RESUMO
Near-infrared spectroscopy (NIRS) could be a useful continuous, non-invasive technique for monitoring the effect of partial pressure of carbon dioxide (PaCO2) fluctuations in the cerebral circulation during ventilation. The aim of this study was to examine the efficacy of NIRS to detect acute changes in cerebral blood flow following PaCO2 fluctuations after confirming the autoregulation physiology in piglets. Fourteen piglets (<72 h of life) were studied. Mean arterial blood pressure, oxygen saturation, pH, glycemia, hemoglobin, electrolytes, and temperature were monitored. Eight animals were used to evaluate brain autoregulation, assessing superior cava vein Doppler as a proxy of cerebral blood flow changing mean arterial blood pressure. Another 6 animals were used to assess hypercapnia generated by decreasing ventilatory settings and complementary CO2 through the ventilator circuit and hypocapnia due to increasing ventilatory settings. Cerebral blood flow was determined by jugular vein blood flow by Doppler and continuously monitored with NIRS. A decrease in PaCO2 was observed after hyperventilation (47.6±2.4 to 29.0±4.9 mmHg). An increase in PaCO2 was observed after hypoventilation (48.5±5.5 to 90.4±25.1 mmHg). A decrease in cerebral blood flow after hyperventilation (21.8±10.4 to 15.1±11.0 mL/min) and an increase after hypoventilation (23.4±8.4 to 38.3±10.5 mL/min) were detected by Doppler ultrasound. A significant correlation was found between cerebral oxygenation and Doppler-derived parameters of blood flow and PaCO2. Although cerebral NIRS monitoring is mainly used to detect changes in regional brain oxygenation, modifications in cerebral blood flow following experimental PaCO2 changes were detected in newborn piglets when no other important variables were modified.
Assuntos
Hipocapnia , Respiração Artificial , Animais , Animais Recém-Nascidos , Dióxido de Carbono , Circulação Cerebrovascular/fisiologia , Hipercapnia , Oxigênio , SuínosRESUMO
Near-infrared spectroscopy (NIRS) could be a useful continuous, non-invasive technique for monitoring the effect of partial pressure of carbon dioxide (PaCO2) fluctuations in the cerebral circulation during ventilation. The aim of this study was to examine the efficacy of NIRS to detect acute changes in cerebral blood flow following PaCO2 fluctuations after confirming the autoregulation physiology in piglets. Fourteen piglets (<72 h of life) were studied. Mean arterial blood pressure, oxygen saturation, pH, glycemia, hemoglobin, electrolytes, and temperature were monitored. Eight animals were used to evaluate brain autoregulation, assessing superior cava vein Doppler as a proxy of cerebral blood flow changing mean arterial blood pressure. Another 6 animals were used to assess hypercapnia generated by decreasing ventilatory settings and complementary CO2 through the ventilator circuit and hypocapnia due to increasing ventilatory settings. Cerebral blood flow was determined by jugular vein blood flow by Doppler and continuously monitored with NIRS. A decrease in PaCO2 was observed after hyperventilation (47.6±2.4 to 29.0±4.9 mmHg). An increase in PaCO2 was observed after hypoventilation (48.5±5.5 to 90.4±25.1 mmHg). A decrease in cerebral blood flow after hyperventilation (21.8±10.4 to 15.1±11.0 mL/min) and an increase after hypoventilation (23.4±8.4 to 38.3±10.5 mL/min) were detected by Doppler ultrasound. A significant correlation was found between cerebral oxygenation and Doppler-derived parameters of blood flow and PaCO2. Although cerebral NIRS monitoring is mainly used to detect changes in regional brain oxygenation, modifications in cerebral blood flow following experimental PaCO2 changes were detected in newborn piglets when no other important variables were modified.
RESUMO
Meconium aspiration syndrome causes respiratory failure after birth and in vivo monitoring of pulmonary edema is difficult. The objective of the present study was to assess hemodynamic changes and edema measured by transcardiopulmonary thermodilution in low weight newborn piglets. Additionally, the effect of early administration of sildenafil (2 mg/kg vo, 30 min after meconium aspiration) on this critical parameter was determined in the meconium aspiration syndrome model. Thirty-eight mechanically ventilated anesthetized male piglets (Sus scrofa domestica) aged 12 to 72 h (1660 ± 192 g) received diluted fresh human meconium in the airway in order to evoke pulmonary hypertension (PHT). Extravascular lung water was measured in vivo with a PiCCO monitor and ex vivo by the gravimetric method, resulting in an overestimate of 3.5 ± 2.3 mL compared to the first measurement. A significant PHT of 15 Torr above basal pressure was observed, similar to that of severely affected humans, leading to an increase in ventilatory support. The vascular permeability index increased 57 percent, suggesting altered alveolocapillary membrane permeability. Histology revealed tissue vessel congestion and nonspecific chemical pneumonitis. A group of animals received sildenafil, which prevented the development of PHT and lung edema, as evaluated by in vivo monitoring. In summary, the transcardiopulmonary thermodilution method is a reliable tool for monitoring critical newborn changes, offering the opportunity to experimentally explore putative therapeutics in vivo. Sildenafil could be employed to prevent PHT and edema if used in the first stages of development of the disease.
Assuntos
Animais , Humanos , Recém-Nascido , Masculino , Água Extravascular Pulmonar/efeitos dos fármacos , Hipertensão Pulmonar/prevenção & controle , Síndrome de Aspiração de Mecônio/tratamento farmacológico , Piperazinas/administração & dosagem , Sulfonas/administração & dosagem , Vasodilatadores/uso terapêutico , Animais Recém-Nascidos , Modelos Animais de Doenças , Pulmão/efeitos dos fármacos , Pulmão/patologia , Síndrome de Aspiração de Mecônio/patologia , Purinas/administração & dosagem , Sus scrofa , Fatores de Tempo , Termodiluição/métodosRESUMO
Meconium aspiration syndrome causes respiratory failure after birth and in vivo monitoring of pulmonary edema is difficult. The objective of the present study was to assess hemodynamic changes and edema measured by transcardiopulmonary thermodilution in low weight newborn piglets. Additionally, the effect of early administration of sildenafil (2 mg/kg vo, 30 min after meconium aspiration) on this critical parameter was determined in the meconium aspiration syndrome model. Thirty-eight mechanically ventilated anesthetized male piglets (Sus scrofa domestica) aged 12 to 72 h (1660 ± 192 g) received diluted fresh human meconium in the airway in order to evoke pulmonary hypertension (PHT). Extravascular lung water was measured in vivo with a PiCCO monitor and ex vivo by the gravimetric method, resulting in an overestimate of 3.5 ± 2.3 mL compared to the first measurement. A significant PHT of 15 Torr above basal pressure was observed, similar to that of severely affected humans, leading to an increase in ventilatory support. The vascular permeability index increased 57%, suggesting altered alveolocapillary membrane permeability. Histology revealed tissue vessel congestion and nonspecific chemical pneumonitis. A group of animals received sildenafil, which prevented the development of PHT and lung edema, as evaluated by in vivo monitoring. In summary, the transcardiopulmonary thermodilution method is a reliable tool for monitoring critical newborn changes, offering the opportunity to experimentally explore putative therapeutics in vivo. Sildenafil could be employed to prevent PHT and edema if used in the first stages of development of the disease.
Assuntos
Água Extravascular Pulmonar/efeitos dos fármacos , Hipertensão Pulmonar/prevenção & controle , Síndrome de Aspiração de Mecônio/tratamento farmacológico , Piperazinas/administração & dosagem , Sulfonas/administração & dosagem , Vasodilatadores/uso terapêutico , Animais , Animais Recém-Nascidos , Modelos Animais de Doenças , Humanos , Recém-Nascido , Pulmão/efeitos dos fármacos , Pulmão/patologia , Masculino , Síndrome de Aspiração de Mecônio/patologia , Purinas/administração & dosagem , Citrato de Sildenafila , Sus scrofa , Termodiluição/métodos , Fatores de TempoAssuntos
Coleta de Dados , Revisão , Medicina , Métodos , Pesquisa , Estudos de Amostragem , EstatísticaRESUMO
A serological study was conducted to evaluate 3 variants of the positive hemagglutination technique (HA) with the use of formalized erythrocytes of fresh lamb (HC) and of formalized Type O, Rh-negative human red blood cells (HH). No significant statistical difference were found between the results of HA and HC and between HC and HH. Unspecific reaction was only observed in 2 of the 200 sera studied by HH and HC. Heterophil antibodies were just observed in 2.5% of the sera studied by HH, and in 100% of the sera studied by HC. The qualitative parameters were determined for the variants used, and this way the repetition and reproducibility of the most useful variant was evaluated.
Assuntos
Leptospirose/sangue , Leptospirose/diagnóstico , Testes de Hemaglutinação/métodos , Humanos , Reprodutibilidade dos TestesRESUMO
The effect of oronasopharyngeal suction (ONPS) on arterial oxygen saturation (SaO2) is described in a controlled study of 30 normal term newborn infants. In 15 of them, ONPS was performed immediately after birth. The SaO2 value was recorded through a pulse oximeter. The ONPS group had a significantly lower SaO2 between the first and the sixth minutes of life and took longer to reach 86% and 92% saturation. According to this study, ONPS should not be performed as a routine procedure in normal, term, vaginally born infants.
Assuntos
Parto Obstétrico/métodos , Recém-Nascido/sangue , Oxigênio/sangue , Sucção/efeitos adversos , Feminino , Sangue Fetal , Humanos , Masculino , Oximetria , GravidezRESUMO
Gestational age assessed by dorsal spine length (DSL) was compared with that based on date of the last menstrual period (LMP). This study was performed in 70 newborn infants admitted to a neonatal intensive care unit requiring chest radiography, by which dorsal spine length was measured (figure 1). Gestational age ranged from 23 to 42 weeks. Regression analysis were performed on DSL and gestational age. Estimation error was evaluated based on the percentage of agreement in weeks (validity) and the difference in averages between both methods (accuracy) (table I and figure 2). Variations during the first week of life were also studied and no significant differences were found. For infants born at 31 weeks or less, DSL overestimated gestational age in one week. There was no differences between 32 and 36 weeks, and over 37 weeks, underestimation was one week (figure 3). With this correction a table was built estimating gestational age for different DSL; percentage of agreement was 91.4% for +/- 3 weeks (table III). This methodology assists the clinician to evaluate gestational age by an objective method, that does not vary during the first week of life and that can be obtained retrospectively.
Assuntos
Idade Gestacional , Coluna Vertebral/anatomia & histologia , Desenvolvimento Embrionário e Fetal/fisiologia , Feminino , Retardo do Crescimento Fetal/patologia , Macrossomia Fetal/patologia , Humanos , Gravidez , Radiografia , Análise de Regressão , Coluna Vertebral/diagnóstico por imagem , Coluna Vertebral/embriologiaRESUMO
Impact of surfactant administration, on neonatal mortality, morbidity and resource use, was assayed in a historically controlled study in 19 NICUs from 5 Latin American countries. Data from clinical records of infants with HMD were retrospectively reviewed for the previous 2 years (PRE phase n = 666 cases), and prospectively in cases that received surfactant (SURF phase, 348 cases). Birth weight stratified relative risk, with 95% confidence interval (RR +/-95% CI) for death, in the SURF as compared to the PRE was 0.60 (0.49-0.74), 0.79 (0.68-0.92) and 0.82 (0.71-0.94), for days 7, 28 and at discharge, respectively. At all ages mortality was significantly lower during SURF. Significant increases were observed in the occurrence of pulmonary interstitial emphysema, pulmonary hemorrhage, patent ductus arteriosus, bronchopulmonary dysplasia, intrahospital infection and necrotizing enterocolitis. Resource use increased significantly. It is concluded that the use of surfactant in the region is an important advance, and the efficacy of management of the late complications of the very premature and labile HMD survivors must increase. More attention should be given to thermal regulation, nutrition and management of infection in the survivors, before a more marked effect of surfactant can be seen.
Assuntos
Álcoois Graxos/uso terapêutico , Doença da Membrana Hialina/tratamento farmacológico , Recém-Nascido Prematuro , Fosforilcolina , Polietilenoglicóis/uso terapêutico , Surfactantes Pulmonares/uso terapêutico , Peso ao Nascer , Combinação de Medicamentos , Álcoois Graxos/administração & dosagem , Feminino , Humanos , Doença da Membrana Hialina/mortalidade , Mortalidade Infantil , Recém-Nascido , Terapia Intensiva Neonatal , América Latina , Masculino , Polietilenoglicóis/administração & dosagem , Estudos Prospectivos , Surfactantes Pulmonares/administração & dosagem , Estudos RetrospectivosRESUMO
Growth and development were followed in 7 preterm newborn infants who received fluoroquinolones in the neonatal period. Quinolones were used as a "life saving" therapy in cases of sepsis caused by bacterial agents sensitive only to these drugs. Two other groups of neonates matched for gender, birth weight and gestational age served as controls. Although the quinolone group had more severe illness, no statistically significant differences were observed in growth and development between the groups. No osteoarticular problems or joint deformities were observed in the quinolone group. Therefore, quinolones could be a therapeutic option for newborns with sepsis caused by multiply resistant organisms.