RESUMO
Hyperreflexia of the peripheral chemoreceptors is a potential contributor of apnoeas of prematurity (AoP). Recently, it was shown that elevated P2X3 receptor expression was associated with elevated carotid body afferent sensitivity. Therefore, we tested whether P2X3 receptor antagonism would reduce AoP known to occur in newborn rats. Unrestrained whole-body plethysmography was used to record breathing and from this the frequency of apnoeas at baseline and following administration of either a P2X3 receptor antagonist - AF-454 (5 mg/kg or 10 mg/kg s.c.) or vehicle was derived. In a separate group, we tested the effects of AF-454 (10 mg/kg) on the hypoxic ventilatory response (10 % FiO2). Ten but not 5 mg/kg AF-454 reduced the frequency of AoP and improved breathing regularity significantly compared to vehicle. Neither AF-454 (both 5 and 10 mg/kg) nor vehicle affected baseline respiration. However, P2X3 receptor antagonism (10 mg/kg) powerfully blunted hypoxic ventilatory response to 10 % FiO2. These data suggest that P2X3 receptors contribute to AoP and the hypoxic ventilatory response in newborn rats but play no role in the drive to breathe at rest.
Assuntos
Apneia/prevenção & controle , Antagonistas do Receptor Purinérgico P2X/uso terapêutico , Receptores Purinérgicos P2X3/fisiologia , Animais , Animais Recém-Nascidos , Apneia/fisiopatologia , Corpo Carotídeo/efeitos dos fármacos , Corpo Carotídeo/fisiopatologia , Hipóxia/tratamento farmacológico , Hipóxia/fisiopatologia , Masculino , Pletismografia Total/métodos , Antagonistas do Receptor Purinérgico P2X/farmacologia , Ratos , Ratos WistarRESUMO
BACKGROUND: In obese patients, reduced functional residual capacity exacerbated by supine position might decrease the effectiveness of pre-oxygenation and the tolerance to apnoea. The aim of this study was to compare the effect of body posture during pre-oxygenation, sitting or supine, on its effectiveness in obese patients. METHODS: Forty obese patients (BMI > or =35 kg m(-2)) undergoing surgery with general anaesthesia were randomly assigned to one of two groups: Group 1 (sitting, n=20) or Group 2 (supine, n=20). In the predetermined body position, pre-oxygenation was achieved with eight deep breaths within 60 s and an oxygen flow of 10 litre min(-1). After rapid sequence induction of anaesthesia in decubitus position, the trachea was intubated and the patient was left apneic and disconnected from the anaesthesia circuit until Sp(o2) decreased to 90%. The time taken for desaturation to 90% from the end of induction of anaesthesia was recorded. Arterial blood oxygen tension was measured before (baseline) and after pre-oxygenation. Values were compared with two-way anova and unpaired Student's t-test. RESULTS: Oxygen and carbon dioxide tensions were similar between groups, both at baseline and after pre-oxygenation. However, the mean time to desaturation to 90% was significantly longer in the sitting group compared with the supine group [mean (SD): 214 (28) vs 162 (38) s, P<0.05]. CONCLUSIONS: Pre-oxygenation in sitting position significantly extends the tolerance to apnoea in obese patients when compared with the supine position.
Assuntos
Apneia/prevenção & controle , Complicações Intraoperatórias/prevenção & controle , Obesidade/complicações , Oxigenoterapia/métodos , Cuidados Pré-Operatórios/métodos , Adulto , Anestesia Geral , Antropometria , Dióxido de Carbono/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Oxigênio/sangue , Pressão Parcial , Postura , Decúbito DorsalRESUMO
Os autores realizaram uma revisäo da literatura sobre o metabolismo da cafeina e seu uso na apnéia neonatal. A cafeina é uma droga eficaz no tratamento da apnéia neonatal estimulando o centro respiratório por bloqueio dos receptores de adenosina. Possui boa absorçäo gastrointestinal, sendo esta a via preferencial de administraçäo. A cafeina é metabolizada no fígado pelo citrocromo P-450; porém, no neonato esta via metabólica é deficiente, sendo que 85% da droga ingerida é eliminada intacta na urina. Em doses terapêuticas (10 - 15mg/Kg/24 horas dose inicial e 2mg/Kg/dia dse de manutençäo) näo se observaram efeitos de toxicidade aguda como vômitos, distensäo abdominal, tremores ou desidrataçäo. Porém, os níveis séricos de bilirrubinas e glicose, frequência cardíaca e presäo arterial, devem ser acompanhados durante o tratamento. Efeitos da toxicidade tardia, como alteraçöes no comprimento, peso, perímetro cefálico e seqüelas neurológicas näo foram observadas aso 6 e 12 meses de idade em crianças tratadas com cafeína no período neonatal
Assuntos
Humanos , Recém-Nascido , Lactente , Pré-Escolar , Apneia/metabolismo , Cafeína/metabolismo , Apneia/prevenção & controle , Apneia/tratamento farmacológico , Recém-Nascido Prematuro/metabolismo , Sistema Cardiovascular/efeitos dos fármacos , Sistema Nervoso Central/efeitos dos fármacos , Sistema Digestório/efeitos dos fármacos , Cafeína/farmacologia , Cafeína/uso terapêutico , Circulação Cerebrovascular , RespiraçãoRESUMO
A blinded, randomized, placebo-controlled trial was conducted to evaluate the effectiveness of theophylline and doxapram therapy in 31 infants with significant apnea of prematurity. Of 10 infants, two had a short-term response to placebo, 8 of 10 infants to theophylline, and 7 of 11 infants to doxapram (placebo vs treatment with theophylline or doxapram: p = 0.01). The two infants who initially responded to placebo remained responsive for the duration of the study. Of the eight infants in whom treatment with placebo failed, five were randomly assigned to receive theophylline, for a total of 15 infants treated with theophylline, and two of the eight were randomly assigned to receive doxapram, for a total of 13 infants treated with doxapram; the remaining infant required tracheal intubation. Of the 15 infants randomly assigned to receive theophylline, seven responded for the duration of the study; of the eight infants who did not respond to treatment with theophylline, five responded to doxapram, one responded to a combination of theophylline and doxapram, and two remained resistant to treatment. Of the 13 infants randomly assigned to receive doxapram four responded for the duration of the study; of the nine who did not respond to doxapram, seven responded to theophylline, one responded to a combination of theophylline and doxapram, and one remained resistant to treatment. This study demonstrates that although therapy with theophylline or doxapram is associated with a significant short-term reduction in the incidence of apnea compared with that in placebo-treated infants, the long-term response to treatment is frequently incomplete and is not sustained more than 1 week.
Assuntos
Apneia/tratamento farmacológico , Doxapram/uso terapêutico , Recém-Nascido Prematuro , Teofilina/uso terapêutico , Apneia/prevenção & controle , Doxapram/administração & dosagem , Doxapram/sangue , Combinação de Medicamentos , Feminino , Humanos , Recém-Nascido , Infusões Intravenosas , Masculino , Placebos , Ensaios Clínicos Controlados Aleatórios como Assunto , Método Simples-Cego , Teofilina/administração & dosagem , Teofilina/sangueRESUMO
Se presentan 3 casos de monitoría electrónica en el domicilio a niños con riesgo de muerte súbita, de un programa del Hospital Luis Calvo Mackenna. Un lactante aparentemente sano, sin enfermedades previas, con dos hermanos fallecidos en forma inexplicable, que a los 2 meses de edad tuvo un episodio compatible con casi síndrome de muerte súbita (SMSI). Durante la vigilancia tuvo tres alarmas verdaderas que respondieron a estímulos. Se retiró el monitor a los 9 meses de edad y actualmente está sano. El segundo paciente tenía antecedentes de 6 hermanos fallecidos entre los 2 y 5 meses de edad sin causa aparente, sufrió un episodio sugerente de casi -SMSI a los 2 meses y falleció a los 4 meses de edad a pesar de que el monitor dio aviso y se realizaron maniobras oportunas. Finalmente un tercer lactante que fue vigilado desde los dos meses de edad porque su hermano había fallecido en forma súbita, no tuvo alarmas verdaderas en 4 meses de vigilancia en domicilio. Es fundamental definir un criterio sobre qué niños en riesgo de muerte súbita deberían ser vigiladios y dar instrucciones, apoyo y seguimiento al grupo familiar. Nuestra experiencia es aún pequeña para emitir un juicio sobre la eficacia de la monitoría en domicilio y aunque no hay evidencia de que ésta disminuya la mortalidad por SMSI, debe continuar planteándose en niños que han tenido episodios de casi -SMSI, especialmente si existen antecedentes de hermanos fallecidos y alto nivel de ansiedad en la familia
Assuntos
Lactente , Humanos , Masculino , Apneia/prevenção & controle , Morte Súbita do Lactente/prevenção & controle , Serviços de Assistência Domiciliar , Monitorização FisiológicaRESUMO
To investigate claims that oscillating mattresses reduce apnea of prematurity and improve growth and neurobehavioural development, we performed a randomized clinical trial using a predetermined sample size. Preterm infants weighing from 750 to 1750 gm at birth were randomly assigned, by 250 gm strata, to either a conventional mattress (n = 63) or to an air mattress (n = 59) oscillating at 14 to 16 regular pulses per minute. Infants remained on the oscillating air mattress for at least 7 days or until 34 weeks postmenstrual age. Apneic episodes occurred and required treatment equally in the two groups; this lack of an effect was seen for both sexes and all weight groups. Both weight and energy intake were similar. Neurobehavioral development as shown by sleep state, habituation testing, and behavioral assessment at term, 3, 6, and 12 months was similar in the two groups. There was no difference in the incidence of neurologic abnormalities. We conclude that an oscillating air mattress has no prophylactic value in reducing apnea and does not enhance growth and development.