Effects of vitamin D and phosphorus supplementation on calcium retention in preterm infants fed banked human milk

Abstract

aminophylline demonstrated decreased Paco2, increased minute ventilation, and increased respiratory rate, as compared with Pretreatment values. One explanation for the successful extubation of infants after aminophylline therapy is suggested by the increase in minute ventilation coinciding with a decrease in arterial carbon dioxide tension in treated infants. Theophylline increases metabolic rate in animals, 4 decreases apnea, 15'6 increases respiratory muscle efficiency, 7 and increases central COz responsivenessY ~ Improved ventilatory response to lower carbon dioxide levels suggests that aminophylline stimulates the central nervous system chemoreceptors for CO2 response? This hypothesis is consistent with the observation that many very LBW infants appear apneic when ventilated at rates less than 6 bpm, but when given aminophylline, may improve sufficiently to be extubated. A previous study of infants with bronchopulmonary dysplasia 3 suggested that theophylline relaxed smooth muscle in hypertrophied small bronehioles. The infants in our study did not demonstrate clinical, radiographic, or pulmonary function evidence of bronchopulmonary dysplasia, and therefore smooth muscle relaxation is an unlikely explanation for the improvement observed. Aminophylline therapy allowed weaning of LBW infants with respiratory distress syndrome from low levels of mechanical ventilatory support and successful endotracheal extubation of most treated patients. Methylxanthine therapy should be considered to promote weaning of infants with respiratory distress syndrome from low rates of ventilatory support and to facilitate extubation. REFERENCES 1. Aranda .IV, Turmen T: Methylxanthines in apnea of prematurity. Clin Perinatol 6:87, 1979. 2. Daily W JR, Klaus M, Meyer HBP: Apnea in premature infants: Monitoring, incidence, heart rate changes and an effect of environmental temperature. Pediatrics 43:510, 1969. 3. Rooklin AR, Moomjian AS, Shutack JG, Schwartz JG, Fox WW: Theophylline therapy in bronchopulmonary dysplasia. J P~DIATR 95:882, 1979. 4. Thurston JH, Hauhart RE, Dirgo JA: Aminophylline increases cerebral metabolic rate and decreases anoxic survival in young mice. Science 201:649, 1978. 5. Aranda .IV, Grondin D, Sasyniuk BI: Pharmacologic considerations in the therapy of neonatal apnea. Pediatr Clin North Am 28:113, 1981. 6. Bednarek F.I, Roloff DW: Treatment ofapnea of prematurity with aminophylline. Pediatrics 58:335, 1976. 7. Aubier M, Detroyer A, Sampson M, Maklim PT, Ronssoc C: Amonophylline improves diaphragmatic contractility. N Engl .I Med 305:249, 1981. 8. Aranda .IV, Zinman R, Collinge J, Outerbridge EW: Effect of caffeine on control of ventilation in premature infants with apnea. Clin Pharmacol Ther 25:212, 1979. 9. Gerhardt T, McCarthy J, Bancalari E: Effect of aminophylline on respiratory center activity and metabolic rate in premature infants with idiopathic apnea. Pediatrics 63:537, 1979. 10. Davi M J, Sankaran K, Simons K J, Simons ER, Seshia MM, Rigatto H: Physiologic changes induced by theophylline in the treatment of apnea in preterm infants. J PEDIATR 92:91, 1978.