PubMed Health⌕ Search

Biomedical subjects

L D Devoe

Publications and source records attributed to L D Devoe.

At least 73 records · Page 4Linked to original sources
PubMed1992

Failure of microchromatographic measurement of fetal hemoglobin in beta zero thalassemia-hereditary persistence of fetal hemoglobin.

We report microchromatographic measurement of fetal hemoglobin (HbF) proportions in a 36-year-old African-American multigravida woman. At 34 weeks she delivered a 630-g male infant who subsequently did well. Hemoglobin electrophoresis of the hemolysate revealed nearly 100% HbF without HbA, an extremely unusual naturally occurring sample. Family studies revealed a combination of hereditary persistence of fetal hemoglobin (HPFH) and beta zero-thalassemia minor. Southern blot technique confirmed heterozygous alpha 2 thalassemia and HPFH but failed to identify the beta thalassemic lesion. The absence of HbA and the very high amounts of HbF led us to measure HbF by several methods to confirm the accuracy of microchromatography of HbF at values approaching 100%. HPLC revealed a 14% F1 suggestive of microchromatographic underestimation due to glycated HbF. We conclude that cation-exchange microchromatography and the Betke method of alkali denaturation underestimate HbF values as they approach 100% and do not recommend these procedures in this rare situation.

Adult↗
PubMed1992

The prediction of "controlled" uterine rupture by the use of intrauterine pressure catheters.

OBJECTIVE: To determine whether uterine activity, assessed by either fluid-filled or solid pressure catheters, changes with uterine incision at cesarean delivery. METHODS: Uterine activity was recorded continuously during low transverse cesarean delivery in ten parturients using fluid-filled pressure catheters and in ten women with solid pressure catheters. Visual analyses were performed of the last 30 minutes of uterine recording before uterine incision and of the period after incision; the analyses were then compared within and between the catheter groups for mean uterine tone and contraction amplitude, frequency, and duration. Oxytocin use, anesthesia method, mean gestational age, birth weight, length of labor, duration of monitoring, and uterine incision-to-delivery time were compared between the groups. RESULTS: All obstetric end points were similar in both catheter groups except for a higher mean birth weight in the solid-catheter group. The mean (+/- standard deviation) duration of post-incision monitoring was 4.7 +/- 0.94 minutes. After uterine incision, mean tone and contraction amplitude were unchanged, whereas mean contraction frequency and duration decreased significantly. CONCLUSIONS: Though intrauterine monitoring was brief, this model allows a unique view of "controlled" uterine rupture. Spontaneous uterine rupture may evolve more gradually; however, neither catheter type would be likely to aid its early recognition.

Adult↗
PubMed1992

The significance of increasing umbilical artery systolic-diastolic ratios in third-trimester pregnancy.

OBJECTIVE: To evaluate the clinical significance of a marked increase in the systolic-diastolic ratios (S/Ds) of the umbilical artery (UA) Doppler velocity waveforms of third-trimester fetuses. METHODS: We evaluated 552 pregnancies at risk for placental insufficiency. Each patient had at least five successive weekly UA Doppler velocimetry studies between 32-42 weeks and a highest S/D within the normal range for gestational age. The S/D was considered markedly increased if it was at least 20% higher than the mean of four previous values. Clinical end points reviewed included mortality, fetal distress, 5-minute Apgar score below 7, metabolic acidosis, and neonatal intensive care unit (NICU) admissions for reasons other than prematurity. RESULTS: The S/Ds were normal in 478 patients and were markedly increased in 74. The two groups were similar in mean gestational age at testing and delivery and in the rates of fetal growth retardation and low 5-minute Apgar scores. The group without increased S/Ds had a higher mean birth weight and lower incidences of perinatal death, cesarean delivery for fetal distress, acidosis, and NICU admission. The overall sensitivity (43%), specificity (90%), positive predictive value (27%), and negative predictive value (95%) were similar to our previous experience in which we used a criterion of S/D above the 90th percentile. CONCLUSION: Marked increases in UA S/Ds, even if within an institutional "normal" range, may indicate a fetus at increased risk of compromise.

Blood Flow Velocity↗
PubMed1992

Maternal coagulation inhibitors and the effects of cesarean delivery.

Maternal hypercoagulability in normal pregnancy results from significant increases in blood factors that promote thrombosis or decreases in factors that inhibit thrombosis, such as antithrombin III (AT-III) and proteins C and S. The precise role of these factors in puerperal hemostasis is not clear. In 10 normal, pregnant women at term undergoing scheduled repeat cesarean section, the percent activities of AT-III, proteins C and S, and C4b-binding protein were determined in peripheral venous blood preoperatively and in samples of uterine venous blood before the uterine incision was made and 5 and 15 minutes after placental delivery using the Laurell Rocket electroimmunodiffusion technique. The mean percent activities of AT-III (73%), protein S (81%) and C4b-binding protein (85%) were lower than those in nonpregnant controls, were similar in peripheral and uterine venous blood and were unchanged after placental delivery. These data suggest that such factors may not play an important role in acute uteroplacental hemostasis during normal pregnancy.

Antithrombin III↗
PubMed1992

Antepartum assessment of the maternal peripheral venous system with light reflection rheology.

The noninvasive detection of deep venous thrombosis (DVT) in pregnancy is a significant problem. The Hemodynamics AV-1000 uses light reflection rheology in superficial capillaries to detect DVT but has not been evaluated adequately in pregnancy. Four hundred one pregnant women in the second and third trimesters were studied with the AV-1000; none had symptoms of DVT or thrombophlebitis, and all had uncomplicated pregnancy outcomes. AV-1000 reflection curves were related to maternal age, gestational age, weight gain, Quetelet index and device sensitivity settings. No statistically significant differences in test outcomes were found for any variable. The high incidence of abnormal (25%) and inadequate (19%) tracings, coupled with an overall specificity of 45%, suggests that the system would not be useful in distinguishing patients with DVT from normal ones and could lead to excessive follow-up testing.

Academic Medical Centers↗
PubMed1991

Antepartum fetal assessment in hypertensive pregnancies.

Antepartum fetal assessment in hypertensive pregnancies helps to prevent perinatal morbidity and mortality. The pathophysiology of chronic maternal hypertension often leads to placental insufficiency and fetal growth retardation. Current testing schemes include serial ultrasonographic assessment of fetal growth, placental morphology, and amniotic fluid volume; fetal heart rate testing using either non-stress or contraction stress methods; multiple parameter biophysical profile; and Doppler flow velocimetry of fetal umbilical and maternal uterine arteries. The values of individual and combined testing approaches are evaluated and an integrated scheme for fetal management, illustrated by case examples, is presented.

Biophysical Phenomena↗
PubMed1991

The effects of epidural anesthesia on the Doppler velocimetry of umbilical and uterine arteries in normal and hypertensive patients during active term labor.

To study the effects of epidural anesthesia on uterine and umbilical artery blood flow in preeclampsia, we observed 25 patients in active labor at 36 or more weeks' gestation. Seven had preeclampsia, eight had chronic hypertension, and ten had no complications. Doppler velocimetry of the uterine and umbilical arteries was performed before and after intravenous fluid loading and at 30 and 60 minutes after epidural blockade. Maternal vital signs and fetal heart rate were monitored continuously. After epidural block, mean maternal blood pressure fell significantly in all groups, but no maternal hypotension was observed. Mean maternal and fetal heart rates were unchanged. After epidural block, mean uterine artery systolic-diastolic (S-D) ratios did not change in the chronic-hypertension and normal groups, but fell significantly in the preeclamptic group to values similar to those of the normal group. Umbilical artery S-D ratios did not change in any group. In preeclamptic pregnancy, epidural anesthesia may help to reduce uterine artery vasospasm and may benefit intrapartum fetal well-being.

Adult↗
PubMed1990

Vibroacoustic stimulation and fetal behavioral state in normal term human pregnancy.

Vibroacoustic stimulation may affect human fetal behavior. Continuous graphic records of simultaneous ultrasonographic observations of fetal activities and electronic fetal heart rate tracings of 30 normal term fetuses were examined visually for the occurrence of behavioral state 30 minutes before and after 3 seconds of vibroacoustic stimulation. After vibroacoustic stimulation, the total time spent in state 1 decreased significantly, that spent in state 4 increased significantly, and times spent in state 2 and indeterminate state (no state established for at least 3 minutes) were unchanged. No fetus exhibited state 3 before or after vibroacoustic stimulation. State 4 occurred in 22 fetuses after vibroacoustic stimulation with a duration of at least 30 minutes in four fetuses, and was noted in all fetuses in pre-vibroacoustic stimulation state 1 and 11 of 16 fetuses in pre-vibroacoustic stimulation state 2. Fetal heart rate accelerations occurred within 10 seconds after vibroacoustic stimulation in 94% of the fetuses studied regardless of their prior behavioral state. The variation in the onset and duration of behavioral state responses in most fetuses after vibroacoustic stimulation may depend on previous behavioral state and could be important for interpretation of antenatal assessment that uses this stimulus.

Acoustic Stimulation↗
PubMed1990

The diagnostic values of concurrent nonstress testing, amniotic fluid measurement, and Doppler velocimetry in screening a general high-risk population.

To determine the values of individual and combined biophysical fetal surveillance tests in a general high-risk population, we examined 1000 consecutive pregnancies complicated by either postdatism, hypertension, intrauterine growth retardation, or diabetes mellitus. Nonstress tests, amniotic fluid pocket measurements, and umbilical artery Doppler velocimetry were performed on each patient; each test was rated against gestational age-adjusted standards. Clinical end points included perinatal mortality, intrapartum fetal distress, 5-minute Apgar score less than 7, and neonatal acidosis in pregnancies without major anomalies or extreme prematurity (age at birth greater than 32 weeks), delivered within 72 hours of final tests. Each testing method had specificity greater than 90%. Sensitivities ranged from 69% (nonstress test) to 21% (Doppler velocimetry). Negative predictive values of each method exceeded 85%; positive predictive values ranged from 81% (nonstress test) to 42% (amniotic fluid measurements). The positive predictive value for any abnormal test was 54% and increased to 100% when all tests were abnormal; this latter condition occurred in only 2% of the total population. Amniotic fluid measurements or Doppler velocimetry, when compared with the nonstress test, appeared to be less powerful "stand-alone" screening tests. The performance of all tests in a single session confers little improvement in detection of fetal compromise if the nonstress test is normal; however, this approach may aid decision-making in the management of pregnancies when fetal maturity is not established.

Amniotic Fluid↗
PubMed1990

The effects of epidural anesthesia on the Doppler velocimetry of umbilical and uterine arteries in normal term labor.

To study the possible effects of epidural anesthesia on the Doppler velocimetry of the fetal umbilical and maternal uterine arteries, 15 normal term parturients were examined during active labor. Each Doppler study, conducted over 90 minutes after a 500-mL intravenous volume pre-load, was divided into three phases: 30 minutes of pre-anesthetic control, 30 minutes during epidural catheter placement and dosing, and 30 minutes after establishing effective regional blockade. During each phase, maternal blood pressure and pulse were monitored every 5 minutes, and continuous-wave Doppler recordings of the umbilical and uterine arteries were made at three separate intervals. Epidural placement and dosage techniques were similar for all patients; 0.25% bupivacaine solution was used and sensory levels of T6 obtained. The mean maternal systolic and diastolic blood pressures and pulse rate declined significantly, but no woman experienced hypotension. Mean systolic/diastolic ratios and pulsatility indices of the umbilical and uterine arteries did not change significantly during the study. We conclude that effective epidural anesthesia does not have a significant impact on Doppler flow characteristics of either the maternal or fetal umbilical vasculature, despite lowered maternal blood pressure and pulse rate.

Anesthesia, Epidural↗
PubMed1990

The nonstress test.

No currently available single test of fetal well-being is a universal, infallible clinical tool that stands apart from the more general context of the total pregnancy. It is tempting to place a substantial emphasis on the results of a test when medical decision-making is needed. Perhaps some sense of proportion should be invoked at this point, beginning with the recognition that fetal heart rate data, regardless of how they are obtained, provide a limited window to view the fetus and its environment. The fact remains that the relatively low incidence of real fetal compromise and subsequent poor outcomes biases the efficacy of the NST and other well-being tools. Most high-risk populations have a prevalence of poor outcomes of approximately 10 per cent; consequently, the target population for any assessment test is quite small. One must be reassured by the extremely large reported experience of Platt et al that nonstress testing is clinically useful in the overwhelming majority of cases. The NST appears to be an excellent predictor of the healthy fetus. The test is very good at predicting the fetus who does not require acute or premature obstetric intervention: it thereby prevents pregnancies from being subjected to unnecessary iatrogenic risks and from incurring tremendous medical and emotional costs. Can the NST be improved? I think that there is still considerable opportunity for making this test more effective and accurate. Our experience supports the concepts of standardized testing conditions, the use of baseline data in addition to reactivity alone, the prolongation of test sessions to achieve a more representative view of the fetus, and ultimately an automated analysis that will aid the clinician in making more reliable assessments of the fetal heart rate data present in the actual tracing. It would be useful to see the NST better integrated into management schemes that incorporate other assessment techniques as well as pertinent clinical data. The tendency to view the test as a "stand alone" modality has underscored weaknesses inherent in all surveillance methods that have a naturally limited perspective on complex developmental and adaptive problems. There is also a need for the development of academic standards so that collected experiences can be directly compared and communication of testing results made less ambiguous. These are some of the goals that should be set for the future and whose realization will effect better care for the unique population served by obstetricians.

Female↗
PubMed1989

Value of observation of fetal breathing activity in antenatal assessment of high-risk pregnancy.

While observation of fetal breathing movements has been used in fetal assessment, quantitative parameters (percent time spent in breathing [incidence], breath rate, or breath rate variability) have not been adequately evaluated as predictive tools. We examined 283 patients with high-risk pregnancies between 32 and 42 weeks' gestation and correlated their fetal breathing movement parameters with the rates of perinatal mortality, intrapartum fetal distress, neonatal acidosis, low 5-minute Apgar score, and intrauterine growth retardation. Fetal breathing data from standardized 60-minute biophysical tests were analyzed and compared with our institutional standards. Parameter values greater than 2 SD from the means of a previously studied normal population were considered abnormal. Whereas no individual parameter was a highly accurate predictor of adverse outcome, a fetal breathing movement incidence of less than 5% provided the best cutoff for diagnostic accuracy. Seventy percent of fetuses with 30 minutes of apnea had normal outcomes, whereas abnormally high breath rates (greater than 60 breaths/min) and low breath rates (less than 33 breaths/min) occurred with equal frequency among normal and pathologic fetuses. Breath interval variability was of no benefit in detecting fetuses with poor outcomes. Observation of fetal breathing movement incidence appeared to be most effective in pregnancies complicated by chronic hypertension and least effective in those with preeclampsia.

Apgar Score↗
PubMed1989

The preterm nonstress test: effects of gestational age and length of study.

The application of the nonstress test between 24 and 32 weeks' gestation has been limited by high rates of "false" nonreactivity in normal fetuses, by use of term criteria, and the lack of age-appropriate interpretative standards. To establish such standards, we studied 30 normal fetuses undergoing 90-minute fetal heart rate recordings at 2-week intervals from 24 to 32 weeks' gestational age. Using a specially programmed computer we quantified (1) baseline fetal heart rate, (2) incidence of 10- and 15-beat accelerations, and (3) incidence of fetal heart rate decelerations. With a criterion of three 15-beat accelerations per 30 minutes 91% of tests were reactive within 90 minutes. A criterion of three 10-beat accelerations per 30 minutes was associated with 100% reactivity within 60 minutes. Suitable interpretative criteria may be established for nonstress tests before 32 weeks' gestation by extending the testing time or by decreasing the minimum amplitude required of fetal heart rate accelerations.

Adult↗
PubMed1989

The effects of vibratory acoustic stimulation on baseline fetal heart rate in term pregnancy.

Fetal heart rate responses to vibratory acoustic stimulation have been studied in normal and complicated pregnancies. To determine the precise nature of these responses, we studied 50 normal term fetuses with 60 minutes of electronic antepartum fetal heart rate monitoring divided in two 30-minute segments separated by 3 seconds of vibratory acoustic stimulation. All tracings were analyzed by a programmed microcomputer. Comparison of grouped mean 30-minute values before and after vibratory acoustic stimulation showed significant increases in baseline fetal heart rate, fetal heart rate variation, frequency of accelerations exceeding 10 and 15 beats/min, duration of accelerations exceeding 15 beats/min, and frequency of decelerations after vibratory acoustic stimulation. Mean baseline fetal heart rate elevation greater than 10 beats/min occurred within 7.6 +/- 4.4 seconds in 42 of 50 fetuses and lasted for 596 +/- 531 seconds. Reactive tests increased from 35 (70%) to 47 (94%) after vibratory acoustic stimulation. Most healthy term fetuses exhibit fetal heart rate responses after differing in frequency or magnitude from spontaneous fetal heart rate changes. Vibratory acoustic stimulation may be a valid fetal assessment tool but cannot be considered the physiologic equivalent of nonstress testing.

Acoustic Stimulation↗
PubMed1989

Effects of maternal hyperoxia on the biophysical assessment of fetuses with suspected intrauterine growth retardation.

Fifty-two third-trimester fetuses with suspected intrauterine growth retardation were studied by means of a computer-assisted biophysical assessment scheme, which used maternal hyperoxia as a diagnostic probe. Biophysical data examined included percentage of time spent in breathing, mean breath rate, and percentage of time spent in body movement during a 90-minute observation: 30-minute baseline, 15-minute hyperoxia, and 45-minute posthyperoxia. Mean baseline movement in fetuses found as neonates to have intrauterine growth retardation (N = 18) was significantly lower than that of normal fetuses (N = 34). Fetal body movements and breathing movements increased significantly after hyperoxia in the intrauterine growth retardation group but not in the normal group. Increases of more than 75% over baseline for fetal breathing and more than 250% over baseline for fetal body movements yielded a sensitivity of 56%, specificity of 94%, positive predicative value of 83%, and negative predicative value of 80%. Maternal hyperoxia during biophysical testing may improve the accuracy of detecting intrauterine growth retardation.

Female↗
PubMed1989

The effects of vibroacoustic stimulation on baseline heart rate, breathing activity, and body movements of normal term fetuses.

To determine the fetal biophysical effects of vibroacoustic stimulation produced by an electronic artificial larynx we studied 20 normal term pregnancies assigned either to control (no stimulus) or experimental (stimulus) groups. Each fetus was observed for 3 hours; either no stimulus or a 3-second stimulus was delivered after the first hour. Fetal heart rate baseline and variation, breathing movement incidence, rate, and variation, and body movement incidence data were acquired concurrently and analyzed at 15-minute intervals. Intergroup comparisons showed that, after stimulation, fetal heart rate baseline and variation increased significantly, whereas breathing incidence fell during the first 15 minutes. Within-group analyses showed that poststimulus elevation of fetal heart rate baseline was the only significant time interaction over the 3 hours. Vibroacoustic stimulation appears to be primarily associated with transient alterations in fetal heart rate baseline; concomitant changes in breathing activity probably reflect normal biologic cycles.

Acoustic Stimulation↗
PubMed1989

The effects of acute alcohol intoxication on biophysical activities: a case report.

A computer-assisted biophysical assessment was performed in a woman with chronic alcoholism at 37 weeks' gestation. She was first seen in a state of acute alcohol intoxication (322 mg/dl). Although fetal breathing movement incidence was normal (30%), fetal tachypnea (67 breaths per minute) and decreased fetal body movements (0.11%) were seen. Because these findings differ from those previously reported with regard to normal pregnancies exposed to lower levels of alcohol, their implications are discussed.

Adult↗