RESUMO
The ventilatory response to an added external dead space was assessed in preterm babies, recovering from respiratory distress syndrome, immediately prior to extubation. All babies were ready for extubation as defined by routine clinical criteria. Baseline measurements of respiratory rate, tidal volume, and minute ventilation were made over a 2 min period using a computerized system consisting of a pneumotachometer connected directly to the proximal end of the endotracheal tube. The measurements were repeated after addition of an external dead space equivalent to 2 anatomical dead spaces (4.4 mL/kg body weight). Thirty-four babies were studied on 40 occasions. Twenty-four infants (60%) were successfully extubated and 16 (40%) required reintubation. Infants in the success and failure groups were matched for gestation at birth, postconceptional age and weight at the time of study, maximum ventilatory requirements, and treatment with methylxanthines. The added external dead space resulted in an increase in minute ventilation in 38 out of the 40 studies. Extubation success and failure groups were compared by expressing the minute ventilation after addition of the external dead space as a percentage of the baseline minute ventilation (%MV1). Successful extubation was associated with a higher median %MV1 compared with babies who failed extubation (156; range, 89.3 to 230; compared to 131; range, 75.2 to 165; P = 0.006). This test may be useful in deciding which babies could be successfully extubated.
Assuntos
Espaço Morto Respiratório , Síndrome do Desconforto Respiratório do Recém-Nascido/terapia , Humanos , Recém-Nascido , Recém-Nascido Prematuro/fisiologia , Síndrome do Desconforto Respiratório do Recém-Nascido/fisiopatologia , Mecânica RespiratóriaRESUMO
Initial observations on healthy term infants using the forced partial expiratory flow-volume technique with an inflatable jacket suggested that this technique was stimulating the Hering-Breuer deflationary reflex, a reflex which has not been systematically studied in man. To investigate this fully, esophageal pressure, jacket pressure, flow and volume at the mouth were recorded during the forced partial expiratory flow-volume maneuver on 10 infants (mean age, 3.1 days; birth weight, 3533 g; gestation, 39.8 weeks). A total of 186 measurements were performed at different points in the respiratory cycle. In 159 (85%) recordings inspiratory effort was evident with a fall in esophageal pressure within 166 msec; in some cases this occurred before the jacket was fully inflated. This was associated with a reduction of 23.4 cm H2O in mean intrathoracic pressure, which was 2.5 times that occurring during normal tidal breathing. In the remaining 27 measurements a plateau pressure was associated with closure of the upper airway. When the squeeze was applied at low lung volumes (end-expiration) the inspiratory effort occurred significantly earlier (133 msec) and stronger (reducing peak intrathoracic pressure to 15.8 cm H2O) than when applied at end-inspiration (181 msec with a reduction in intrathoracic pressure to 25.2 cm H2O). The observed inspiratory response was highly consistent, representing the deflationary reflex as described by Hering and Breuer in 1868. The stronger and more rapid onset of inspiration at low lung volume supports the claim made by Breuer that it has a protective role on functional residual capacity (FRC) in young infants.
Assuntos
Recém-Nascido/fisiologia , Pulmão/fisiologia , Reflexo , Respiração/fisiologia , Testes de Função Respiratória , Feminino , Fluxo Expiratório Forçado , Humanos , Masculino , Testes de Função Respiratória/instrumentação , Trabalho RespiratórioRESUMO
Variation in body position has been shown to affect respiratory function in adults and neonates with and without respiratory illness. At present it remains unclear why respiratory function should be affected by different body positions. We hypothesized that the effect of body weight on the relatively compliant chest wall of the newborn infant in the prone position would cause a reduction in functional residual capacity (FRC) and a compensatory improvement in ventilation/perfusion matching as measured by effective pulmonary blood flow. To evaluate this, a paired crossover study was performed on 12 normal newborn infants. The inert gas (argon) rebreathing method adapted for neonates was used to measure FRC. Simultaneously effective pulmonary blood flow (Qpeff) was determined using Freon 22 and a mass spectrometer with computerized analysis. The babies were studied in three different positions in random order: prone, supine and right lateral decubitus. The means (95% confidence intervals) of the three groups of FRC were 23.8 (19.2 to 28.4), 23.8 (20.2 to 27.5), and 24.3 (19.5 to 29.2) ml/kg, respectively (P = 0.59) and for Qpeff were 104 (91 to 116), 108 (95 to 122), 109 (97 to 122) ml/ kg-min, respectively (P = 0.11). Thus no significant differences were demonstrated. In nine of the babies, a repeat supine measurement was taken at the end of the study to assess repeatability of the method. In these nine babies alone the results were 22.7 (19.1 to 26.3) and 22.1 (18.6 to 25.6) ml/kg for FRC, and 102 (89 to 116) and 98 (90 to 107) ml/kg-min for Qpeff. The coefficients of repeatability were 4.7 ml/kg for FRC (21%) and 30 ml/kg-min for Qpeff (30%).
Assuntos
Capacidade Residual Funcional/fisiologia , Recém-Nascido/fisiologia , Postura/fisiologia , Circulação Pulmonar/fisiologia , Sono/fisiologia , Argônio , Peso Corporal , Clorofluorcarbonetos de Metano , Estudos Cross-Over , Humanos , Decúbito Ventral , Reprodutibilidade dos Testes , Morte Súbita do Lactente/prevenção & controle , Decúbito DorsalRESUMO
AIMS: To assess the effects of smoking during pregnancy on lung mechanics and lung volumes in the immediate neonatal period, before infants are exposed to passive smoking. METHODS: Lung function tests were carried out within 72 hours of delivery in infants born to 100 non-smoking and 189 smoking mothers. Lung growth was assessed by plethysmography and lung mechanics using the single breath occlusion technique and oesophageal balloon/pneumotachography. Antenatal maternal serum cotinine values were obtained from 133 mothers. RESULTS: Smoking was associated with a significant reduction in birthweight (mean 256 g, 95% CI 0.164 to 0.392), and length (mean 1.26 cm, 95% CI 0.48 to 2.00). Lung volume was not reduced when related to weight. Smoking was associated with a highly significant reduction in static compliance (Crs). This effect remained significant after relating Crs to weight and lung volume. Regression analyses showed that the Crs association was limited to the boys. Smoking was associated with a small but significant reduction in respiratory system conductance (Grs) (single breath occlusion technique) and total pulmonary conductance (Gp). These associations were limited to girls. CONCLUSIONS: Smoking in pregnancy reduces static compliance in boys and conductance in girls. There was no evidence that maternal smoking adversely affected fetal lung growth.
Assuntos
Desenvolvimento Embrionário e Fetal , Pulmão/fisiologia , Mecânica Respiratória , Fumar/efeitos adversos , Adulto , Peso ao Nascer , Estatura , Feminino , Humanos , Recém-Nascido , Pulmão/embriologia , Complacência Pulmonar , Masculino , Pletismografia , Gravidez , Análise de Regressão , Fatores SexuaisRESUMO
Although Acinetobacter is usually a species of low virulence, it is becoming increasingly more important as a cause of hospital outbreaks, particularly on intensive care units. Antibiotic resistance can develop rapidly. This organism has not been reported to cause skin abscesses previously. We describe a case of a neonate who developed an Acinetobacter abscess on our neonatal intensive care unit.
Assuntos
Infecções por Acinetobacter/diagnóstico , Acinetobacter baumannii/isolamento & purificação , Infecção Hospitalar/diagnóstico , Recém-Nascido Prematuro , Dermatopatias Bacterianas/diagnóstico , Abscesso/diagnóstico , Abscesso/patologia , Infecções por Acinetobacter/patologia , Infecção Hospitalar/patologia , Diagnóstico Diferencial , Farmacorresistência Bacteriana , Humanos , Recém-Nascido , Masculino , Dermatopatias Bacterianas/patologiaAssuntos
Pulmão/anormalidades , Transtornos Respiratórios/etiologia , Feminino , Humanos , Lactente , Recém-Nascido , MasculinoRESUMO
In the fetal lamb model of hypoxic-ischaemic injury, the insult is followed by EEG depression, after which seizures emerge at 7-13 hours. We explored the relationship between the emergence of electrographic seizures and our estimate of the time of the cerebral injury in nine babies who underwent continuous video-EEG monitoring from soon after birth. Babies with prelabour insults had their first seizures before 12 hours of age, whereas those whose insult was peripartum had seizure onset at 18-20 hours of age. EEG seizure onset time could have important clinical and medico-legal applications, and be related to the time or severity of the insult, or both.
Assuntos
Traumatismos do Nascimento/complicações , Isquemia Encefálica/etiologia , Doenças Fetais , Complicações na Gravidez , Convulsões/etiologia , Eletroencefalografia/métodos , Feminino , Humanos , Recém-Nascido , Gravidez , Resultado da Gravidez , Convulsões/diagnóstico , Fatores de TempoRESUMO
UNLABELLED: The aim of this study was to investigate the role of oral salbutamol and prednisolone in the treatment of acute episodes of wheezing in infants under 15 months of age. Sixty-two acute episodes of wheezing were studied in 59 babies (age range 3-14 months; mean 7 months), who had all suffered at least one previous wheezy episode. Patients were randomised to receive either salbutamol and prednisolone, salbutamol and placebo or double placebo. Parents were requested to keep a diary card record of twice daily scoring of their baby's symptoms over the next 14 days. A significantly greater number of treatment failures occurred in the placebo group compared to babies treated with oral salbutamol (relative risk 2.51; 95% confidence intervals for relative risk 1.09-5.79). There was no difference in the number of treatment failures between babies treated with a combination of salbutamol and placebo and those treated with salbutamol and prednisolone (relative risk 0.71; 95% confidence intervals for relative risk 0.18-2.80). CONCLUSION: This study demonstrates that oral salbutamol is beneficial in the treatment of acute episodes of wheezing in infancy. A combination of oral salbutamol and oral prednisolone appeared to have no additional benefit over treatment with oral salbutamol alone.
Assuntos
Agonistas Adrenérgicos beta/administração & dosagem , Albuterol/administração & dosagem , Anti-Inflamatórios/administração & dosagem , Prednisolona/administração & dosagem , Sons Respiratórios/efeitos dos fármacos , Administração Oral , Agonistas Adrenérgicos beta/efeitos adversos , Albuterol/efeitos adversos , Anti-Inflamatórios/efeitos adversos , Quimioterapia Combinada , Feminino , Humanos , Lactente , Masculino , Prednisolona/efeitos adversosRESUMO
We describe two cases of congenital chylothorax in siblings with important differences from previously described familial cases. Our findings support the likelihood of an autosomal recessive inheritance in some cases of this condition, rather than X-linked recessive inheritance, which has also been suggested. Autopsy findings from one of these cases and others previously described suggest that the pathophysiological mechanisms involved may be variable.
Assuntos
Quilotórax/congênito , Quilotórax/genética , Quilotórax/diagnóstico por imagem , Evolução Fatal , Feminino , Humanos , Recém-Nascido , Masculino , Núcleo Familiar , Gravidez , Ultrassonografia Pré-NatalRESUMO
BACKGROUND: Previous studies suggest that recurrent episodes of coughing and wheezing occur in up to 75% of infants after acute viral bronchiolitis. AIM: To assess the efficacy of budesonide given by means of a metered dose inhaler, spacer, and face mask in reducing the incidence of coughing and wheezing episodes up to 12 months after acute viral bronchiolitis. METHODS: Children under the age of 12 months admitted to hospital with acute viral bronchiolitis were randomised to receive either budesonide or placebo (200 microg or one puff twice daily) for the next eight weeks. Parents kept a diary card record of all episodes of coughing and wheezing over the next 12 months. RESULTS: Full follow up data were collected for 49 infants. There were no significant differences between the two study groups for the number of infants with symptom episodes up to six months after hospital discharge. At 12 months, 21 infants in the budesonide group had symptom episodes compared with 12 of 24 in the placebo group. The median number of symptom episodes was 2 (range, 0-13) in those who received budesonide and 1 (range, 0-11) in those who received placebo. Because there is no pharmacological explanation for these results, they are likely to be caused by a type 1 error, possibly exacerbated by there being more boys in the treatment group. CONCLUSION: Routine administration of budesonide by means of a metered dose inhaler, spacer, and face mask system immediately after acute viral bronchiolitis cannot be recommended.
Assuntos
Anti-Inflamatórios/administração & dosagem , Bronquiolite Viral/complicações , Broncodilatadores/administração & dosagem , Budesonida/administração & dosagem , Sons Respiratórios/efeitos dos fármacos , Doença Aguda , Administração por Inalação , Administração Tópica , Pré-Escolar , Método Duplo-Cego , Feminino , Seguimentos , Glucocorticoides , Humanos , Lactente , Recém-Nascido , Masculino , Nebulizadores e VaporizadoresRESUMO
The authors conducted a randomized trial of second-line anticonvulsant treatments for neonates. The response to treatment was assessed using continuous video-EEG because the clinical diagnosis of seizure in neonates is known to be unreliable. Of 27 neonates with EEG-confirmed seizures, 5 were excluded because of protocol violations, and 11 responded to phenobarbitone in a dose of 40 mg/kg as first line. Three of five neonates treated with lignocaine responded. Six neonates were treated with benzodiazepines as second line: None responded, and their neurodevelopmental outcome was poor.
Assuntos
Anticonvulsivantes/uso terapêutico , Eletroencefalografia , Epilepsia/tratamento farmacológico , Clonazepam/uso terapêutico , Resistência a Medicamentos , Epilepsia/congênito , Feminino , Humanos , Recém-Nascido , Lidocaína/uso terapêutico , Masculino , Midazolam/uso terapêutico , Fenobarbital/uso terapêutico , Transtornos Psicomotores/etiologia , Falha de Tratamento , Gravação em VídeoRESUMO
From a sample of 848+/-44 D(+)(s)-->pi(-)pi(+)pi(+) decays, we find gamma(D(+)(s)-->pi(-)pi(+)pi(+))/gamma(D(+)(s)-->straight phipi(+)) = 0.245+/-0.028(+0.019)(-0.012). Using a Dalitz plot analysis of this three body decay, we find significant contributions from the channels rho(0)(770)pi(+), rho(0)(1450)pi(+), f(0)(980)pi(+), f(2)(1270)pi(+), and f(0)(1370)pi(+). We also present the values obtained for masses and widths of the resonances f(0)(980) and f(0)(1370).
RESUMO
From a sample of 1172 +/- 61 D(+)-->pi(-)pi(+)pi(+) decays, we find gamma(D(+)-->pi(-)pi(+)pi(+))/gamma(D(+)-->K-pi(+)pi(+)) = 0.0311 +/- 0.0018(+0.0016)(-0.0026). Using a coherent amplitude analysis to fit the Dalitz plot of these decays, we find strong evidence that a scalar resonance of mass 478(+24)(-23) +/- 17 MeV/c(2) and width 324(+42)(-40) +/- 21 MeV/c(2) accounts for approximately half of all decays.
RESUMO
We report results of a search for flavor-changing neutral current (FCNC), lepton flavor, and lepton-number violating decays of the D0 (and its antiparticle) into three and four bodies. Using data from Fermilab charm hadroproduction experiment E791, we examine modes with two leptons (muons or electrons) and a rho(0), K( *0), or straight phi vector meson or a nonresonant pi(pi), Kpi, or KK pair of pseudoscalar mesons. No evidence for any of these decays is found. Therefore, we present branching-fraction upper limits at 90% confidence level for the 27 decay modes examined (18 new).
RESUMO
We present the first direct measurements of the pion valence-quark momentum distribution which is related to the square of the pion light-cone wave function. The measurements were carried out using data on diffractive dissociation of 500 GeV/c pi(-) into dijets from a platinum target at Fermilab experiment E791. The results show that the /q&q> light-cone asymptotic wave function describes the data well for Q2 approximately 10 (GeV/c)(2) or more. We also measured the transverse momentum distribution of the diffractive dijets.
RESUMO
We have studied the diffractive dissociation into dijets of 500 GeV/c pions scattering coherently from carbon and platinum targets. Extrapolating to asymptotically high energies (where t(min)-->0), we find that when the per-nucleus cross section for this process is parametrized as sigma = sigma0Aalpha, alpha has values near 1.6, the exact result depending on jet transverse momentum. These values are in agreement with those predicted by theoretical calculations of color-transparency.
RESUMO
We study the Dalitz plot of the decay D(+)-->K(-)pi(+)pi(+) with a sample of 15090 events from Fermilab experiment E791. Modeling the decay amplitude as the coherent sum of known Kpi resonances and a uniform nonresonant term, we do not obtain an acceptable fit. If we allow the mass and width of the K(*)(0)(1430) to float, we obtain values consistent with those from PDG but the chi(2) per degree of freedom of the fit is still unsatisfactory. A good fit is found when we allow for the presence of an additional scalar resonance, with mass 797+/-19+/-43 MeV/c(2) and width 410+/-43+/-87 MeV/c(2). The mass and width of the K(*)(0)(1430) become 1459+/-7+/-5 MeV/c(2) and 175+/-12+/-12 MeV/c(2), respectively. Our results provide new information on the scalar sector in hadron spectroscopy.