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Biomedical subjects

L D Devoe

Publications and source records attributed to L D Devoe.

At least 55 records · Page 3Linked to original sources

Fetal biophysical activities in third-trimester pregnancies complicated by diabetes mellitus.

OBJECTIVE: Our purpose was to compare third-trimester fetal biophysical activities in normal and well-controlled insulin-dependent diabetic pregnancies. STUDY DESIGN: We performed serial bimonthly fetal biophysical studies from 30 to 38 weeks in 18 normal and 18 well-controlled insulin-dependent diabetic pregnancies (White classes B through D). Each study contained 60 minutes of simultaneous ultrasonographic recordings of fetal breathing movements and rates, baseline heart rate, and body movements. Mean daily blood glucose levels of diabetic patients were determined from home monitors; HbA1c was determined every 6 weeks and ultrasonographic fetal growth rates every 3 weeks. Data were compared with t tests, analysis of variance with repeated measures, and chi 2 tests. RESULTS: Women in the diabetic group maintained good glycemic control and were delivered of normal infants of weights similar to those of nondiabetic gravidas. Their fetuses had higher mean incidences of fetal breathing movement, fetal heart rates, and fetal breathing rates but lower fetal movements and fetal heart rate acceleration counts than did controls throughout the study. Neither short- nor long-term maternal glycemic levels correlated well with fetal biophysical performance. CONCLUSIONS: In spite of good maternal glycemic control fetuses of diabetic women behaved differently from those of nondiabetic women. Modulation of their biophysical activities may be affected by maternal glycemic status before the last trimester. Different standards might need to be applied to interpret their tests.

Adult↗

The nonstress test. Reassessment of the "gold standard".

The NST is simpler, less invasive, less time-consuming, and less expensive than its predecessor, the CST. It may be conducted in the outpatient setting with less skilled personnel. If the NST is to remain an important diagnostic modality, the issues of interpretative criteria, test conditions, and population composition must be reconsidered. In the future, authors must specify these data in detail and present their parameters of sensitivity, specificity, predictive values, and prevalence clearly. They also would be well advised to consider the value of adding other FHR information, such as baseline rate and variability to their interpretative criteria. Because clinical management--i.e., whether or not to intervene--may be influenced by or directly follow the outcome of an NST, it is even more important that such critical questions be addressed. The testing process should be cost effective, accurate, and sensitive enough to detect pregnancies at risk, yet specific enough to identify pregnancies that will have a good outcome. We believe that the issue of stand-alone NSTs should be examined for all indications and gestational ages commonly encountered. In our laboratory, current practice suggests that most conditions, at most gestational ages, benefit from an approach that combines the NST with amniotic fluid assessment and that uses age-adjusted standards to avoid misclassification of normal infants.

Cardiotocography↗

Amniotic fluid assessment. Methods and role in fetal assessment.

AFV assessment by one method or another has become an adjunct to nonstress testing in most pregnancies requiring surveillance. Evaluation by nonstress test and amniotic fluid assessment for fetuses with maternal risk factors in a protocol such as that outlined by Devoe is common practice. Adaptation of that algorithm (Fig. 4) to the needs of the clinical setting are simple. Quantitative and nonquantitative methods show an increase in perinatal morbidity and mortality with abnormal values. Those trends are most evident in studies involving postdate gestations, such as those by Marks and Lagrew. The literature and its applied lessons for clinical practice are confused by the many variables considered by those investigating AFV assessment. Superiority of one method over another has not been demonstrated consistently from one study to the next. The good correlation in AFV estimated by ultrasonography and determined by dye-dilution techniques is still based on limited studies that are unlikely to be replicated soon because of the invasive nature of the test. Even in the best circumstances, errors at extremes of AFV are common with the use of ultrasonography. At present, the best recommendations from the literature seem to take two main directions. Antenatal testing of the fetus at risk should include some evaluation of AFV. The fetus with apparently abnormal AFV should be studied anatomically and considered for delivery if decreased AFV is associated with other test abnormalities--i.e., a nonreactive nonstress test.

Amniotic Fluid↗

Automated methods of fetal assessment. The future of antenatal testing.

Conventional approaches to antenatal assessment require considerable input from domain experts to provide their maximum benefit. Many of the tests commonly used suffer from inter- or intraobserver errors, lack of objectivity and reproducibility, and inappropriate application by less experienced personnel. Recent developments in computer-assisted analyses of fetal heart rate testing and biophysical testing are presented to address some of these concerns. The development and validation of expert systems which address the use of domain knowledge to improve diagnostic, prognostic, and therapeutic approaches to antenatal management are described. Future areas of investigation are suggested.

Diagnosis, Computer-Assisted↗

Effects of amniotic fluid on proteases: a possible role of amniotic fluid in fetal wound healing.

Fetuses are surrounded by amniotic fluid rich in nutrients and other factors essential to fetal development and possibly to its scarless wound healing. The purpose of this study was to determine whether amniotic fluid contains factors that regulate activities of major proteases involved in the process of wound healing (e.g., collagenase, hyaluronidase, elastase, and cathepsin B). Human amniotic fluid was assayed in vitro for inhibition or stimulation of the activity of these enzymes. Our results showed that amniotic fluid enhanced collagenase activity at a concentration of 66 micrograms protein (p < 0.01), but inhibited activities of hyaluronidase (132 micrograms protein; p < 0.05), elastase (170 micrograms protein; p < 0.05), and cathepsin B (19 micrograms protein; p < 0.01). This finding suggests that amniotic fluid could have an important role in flawless fetal wound healing by regulating these matrix-degrading enzymes.

Amniotic Fluid↗

Can fetal biophysical observations anticipate outcome in preterm labor or preterm rupture of membranes?

OBJECTIVE: To evaluate fetal biophysical testing as a predictor of preterm delivery after preterm labor or preterm rupture of the membranes (PROM). METHODS: We studied 50 women with suspected preterm labor and intact membranes and 25 women with PROM but not in labor between 28 and 36 weeks' gestation. Before treatment, each subject had cervical Bishop scoring and 1-hour ultrasound observation of fetal heart rate, breathing, body movements, and flexion-extensions. Data were compared with t tests, chi 2 tests, or receiver operating curves. RESULTS: The mean gestational age at entry was similar in both groups. Twenty (80%) PROM and ten (18%) preterm labor patients delivered within 72 hours of admission; two (8%) PROM and 38 (76%) preterm labor patients delivered more than 7 days after admission. Absent breathing and body movements had high positive predictive values (100%) but moderate sensitivities (less than 55%) for predicting delivery within 72 hours or 7 days in the PROM and preterm labor groups. These sensitivities increased to nearly 70% with the addition of Bishop scores. The optimal diagnostic cutoffs for delivery within 72 hours or 7 days were a breathing incidence below 1% for the PROM group and a body movement incidence below 1% for the preterm labor group, and a breathing incidence of at most 5%. CONCLUSIONS: Complete absence of one biophysical variable confers limited sensitivity but high positive predictive value for early delivery in patients with preterm labor or PROM. The use of cutoff percentages for the incidence of individual variables improved sensitivity for both conditions. Cervical scoring added to biophysical monitoring by improving the sensitivity for early delivery of patients in preterm labor.

Chi-Square Distribution↗

A rapid test for abruptio placentae: evaluation of a D-dimer latex agglutination slide test.

OBJECTIVE: Our purpose was to evaluate a rapid latex agglutination slide test for D-dimer, a byproduct of clot lysis, in the prediction of abruptio placentae. STUDY DESIGN: Four groups were studied: (1) 15 patients with normal pregnancies at 40 weeks' gestation, (2) 17 participants with preeclamptic pregnancies, (3) 14 patients with preterm labor, and (4) 15 patients with confirmed abruptio placentae. The latex agglutination slide test was performed with positive and negative reference solutions and plasma dilutions of 1:1, 1:2, 1:4, and 1:8. A test was considered positive if, at 2 minutes, agglutination was present at dilutions of > or = 1:2 (> or = 1.0 micrograms/ml fibrin equivalent units). Test results were compared in patient groups with and without abruptio placentae by means of the chi 2 test. RESULTS: The likelihood of a positive D-dimer test result was not significantly different among patients in the non-abruptio placentae groups (p = 0.454). Patients in the abruptio placentae group were significantly more likely to have a positive D-dimer slide test result than those in the non-abruptio placentae groups (p = 0.0001). The D-dimer test conferred sensitivity, specificity, positive predictive value, and negative predictive value of 67%, 93%, 91%, and 48%, respectively. In contrast, other laboratory measures of coagulation (e.g., platelet count, prothrombin time, partial thromboplastin time, and fibrinogen levels) yielded no better than a 20% sensitivity for abruptio placentae. CONCLUSIONS: The D-dimer slide test may be a superior rapid method to improve early diagnosis of abruptio placentae.

Abruptio Placentae↗

Maternal caffeine consumption and fetal behavior in normal third-trimester pregnancy.

OBJECTIVE: Our aim was to perform a longitudinal cohort study of 20 normal third-trimester pregnancies to observe whether the level of long-term maternal caffeine ingestion influenced fetal behavior. STUDY DESIGN: By dietary history 10 normal pregnant women were categorized as "high" caffeine consumers (> 500 mg/day, group H) and 10 as "low" caffeine consumers (> 200 mg/day, group L). Between 30 and 40 weeks biweekly 2-hour continuous ultrasonographic observations of fetal heart rate; breathing activity; and eye, trunk, and extremity movements were conducted. Maternal caffeine levels were determined at each session, and fetal states were identified and their duration quantified. Data were compared by analysis of variance by means of repeated measures or t tests. RESULTS: When compared with group L fetuses, group H fetuses spent similar mean time in state 1F (quiet sleep), less mean time in state 2F (active sleep), and much greater mean time in state 4F (arousal). The mean time spent in no state decreased significantly in group L, was unchanged in group H, and was similar for both groups at term. Both groups had similar mean numbers of state changes at all gestational ages studied. Mean maternal serum caffeine levels in group H were always significantly higher than those in group L. CONCLUSION: Evolving fetal behavior may be influenced by the level of maternal caffeine consumption during the last trimester.

Adult↗

A comparison of visual and automated methods of analyzing fetal heart rate tests.

OBJECTIVES: Our objective in this study was to compare evaluation and clinical implications of visual versus computerized analysis of nonstress tests. METHODS: Nonstress tests of 575 high-risk patients were analyzed visually and by a computer using the Oxford Sonicaid System 8000. Standard reactivity criteria were used for visual assessment; the System 8000 used an algorithm with the Dawes-Redman criteria. RESULTS: Ninety-six percent of nonstress tests that met Dawes-Redman criteria were reactive by visual analysis; 93% of reactive nonstress tests met Dawes-Redman criteria. Only 30% of tests that failed Dawes-Redman criteria were nonreactive, whereas 44% of nonreactive tests failed to meet Dawes-Redman criteria. Sensitivities, specificities, and positive and negative predictive values were similar for both approaches. Additional tests or interventions would have occurred in 9% of the cases analyzed by System 8000 and in 49% of the cases analyzed visually. CONCLUSIONS: Although these approaches rate nonstress tests differently, their diagnostic performances are similar. Automated fetal heart rate testing may become an acceptable alternative to conventional visual analysis.

Female↗

Superiority of amniotic fluid index over amniotic fluid pocket measurement for predicting bad fetal outcome.

Semiquantitative amniotic fluid volume (AFV) determination is a component of the fetal biophysical profile (BPP). To assess decreased AVF we did BPPs of 174 fetuses within 1 week of delivery. Two methods were used: measurement of the single largest vertical pocket (oligohydramnios = depth < 1 cm) and the four-quadrant amniotic fluid index (AFI) (oligohydramnios = AFI < or = 5 cm). AFV, as determined by each method, was related to measures of fetal outcome (perinatal mortality, fetal distress, Apgar score, meconium-stained amniotic fluid, and intrauterine growth retardation [IUGR]). The AFI was more sensitive in predicting mortality (87.5%) and the following measures of perinatal morbidity: low 5-minute Apgar score (88.8%), fetal distress during labor (86.6%), meconium-stained amniotic fluid (63.6%), and the presence of IUGR (79.4%). The sensitivity of amniotic fluid pocket measurement of < 1 cm was 75%, 72.2%, 66.6%, 47.7%, and 55.8%, respectively, for the same measures. Using the AFI instead of a single pocket measurement in BPP assessment increased the sensitivity and positive predictive value of the BPP from 64.7% to 76.4% and from 45.8% to 68.4%, respectively. Our data suggest that qualitative AFV measurement using the AFI is superior to that of the single largest pocket in multiple component fetal biophysical testing.

Amniotic Fluid↗

Intrauterine pressure catheter performance in an in vitro uterine model: a stimulation of problems for intrapartum monitoring.

OBJECTIVE: To compare pressure recordings from fluid-filled and sensor-tip catheters under varying intrauterine conditions in a uterine model. METHODS: The uterine model was a 4.1-L dual-walled polyurethane bladder with ports for dual catheter insertion. "Contractions," generated by a programmable pump, were analyzed by computer. The first three experiments used an internal volume of normal saline and included either "normal" catheter placement, distal end of the catheter coated with petroleum jelly, or distal end of the catheter kinked at 150 degrees. The fourth and fifth experiments were similar to the first except that the internal volume was either pea soup or bovine blood. Each study had at least 20 consecutive pressure waveform sequences with peaks of 100, 60, and 20 mmHg, and a resting baseline of 10 mmHg. Ascent and descent phases were each 25 seconds. Peak and baseline pressure phases were each 10 seconds. RESULTS: Each catheter generated satisfactory pressure waveforms, which were similar in all experiments except for the one involving simulated meconium. In this trial, significant waveform damping occurred when pea soup filled the fluid catheter line (P < .05, t test). CONCLUSIONS: In most extreme experimental conditions, the catheter types behaved similarly when detecting "intrauterine" pressure. The sole exception, thick meconium simulation, suggests that fluid-filled catheters would be less reliable in this condition unless flushed continuously with saline.

Catheterization↗

Maternal plasma D-dimer levels in normal and complicated pregnancies.

OBJECTIVE: To evaluate D-dimer as a marker for fibrinolysis in normal and complicated pregnancies using an enzyme-linked immunosorbent assay (ELISA) technique. METHODS: Four groups of pregnant women were enrolled: 17 normal women followed longitudinally from 28-40 weeks' gestation, 14 patients with preterm labor at 28-34 weeks, 17 patients with preeclampsia at term (37-40 weeks), and 14 patients with abruptio placentae (32-40 weeks). We assayed peripheral venous blood samples from each patient for D-dimer levels using a commercial ELISA kit. D-dimer values were calculated by regression analysis using internal standards and controls for each assay. Data were compared using Student t test or analysis of variance with repeated measures. RESULTS: D-dimer values increased slightly with increasing gestational age. Patients with preterm labor, preeclampsia, and abruptio placentae had mean D-dimer values significantly greater than those of controls (P < .003). D-dimer values of the abruption group were approximately twice those of the control group (3393 +/- 2086 versus 1750 +/- 839 ng/dL). CONCLUSION: An increase in fibrinolysis may be associated with the pregnancy complications studied, as reflected by alterations in maternal plasma D-dimer levels.

Abruptio Placentae↗

Refining the biophysical profile with a risk-related evaluation of test performance.

OBJECTIVE: Our objective was to determine the ability of biophysical profile variables to predict bad perinatal outcome in high-risk third-trimester pregnancy. STUDY DESIGN: The outcomes of 1146 fetuses were correlated with abnormal single or multiple variables occurring in biophysical profile done within 72 hours of delivery. Theoretic risks of poor outcomes for different combinations of abnormal variables, calculated with Shortlife's formula, were compared with the actual risks observed (chi 2 tests). RESULTS: Two hundred forty-six fetuses had at least one abnormal biophysical profile variable with the risk of bad outcome, for a single abnormal variable, ranging from 8% (body movements) to 100% (tone) and increasing from 14% (any variable abnormal) to 63% (all variables abnormal). In most (57%) observed combinations of biophysical profile variables, significant differences between theoretic and actual risks of bad outcomes were found. By stepwise logistic regression the best predictive model contained all variables except fetal movement. CONCLUSIONS: Dynamic biophysical profile variables appear to be interdependent. Not all combinations of abnormal variables occur and specific combinations improve prediction of poor outcome. Risk-related scales for biophysical profile outcomes might prove superior to more conventional scoring systems.

Biophysics↗

Do semiquantitative amniotic fluid indexes reflect actual volume?

OBJECTIVE: Our objective was to determine how well semiquantitative ultrasonographic measures of amniotic fluid, i.e., maximal amniotic fluid vertical pocket and amniotic fluid index, reflect actual amniotic fluid volumes in 50 near-term patients whose amniotic fluid volume estimates were normal by visual inspection. STUDY DESIGN: Before amniocentesis for fetal lung maturity, each patient had visual amniotic fluid volume estimates, maximal amniotic fluid vertical pocket, and amniotic fluid index performed by the same examiner, and then each received intraamniotic injection of a 10% paraaminohippurate solution. Amniotic fluid volume was quantitated by spectrophotometric assay of paraaminohippurate concentration. Oligohydramnios and polyhydramnios were defined as < 300 and > 2000 ml, respectively. RESULTS: Quantitative amniotic fluid volume was positively related to both amniotic fluid index and maximal amniotic fluid vertical pocket (r = 0.75 and 0.60, respectively). True-positive rates for oligohydramnios (amniotic fluid index < 5 cm or maximal amniotic fluid vertical pocket < 2 cm) were 100% and 0%, respectively; false-positive rates with either method were 0%. True-positive rates for polyhydramnios (amniotic fluid index > 20 cm and maximal amniotic fluid vertical pocket > 8 cm) were 0%; false-positive rates were 16% and 24%, respectively. CONCLUSIONS: Amniotic fluid index appears to be slightly better than maximal amniotic fluid vertical pocket for reflecting actual amniotic fluid volume. Both indirect methods tend to overestimate actual amniotic fluid volume at the upper end of its extremes.

Amniotic Fluid↗