Absence Of Respiratory Distress Syndrome Research Articles

Noninvasive Fetal Lung Maturity Prediction Based on Amniotic Fluid Turbidity Using Ultrasonic Histogram Measurement Function

Background: Amniotic fluid turbidity increases with fetal lung maturation due to vernix and lung surfactant micelles suspended in the amniotic fluid. This study focused on this phenomenon and evaluated the presence or absence of respiratory distress syndrome (RDS)/transient tachypnea of the newborn (TTN) by quantitatively assessing the brightness of the amniotic fluid turbidity using a noninvasive ultrasound histogram measurement function. Methods: We included cases of singleton pregnancies managed at the Niigata University Medical and Dental Hospital between November 2020 and March 2022. Histograms of amniotic fluid turbidity were measured at the center of the amniotic fluid depth, avoiding the fetus, placenta, and umbilical cord, with the gain setting set to 0, and the average value was obtained after three measurements. Histograms of fetal urine in the bladder were measured similarly. The value obtained by subtracting the fetal bladder brightness value from the amniotic brightness value based on histogram measurements was used as the final amniotic fluid brightness value. Results: We included 118 cases (16 of RDS/TTN and 102 of control). The gestational age of delivery weeks was correlated with amniotic fluid brightness (Spearman’s rank correlation coefficient was 0.344; p = 0.00014). Amniotic fluid brightness values were significantly lower in the RDS/TTN group than in the control group (RDS/TTN: 16.2 ± 13.5, control: 26.3 ± 16.3; p = 0.020). The optimal cutoff value of amniotic fluid brightness to predict RDS/TTN was 20.3. For predicting RDS/TTN, the sensitivity, specificity, positive predictive value, and negative predictive value were 91.7%, 69.6%, 26.2%, and 94.1%, respectively. Conclusions: The quantitative value of the amniotic fluid brightness by histogram measurements may provide an easy and objective index for evaluating the presence or absence of RDS/TTN.

Hospital Variation in Medical and Surgical Treatment of Patent Ductus Arteriosus

This study aims to characterize population risks for diagnosis, medical treatment, and surgical ligation of patent ductus arteriosus (PDA) in very low-birth-weight infants. Maternal and neonatal data were collected in 40 hospitals in California during 2011 for infants with birth weight ≤ 1,500 g without any congenital malformation, with a diagnosis of PDA. Multivariable logistic regression was used to determine independent risks for PDA diagnosis and for surgical ligation. There were 770/1,902 (40.4%) infants diagnosed with PDA. Low birth weight, gestational age, respiratory distress syndrome, and surfactant administration were associated with PDA diagnosis. Ligation occurred in 43% of patients with birth weight ≤ 750 g, in 24% of patients weighing between 715 and 1,000 g, and in 12% of patients weighing from 1,001 to 1,500 g. Older gestational age (1 week, odds ratio 0.55, 95% confidence interval 0.48-0.63) and absence of respiratory distress syndrome (odds ratio 0.14, 95% confidence interval 0.03-0.59) were associated with lower ligation risk. The median hospital ligation rate was 14% (interquartile range 0-38%). Most patients with PDA receive treatment for closure. Practice variation may set the stage for further exploration of experimental trials.

Genetic polymorphisms of antioxidant enzymes as risk factors for oxidative stress-associated complications in preterm infants

We aimed to identify specific polymorphisms of genes encoding for superoxide dismutase (SOD) 1 (cytoplasmic Cu/ZnSOD), SOD2 (mitochondrial MnSOD), SOD3 (extracellular Cu/ZnSOD) and CAT in a cohort of preterm infants and correlate their presence to the development of respiratory distress syndrome (RDS), bronchopulmonary dysplasia (BPD), intraventricular haemorrhage (IVH) and retinopathy of prematurity (ROP). We carried out a retrospective study to evaluate the allele frequency and the genotype distribution of polymorphisms of SODs and CAT in a population of preterm neonates (n = 152) with a gestational age ≤ 28 weeks according to the presence or absence of RDS, BPD, IVH and ROP. Moreover, we evaluated through the haplotype reconstruction analysis whether combinations of the selected polymorphisms are related to the occurrence of RDS, BPD, IVH and ROP. We found that rs8192287 SOD3 polymorphism is an independent protective factor for all grade IVH, while rs4880 and rs5746136 SOD2 polymorphisms are associated with a lower gestational age (rs4880, rs5746136) and birth weight (rs4880). Haplotypes reconstruction showed that SOD1 (GG) decreased the risk of RDS, IVH and ROP; SOD2 (GT) increased the risk of BPD and decreased the risk of RDS, IVH and ROP; SOD3 (TGC) decreased the risk of BPD and IVH; and 4) CAT (CTC) decreased the risk of RDS. The rs8192287 SOD3 polymorphism is per se an independent predictor of a decreased risk of developing IVH. Different SOD2 polymorphisms are associated per se with a lower gestational age and/or birth weight, and haplotypes of SOD1, SOD3 and CAT genes may be independent protecting or risk markers for prematurity complications.

Avaliação da maturidade pulmonar fetal pela contagem dos corpos lamelares no líquido amniótico

To compare the lamellar body number density (LBND) count in amniotic fluid using the fluorescent polarization (FP) test as a diagnostic parameter for the assessment of fetal pulmonary maturity. This was an analytical, controlled cross-sectional study conducted on 60 pregnant women from March 2002 to December 2007. Amniotic fluid specimens were obtained by amniocentesis or at the time of caesarean section, and submitted to the LBND and FP tests (TDxFLM, Abbott Laboratories), the latter considered to be a reference test, and compared in terms of the presence or absence of respiratory distress syndrome (RDS). Cut-off values for maturity were established at 30,000 lamellar bodies/microL for the LBND test and 55 mg/g albumin for the FP test. Maternal and perinatal characteristics and neonatal evolution were evaluated, and the performance of the diagnostic tests regarding fetal pulmonary maturity was determined. In the statistical analysis, descriptive measures were used and the sensitivity, specificity and positive and predictive values of the tests were determined with the level of significance set at p<0.05. Maternal age ranged from 15 to 34 years (mean: 26.6 years) and gestational age ranged from 24.3 to 41.6 weeks (mean: 35.1 weeks). RDS was diagnosed in 35.1% of neonates. Perinatal characteristics such as weight, Apgar score, and RDS incidence were compared to the results of the LBND and FP tests and a significant correspondence (p<0.05) was observed between the groups of neonates clinically classified as mature and immature in both tests. The tests were concordant in 68.3% of the cases. Comparison of the PF and LBND tests revealed 100% specificity for both and a higher specificity for the LBND test (73.1% as opposed to 51.9% for the PF test). The gold standard for the determination of fetal maturity is the occurrence of RDS. The positive predictive value of the LBND test was higher (36.4%) than that of the FP test (24.2%) (p<0.05) and the negative predictive value was 100% for both tests. The present study demonstrated that the LBND test has 100% sensitivity and higher specificity than the reference test (FP). In addition, the LBND test is considered to be rapid, accessible, inexpensive and feasible for the Brazilian reality, and it can be used as a reliable test for the prediction of fetal pulmonary maturity.

Association of development of chronic lung disease of newborns with neonatal colonization of Ureaplasma and cord blood interleukin‐8 level

The aim of the present study was to investigate the association of chronic lung disease (CLD), neonatal Ureaplasma colonization, and interleukin-8 (IL-8) level of cord blood in preterm infants. In 77 infants of <32 weeks gestation, the relationship between IL-8 level of cord blood, neonatal colonization of Ureaplasma, histological chorioamnionitis (CAM), and development of CLD was studied. Five infants died and 29 infants developed CLD. The CLD group had significantly lower gestation (mean ± SD: 26.6 ± 1.8 weeks) compared with the infants without CLD (28.9 ± 1.9 weeks, P < 0.0001). Logistic analysis showed that the development of CLD was associated with gestational age (odds ratio [OR], 0.5; 95% confidence interval (CI): 0.4-0.8) and Ureaplasma colonization (OR, 4.1; 95%CI: 1.2-14.4). Ureaplasma colonization was also associated with CAM (OR, 6.5; 95%CI: 1.8-23.5), absence of respiratory distress syndrome (OR, 6.2; 95%CI: 1.3-30.5), and development of CLD (OR, 4.0; 95%CI: 1.1-15.3). Elevated cord blood IL-8 ≥100 pg/mL was associated with female sex and the isolation of microorganisms (OR, 49.4; 95%CI: 4.6-525). The development of CLD defined by oxygen requirement at 36 weeks was associated with neonatal Ureaplasma colonization but not with IL-8 level of cord blood. Elevated cord blood IL-8 was associated with neonatal microorganisms isolation.

746: The reliability of lamellar body count from transvaginal and transabdominal amniotic fluid samples in predicting absence of respiratory distress syndrome

746: The reliability of lamellar body count from transvaginal and transabdominal amniotic fluid samples in predicting absence of respiratory distress syndrome

The reliability of lamellar body count in predicting absence of respiratory distress syndrome from transvaginal and transabdominal amniotic fluid samples

THE EXPECTED CHANGE OVER TIME? SHAD DEERING, SARAH POGGI, CATHERINE SPONG, FRANCA BARTON, KATIE GOODWIN, ALESSANDRO GHIDINI, Georgetown University, Obstetrics and Gynecology, Washington, DC Georgetown University, Biostatistics, Washington, DC OBJECTIVE: To assess the change in the lamellar body count (LBC) in patients undergoing repeat testing for fetal lung maturity to see if a predictable change in LBC over a given period of time exists. STUDY DESIGN: We analyzed a cohort of women from 1998 to 2003 at a single institution who underwent amniotic fluid sampling at least twice during pregnancy for determination of fetal lung maturity. Charts were reviewed and maternal demographic information, as well as data regarding the gestational age at sampling and the LBC, were recorded. This study was approved by the institutional review board. Statistical analysis included linear regression of LBC and gestational age. RESULTS: There were a total of 24 patients who had at least two samples taken during the study period for a total of 57 samples. Themean gestational age at sampling was 34.8 ± 0.3 weeks. Linear regression demonstrated that the LBC count increased by 5087 per week (P = 0.008). This increase did not change significantly with increasing gestational age. CONCLUSION: The LBC count increases approximately 5100 per week during pregnancy after 28 weeks’ gestation and the rise appears to be consistent and linear. This information may be beneficial in determining when a patient can be expected to have a level consistent with fetal lung maturity after a given LBC and therefore have a low risk of RDS.

The association between respiratory distress and nonpulmonary morbidity at 34 to 36 weeks' gestation

Objective The study was undertaken to determine whether respiratory distress syndrome (RDS) is associated with an increased risk of nonpulmonary morbidity in neonates born between 34 to 36 weeks' gestation. Study design We performed a matched case-control study of 75 infants with (cases) and 75 without (controls) RDS, delivered between 34 and 36 weeks' gestation. Infants with RDS and no other causes for respiratory failure (anomalies, hydrops, asphyxia) were included. Controls were matched for gestational age at birth, year of care, gender, plurality, and race. Inpatient records were reviewed for the incidence of nonpulmonary morbidities before discharge. McNemar test and conditional logistic regression were used to evaluate differences between cases and controls. Results Our study cohort was 69% male, 48% white, 33% African American, and 19% Hispanic. Cases had longer hospital (11 vs 7days) and neonatal intensive care unit stays (10 vs 7days), and more frequent apnea-bradycardia (30% vs 5%), pneumonia (12% vs 1%), and suspected sepsis diagnoses (27% vs 3%), P ≤ .008 for each. Antibiotic use (96% vs 45%), transfusion (20% vs 0%), phototherapy (57% vs 29%), and hyperalimentation (57% vs 4%) were more common in the RDS group, P ≤ .002 for each. Other major morbidities (intraventricular hemorrhage, patent ductus arteriosus, necrotizing enterocolitis, bronchopulmonary dysplasia) were uncommon in cases and controls. Similar results were obtained when controlling for mode of delivery and antenatal steroid use. Conclusion RDS at 34 to 36 weeks is associated with increased morbidity and neonatal interventions. In the absence of RDS, major morbidity is uncommon.

Bronchopulmonary dysplasia: an enduring challenge.

1. Yvonne E. Vaucher, MD, MPH* 1. *Clinical Professor of Pediatrics, Division of Neonatology, University of California, San Diego, Calif. After completing this article, readers should be able to: 1. Describe the most common cause of chronic lung disease during infancy. 2. Explain the importance of a history of bronchopulmonary dysplasia throughout childhood. 3. Identify infants at high risk for developing bronchopulmonary dysplasia. 4. List the adverse effects associated with postnatal corticosteroids. Despite clinical advances in antepartum, intrapartum, and neonatal care, bronchopulmonary dysplasia (BPD) continues to challenge infants who have been in neonatal intensive care units and their caretakers. BPD is the most common cause of chronic respiratory disease during infancy and remains a major cause of long-term medical, pulmonary, and neurodevelopmental morbidity, increasing the cost of health care and the utilization of medical and educational resources throughout childhood. BPD is a clinical diagnosis, defined by oxygen dependence for a specific period of time after birth and accompanied by characteristic radiographic findings that correspond to anatomic abnormalities. Thus far, a precise physiologic definition of BPD is lacking. As the clinical presentation has evolved over the past 30 years, so has the definition. As originally described by Northway in the 1960s, the diagnosis of classic BPD was based on progressive radiographic changes in preterm infants who were treated for severe respiratory distress syndrome (RDS) immediately after birth and had prolonged ventilator and oxygen dependence. This form of BPD occurred in larger, relatively mature preterm infants, who required treatment with high-pressure mechanical ventilation and high concentrations of oxygen. Although the acute respiratory disease initially improved in these infants, oxygen requirements increased 7 to 10 days after birth and persisted for at least 28 days. The definition of BPD subsequently was modified by Bancalari to include preterm infants who had less severe RDS that initially required short-term mechanical ventilation, but who also developed persistent respiratory symptoms and an oxygen requirement for at least 28 days after birth …

Performance of the dipalmitoyl phosphatidylcholine test in predicting respiratory distress syndrome in contaminated samples of amniotic fluid

To evaluate the reliability of the dipalmitoyl phosphatidylcholine test in predicting respiratory distress syndrome (RDS) in the presence of common contaminants of amniotic fluid. Forty specimens of amniotic fluid collected within 72 hours of delivery were divided in five 25 microL aliquots and diluted with either phosphate-buffered saline (control), meconium, blood, vaginal fluid, or semen. The concentration of dipalmitoyl phosphatidylcholine in all five groups of samples, as measured by the dipalmitoyl phosphatidylcholine test, was compared by paired t test, Dunnett test, and analysis of variance, and correlated with the neonatal respiratory status of the newborns. No significant differences in the concentration of dipalmitoyl phosphatidylcholine were found between control and the corresponding contaminated samples (P = .33). Of the 200 samples evaluated, 80 had dipalmitoyl phosphatidylcholine concentrations below 12 micrograms/mL and 120 had at least 12 micrograms/mL. Using a cutoff dipalmitoyl phosphatidylcholine concentration of 12 micrograms/mL, the presence of RDS was predicted accurately in all 15 control and in 61 of 65 contaminated samples. The absence of RDS, as predicted by a dipalmitoyl phosphatidylcholine value at least 12 micrograms/mL, was predicted accurately in 24 of 25 control samples and 96 of 100 contaminated samples. The overall accuracy of the dipalmitoyl phosphatidylcholine test in predicting RDS in contaminated samples was 98%. The dipalmitoyl phosphatidylcholine test is a reliable predictor of RDS in contaminated samples.

Prediction of Fetal Lung Maturity in Infants of Diabetic Mothers Using the FLM S/A and Disaturated Phosphatidylcholine Tests

The authors evaluated the performance of the amniotic fluid surfactant to albumin ratio (FLM S/A), and disaturated phosphatidylcholine (DSPC) tests in assessing fetal lung maturity in infants of mothers with insulin-dependent diabetes mellitus antedating pregnancy. The distribution of the study population (n = 180) by class of diabetes was class B (27%); class C (28%); class D (29%); class F, FR and T (8%); and class R patients (8%). The diagnosis of respiratory distress syndrome (RDS) was the standard for evaluating the performance of FLM S/A and DSPC. The mean estimated gestational age was 37.4 weeks. Three infants (1.7%) were diagnosed with RDS. All three were delivered before 36 weeks. FLM S/A at the cut-off for "maturity" of > or = 70 mg/g, had a sensitivity of 66.6%, specificity of 94.9%, positive predictive value (PPV) of 18.2%, and negative predictive value (NPV) of 99.4%. DSPC at the cut-off for "maturity" of 1,000 micrograms/dL, had identical sensitivity and NPV, but lower specificity (89.2%) and PPV (9.5%) than FLM S/A. Both tests mispredicted maturity in the same case of RDS. The false "mature" rate of FLM S/A was 0.6% (95% confidence interval 0.0%-3.2%). The FLM S/A result of > or = 70 mg/g, obtained at or near-term, is a reliable predictor of the absence of RDS in infants of mothers with diabetes mellitus antedating pregnancy.

A predictive model for fetal lung maturity employing gestational age and test results.

Most laboratory tests for fetal lung maturity (FLM) are optimized to exclude false-negative predictions of absence of respiratory distress syndrome (RDS), with a reciprocal low predictive value for maturity. The authors employed FLM Surfactant/Albumin Ratio (FLM S/A) test results to construct a predictive model for FLM that included the obstetric estimates of gestational age. The charts of 388 newborns were abstracted and reviewed. The clinical outcome was the gold standard of the multivariate logistic analysis. Both the obstetric estimates of gestational age and the test result were significant predictors of the clinical outcome (P values of < .0002 and .001, respectively). The prediction rule for RDS as a function of both of these variables allows for adjustment of the test cutoffs, so that there is a consistent probability of RDS at the cutoff FLM S/A result for different gestational ages. Fetal lung maturity probability reporting may facilitate clinical decision-making.

Use of quantitative amniotic fluid phosphatidylglycerol as a criterion for fetal lung maturation.

Phosphatidylglycerol (PG) in amniotic fluid was quantitatively measured by thin-layer chromatography (TLC) in 941 amniotic fluid samples and related to the presence or absence of respiratory distress syndrome (RDS) in neonates born within 7 days of the amniocentesis. In 639 case tests with PG 1 nmol/ml or more of amniotic fluid, there was no RDS. However, there were six cases of RDS associated with 109 tests of PG from 0 to less than 1 nmol/ml. These 109 tests would all have been reported as PG positive if PG were only qualitatively assessed on the TLC plate by the naked eye. The highest incidence of RDS occurred when PG was absent (23 RDS of 193 patients). Hence, this study suggests that quantitative analysis of PG determines a cutoff point of PG that eliminates false-positive PG assessments (1 nmol/ml in our laboratory). There was no difference in the levels of PG between males and females at equal gestational ages, but the incidence of RDS among male neonates was 2.4 times higher (p less than 0.05) than female neonates in the group with an immature amniotic fluid lecithin to sphingomyelin ratio and PG less than 1.0 nmol/ml.

Duration of ductal shunting in healthy preterm infants: An echocardiographic color flow doppler study

The purpose of this investigation was to assess the duration of ductal shunting after birth in healthy preterm infants (30 to 37 weeks gestational age) without evidence of respiratory distress. Thirty-six infants were evaluated in the first 12 hours of life by means of two-dimensional echocardiography and color flow Doppler techniques, and then once daily until no ductal flow was detected (defined as functional closure). Preterm infants were subdivided into two groups by gestational age: group 1 = 30 to 33 weeks (n = 12); group 2 = 34 to 37 weeks (n = 24). Sixteen full-term infants (38 to 41 weeks) were similarly evaluated as control subjects (Group 3). One infant from each group had a closed ductus at the time of the first study (performed at a mean of 7.7 +/- 3.2 hours). Subsequent studies for the entire group were performed at a mean of 31.3 +/- 5.4 hours (day 2), 55.0 +/- 4.5 hours (day 3), and 80.3 +/- 6.1 hours (day 4). For the three groups, the rates of ductal closure ranged from 50.0% to 58.3% on day 2 and 81.3% to 87.5% on day 3. For the entire group, all but one infant had demonstrated closure of the ductus arteriosus by day 4. Within the range of gestational ages studied, we conclude that prematurity, in the absence of respiratory distress syndrome, does not prolong the initial duration of physiologic ductal shunting.

Assay of disaturated phosphatidylcholine in amniotic fluid as a test of fetal lung maturity: experience with 2000 analyses.

We determined concentrations of disaturated phosphatidylcholine (DSPC) in nearly 2000 amniotic fluid samples obtained either transabdominally or as vaginal pools. Here we report our comparison of these DSPC values with the lecithin/sphingomyelin (L/S) ratios for amniotic fluid samples obtained from diabetic and nondiabetic pregnancies and also between transabdominally or vaginally collected samples uncontaminated by blood or meconium. DSPC measurement is at least as good as the L/S ratio in predicting the absence of respiratory distress syndrome. DSPC concentrations were, however, lower in diabetic than in nondiabetic pregnancies, supporting the hypothesis that DSPC synthesis may be impaired in fetuses of diabetic mothers. Visually uncontaminated samples collected transabdominally or vaginally, when grouped according to length of gestation, have similar DSPC values but different L/S ratios. Thus, even in the absence of blood or meconium, DSPC may be a more useful test than the L/S ratio for vaginally pooled samples.

A case control study of necrotizing enterocolitis occurring over 8 years in a neonatal intensive care unit.

The perinatal histories of 27 newborn infants with NEC were compared to those of 54 infants of equivalent birth weight who did not have NEC during an 8-year study period to see if possible predisposing factors were independent of the confounding effect of birth weight. No differences were observed in gestational age, degree of intrauterine growth retardation, premature rupture of membranes, perinatal asphyxia, skin temperature at admission, haematocrit, presence or absence of respiratory distress syndrome, umbilical catheter placement, start and type of feeding or presence of positive blood cultures. Prematurity is the greatest risk factor predisposing to the development of NEC and the perinatal problems which precede the onset of NEC are common among all premature infants.

Relationship of placental grade to fetal pulmonary maturity and respiratory distress syndrome.

Real-time sonographic placental grading was performed on 215 patients who had amniocentesis for determination of fetal pulmonary maturity between 26 and 42 weeks of gestation. The results of this placental grading were correlated with clinical gestational age and fetal pulmonary maturity, assessed by lecithin-sphingomyelin ratio, phosphatidylglycerol, and the subsequent presence or absence of respiratory distress syndrome. This study showed a statistically significant correlation of placental grade with gestational age, pulmonary maturity, and respiratory distress. Grade 3 placentas were seen in 20% of the cases studied, and in every instance was associated with an absence of subsequent neonatal respiratory distress. Placental grade appeared to be an accurate predictor of fetal pulmonary maturity in the population studied.

Laboratory and clinical evaluation of a rapid slide agglutination test for phosphatidylglycerol

Amniostat-FLM is a recently developed rapid slide agglutination test for amniotic fluid phosphatidylglycerol. We compared phosphatidylglycerol quantitated by two-dimensional thin-layer chromatography with phosphatidylglycerol determined by Amniostat-FLM in 180 amniotic fluid samples. If any level of phosphatidylglycerol by thin-layer chromatography, including a trace, was considered positive, then phosphatidylglycerol by thin-layer chromatography and Amniostat-FLM were concordant in 171 of 180 samples (95%). Both were positive in 123 and both negative in 48 samples. The nine amniotic fluid samples with discrepant results were as follows: Five negative Amniostat-FLM results were associated with trace phosphatidylglycerol by thin-layer chromatography (1% to 2% of total phospholipids), one negative Amniostat-FLM result was associated with 3% phosphatidylglycerol by thin-layer chromatography, and three positive Amniostat-FLM results were associated with negative phosphatidylglycerol by thin-layer chromatography results. There were 14 samples with trace phosphatidylglycerol by thin-layer chromatography; of these, there were nine positive and five negative Amniostat-FLM results. If >2% phosphatidylglycerol by thin-layer chromatography was considered positive, concordance between the two tests was 93% (167 of 180). From these samples, 119 infants were delivered within 72 hours of amniocentesis. There were 100 positive Amniostat-FLM results and all were associated with the absence of respiratory distress syndrome; of the 19 negative Amniostat-FLM results, five were associated with infants who developed respiratory distress syndrome. The present study confirms that Amniostat-FLM is a sample, rapid, and accurate test for determining the presence of phosphatidylglycerol in amniotic fluid.

Postasphyxial lung disease in newborn infants with severe pennatal acidosis

The pulmonary course and respiratory management of 65 asphyxiated infants with at least one arterial pH less than or equal to 7.00 within the first 2 hours of life was determined. Asphyxia in the preterm and term infants in the absence of respiratory distress syndrome or meconium aspiration syndrome was associated with a transient respiratory insufficiency requiring assisted ventilation which markedly improved in the first 24 hours of life. In contrast, infants with asphyxia complicated by respiratory distress syndrome or meconium aspiration syndrome developed profound lung disease including pulmonary hemorrhage and persistence of the fetal circulation. The course of their illness was significantly worse than control infants without asphyxia. Ineffective neonatal resuscitation allowing for the development of meconium aspiration syndrome and persistent respiratory acidosis contributed to the severity of illness in more than 50% of the infants. Central nervous system pathologic conditions were present in asphyxiated infants with and without severe pulmonary disease. We conclude that severe asphyxia in the absence of underlying lung disease results in a predictable postasphyxial transient respiratory insufficiency, with marked improvement in the first 24 hours of life.

Fetal pulmonary maturity: Relationship between optical density (650 nm) to the lecithin/sphingomyelin ratio and phosphatidylglycerol in amniotic fluid

An optical density value ⩾0.15 at A 650 nm of amniotic fluid obtained through transabdominal amniocentesis from a high risk obstetrical population, which excluded diabetes mellitus, isoimmunization, and amniotic fluid infection, correlated 98.6% with a mature lecithin to sphingomyelin ratio ( L S ) ⩾ 2.0% and 41.6% with the presence of phosphatidylglycerol (PG). The corresponding false positive rates were 1.4% and 16.8%, respectively. In 30 infants delivered within 48 h of testing, A 650 nm ⩾0.15 correlated 100% with absence of respiratory distress syndrome. A 650 nm is not recommended for Rhesus immunized gestations, diabetic pregnancies and amniotic fluid infection due to a high false positive rate with A 650 nm compared to L S and PG.