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Biomedical subjects

J L Steven

Publications and source records attributed to J L Steven.

12 recordsLinked to original sources
PubMed2001

Cerebral oxygen saturation before congenital heart surgery.

BACKGROUND: In congenital heart disease (CHD), neurologic abnormalities suggestive of hypoxia-ischemia are often apparent before cardiac surgery. To evaluate preoperative cerebral oxygenation, this study determined cerebral O2 saturation (ScO2) in CHD and healthy children. METHODS: Ninety-one CHD and 19 healthy children aged less than 7 years were studied before surgical or radiologic procedures. Arterial saturation (SaO2) and ScO2 were measured by pulse-oximetry and near infrared cerebral oximetry. Cerebral O2 extraction (CEO2) was calculated (SaO2-ScO2). SaO2, ScO2, and CEO2 were compared among diagnoses. Multivariable regression was performed between ScO2 and clinical variables. RESULTS: In healthy subjects, ScO2 (68%+/-10%) and CEO2 (30%+/-11%) were similar to patients with ventricular septal defect, aortic coarctation, and single ventricle after Fontan operation. ScO2 was significantly decreased in patients with patent ductus arteriosus (53%+/-8%), tetralogy of Fallot (57%+/-12%), hypoplastic left heart syndrome (46%+/-8%), pulmonary atresia (38%+/-6%), and single ventricle after aortopulmonary shunt (50%+/-7%), or bidirectional Glenn operation (43%+/-6%). CEO2 was significantly different only in patent ductus arteriosus (46%+/-8%) and hypoplastic left heart syndrome (38%+/-12%). In multivariable regression, only SaO2 was related to ScO2 (R = 0.63, p < 0.001). CONCLUSIONS: Cerebral oxygenation in CHD varies with anatomy and arterial saturation, and in some patients, it is very low compared with healthy subjects.

Brain Ischemia↗
PubMed1977

The EMI scanner.

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Brain Diseases↗
PubMed1976

Intracranial pressure during ventriculography using meglumine iothalamate.

A small increase in ventricular fluid pressure (1.3 +/- 0.3 mm Hg) occurs on isovolumetic addition of meglumine iothalamate to the lateral ventricle. A marked increase (46.3 +/- 3.2 mm Hg: P less than 0.001) in pressure occurs on passage of the contrast medium into the posterior part of the third ventricle; the aqueduct and the fourth ventricle. Theoretical mechanisms are discussed.

Aged↗
PubMed1976

Computerized tomography in the diagnosis of cerebral atrophy.

Computerized tomograms were studied of 67 adults whose lumbar pneumoencephalograms were normal or showed ventricular dilatation with or without widening of the sulci. The maximum ventricular area, measured from 80 x 80 matrix printouts, correlates well with measures of ventricular size on the pneumoencephalogram. An area of 10 cm2 is suggested as the upper limit of normal. The correlation between measures of sulcal width on computerized tomography and pneumoencephalography is less precise, but normal sulci and gross degrees of cortical atrophy can be identified.

Adolescent↗
PubMed1976

Computed tomography in the diagnosis of colloid cyst.

The diagnosis of colloid cyst of the third ventricle is notoriously difficult and contributes significantly to the high mortality. Three cases are presented in which computed tomography has contributed to the diagnosis by showing (1) the dilatation of the lateral ventricles without dilatation of the midline ventricular system, and (2) the lesion as an area of increased density within the third ventricle. Computed tomography may reduce the overall mortality in this condition by reducing the number of patients who succumb undiagnosed during an acute phase of raised intracranial pressure.

Adult↗
PubMed1975

Effect of intracranial pressure of meglumine iothalamate ventriculography.

Intraventricular pressure was studied in 12 patients undergoing ventriculography with a water soluble positive contrast medium. Isovolumetric instillation of meglumine iothalamate into the lateral ventricles and the anterior part of the third ventricle caused only a small increase in ventricular fluid pressure (1.3 +/- 0.3 mmHg), but the pressure increased markedly (46.3 +/- 3.7 mmHg; P less than 0.001) when the contrast medium entered the posterior end of the third ventricle, aqueduct of Sylvius,, and fourth ventricle. This sharp increase in intracranial pressure could not be attributed solely to the postural changes or to alterations in arterial blood pressure. Possible mechanisms are discussed.

Adolescent↗