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Biomedical subjects

M Dehan

Publications and source records attributed to M Dehan.

At least 109 records · Page 6Linked to original sources
PubMed1989

[Hyaline membrane disease in the premature infant: diagnostic aspects and therapeutic prospects (excluding mechanical ventilation)].

Hyaline membrane disease is attributed to a temporary lack of pulmonary surfactant. Its diagnosis, relatively easy, is based on clinical signs (respiratory distress with a 3-4 days cycle in a premature infant) and on radiological signs (reduced chest expansion, diffusion microgranulations, air-filled bronchi). In patients with few symptoms or when the disease is associated with infection or aspiration, the diagnosis is facilitated by biochemical methods, notably measurement of the lecithin/sphyngomyelin ratio and phosphatidylglycerol assay. The principal therapeutic prospects are based on the development of exogenous surfactant supply. This is either natural surfactants extracted from animal lungs or human amniotic fluid, or synthetic surfactants of varied composition. The first results of clinical trials are in favour of natural surfactants, but many technical, pharmacological and clinical problems will have to be solved before these products can be used on a wide scale.

Humans↗
PubMed1989

Passive total respiratory system compliance and gas exchange in newborns with hyaline membrane disease.

Passive total respiratory system compliance (CRS) and gas exchange measurements were performed in nine newborns during the course of hyaline membrane disease. None of the subjects presented bronchopulmonary dysplasia at follow-up investigations. Gestational age ranged from 29 to 37 weeks. CRS was measured by the multiple occlusion technique. Gas exchange parameters were the fraction of inspired oxygen concentration (FIO2) and the arterial/alveolar ratio for oxygen (a/AO2 ratio). In each subject four tests were performed: test 1 during the first day of life; test 2 during the second day of life; test 3 between the fourth and the seventh days of life; test 4 after extubation. CRS/BW (CRS normalized for body weight) was not statistically different at tests 1-3, but it significantly increased (P less than 0.001) between tests 3 and 4. FIO2 and a/AO2 ratio presented no statistical difference at tests 1-2 but several significant differences were noted thereafter: FIO2 decreased significantly (P less than 0.001) when results from tests 2 and 3 were tabulated. The a/AO2 ratio increased significantly between tests 2 and 3 (P less than 0.001), and a further significant increase (P less than 0.01) was also noted when results obtained during tests 3 and 4 were compared. A significant relationship existed during the evolution of the disease between CRS/BW and gas exchange parameters (FIO2 and a/AO2 ratio) (P less than 0.01), but gas exchange improved earlier than lung mechanics.

Bronchopulmonary Dysplasia↗
PubMed1989

Accuracy of two wavelength pulse oximetry in neonates and infants.

In 60 neonates (gestational age, 26.5-40 weeks; postnatal age, 1-14 days) and in 11 infants (gestational age, 26-33 weeks; postnatal age, 4.5-38 weeks), the accuracy of two wavelength pulse oximetry was examined. A total of 112 comparisons between transcutaneous pulse oximetry saturation (StcO2, NELLCOR N-100) and arterial oxygen saturation (SaO2, OSM2 RADIOMETER) were obtained. SaO2 ranged from 80 to 100%. Criteria for comparison between StcO2 and SaO2 were standardized: patients in behavioral state 1, StcO2 stable for 2 min, and arterial samples drawn from an indwelling arterial line. StcO2 was significantly related to SaO2 (P less than 0.01), but the difference, StcO2 - SaO2, significantly increased when SaO2 decreased [StcO2 - SaO2(%) = -0.39 SaO2(%) + 37.95; r = -0.64, P less than 0.01]. No significant relationship was found between StcO2 - SaO2 and either bilirubinemia (range, 5-222 mumol/L) or fetal hemoglobin (HbF) (range, 12-95%). We conclude that StcO2 overestimates SaO2 when SaO2 decreases, and this overestimation is not due to high levels of bilirubin or HbF.

Bilirubin↗
PubMed1989

Effects of sleep deprivation on respiratory events during sleep in healthy infants.

This study was designed to determine the effects of sleep deprivation on respiratory events during sleep in healthy infants. Ten unsedated full-term infants (1-6 mo) were monitored polygraphically during "afternoon naps" on a control day and on the day after sleep deprivation. Respiratory events, i.e., central apnea, obstructive apnea and hypopnea, and periodic breathing were tabulated. Results for respiratory events were expressed as 1) indexes of the total number of respiratory events and of specific respiratory events per hour of total sleep (TST), "quiet" sleep (QS) and "active" sleep (AS) times; 2) total duration of total and specific respiratory events, expressed as a percentage of TST, QS, and AS times. After sleep deprivation, significant increases were observed for 1) respiratory event (P less than 0.001), central apnea (P less than 0.05), and obstructive respiratory event (P less than 0.01) indexes; 2) respiratory event time as a percentage of TST (P less than 0.002) and as a percentage of AS time (P less than 0.001); 3) obstructive respiratory event time as a percentage of TST (P less than 0.01), QS (P less than 0.05), and AS times (P less than 0.002). The present study shows that short-term sleep deprivation in healthy infants increases the number and timing of respiratory events, especially obstructive events in AS.

Female↗
PubMed1989

Technique of on-line analysis of diaphragmatic electromyogram activity in the newborn.

The present study provides an on-line analysis of diaphragmatic electromyographic activity (EMGdi) in newborns. EMGdi was recorded using surface electrodes. EMGdi signals were processed using a microcomputer (Apple IIe). The centroid frequency (Fc) and the high over low (H/L) frequencies ratio of the power spectrum were calculated. Furthermore the model frequency (Fo) was computed by an autoregressive model of the EMG signal. EMGdi analysis was performed in seven healthy spontaneously breathing preterm newborns. Fc ranged from 46-62 Hz. Fc was significantly lower than Fo in four of the seven preterm newborns. The coefficient of variation for Fc was significantly lower than for the H/L ratio (p less than 0.001). The coefficients of variation for Fo and Fc were not significantly different, but the percentage of rejected calculations for Fo was significantly higher than for Fc (p less than 0.01). Therefore, in healthy preterm newborns, Fc appears to be the best index of EMGdi analysis.

Diaphragm↗
PubMed1988

Passive compliance of total respiratory system in preterm newborn infants with respiratory distress syndrome.

The passive compliance of the total respiratory system (CRS) was measured by the occlusion technique in 34 preterm newborn infants with respiratory distress syndrome. Gestational age ranged from 27 to 33 weeks. Preterm newborn infants were divided into four groups on the basis of clinical criteria. Group 1 consisted of 10 infants tested during the first postnatal days (1 to 3 days) while acutely ill and requiring ventilation and oxygen therapy. After the acute phase of respiratory distress syndrome, two groups were tested: group 2 consisted of nine infants (5 to 22 days of age) who no longer required ventilation, and group 3 consisted of six infants (7 to 28 days of age) who subsequently had bronchopulmonary dysplasia. Group 4 consisted of nine infants older than 1 month of age with confirmed bronchopulmonary dysplasia. Group 1 had significantly lower CRS and CRS normalized for body weight (CRS/BW) than group 2 had (P less than 0.001). In groups 3 and 4 CRS was significantly lower than in group 2 (P less than 0.001), as was CRS/BW (P less than 0.001). There was no significant difference in CRS and CRS/BW values between groups 3 and 4. This cross-sectional study in preterm infants with respiratory distress syndrome suggests that CRS may have predictive value in regard to development of bronchopulmonary dysplasia after the acute phase of respiratory distress syndrome.

Bronchopulmonary Dysplasia↗
PubMed1988

Effect of maturation on heart rate response to ocular compression test during rapid eye movement sleep in human infants.

Thirty-three premature and full-term infants (31.5-50 wk postconceptional age) free from neurologic and cardiopulmonary disease at time of testing, underwent a standardized ocular compression test during polygraphically controlled rapid eye movement sleep. RR intervals were measured on the ECG before and during ocular compression. RR interval changes during ocular compression were compared to the preceding 60-s mean RR interval in each infant. Results were analyzed relative to gestational age, postnatal age, and postconceptional age. Baseline heart rate during REM sleep decreased with postconceptional age. During ocular compression, there was a significant negative correlation between the longest RR interval or the "latency" variable with postconceptional age. Latency is defined as the time, in milliseconds, from beginning of eyelid pressure to the first measurable RR increase compared to mean control RR + 1 SD. Our results indicate that during rapid eye movement sleep, "baseline heart rate" decreases with maturation, an effect supposedly related to increased vagal activity, whereas the heart rate response on ocular pressure stimulus, a vagally mediated reflex, is significantly influenced and blunted with maturation.

Autonomic Nervous System↗
PubMed1988

[Neonatal pulmonary pathology].

The authors study the detailed symptomatology of the respiratory distress syndrome in the new born, and review the principal pulmonary pathologies encountered in the neonatal period. For each one the physiology, epidemiology and the clinical and paraclinical aspects were studied as well as those factors concerning the evolution and prognosis. Therapy was also discussed and for certain disorders the future prospects in this field.

Bronchopulmonary Dysplasia↗
PubMed1988

[Comparison of arterial and transcutaneous oxygen partial pressure in infants with bronchopulmonary dysplasia].

Transcutaneous PO2 (PTCO2) (Radiometer electrode heated to 44 degrees C) was compared to arterial PO2 (PaO2) in 19 infants with bronchopulmonary dysplasia: 12 infants were tested once, at the mean postnatal age of 14 weeks (range 4-43 weeks), the other 7 infants were studied longitudinally from 5 weeks (range 2-8 weeks) to 12 weeks (range 6-18 weeks) of postnatal age. The protocol was standardized: measurement during behavioral stage 1, using a peripheral arterial line. Twenty-eight comparisons between PTCO2 and PaO2 were obtained. PTCO2 was significantly related to PaO2 [PTCO2 (mmHg) = 0.81 PaO2 + 5.2, r = 0.73, p less than 0.01]. The mean difference PTCO2 - PaO2 was -7.2 mmHg (range: -34.5 to + 33); in the studied age range the PTCO2 - PaO2 was not significantly related to postnatal age (r = -0.24; p greater than 0.1).

Blood Gas Monitoring, Transcutaneous↗
PubMed1988

[Clinical and anatomo-pathologic study of 59 cases of sudden infant death].

A proper organization has been set up at Antoine-Béclère's hospital in order to study the infants who died suddenly. Between July 1985 and July 1987, 69 cases (10 babies less than 1 week of age) were admitted. The purpose of this work was, for the 59 sudden deaths of infants aged more than 1 week (35 males, 24 females), to present the results of a definite protocol of investigation (past history, clinical examination, laboratory and pathological data) for determining either the etiology or the mechanism of these deaths. A thorough investigation was performed in 45/52 cases (no autopsy in 7 cases). A definite diagnosis was possible in 38/45: 13 viral infections, 5 gastro-esophageal reflux, 13 viral infections associated with reflux, 9 with an additional event (massive alimentary inhalation, slipping under blankets, major hyperthermia) to either a viral infection or a reflux, 1 cardiac malformation, 1 metabolic disorder, 2 accidents and 1 infanticide. With this protocol, 7/45 deaths remained unexplained. This medical approach of the problem of sudden deaths in infants is beneficial to the counselling of the parents and to the management of subsequent children.

Autopsy↗
PubMed1987

Phosphatidylglycerol in tracheal aspirates for diagnosis of hyaline membrane disease.

Lecithin:sphingomyelin ratio and phosphatidylglycerol were determined by a rapid, simple method in tracheal aspirates obtained from 132 newborn infants with respiratory diseases, sixty five of whom developed hyaline membrane disease. Phosphatidylglycerol determination was more sensitive (97%) than lecithin:sphingomyelin ratio, but their specificities were similar (76%).

Humans↗
PubMed1987

Study of the pharmacokinetics and pharmacodynamic activity of almitrine bismesylate in infants during the recovery phase following bronchopulmonary dysplasia.

The efficacy and pharmacokinetics of almitrine bismesylate were studied in 6 infants (age 2.5-9.5/months) during the recovery phase following bronchopulmonary dysplasia. The infants did not require assisted ventilation, but needed oxygen therapy with an FiO2 of 25-30% in stable condition. One to three hours after a single oral dose of almitrine (1.5 mg/kg), there was a marked increase in transcutaneous PO2 (TcPO2) (mean 2kPa) followed by a regular decrease to the baseline level. Nine to fourteen days after repeated administration of almitrine (1.5 mg/kg/12 h) in 4 children, the mean gain in TcPO2 was only 0.85 kPa. There was a very early flagging in efficacy of almitrine, since none of the children could be weaned from oxygen therapy. The absorption peak occurred 1-3 h after the administration of the compound. The maximum almitrine concentration was 173 +/- 44 ng/ml; plasma clearance was 21.9 +/- 6.6 ml/min and the volume of distribution was 18.7 +/- 2.1 liters/kg. The drug was eliminated biphasically. In the 4 studies with repeated drug administration, the pharmacokinetic results suggested that a steady state was still not achieved after 9-14 days of treatment. These results and the absence of any sustained effect of repeated doses of the drug raise the problem of a particular type of almitrine metabolization in the infant.

Administration, Oral↗
PubMed1987

[Comparative pharmacokinetics of fosfomycin in the neonate: 2 modes of administration].

In newborn, fosfomycin-cefotaxime in combination is more and more commonly used for the treatment of nosocomial infections. A pharmacokinetic study was conducted in ten newborns in the aim of suggesting a therapeutic schedule of the fosfomycin. Each newborn received 200 mg/kg, intravenously twice a day. Two groups have been formed according to the time of perfusion: 2 h or 30 min. The study of pharmacokinetic parameters do not demonstrated significant difference between the two populations. In addition, residual serum concentrations, twelve hours after the administration, are greater than the minimal inhibitory concentrations of most common pathogens causing nosocomial infections in neonates.

Age Factors↗