title: A randomized trial of moderately early low-dose dexamethasone therapy in very low birth weight infants: dynamic pulmonary mechanics, oxygenation, and ventilation.
abstract: OBJECTIVE
  Dexamethasone is used in very low birth weight (VLBW) ventilator-dependent infants to prevent or decrease the severity of chronic lung disease. We reported a significant increase in respiratory compliance during a 7-day weaning course of moderately early dexamethasone therapy (0.5 mg/kg/d) in VLBW infants, along with a shorter duration of mechanical ventilation and O2 supplementation. Although 0.5 mg/kg/d has been the most commonly used dose in preterm infants, the use of a lower dose of dexamethasone may reduce potential adverse effects of steroid therapy. Quantification of dynamic pulmonary mechanics in VLBW infants who receive low-dose dexamethasone has not been reported. The objective of this study was to compare the effect of 2 dose regimens of dexamethasone on dynamic pulmonary mechanics, mean airway pressure (MAP), and fractional inspired oxygen concentration (Fio2) in intubated VLBW infants who were at risk for chronic lung disease.
  
  
  METHODS
  We studied 47 VLBW (birth weight: 550-1290 g; gestational age: 24-30 weeks) ventilator-dependent infants at 7 to 14 days of age. Twenty-three infants were randomized to receive dexamethasone at 0.5 mg/kg/d intravenously for 3 days (high dose), 0.25 mg/kg/d for 3 days, and 0.1 mg/kg/d during the 7th day; 24 infants received low-dose dexamethasone as 0.2 mg/kg/d for 3 days and 0.1 mg/kg/d for 4 days. Respiratory compliance (Crs) and resistance were measured before and on days 2, 5, and 7 of dexamethasone therapy. We recorded airway pressure, flow, and tidal volume, and mechanical breaths were analyzed.
  
  
  RESULTS
  Crs significantly increased during dexamethasone therapy in both groups of infants when compared with baseline (74% increase in the high-dose group and 66% increase in the low-dose group). Dexamethasone increased tidal volume and significantly reduced Fio2 and MAP in both groups of infants. A transient increase in blood pressure was noted in both groups.
  
  
  CONCLUSIONS
  Our findings indicate that 1) comparable significant increases in Crs are present in the low-dose dexamethasone as well as the high-dose dexamethasone groups on days 2, 5, and 7 of steroid therapy; and 2) MAP and Fio2 are significantly decreased during dexamethasone therapy in both groups of infants. We conclude that low-dose and high-dose dexamethasone, as used in this study, have comparable beneficial effects on dynamic pulmonary mechanics and subsequently on oxygen requirement and applied ventilatory support in VLBW infants.
authors.affiliation: Division of Neonatal-Perinatal Medicine, Department of Pediatrics, Los Angeles County-University of Southern California Medical Center, Los Angeles, California 90033, USA. mdurand@hsc.usc.edu
authors.forename: Manuel
authors.initials: M
authors.lastname: Durand
authors.forename: Maria E
authors.initials: ME
authors.lastname: Mendoza
authors.forename: Phuket
authors.initials: P
authors.lastname: Tantivit
authors.forename: Amir
authors.initials: A
authors.lastname: Kugelman
authors.forename: Cindy
authors.initials: C
authors.lastname: McEvoy
mesh_terms: D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D001997:Bronchopulmonary Dysplasia / Q000188:drug therapy / Q000517:prevention & control; D003907:Dexamethasone / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D015658:HIV Infections / Q000188:drug therapy; D006801:Humans; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight; D008170:Lung Compliance / Q000187:drug effects; D008171:Lung Diseases / Q000188:drug therapy* / Q000517:prevention & control; D011446:Prospective Studies; D011480:Protease Inhibitors / Q000627:therapeutic use; D012123:Pulmonary Ventilation / Q000187:drug effects; D012121:Respiration, Artificial; D012127:Respiratory Distress Syndrome, Newborn / Q000188:drug therapy / Q000517:prevention & control; D012129:Respiratory Function Tests; D015656:Respiratory Mechanics / Q000187:drug effects; D016896:Treatment Outcome
chemical_list: D000893:Anti-Inflammatory Agents; D011480:Protease Inhibitors; D003907:Dexamethasone