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Biomedical subjects

L D Platt

Publications and source records attributed to L D Platt.

At least 199 records · Page 11Linked to original sources
PubMed1982

Fetal echocardiography. I. Normal anatomy as determined by real-time--directed M-mode ultrasound.

With current ultrasound technology, it is now possible to obtain accurate real-time and M-mode information from the fetal heart with the use of real-time--directed M-mode echocardiography. With this method, the M-mode cursor is directed to the fetal cardiac structures of interest while the image is obtained in the real-time mode. This enables M-mode echocardiograms to be obtained in an accurate, reproducible manner. The most useful imaging planes for cardiac evaluation are the long axis four-chamber plane, the short axis plane through the atrioventricular valves, and the short axis plane through the aortic and pulmonic outflow tracts. Once normal fetal cardiac anatomy is understood, structural defects and/or alterations of function can be evaluated accurately antenatally.

Echocardiography↗
PubMed1982

Sympathoadrenal activity in infants of diabetic mothers.

We assessed the activity of the sympathoadrenal system in infants of diabetic mothers. Concentrations of metanephrine in the amniotic fluid were correlated to amniotic fluid lung profiles. At the time of delivery, the levels of umbilical artery and vein plasma catecholamines were compared to the incidence of neonatal complications. Mature lung profiles correlated significantly with progressively rising metanephrine concentrations. Infants who had a higher incidence of neonatal complications at delivery had significantly higher plasma catecholamine levels as well. It is concluded that in infants of diabetic mothers there is a higher significant association between the sympathoadrenal activity and lung maturation. The majority of infants of diabetic mothers have excessive sympathoadrenal activity at birth, which could potentially lead toward catecholamine depletion and related complications in the first days of life.

Adrenal Glands↗
PubMed1982

Fetal lung maturity: the adjunctive use of ultrasound.

Ultrasonic cephalometry (BPD) was retrospectively studied in 268 patients at risk for the development of hyaline membrane disease (HMD). Thirty-seven patients were diagnosed as having diabetes and were excluded. Of the remaining 231 patients, 123 (53%) were found to have a biparietal diameter of (BPD) greater than or equal to 9.2 cm. There were 92 patients delivered within 5 days of scanning and none developed HMD. A BPD of 9.2 cm corresponded to an L/S ratio of 2.8 (r = 0.45, p less than 0.05). The above results indicate that it is safe to deliver a nondiabetic patient in whom a fetal BPD of 9.2 cm has been obtained.

Amniotic Fluid↗
PubMed1982

Real-time ultrasound of the placenta in assessment of fetal pulmonic maturity.

The use of ultrasound is a noninvasive method of assessing fetal maturity. However, in order for it to be a substitute for amniocentesis, a high degree of accuracy is required. Static ultrasound examination of placental development has revealed certain patterns of maturity which have suggested to be predictors of fetal pulmonary maturity. This study analyzes 100 patients near term for the accuracy of placental grade in predicting pulmonary maturity when measured by the lecithin/sphingomyelin ratio and by clinical development of the respiratory distress syndrome in the neonate. A mature placental grade (Grade III) determined by real-time sonography corresponded to fetal lung maturity in all cases (n = 15). Placental grade as determined by this methodology appeared to be an accurate predictor of fetal maturity in the population examined.

Amniotic Fluid↗
PubMed1982

Urinary tract injury during cesarean section.

Lower urinary tract injury at the time of cesarean section is an uncommon complication. During a 5-year period, the incidence of bladder and ureter injuries at the Los Angeles County/University of Southern California Medical Center was .31 and .09%, respectively. When bladder injury occurs, it usually is due to surgical difficulty encountered while developing the bladder flap over the lower uterine segment. The difficulty is caused usually by scar tissue from previous surgery. Ureteral injury is a rare complication of cesarean section. It is attributable most often to ureteral transection or ligation associated with uterine incision extensions in the lower uterine segment or the vagina, and to attempts to achieve hemostasis. The data presented in this report indicate that cystotomy, when adequately repaired, is not associated with any complications. Furthermore, diagnostic cystotomy with intravenous injection of indigo carmine is a rapid, safe method of evaluating ureteral patency.

Cesarean Section↗
PubMed1982

In utero diagnosis of hydrops fetalis: ultrasound methods.

The advent of diagnostic ultrasound has now made it possible to evaluate early markers of developing fetal hydrops. Because of these developments, the recognition of these adverse findings can be treated and the disease process reversed. This has been done in cases of Rh disease by intervening intrauterine transfusion, by medically treating the fetal arrhythmias, and/or by treating the basic underlying maternal disorder. The ultrasound examination of the hydropic fetus must include a thorough evaluation for structural anomalies, which can best be accomplished at referral centers where Stage II ultrasound examinations can be carried out. Not all conditions associated with hydrops fetalis are lethal. We therefore believe that timed delivery and atraumatic birth are essential to ensure the optimal outcome.

Cesarean Section↗
PubMed1981

Amniocentesis in the second trimester: the effect on fetal movement.

Linear array real-time ultrasound was utilized to observe gross fetal body movements before and after second-trimester amniocentesis. No significant differences were found between the two observation periods. All pregnancies continued to term, and no evidence of fetal trauma was found at delivery.

Amniocentesis↗
PubMed1981

I. Maternal cardiovascular and metabolic responses in normal pregnancy.

We investigated cardiovascular and metabolic responses in 23 healthy pregnant volunteers in their third trimester prior to, during, and after a 15-minute period of treadmill exercise. The energy utilization of this exercise was 2.33 MET with an oxygen consumption under 0.5 L/minute. Exercise induced a significant increase in maternal heart rate and a shortening of the R time intervals; both returned to baseline by 30 minutes of recovery. This light exercise also induced a significant increase in glucagon, norepinephrine, and epinephrine concentrations, all of which were transitory and reversed within 30 minutes of the recovery period. No change in glucose or cortisol concentration resulted from this exercise. We conclude that light exercise of brief duration elicits appropriate and transitory cardiovascular and metabolic responses in normal pregnancy.

Adult↗
PubMed1981

Qualitative amniotic fluid volume determination by ultrasound: antepartum detection of intrauterine growth retardation.

Qualitative amniotic fluid volume (AFV) was determined by a linear array ultrasound method in 120 patients referred with a diagnosis of intrauterine growth retardation (IUGR). Eighty-nine of these patients were delivered of a normal infant; the false positive rate by clinical methods alone was 74.2%. Qualitative AFV was termed normal if at least one pocket of amniotic fluid measuring 1 cm in its broadest diameter was identified. Qualitative AFV was normal in 91 patients, and 86 were delivered of a normal fetus (93.4%). In contrast, qualitative AFV was decreased in 29 patients, and 26 were delivered of a fetus with IUGR (89.9%). These differences were highly significant. Perinatal morbidity was increased tenfold in patients with decreased AFV. Overall, 26 of 31 IUGR fetuses (83.4%) demonstrated decreased qualitative AFV.

Amniotic Fluid↗
PubMed1980

Effect of blood in amniotic fluid on the detection of phosphatidylglycerol.

Samples of amniotic fluid were mixed with serum or red blood cells (RBC) in order to determine the effect of blood contamination on the detection of phosphatidylglycerol (PG). Samples of amniotic fluid was obtained from patients in the second trimester of pregnancy and at term, PG standard was added to half of the aliquots of the second-trimester fluid. The samples of fluid were tested before and after the addition of maternal or fetal serum or RBC in concentrations up to 20%. Two-dimensional thin-layer chromatographic procedures were performed to determine the presence or absence of PG. The results obtained showed that serum of RBC contamination of amniotic fluid without PG did not result in the appearance of a PG spot on the chromatographic plate. Neither serum nor RBC contamination interfered with the detection of PG in those fluids in which it was present. Maternal and fetal blood were similar in their failure to affect the detection of PG. These data suggest that PG determination for fetal lung maturity is a reliable test in the presence of bloody amniotic fluid.

Amniotic Fluid↗
PubMed1980

Antepartum fetal evaluation: development of a fetal biophysical profile.

Five fetal biophysical variables, fetal breathing movements, fetal movements, fetal tone, qualitative amniotic fluid volume, and the nonstress test, were measured in the same observation period in 216 patients with high-risk pregnancies. All delivered within one week of the last observation. The relationship between individual biophysical variables and combinations of variables to the outcome of pregnancy as judged by five-minute Apgar score, fetal distress in labor, and perinatal mortality rate (PMN) was determined. For any single test, the false negative rate was low and was similar between tests, but the false positive rate was high (greater than 50%) and varied significantly between tests. Combining tests resulted in a significant change in both the false negative and false positive rates as compared to any single test. The most accurate differentiation of the normal from the compromised fetus was obtained when all five variables were studied. The PNM ranged from 0 when all variables were normal to 600 per 1,000 when all were abnormal. These data suggest that combined fetal biophysical testing is a more accurate method of antepartum fetal evaluation than any single method.

Adult↗