Search PubMed⌕ Search

Biomedical subjects

D C Stevens

Publications and source records attributed to D C Stevens.

31 records · Page 2Linked to original sources
PubMed1980

An analysis of tolazoline therapy in the critically-ill neonate.

There were 47 seriously-ill neonates with medical causes of respiratory distress and 10 infants with severe respiratory distress secondary to a congenital diaphragmatic hernia treated with tolazoline according to a strict protocol designed to manage persistent fetal circulation (PFC). Of the 47 infants, 28 (60%) had a positive response defined as an increase in the pO2 greater than or equal to 24 mm Hg within 4 hr of beginning the drug. Of 7 infants, 4 with congenital diaphragmatic hernia had a positive response. The mean increase in the pO2 for the 47 infants was statistically significant (p less than .05). Of the 47 infants with medical disorders, 27 survived (survival 57%), whereas only 2 of the 10 infants with congenital diaphragmatic hernia and severe persistent fetal circulation survived (survival 28%). Erythema (60%), hematest positive gastric aspirates (55%), thrombocytopenia (45%), hyponatremia (40%) and increased gastric aspirates (36%) were the most common adverse effects occurring during tolazoline infusion. Hypotension occurred in nine cases, but was transient. Of the 27 survivors, 20 with medical causes of persistent fetal circulation were evaluated at age 1 yr. Eighty percent of these infants studied were considered normal as defined by an MDI and PI of the Bayley Scales of greater than or equal to 70. These data suggest that tolazoline is a useful adjunct in the management of neonates with PFC. In addition, tolazoline was more effective in mechanically ventilated neonates treated with respiratory paralytic agents. Although tolazoline resulted in a significant improvement in the paO2 in 4 infants with congenital diaphragmatic hernia, it did not appear to improve mortality in these infants.

Erythema↗
PubMed1979

Increased incidence of lactobezoars in low birth weight infants.

Fifteen low birth weight infants had their conditions complicated by the formation of a lactobezoar. The mean gestational age was 30.3 weeks; mean birth weight was 1,184 g, and the mean age at the time of diagnosis was 11.8 days. Twelve of the infants were receiving an 80 kcal/dL-formula and one infant, a 40 kcal/dL-formula designed for the premature infant. Symptoms included abdominal distension, emesis or increased gastric residual, diarrhea, hematest-positive stools, abdominal mass, and gastric perforation.

Bezoars↗
PubMed1979

Respiratory paralysis to improve oxygenation and mortality in large newborn infants with respiratory distress.

The nonsynchronous respiratory efforts of neonates with surgically correctable disorders may inhibit effective mechanical ventilation. The records of 25 infants treated with metocurine for muscular paralysis to improve mechanical ventilation were reviewed. All patients were greater than 35 (37.6 +/- 2.1) weeks gestation and 2.27 (2.98 +/- .47) kg. All required ventilatory support with an FiO2 of 100%. The mortality rate of this group of infants was 20% as compared with 73% (p < .001) in a similar group of 26 infants managed without paralysis. In 10 of the 25 infants treated with metocurine, pre- and 1 hr postparalysis paO2 values were available. The mean paO2 prior to paralysis was 62 (45--111) mm Hg and the mean post-paralysis paO2 was 144 (75--227) mm Hg, representing at 132% increase in paO2 (p < .001). The mean dosage for metocurine was 3.5 (1.45--6.79) mg/kg/day; however, those requiring paralysis for greater than 7 days showed a dramatically increasing requirement. These preliminary data suggest that respiratory paralysis reduces right-to-left shunting, improves paO2 and decreases mortality in large infants with severe respiratory distress requiring ventilatory support.

Diaphragm↗
PubMed1979

Fetal and neonatal ventricular arrhythmia.

Ventricular arrhythmia in the perinatal period is observed with greater frequency than reported in the literature. Four cases from the authors' experience and an analysis of the literature are presented. Of the total of 45 cases, nine were detected in utero, three persisted beyond the neonatal period, and two resulted in death with associated disorders. Twenty-four percent of the entire group had serious medical disorders associated with arrhythmia; however, 43% of the group with ventricular tachycardia had major associated disease.

Arrhythmias, Cardiac↗
PubMed1975

Adiabatic evolution of plasma equilibrium.

A new theory of plasma equilibrium is introduced in which adiabatic constraints are specified. This leads to a mathematically nonstandard structure, as compared to the usual equilibrium theory, in which prescription of pressure and current profiles leads to an elliptic partial differential equation. Topologically complex configurations require further generalization of the concept of adiabaticity to allow irreversible mixing of plasma and magnetic flux among islands. Matching conditions across a boundary layer at the separatrix are obtained from appropriate conservation laws. Applications are made to configurations with planned islands (as in Doublet) and accidental islands (as in Tokamaks). Two-dimensional, axially symmetric, helically symmetric, and closed line equilibria are included.

Journal Article↗