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Biomedical subjects

S D Minton

Publications and source records attributed to S D Minton.

7 recordsLinked to original sources

Nonlinear dobutamine pharmacokinetics in a pediatric population.

OBJECTIVE: To evaluate a linear kinetic model for dobutamine clearance. DESIGN: A prospective evaluation of pediatric patients receiving continuous infusions of dobutamine at varying doses. SETTING: A pediatric critical care unit. PATIENTS: Twelve patients age 2 days to 9 yrs and weighing 2.7 to 33 kg who required vasopressor therapy. Infusion rates for dobutamine ranged from 2 to 15 micrograms/kg.min. MEASUREMENTS AND MAIN RESULTS: Serum concentrations varied from 6.4 to 347 ng/mL (21 to 1151 nmol/L). Concentration was found to increase with dose. However, the relationship of clearance to steady-state concentration had a negative slope. Values for clearance varied from 32 to 625 mL/kg.min. Multiple analysis of variance on age, weight, and co-infused dopamine showed that these factors did not influence the relationship of clearance to steady-state concentration. Analysis to show an underlying model failed to differentiate Michaelis-Menten from nonlinear binding or mixed models on the basis of these data. CONCLUSIONS: Dobutamine pharmacokinetics do not appear to follow a simple linear model. Based on the current data, neither age nor the added infusion of dopamine affects the clearance of dobutamine.

Age Factors

Ceftizoxime disposition in neonates and infants during the first six months of life.

The single-dose pharmacokinetics of ceftizoxime sodium were studied in 52 neonates and infants between 0.1 and 189 days of age. Subjects received ceftizoxime 25 or 50 mg/kg iv over 15-30 minutes. The drug was administered q8-12h for five days to permit tolerance evaluation on repetitive dosing. No differences were observed in ceftizoxime pharmacokinetic parameter estimates relative to dose. However, marked differences were observed in ceftizoxime pharmacokinetic characteristics relative to infant age; ceftizoxime half-life and mean residence time decreased, whereas body clearance increased with infant age. Ceftizoxime volume of distribution remained relatively constant over infant age. No adverse effects associated with ceftizoxime administration were observed. These data suggest that ceftizoxime 50 mg/kg q12h be used for infants less than or equal to 2 weeks of age (less than or equal to 40 weeks postconceptional age) and that 50 mg/kg q8h be administered for older infants.

Aging

In utero ischemic injury: sonographic diagnosis and medicolegal implications.

The antenatal diagnosis of fetal neurologic injury has profound medical and legal implications. We report a case of antenatally diagnosed intracranial lesions including parenchymal hemorrhage in an otherwise physically normal infant. Computerized tomography in the newborn period demonstrated diffused ischemic damage with secondary cystic changes in addition to intracranial hemorrhage.

Cerebral Hemorrhage

Bone mineral content in term and preterm appropriate-for-gestational-age infants.

Photon absorptiometry adapted for use in small infants was utilized to measure bone mineral content in 42 term and 30 perterm appropriate-for-gestational-age infants. BMC at birth correlated significantly with gestational age and birth weight. Sequential measurements of BMC in premature infants during the first three months showed that the postnatal increase in BMC was significantly less than the BMC expected in utero. We speculate that decreased intake of calcium and phosphate effects postnatal bone mineralization in premature infants.

Birth Weight

Gastroesophageal reflux causing respiratory distress and apnea in newborn infants.

Respiratory distress, apnea, and chronic pulmonary disease since birth were identified in 14 infants who also had symptomatic gastroesophageal reflux. Birth weights varied from 760 to 4,540 gm. All infants had radiographic changes similar to those in bronchopulmonary dysplasia. Cessation of apnea and improvement of pulmonary disease occurred only after medical (8) or surgical (6) control of gastroesophageal reflux. Simultaneous tracings of esophageal pH, heart rate, impedance pneumography, and nasal air flow in five infants demonstrated that reflux preceded apnea. Apnea could be induced by instillation of dilute acid, but not water or formula, into the esophagus. Prolonged monitoring of esophageal pH more than two hours after feeding in 14 other infants less than 6 weeks of age (birth weight 780 to 3,350 gm) without a history of recent vomiting indicated that reflux was not greater than in normal older children.

Apnea

Use of pertussis vaccine in an epidemic involving hospital staff.

An epidemic of pertussis occurred among hospital staff caring for paediatric patients. Eight physicians and five nurses were affected. Pertussis developed in six newborn infants exposed to infected hospital staff in the nursery. Erythromycin prophylaxis was used to control the epidemic. Clinical pertussis developed in five adults infected with Bordetella pertussis before erythromycin was used, whereas symptoms developed in only one of the eight adults who became infected after erythromycin prophylaxis was started. Pertussis vaccine was given to adult volunteers in the hospital, and in 77% of two hundred and eighty-six vaccinees there was a fourfold rise in pertussis agglutinins. Local reactions were common, and in two vaccinees generalised rashes developed. One of these required treatment with corticosteroids. The risk of pertussis occurring in adults providing medical care for children should be recognised, and employees with symptoms should be removed from the hospital environment.

Adolescent