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Biomedical subjects

M Dehan

Publications and source records attributed to M Dehan.

At least 73 records · Page 4Linked to original sources

[Limitations of extreme prematurity].

The extreme limit of viability in premature infants, related to pulmonary maturity, cerebral structuration and the capacity to maintain homeostasis and metabolic functions is approximately 23-24 weeks of gestation. Currently at 25-26 weeks, with a birth-weight of 600 g, the probability of survival at 1 year is 50%; at 27-28 weeks 1 year survival rises to 60-80% and at 29 weeks reaches 90%. Motor, sensorial and intellectual or psychological sequellae are seen in approximately 20% of the infants born after less than 27 weeks gestation. Over the last twenty years the gain in the number of normal surviving infants has been multiplied by 20, and therefore, despite a decrease in the percentage of children with sequellae, the total number of handicapped children has also increased. From an ethical point of view, every newborn, whatever his birthweight, gestational age or clinical distress is a human being and has a right to the preservation of his potential for survival. Although current legislation sets a limit of 22 weeks or 500 g for declaration of birth, the real question is to determine the medically ethical limit for intensive care.

Ethics, Medical↗

Measurement of oxygen uptake in newborn infants during assisted and spontaneous ventilation.

Measurements of oxygen uptake (VO2) and CO2 output (VCO2) are useful in critically ill patients. However, VO2 is not routinely measured in intensive care during mechanical ventilation (MV) especially in premature newborns. The present study describes a new method of measuring VO2 and VCO2 using a double open circuit which accounts for gas leaks around the uncuffed tracheal tube. The accuracy of the method was assessed with N2 and CO2 infusion. In case of leaks, VO2 and VCO2 measurement was significantly underestimated by the simple circuit method. This underestimation was not present with double circuit method. Five preterm newborns were studied. VO2 and VCO2 using the double open circuit were compared with the classic simple circuit. During MV, the mean underestimation assessed by the difference between simple and double circuit measurement was -12% (range from 0 to -29%) for VO2 and -14% (range 0 to -26%) for VCO2.

Carbon Dioxide↗

[Pain symptomatology in premature infants].

BACKGROUND: Assessing pain in premature babies is difficult because of their limited capacities to communicate. The aim of this study was to recognize manifestations of acute and chronic pain or, on the contrary, of well-being state, and to validate a "pain scale" for premature babies. POPULATION AND METHODS: Premature babies less than 28 days of age (most of them less than 32 weeks of gestational age) were carefully observed during their stay in a neonatal intensive care unit by nurses, physicians, physiotherapists and a psychiatrist. All signs and symptoms were collected during situations a priori painful and compared to the behavior of the well-being states. Photographs and videofilms were also analysed. RESULTS: Five items, scored from 0 to 4, were established, based on facial activity, movements and posture of the body, quality of sleep, relationship with the examiner, and efficacy of measures of comforting. These items permitted to describe four patterns corresponding to 1: well-being status, 2: acute pain, 3 and 4: durable pain or discomfort either through clinical picture of irritability or motionlessness. A strict concordance of scores for the five items between the different examiners was found in 80% of the 50 babies studied. The sensibility of the scale (studied in 12 babies) appeared accurate (77% of variation of the scores during hospitalization). CONCLUSIONS: An objective assessment of pain and discomfort in premature babies can be made using a "pain scale" useful for care and therapeutic decisions.

Evaluation Studies as Topic↗

Task force report on the outcome of pregnancies and children conceived by in vitro fertilization (France: 1987 to 1989).

OBJECTIVE: To describe the outcome of pregnancies conceived by IVF and the follow-up of the children after a minimum of 1 year of life. DESIGN: Survey of clinical pregnancies and follow-up of the children and comparison with national statistics. SETTINGS: All clinical pregnancies from 11 French centers between January 1987 and June 1989. PATIENTS: A total of 1,637 pregnancies resulting in 1,263 deliveries and 1,669 live-born or still-born children and 1,411 alive children after 1 year. MAIN OUTCOME MEASURES: Gestational age of birth, birth weight, mortality rates, prevalence of congenital malformation, and prevalence of disorders during the follow-up of the children. RESULTS: The preterm birth rate was 22.7% of all deliveries and 12.2% of single deliveries compared with 5.6% in France, and 34.7% of babies weighed < 2,500 g compared with 5.2% in France. The rate of perinatal, neonatal, and infant mortality were higher than the national average. The rate of malformation (2.86%) was comparable with national survey (2.08%). The health of children diseased during the whole follow-up was approximately 2%. CONCLUSION: The health of children after 1 year of live is close normal.

Birth Weight↗

Sleep state organization in premature infants of less than 35 weeks' gestational age.

To assess sleep organization in premature infants of < 35 wk gestational age (w GA), we performed polygraphic recordings in 24 neurologically normal neonates (eight per group): artificially ventilated 27-30 and 31-34 w GA infants and nonventilated 31-34 w GA infants. Sleep states were defined by concordance of EEG and rapid eye movement criteria. Uninterrupted active sleep periods of > 13 min and quiet sleep periods of > 5 min were observed in all babies, except in one 33 w GA ventilated infant. Intervals from the beginning of recording to the 1st quiet sleep period varied from 0 to 63 min and intervals to the beginning of the longest sleep cycle varied from 5 to 84 min. Nonventilated 31-34 w GA infants had longer sleep cycles (p < 0.02), principally because of longer active sleep periods. However, percentages of different states in the cycles were similar in all groups. When body movements were required for state definition, amounts of active and quiet sleep diminished and the percentage of indeterminate sleep was augmented significantly. In conclusion, our study demonstrated that 1) sleep state differentiation is present as soon as 27 w GA; and 2) artificial ventilation, performed in a highly specialized neonatal intensive care unit, does not modify sleep organization of neurologically normal premature infants. We hypothesize that this "earlier" sleep state differentiation, compared with previous data, may be related to improvements in neonatal intensive care over recent years.

Electroencephalography↗

[Periventricular leukomalacia of late onset in a premature infant].

BACKGROUND: Periventricular leukomalacia in preterm neonates is usually due to abnormal cerebral blood flow before and/or during delivery. It is diagnosed during the first month of life. This study describes a case of late-developing periventricular leukomalacia. CASE REPORT: A girl was delivered by cesarean section at the 23rd week of gestation that was complicated by placenta previa. She weighted 880 g and immediately required resuscitation. She did not develop respiratory distress syndrome. She was intubated and ventilated for the first two weeks of life and developed bronchopulmonary dysplasia requiring corticosteroid treatment. Extubation was possible on day 43. The neonate had been given antibiotics for the first 10 days of life and indomethacin on day 8 because of a patent ductus arteriosus. Repeated craniosonography showed moderate bilateral intraventricular hemorrhage and occipital areas of hyperechogenicity that disappeared at the end of the first month of life. Repeated electroencephalograms revealed no positive rolandic sharp waves until the infant was 42 days old. Craniosonography on day 48 showed areas of heterogeneous hyperechogenicity and NMR imaging showed bilateral frontoparietal leukomalacia with loss of white matter. The baby died on day 71. CONCLUSIONS: Late periventricular leukomalacia is exceptional and usually seen after postnatal abnormalities in cerebral blood flow and/or prolonged hypoxemia. Both these risk factors were absent in this patient.

Echoencephalography↗

[Risks of sudden death in siblings].

The risk of sudden infant death among siblings has long been overestimated: in all epidemiological studies the risk of recurrence remains at 1% or below, thereby excluding a hereditary hazard. Compared with the general population, the risk is increased in only a small percentage of families which can be detected (familial gastrooesophageal reflux or vagal hyperreflexibility, psychosocial problems and, more rarely, hereditary pathology). In the vast majority of families the relative risk is not objectively augmented. In all cases counselling of the parents is necessary for them to accept a new child.

Family Health↗

Dose-related bronchodilator response to aerosolized salbutamol (albuterol) in ventilator-dependent premature infants.

We used a placebo-controlled standardized protocol to define the dose-response relationship to the beta-adrenergic bronchodilator salbutamol (albuterol) in 10 ventilator-dependent premature infants at a postnatal age of 13.3 +/- 4.9 days. Passive respiratory system resistance and compliance were measured at baseline and 10 minutes after administration of salbutamol via a metered-dose inhaler and spacer device. Salbutamol caused a significant dose-related response with a 33% mean decrease in respiratory system resistance (p less than 0.05) and a 67% mean increase in respiratory system compliance (p less than 0.001). In seven and six patients, respectively, 100 micrograms of salbutamol caused significant improvement in resistance and compliance; 200 micrograms was required in the remainder, but one patient had no improvement in compliance. Oxygen saturation increased linearly with the increase in compliance. In 7 of the 10 infants, the duration of action of 200 micrograms of salbutamol on the following day was 3 hours. We conclude that bronchodilator treatment may be useful in the management of ventilator-dependent neonates with respiratory distress syndrome.

Aerosols↗

Cardiac, respiratory, and arousal responses to an esophageal acid infusion test in near-term infants during active sleep.

This study was designed to determine the cardiac, respiratory, and arousal responses to an esophageal acid infusion test in near-term infants free from neurological, gastroesophageal, and cardiopulmonary disease at time of testing during active sleep. Eight infants (gestational age 28-37.5 weeks, postconceptional age 36-40 weeks) were tested. Using standardized procedures and timing, we compared the cardiac, respiratory and arousal responses during a control period and during distal esophageal saline and acid infusion periods. The duration of each of these periods was 5 min. The pH of the acid infusion was 2.2. We found that this mild distal esophageal acid infusion test induced significant prolongation of the interval between successive electrocardiogram R waves compared with control and saline infusion periods (806.5 +/- 145.7 ms, 478.8 +/- 49.4 ms, and 468.8 +/- 37.2 ms, respectively; p less than 0.01) and of the duration of the respiratory cycle (2.9 +/- 0.7 s, 1.5 +/- 0.3 s, and 1.5 +/- 0.2 s, respectively; p less than 0.01). Esophageal acid infusion elicited significant electroencephalogram (EEG) arousal responses. The number of the EEG arousals was significantly increased during the acid period as compared with control and saline infusion periods (2.9 +/- 1.4, 0.5 +/- 0.5, and 0.4 +/- 0.5, respectively; p less than 0.01). Total arousal duration was significantly increased during acid as compared with control and saline infusion periods (42 +/- 17.5 s, 4.5 +/- 5.1 s, and 3.5 +/- 5.0 s, respectively; p less than 0.01). We conclude that distal esophageal acid stimulation elicits significant cardiac, respiratory, and EEG arousal responses in near-term infants during active sleep.

Administration, Oral↗

Accuracy of measurements of HbF with OSM3 in neonates and infants.

The accuracy of the Radiometer OSM3 oxymeter for measurement of fetal haemoglobin (HbF) in infants was investigated, and compared to one of the standard reference methods using alkali electrophoresis of haemoglobin. Blood samples of 37 infants with different gestational (27-41 weeks) and postnatal (1-198 days) ages were analysed. The two methods gave very close results but a significant mean difference (range -4.5-16.5%). However, agreement between the two methods was judged clinically acceptable (95% limits of agreement -7.5-15.5%). A rapid determination of HbF percentage, using OSM3, is an important determinant for correct assessment of oxygen saturation in newborn infants in intensive care units.

Electrophoresis↗