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Biomedical subjects

S J Danoff

Publications and source records attributed to S J Danoff.

5 recordsLinked to original sources
PubMed1993

The role of gentle ventilation in prevention of subglottic stenosis in the newborn.

Prolonged endotracheal intubation has become the standard of care in most neonatal units for maintenance of mechanical ventilation in the presence of respiratory distress. Unfortunately this approach has become associated with significant complications, including acquired subglottic stenosis. We have successfully used nasal continuous positive airway pressure to avoid or decrease the incidence and duration of endotracheal intubation. With use of this technique we have been able to significantly reduce sequelae (i.e., bronchopulmonary dysplasia, chronic lung disease, intraventricular hemorrhage) and have not encountered subglottic stenosis in more than 200 cases. The use of this technique may be of significant value in preventing or reducing the incidence of acquired subglottic stenosis.

Glottis↗
PubMed1985

Rheology of fetal and maternal blood.

Rheological parameters were measured in 10 pairs of mothers and newborns. Whole blood viscosity was similar despite a higher fetal hematocrit (47.0 +/- 5.1 versus 35.5 +/- 12.0%, mean +/- SD, p less than 0.05). When the hematocrit of the suspension of red cells in plasma was adjusted to 45%, the viscosity was significantly lower in the fetal blood over a wide range of shear rates (0.52-208 S-1). The main reason for the lower viscosity in the fetal blood was the lower plasma viscosity as compared to the maternal blood (1.08 +/- 0.05 versus 1.37 +/- 0.08 centipoise, p less than 0.05); this in turn was attributable to a lower total plasma protein concentration (4.74 +/- 0.71 versus 6.47 +/- 0.64 g/dl, p less than 0.05). All protein fractions were lower in the fetal plasma. The assessment of red cell deformability by filtration through polycarbonate sieves revealed that the resistance of a fetal red cell was three times higher than that of a maternal red cell in a 2.6-micron pore, but there was no significant difference in resistance for these red cells in 6.9-micron pores. This higher filtration resistance of fetal red cells through the small pores was mainly due to their large volume (115.4 +/- 10.8 versus 93.5 +/- 5.9 fl, p less than 0.001). Measurements on membrane-free hemoglobin solutions indicated that the internal viscosity of these two types of red cells was not different.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Viscosity↗
PubMed1984

Rheologic measurements on small samples with a new capillary viscometer.

A newly developed capillary viscometer (capillary diameter 496 micron, length 10 cm) was tested and used for measurement of blood viscosity. The determination of pressure drop along the capillary during a constant flow allowed the calculation of the apparent viscosity. By changing the flow rate, the shear rate could be varied from 0.67 to 590 sec-1. A sample of 0.5 ml was sufficient for readings to be made at 10 shear rates in this range. Measurements of distilled water and standard oils were in good agreement with the expected values. Measurements on adult human plasma and umbilical cord blood were compared with simultaneous readings by Couette viscometer. For whole blood at various shear rates, regression analysis between the viscosity obtained from the capillary viscometer and that from the Couette viscometer yielded excellent correlation (r = 0.968, p less than 0.001). This capillary viscometer with high precision for very small samples is useful for various clinical applications.

Adult↗