infancy.

Anthropometry↗
PubMed1987

Delay in caffeine elimination in breast-fed infants.

Because of a persistently elevated caffeine half-life observed in a breast-fed infant during caffeine maintenance therapy, we conducted this prospective longitudinal study in two groups of infants (five exclusively breast-fed and 12 formula-fed). After 46 weeks' postconceptional age, all five breast-fed infants had a marked delay in caffeine elimination, compared with one infant in the formula-fed group. Four breast-fed infants had measurements of significantly longer caffeine half-lives compared with 12 formula-fed infants (76 +/- 13 hours v 21 +/- 28 hours and 54 +/- 9 hours v 16 +/- 13 hours at 47 to 50 weeks and 51 to 54 weeks postconceptional age, respectively), as well as significantly higher trough blood levels (three- to five-fold) after 46 weeks' postconceptional age. The fifth breast-fed infant accumulated caffeine secondary to a steep increase in caffeine half-life from 102 hours at 44 weeks to 372 hours at 51 weeks. The elevated blood caffeine levels in breast-fed infants was not related to higher daily dosage of caffeine citrate (4.4 mg/kg compared with 8.3 mg/kg in the formula-fed group at 56 weeks' postconceptional age). Daily consumption of caffeine was low or nonexistent in four nursing mothers, and transfer of caffeine to the infant was considered to be trivial. The findings from this study suggest, as does breast milk jaundice due to inhibition of glycuronyl transferase, that some components of human milk (free fatty acid, lipase activity, or other factors) inhibit or repress the postnatal normal maturation process of caffeine metabolism by hepatic cytochrome P-450.

Apnea↗
PubMed1985

Maturational changes of caffeine concentrations and disposition in infancy during maintenance therapy for apnea of prematurity: influence of gestational age, hepatic disease, and breast-feeding.

Twenty-three premature infants receiving caffeine maintenance therapy were followed prospectively for several months. Three to nine determinations of caffeine half-life (peak and trough caffeine levels) were made in each baby. This first longitudinal study confirmed that the half-life of caffeine is prolonged during the neonatal period (97.6 + 32 hours and for as many as 38 weeks' gestation in several very premature babies). Contrary to previous assumptions, gestational age and postconceptional age seem to be closely related to maturation of hepatic caffeine elimination after the neonatal period, although a high variability of caffeine half-life was observed between infants. Adult values (6 hours) were obtained about 60 weeks postconceptional. Caffeine half-life was greatly increased in two infants who had cholestatic hepatitis secondary to prolonged parenteral alimentation and one infant who was breast-fed exclusively. In this last case, the role of maternal hormones in repressing the normal enzymatic maturation process is strongly suspected. Adequate blood levels of caffeine were usually obtained with a caffeine half-life greater than 30 hours up to 46 weeks postconceptional with a dose of 5 mg/kg of caffeine citrate. Caffeine predose monitoring is adequate up to 46 weeks postconceptional, and caffeine half-life determination is mandatory whenever the trough level is too high or too low, icterus is present, and from 46 to 50 weeks postconception.

Aging↗
PubMed1981

Effect of fetal or adult red cells on tissue oxygenation and myocardial function in normoxemic newborn lambs.

Twelve newborn lambs less than 48 hr old had their high oxygen affinity blood exchanged for low-affinity fresh adult blood. Tissue oxygenation, hemodynamic status, blood gases, and myocardial function were compared before and after the exchange transfusion. The P50 was increased from 18 to 29 mm Hg after exchange transfusion; pH and hemoglobin levels remained constant; and there was no change in myocardial function, arteriovenous O2 content difference, O2 consumption, or cardiac output. However, mixed venous PO2 was significantly increased with low affinity red cells (33 versus 23 mm Hg).

Animals↗
PubMed1981

Oxygenation in anemic newborn lambs with high or low oxygen affinity red cells.

Experiments to determine the effect of the oxygen-hemoglobin dissociation curve on oxygen delivery during neonatal anemia, were carried out on 15 sedated and ventilated lambs less than 48 hr of age. Eight of the animals were exchange transfused with adult blood. The P50 of the exchange transfused group was 32.1 mm Hg (low O2 affinity) compared to 19.4 mm Hg for the controls (high O2 affinity). The animals were made anemic by isovolumic exchange transfusions with plasma. At different levels of hemoglobulin defined as mild (8 mg/100 ml), moderate (6 mg/100 ml), and severe (4 mg/100 ml) anemia, tissue oxygenation, hemodynamic status, and blood gases were compared. Mixed venous PO2 was significantly lower in the high affinity group throughout this study. Cardiac output was significantly greater in the low affinity group during severe anemia. Oxygen consumption remained stable in the low affinity group, but decreased significantly in the high affinity group when the anemia was severe. The data indicate that during severe anemia, blood with a high P50 is more capable of adequately oxygenating tissues than that with a low P50.

Anemia, Neonatal↗
PubMed1980

Neonatal necrotizing enterocolitis: the relation of age at the time of onset to prognosis.

A study was undertaken to evaluate the predisposing factors, age at the time of onset and prognosis of neonatal necrotizing enterocolitis in 62 patients treated in a neonatal intensive care unit during a 5-year period (1974-78). Because of a peak frequency during the first week of life, the cases were divided into those of early-onset illness (appearing within the first week of life) and those of late-onset illness (appearing after this week). The main differences between the two groups were in the age at the time of the first enteric feeding (1.6 +/- 0.9 d v. 40 +/- 2.4 d [mean +/- one standard deviation]; P less than 0.001) and the interval between this feeding and the onset of symptoms (3.0 +/- 1.5 d v. 10.6 +/- 6.0 d; P less than 0.01). Furthermore, the early-onset illness was more severe, more often necessitating surgical intervention and carrying a higher mortality, than the late-onset illness. Thus, this study demonstrates that there are two forms of neonatal necrotizing enterocolitis, differing in time of appearance after birth as well as in severity and prognosis.

Age Factors↗
PubMed1980

Elective delivery and the neonatal respiratory distress syndrome.

A prospective study was carried out to determine how often moderate or severe respiratory distress syndrome in infants delivered electively after 32 weeks' gestation or more is avoidable. During a 9-month period 64 such newborns were evaluated. The disease was considered avoidable in 14 (22%) since the indication for elective delivery was questionable. The mean birth weight and gestational age of these 14 infants were 2550 +/- 430 g and 36.3 +/- 1.7 weeks, and the mortality was 14%. This study demonstrated that elective delivery can produce severe neonatal complications, that despite their availability diagnostic tests of fetal age and maturity of the fetal lungs are not being used universally, and that the indications for elective delivery in cases of premature rupture of the membranes must be re-evaluated.

Adult↗