Hyponatremia is common in preterm infants. The causes are usually related to the inability of the premature kidneys to excrete a given water load, excessive sodium losses, or inadequate sodium intake. Here, we present a case of severe hyponatremia in an extreme preterm infant, associated with the use of aminophylline. Aminophylline was administered intravenously on day 1 for the treatment of apnea of prematurity. On day 3, the patient developed hyponatremia which was not responsive to sodium replacement and fluid restriction. Due to concerns of aminophylline‑induced hyponatremia, aminophylline was discontinued on day 6, and within 48 h of discontinuation, serum sodium normalized without the need for sodium supplementation. The purpose of the case report is to present a rare complication associated with aminophylline use and to shed light on potential deleterious effects associated with drug shortages.

Objetivo: Determinar a influência da presença de cafeína no sangue de cordão umbilical na ocorrência de apneia. Métodos: Estudo de coorte prospectivo de recém-nascidos pretermos com peso de nascimento menor de 2.000 g. Os critérios de exclusão foram: mães que receberam opióides , ventilação mecânica durante os primeiros 4 dias de vida, malformação congênita cerebral e cardíaca maiores, asfixia perinatal, hemorragia peri-intraventricular severa, exsanguíneotransfusão antes do quarto dia de vida e uso de metilxantina antes da extubação. Os recém-nascidos foram divididos em: com e sem cafeína detectável no sangue de cordão umbilical e acompanhados nos primeiros quatro dias de vida para a ocorrência de apneia. Resultados: 87 com e 40 sem cafeína detectável no sangue de cordão umbilical foram estudados. A mediana da concentração de cafeína dos 87 pacientes com cafeína detectável no sangue de cordão umbilical foi 2,3 µg/ml (0,2-9,4 µg/ml). Não houve associação entre a ocorrência de apneia e a presença de cafeína no sangue de cordão umbilical. Recém-nascidos com cafeína detectável no cordão umbilical tiveram apnéia mais tarde (66.3 horas) do que aqueles com níveis indetectáveis (54.2 horas). Conclusão: a detecção de níveis de cafeína no sangue de cordão umbilical não diminuiu a ocorrência de apneia da prematuridade. Nós sugerimos que novos estudos com a administração de altas doses de cafeína para mães antes do parto prematuro, como estratégia para prevenir a apneia da prematuridade, devam ser realizados. / Objective: To determine the influence of presence of caffeine in umbilical cord blood on apnea occurrence. Methods: A prospective cohort study with preterm newborns with birth weight less than 2,000 g was undertaken. Exclusion criteria were: mothers that received opioids, mechanical ventilation during the first 4 days of life, cerebral and major cardiac malformations, perinatal asphyxia, severe periintraventricular hemorrhage, exchange transfusion before the fourth day of life, and those that received methylxantine prior to extubation. Neonates were divided in: with detectable and undetectable caffeine in umbilical cord blood. Newborns were followed for the first 4 days for occurrence of apnea spells. Results: 87 with and 40 without detectable caffeine in umbilical cord blood were studied. The median caffeine concentration of the 87 patients with detectable caffeine in umbilical blood was 2.3 µg/ml (0.2-9.4 µg/ml). There was no association between occurrence of apnea spells and presence of caffeine in umbilical cord blood. Neonates with detectable caffeine in umbilical blood had apnea later (66.3 ± 4.14 hours) than those with undetectable levels (54.2 ± 6.26 hours). Conclusion: The detected levels of caffeine in umbilical cord blood did not decrease the occurrence of apnea of prematurity. We suggest that further studies on administration of high dose of caffeine to mothers prior to a preterm delivery as a preventive measure for apnea of prematurity deserve to be conducted.

Objetivo: Determinar a influência da presença de cafeína no sangue de cordão umbilical na ocorrência de apneia. Métodos: Estudo de coorte prospectivo de recém-nascidos pretermos com peso de nascimento menor de 2.000 g. Os critérios de exclusão foram: mães que receberam opióides , ventilação mecânica durante os primeiros 4 dias de vida, malformação congênita cerebral e cardíaca maiores, asfixia perinatal, hemorragia peri-intraventricular severa, exsanguíneotransfusão antes do quarto dia de vida e uso de metilxantina antes da extubação. Os recém-nascidos foram divididos em: com e sem cafeína detectável no sangue de cordão umbilical e acompanhados nos primeiros quatro dias de vida para a ocorrência de apneia. Resultados: 87 com e 40 sem cafeína detectável no sangue de cordão umbilical foram estudados. A mediana da concentração de cafeína dos 87 pacientes com cafeína detectável no sangue de cordão umbilical foi 2,3 µg/ml (0,2-9,4 µg/ml). Não houve associação entre a ocorrência de apneia e a presença de cafeína no sangue de cordão umbilical. Recém-nascidos com cafeína detectável no cordão umbilical tiveram apnéia mais tarde (66.3 horas) do que aqueles com níveis indetectáveis (54.2 horas). Conclusão: a detecção de níveis de cafeína no sangue de cordão umbilical não diminuiu a ocorrência de apneia da prematuridade. Nós sugerimos que novos estudos com a administração de altas doses de cafeína para mães antes do parto prematuro, como estratégia para prevenir a apneia da prematuridade, devam ser realizados. / Objective: To determine the influence of presence of caffeine in umbilical cord blood on apnea occurrence. Methods: A prospective cohort study with preterm newborns with birth weight less than 2,000 g was undertaken. Exclusion criteria were: mothers that received opioids, mechanical ventilation during the first 4 days of life, cerebral and major cardiac malformations, perinatal asphyxia, severe periintraventricular hemorrhage, exchange transfusion before the fourth day of life, and those that received methylxantine prior to extubation. Neonates were divided in: with detectable and undetectable caffeine in umbilical cord blood. Newborns were followed for the first 4 days for occurrence of apnea spells. Results: 87 with and 40 without detectable caffeine in umbilical cord blood were studied. The median caffeine concentration of the 87 patients with detectable caffeine in umbilical blood was 2.3 µg/ml (0.2-9.4 µg/ml). There was no association between occurrence of apnea spells and presence of caffeine in umbilical cord blood. Neonates with detectable caffeine in umbilical blood had apnea later (66.3 ± 4.14 hours) than those with undetectable levels (54.2 ± 6.26 hours). Conclusion: The detected levels of caffeine in umbilical cord blood did not decrease the occurrence of apnea of prematurity. We suggest that further studies on administration of high dose of caffeine to mothers prior to a preterm delivery as a preventive measure for apnea of prematurity deserve to be conducted.

Objetivo: Determinar a influência da presença de cafeína no sangue de cordão umbilical na ocorrência de apneia. Métodos: Estudo de coorte prospectivo de recém-nascidos pretermos com peso de nascimento menor de 2.000 g. Os critérios de exclusão foram: mães que receberam opióides , ventilação mecânica durante os primeiros 4 dias de vida, malformação congênita cerebral e cardíaca maiores, asfixia perinatal, hemorragia peri-intraventricular severa, exsanguíneotransfusão antes do quarto dia de vida e uso de metilxantina antes da extubação. Os recém-nascidos foram divididos em: com e sem cafeína detectável no sangue de cordão umbilical e acompanhados nos primeiros quatro dias de vida para a ocorrência de apneia. Resultados: 87 com e 40 sem cafeína detectável no sangue de cordão umbilical foram estudados. A mediana da concentração de cafeína dos 87 pacientes com cafeína detectável no sangue de cordão umbilical foi 2,3 µg/ml (0,2-9,4 µg/ml). Não houve associação entre a ocorrência de apneia e a presença de cafeína no sangue de cordão umbilical. Recém-nascidos com cafeína detectável no cordão umbilical tiveram apnéia mais tarde (66.3 horas) do que aqueles com níveis indetectáveis (54.2 horas). Conclusão: a detecção de níveis de cafeína no sangue de cordão umbilical não diminuiu a ocorrência de apneia da prematuridade. Nós sugerimos que novos estudos com a administração de altas doses de cafeína para mães antes do parto prematuro, como estratégia para prevenir a apneia da prematuridade, devam ser realizados. / Objective: To determine the influence of presence of caffeine in umbilical cord blood on apnea occurrence. Methods: A prospective cohort study with preterm newborns with birth weight less than 2,000 g was undertaken. Exclusion criteria were: mothers that received opioids, mechanical ventilation during the first 4 days of life, cerebral and major cardiac malformations, perinatal asphyxia, severe periintraventricular hemorrhage, exchange transfusion before the fourth day of life, and those that received methylxantine prior to extubation. Neonates were divided in: with detectable and undetectable caffeine in umbilical cord blood. Newborns were followed for the first 4 days for occurrence of apnea spells. Results: 87 with and 40 without detectable caffeine in umbilical cord blood were studied. The median caffeine concentration of the 87 patients with detectable caffeine in umbilical blood was 2.3 µg/ml (0.2-9.4 µg/ml). There was no association between occurrence of apnea spells and presence of caffeine in umbilical cord blood. Neonates with detectable caffeine in umbilical blood had apnea later (66.3 ± 4.14 hours) than those with undetectable levels (54.2 ± 6.26 hours). Conclusion: The detected levels of caffeine in umbilical cord blood did not decrease the occurrence of apnea of prematurity. We suggest that further studies on administration of high dose of caffeine to mothers prior to a preterm delivery as a preventive measure for apnea of prematurity deserve to be conducted.