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Biomedical subjects

G J Downing

Publications and source records attributed to G J Downing.

28 records · Page 2Linked to original sources
PubMed1992

Antepartum fetomaternal hemorrhage. Report of a case with the use of cordocentesis in diagnosis and management.

Clinical recognition of antepartum fetomaternal hemorrhage (FMH) is most often achieved by the observation of characteristic fetal heart rate (FHR) patterns and positive Kleihauer-Betke acid elution staining. Both methods are noted to lack sensitivity and specificity. A case of suspected antepartum FMH occurred with intermittent sinusoidal FHR tracings. Fetal blood sampling by cordocentesis in situations with equivocal antenatal testing, such as in this case, allows not only confirmation of fetal anemia but assessment of fetal acid-base status. In pregnancies of less than 32 weeks' gestation complicated by severe antepartum FMH, intravascular transfusion may be offered via this technique. Cordocentesis is beneficial in the management of pregnancies with uncertain FHR patterns when antepartum FMH is suspected.

Adult↗
PubMed1991

Furosemide-related renal calcifications in the premature infant. A longitudinal ultrasonographic study.

Low birthweight infants treated with chronic furosemide therapy are at risk for the development of intrarenal calcifications. A prospective longitudinal renal ultrasound investigation was conducted to study the correlation of diuretic therapy, clinical course and ultrasonographic findings. Of 117 premature infants studied ultrasonographically upon discharge from the hospital, 20 had intrarenal calcifications. Eight patients at age 16.3 +/- 2.6 months had sonographic resolution of renal calcifications, 6.6 +/- 1.1 months after furosemide therapy had been discontinued. Of the 12 patients with persistent calcifications, 4 died from severe pulmonary disease and autopsy in 3 of them confirmed the ultrasonographic diagnosis. All 12 children but 2 continued to receive furosemide for their chronic lung disease demonstrating significant association between chronic use of loop diuretics and persistence fo the renal calcifications (p less than 0.001). Two patients required nephrolithotomy and 4 suffered from recurrent urinary tract infections. In 4 patients, 5 kidneys were of small size and in 2 bilateral collecting system dilation was noted. We conclude that discontinuation of furosemide therapy is associated with resolution of the renal calcifications. On the other hand, continued treatment with furosemide is associated with high renal morbidity which indicates ongoing clinical and ultrasonographic follow-up.

Child, Preschool↗
PubMed1991

Comparison of the pulsatility index and input impedance parameters in a model of altered hemodynamics.

Clinical use of Doppler waveform analysis assumes that vascular resistance is accurately represented by the Doppler indices. This assumption was examined by correlating the pulsatility index (PI) with measures of input impedance including peripheral vascular resistance (Zpr), characteristic impedance (Zo), and reflection coefficient (Rc). Assessment of these parameters from the descending aorta was performed in five chronically instrumented, newborn lambs subjected to administration of norepinephrine and hydralazine. Significant increases in PI, Zpr, Zo, and Rc were seen in response to administration of norepinephrine, and decreases in PI and Zpr occurred with hydralazine use. Significant correlation existed between PI and Zpr throughout the study, but changes in PI did not correlate with changes in Zo and Rc. PI appears to reflect changes in Zpr accurately. However, the lack of ability for PI to assess Zo or Rc requires further investigation.

Animals↗
PubMed1991

An interesting case presentation: pulmonary malformations associated with oculoauriculovertebral dysplasia (Goldenhar anomalad).

Oculoauriculovertebral dysplasia (OAV) is a heterogeneous field defect involving the first and second branchial arches and is characterized by microtia, mandibular hypoplasia, vertebral anomalies, and epibulbar dermoids. We report a case of OAV with pulmonary manifestations and review the literature regarding this association. Anomalies identified were previously undescribed tracheal stenosis, along with tracheoesophageal cleft and unilateral pulmonary agenesis. Recognition of the pulmonary malformations associated with OAV may lead clinicians to consider a diagnostic measure such as flexible fiberoptic endoscopy in the evaluation of infants with craniofacial malformations and respiratory distress.

Abnormalities, Multiple↗
PubMed1990

Nonimmune hydrops fetalis caused by a massive fetomaternal hemorrhage associated with elevated maternal serum alpha-fetoprotein levels. A case report.

Chronic fetomaternal hemorrhage led to the development of fetal anemia and nonimmune hydrops fetalis in a term neonate. Antenatal maternal serum alpha-fetoprotein levels were abnormally elevated, with normal amniotic fluid levels. Kleihauer-Betke staining was performed as part of the evaluation. Serial ultrasound examinations can be useful for unexplained elevations in maternal serum alpha-fetoprotein because of the associated increased fetal loss in those pregnancies. If fetomaternal hemorrhage is identified, serial ultrasound examinations are indicated for the detection of fetal hydrops.

Adult↗
PubMedDate not supplied

Pulmonary vasculature changes associated with idiopathic closure of the ductus arteriosus and hydrops fetalis.

Antenatal closure of the ductus arteriosus has been considered as a potential risk factor for the development of hydrops fetalis and persistent fetal circulation of the newborn. We present an infant with antenatal ductal closure who had not received prenatal prostaglandin synthetase inhibitors. The pulmonary vascular morphological findings are described and compared to three additional infants in whom the ductus arteriosus was known to be patent; one with neonatal sepsis and two others with hydrops fetalis. The infants with fetal hydrops, regardless of etiology, had increased muscularization of the acinar pulmonary arteries. In addition, the infant with antenatal closure of the ductus arteriosus also had both a significant decrease in preacinar arterial external diameter and an increase in medial wall thickness. Antenatal closure of the ductus arteriosus appears to enhance in utero pulmonary blood flow and this may be the cause of pulmonary vascular remodeling.

Ductus Arteriosus↗
PubMedDate not supplied

Effects of acute hypoxemia on umbilical arterial Doppler indices in a fetal ovine model.

Changes in umbilical arterial Doppler waveform in response to acute maternal hypoxemia were assessed in a chronic ovine model. Maternal heart rate, blood gases, fetal heart rate and umbilical arterial Doppler indices measured at baseline conditions and during periods of maternal hypoxemia were compared. The indices measured were systolic-diastolic ratio (S/D), pulsatility index (PI) and resistance index (RI). Fetal heart rate decreased (less than 80 beats/min) and umbilical arterial Doppler indices increased (P less than 0.001) during the periods of hypoxemia. Furthermore, the Doppler indices were highly but negatively correlated with alterations in the fetal heart rate (FHR) (P less than 0.001). Analysis of the Doppler waveform phase intervals revealed nearly constant systolic intervals while diastolic intervals varied inversely with the heart rate alterations. Moreover, the umbilical arterial Doppler indices, when corrected for FHR changes, were relatively unchanged from baseline measurements. This study indicates that maternal hypoxemia induced changes in the umbilical arterial Doppler indices may be primarily attributable to the changes in FHR.

Analysis of Variance↗