Gregory L. Jackson, MD                                                                  
Associate Professor, Pediatrics

Altered Calcium Metabolism by Gentamicin in Neonates

Several hundred infants receive gentamicin and ampicillin in the Parkland Hospital Newborn Nursery each year. We recently altered gentamicin therapy to every 24-hour dosing (q24h) as recommended in several articles, a change from our previous every 12-hour dosing schedule (q12h). After this change, we noticed several infants who developed hypocalcemia, some who had seizures. We began more intensive monitoring of blood calcium levels in infants receiving q24h gentamicin, and found ~4% who had significantly low serum calcium levels, compared to 0.4% in a period with q12h dosing.

Animal studies show that urinary calcium excretion is increased in association with gentamicin administration. However, symptomatic low blood calcium levels in relation to gentamicin administration have not been reported in infants. To further study this issue, we will collect blood and urine on infants who are receiving gentamicin for >5 days (q12h group vs q24h group), to determine excretion of calcium, phosphorus, magnesium, and creatinine.
The student who chooses to participate in this study will be involved in literature review, obtaining of consents for study, data collection, and interim data analysis.
Ongoing Studies of Jaundice in the Newborn Nursery

We have completed several studies in which a transcutaneous device is used to estimate total serum bilirubin (TSB) in term and near-term neonates; we continue to refine its use in very preterm and Hispanic neonates.
In addition, bilirubin at various levels can impact the auditory pathway in neonates. We plan to study the alterations of the Auditory Brainstem Response (ABR) in selected babies, and measure differences before and during phototherapy.
Neonatal Pneumonia

We have completed investigations regarding the duration of antibiotic therapy for neonatal pneumonia. In a future randomized study, we will investigate the role of oral antibiotics as a component in the therapeutic regimen for these neonates.
Management of the Neonate Exposed to Chorioamnionitis

We have studied the utility of the complete blood count in the management of term and near-term neonates exposed to maternal chorioamnionitis (Pediatrics 2004;113:1173-1180). In a future randomized study, we will explore various therapeutic options for these neonates.