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1.
Carbohydr Polym ; 165: 229-237, 2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28363545

RESUMO

Certain lipophilic components can be inserted very efficiently as guest molecule in the existing single helical amylose cavities in VH-type crystalline granular cold-water swelling starch (GCWSS). In the present study, ascorbyl palmitate (AscP) was used as a model guest compound. The impacts of temperature (20 and 60°C) and ethanol [48 and 68% (v/v)] and AscP [1.0, 2.5, 5.0, 10.0% (w/w)] concentrations on encapsulation performance were investigated. First, native maize and potato starches were converted into VH-type GCWSS by aqueous ethanol [48% (v/v)] treatment at 95°C. Exposing GCWSS to AscP induced the formation of inclusion complexes when a particular solvent (and temperature) environment was met. In 48% (v/v) ethanol, raising the treatment temperature to 60°C did not significantly impact on the encapsulation performance. Maximum degrees of AscP encapsulation were 2.9 and 1.5% (w/w) for maize and potato starch, respectively, as determined by proton nuclear magnetic resonance measurements. As maize GCWSS contained more 'parent' VH-type crystals, it was capable of entrapping more AscP than potato GCWSS.

2.
Carbohydr Polym ; 165: 402-409, 2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28363566

RESUMO

This study reports on the functionality of V-type crystalline granular cold-water swelling starch (GCWSS) in complex with lipid (functionalized) molecules. Maize and potato GCWSS contain (empty) single helical amylose (AM) crystals which can serve as lipid complexing matrices. Different concentrations of ascorbyl palmitate (AscP) were inserted in the hydrophobic cavities of the GCWSS AM helices by a low temperature infusion method. Volumetric particle size distributions of the ensuing products in water were determined using laser light scattering. Upon contact with water, the parent maize GCWSS formed lumps more than did the parent potato GCWSS. It is hypothesized that variations in the spatial distribution of cold-water soluble V-type crystals are at the origin of this difference. In contrast, GCWSS-AscP inclusion complexes formed homogenous dispersions in water. Furthermore, the impact of inclusion complex formation on cold-water swelling properties was investigated. The close packing concentration increased and the swelling power and carbohydrate leaching decreased when the level of encapsulated AscP increased. Finally, in a Trolox equivalent antioxidant capacity test, encapsulated AscP still had up to 70% of the antioxidant capacity of free AscP.


Assuntos
Ácido Ascórbico/análogos & derivados , Ácido Ascórbico/química , Amido/química , Amilose , Antioxidantes/química , Temperatura Baixa , Solanum tuberosum/química , Água , Zea mays/química
3.
J Clin Monit Comput ; 31(4): 783-791, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27438965

RESUMO

The stress index (SI) is a parameter that characterizes the shape of the airway pressure-time profile (P/t). It indicates the slope progression of the curve, reflecting both lung and chest wall properties. The presence of pleural effusion alters the mechanical properties of the respiratory system decreasing transpulmonary pressure (Ptp). We investigated whether the SI computed using Ptp tracing would provide reliable insight into tidal recruitment/overdistention during the tidal cycle in the presence of unilateral effusion. Unilateral pleural effusion was simulated in anesthetized, mechanically ventilated pigs. Respiratory system mechanics and thoracic computed tomography (CT) were studied to assess P/t curve shape and changes in global lung aeration. SI derived from airway pressure (Paw) was compared with that calculated by Ptp under the same conditions. These results were themselves compared with quantitative CT analysis as a gold standard for tidal recruitment/hyperinflation. Despite marked changes in tidal recruitment, mean values of SI computed either from Paw or Ptp were remarkably insensitive to variations of PEEP or condition. After the instillation of effusion, SI indicates a preponderant over-distension effect, not detected by CT. After the increment in PEEP level, the extent of CT-determined tidal recruitment suggest a huge recruitment effect of PEEP as reflected by lung compliance. Both SI in this case were unaffected. We showed that the ability of SI to predict tidal recruitment and overdistension was significantly reduced in a model of altered chest wall-lung relationship, even if the parameter was computed from the Ptp curve profile.


Assuntos
Complacência Pulmonar , Pulmão/fisiopatologia , Derrame Pleural/fisiopatologia , Volume de Ventilação Pulmonar , Animais , Expiração , Feminino , Pulmão/diagnóstico por imagem , Medidas de Volume Pulmonar , Derrame Pleural/diagnóstico por imagem , Respiração com Pressão Positiva , Pressão , Radiografia Torácica , Reprodutibilidade dos Testes , Respiração Artificial , Mecânica Respiratória , Estresse Mecânico , Suínos , Tomografia Computadorizada por Raios X
4.
Carbohydr Polym ; 114: 196-205, 2014 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-25263882

RESUMO

Native maize starch was gradually converted into granular cold-water swelling starch (GCWSS) by aqueous ethanol treatments at elevated temperatures. At a treatment temperature of 95°C, decreasing ethanol concentrations from 68 to 48% (v/v) led to decreased post-treatment gelatinization enthalpies in excess water, reflecting remaining original A-type crystals. Concomitantly to native A-type crystal melting, VH-type crystals appeared. At an ethanol concentration of 48%, a granular cold-water swelling maize starch was successfully produced. All crystals in its intact granules were of the VH-type and appeared birefringent when studied in ethanol under polarized light. Removal of all residual solvent by high temperature drying did not influence swelling power, proving that a high temperature drying step is not necessary to induce cold-water swelling capacity. Based on in situ calorimetric measurements, the thermal requirements to produce GCWSS from different ethanol:water mixtures were elucidated. This work is the first to demonstrate that the amylose fraction contributes almost exclusively to VH-type crystal formation in GCWSS.


Assuntos
Amido/química , Água/química , Zea mays/química , Temperatura
5.
Transfus Med ; 24(3): 162-8, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24372790

RESUMO

OBJECTIVES: To review outcomes of massive transfusion protocol (MTP) activation and determine the impact of MTP implementation on blood bank use. BACKGROUND: MTP has been established to rapidly provide plasma and packed red blood cells in ratios approaching 1 : 1. Due to availability, MTP has been utilised in non-traumatic haemorrhage despite evidence of benefit in this population. Our hospital-wide implementation of MTP was reviewed for propriety, outcomes and effect on blood bank resources. METHODS: Retrospective cohort study of patients receiving transfusion after MTP activation from October 2009 to 2011. Underlying medical conditions and baseline medication use were determined. In-hospital and 24-h mortality were compared with evaluation for confounding by Acute Physiology And Chronic Health Evaluation (APACHE) score and duration of MTP activation. Blood product use before and after MTP implementation was reviewed. RESULTS: MTP activation occurred in 62 trauma and 63 non-trauma patients. Non-trauma patients were older, had more underlying medical conditions and higher APACHE scores compared with trauma patients; 24-h mortality was higher in trauma compared with non-trauma patients (27·4 vs 11·1%, P = 0·02). There was no significant difference of in-hospital mortality. Transfusion ratio did not differ between trauma and non-trauma patients and was not associated with mortality even when MTP activation duration and APACHE score were considered. Hospital-wide blood product use did not change with MTP implementation. CONCLUSIONS: MTP may be successfully used in trauma and non-trauma settings without significantly impacting overall blood product utilisation. Inclusion of non-trauma patients into prospective studies of resuscitation with blood products is warranted to ensure benefit in these patients.


Assuntos
Bancos de Sangue/normas , Transfusão de Sangue/métodos , Fidelidade a Diretrizes , Hemorragia/terapia , Bancos de Sangue/organização & administração , Hospitais , Humanos , Masculino , Guias de Prática Clínica como Assunto , Ferimentos e Lesões , Armazenamento de Sangue/métodos
6.
Phys Rev Lett ; 102(9): 090402, 2009 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-19392500

RESUMO

We use a Feshbach resonance to tune the scattering length a of a Bose-Einstein condensate of 7Li in the |F=1,mF=1> state. Using the spatial extent of the trapped condensate, we extract a over a range spanning 7 decades from small attractive interactions to extremely strong repulsive interactions. The shallow zero crossing in the wing of the Feshbach resonance enables the determination of a as small as 0.01 Bohr radii. Evidence of the weak anisotropic magnetic dipole interaction is obtained by comparison with different trap geometries for small a.

7.
Phys Rev Lett ; 101(6): 060406, 2008 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-18764443

RESUMO

We measure the effect of a magnetic Feshbach resonance (FR) on the rate and light-induced frequency shift of a photoassociation resonance in ultracold 7Li. The photoassociation-induced loss-rate coefficient K_{p} depends strongly on magnetic field, varying by more than a factor of 10;{4} for fields near the FR. At sufficiently high laser intensities, K_{p} for a thermal gas decreases with increasing intensity, while saturation is observed for the first time in a Bose-Einstein condensate. The frequency shift is also strongly field dependent and exhibits an anomalous blueshift for fields just below the FR.

9.
Am Heart J ; 142(4): 714-9, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11579364

RESUMO

BACKGROUND: Patients with decompensated chronic heart failure (CHF) are frequently evaluated in emergency departments (ED). The outcomes of such patients after discharge to the outpatient setting from the ED are not well known. Risk factors for return ED visits or subsequent hospital admission after ED discharge for CHF also are not known. METHODS: Charts were reviewed from all 112 patients discharged from the Parkland Memorial Hospital ED with a primary diagnosis of CHF from October to December 1998. A composite end point ("failure of outpatient therapy") was prespecified to be a recurrent ED visit for CHF, hospitalization for CHF, or death at 3 months after the index ED discharge. RESULTS: Within 3 months of the index ED visit, 61% of the study population met the composite end point. The median time to failure of outpatient therapy was 30 days. Univariate analysis of 27 clinical and demographic variables demonstrated the respiratory rate at presentation as the only predictor of failure of outpatient therapy (P =.02). Multivariate analysis of a model with 8 prespecified variables also demonstrated respiratory rate to be the only variable independently associated with an increased risk for the composite end point (odds ratio 1.6, 95% confidence interval 1.1-2.6, for each increase of 5 breaths/min). CONCLUSION: There is a high rate of failure of outpatient therapy (61%) in patients discharged with a primary diagnosis of CHF from an urban county hospital ED. Increased respiratory rate on presentation to the ED may be associated with adverse outcomes after ED discharge for CHF.


Assuntos
Serviço Hospitalar de Emergência/estatística & dados numéricos , Insuficiência Cardíaca/diagnóstico , Alta do Paciente/estatística & dados numéricos , Assistência Ambulatorial , Insuficiência Cardíaca/terapia , Hospitalização , Humanos , Readmissão do Paciente , Respiração , Falha de Tratamento , Resultado do Tratamento
10.
Air Med J ; 20(5): 35-7, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11552111

RESUMO

As first reported by Brain(1) by the early 1980s, the laryngeal mask airway (LMA) represented a new approach to airway management. The LMA has been used to facilitate tracheal intubation by a variety of methods. In fact, the LMA has been used to intubate the patient with difficult tracheal access. A recent addition to this technique, the intubating laryngeal mask airway (ILMA), shown in Figure 1, first was proposed by Brain and coworkers in 1995.(1,2) Fig. 1. Components of the intubating laryngeal mask airway. An endotracheal tube may be passed through the airway tube. The ILMA incorporates the standard LMA cuff in sizes 3, 4, or 5, along with a metal airway tube and handle. The handle allows users to manipulate the device within the patient's airway. The airway tube component has a wider internal diameter and is shorter than the standard LMA tube. A silicone rubber bite block surrounds the upper portion of the stem.


Assuntos
Tratamento de Emergência , Máscaras Laríngeas , Humanos , Máscaras Laríngeas/normas , Estados Unidos
11.
N Engl J Med ; 345(8): 574-81, 2001 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-11529211

RESUMO

BACKGROUND: The independent prognostic value of elevated jugular venous pressure or a third heart sound in patients with heart failure is not well established. METHODS: We performed a retrospective analysis of the Studies of Left Ventricular Dysfunction treatment trial, in which 2569 patients with symptomatic heart failure or a history of it were randomly assigned to receive enalapril or placebo. The mean (+/-SD) follow-up was 32+/-15 months. The presence of elevated jugular venous pressure or a third heart sound was ascertained by physical examination on entry into the trial. The risks of hospitalization for heart failure and progression of heart failure as defined by death from pump failure and the composite end point of death or hospitalization for heart failure were compared in patients with these findings on physical examination and patients without these findings. RESULTS: Data on 2479 patients were complete and analyzed. In multivariate analyses that were adjusted for other markers of the severity of heart failure, elevated jugular venous pressure was associated with an increased risk of hospitalization for heart failure (relative risk, 1.32; 95 percent confidence interval, 1.08 to 1.62; P<0.01), death or hospitalization for heart failure (relative risk, 1.30; 95 percent confidence interval, 1.11 to 1.53; P<0.005), and death from pump failure (relative risk, 1.37; 95 percent confidence interval, 1.07 to 1.75; P<0.05). The presence of a third heart sound was associated with similarly increased risks of these outcomes. CONCLUSIONS: In patients with heart failure, elevated jugular venous pressure and a third heart sound are each independently associated with adverse outcomes, including progression of heart failure. Clinical assessment for these findings is currently feasible and clinically meaningful.


Assuntos
Insuficiência Cardíaca/fisiopatologia , Ruídos Cardíacos , Veias Jugulares/fisiologia , Pressão Venosa , Idoso , Análise de Variância , Progressão da Doença , Intervalo Livre de Doença , Feminino , Insuficiência Cardíaca/classificação , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/mortalidade , Hospitalização/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Exame Físico , Prognóstico , Ensaios Clínicos Controlados Aleatórios como Assunto , Estudos Retrospectivos , Índice de Gravidade de Doença
13.
J Am Coll Cardiol ; 38(2): 421-8, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11499733

RESUMO

OBJECTIVES: We sought to determine the relative impact of diabetes mellitus on prognosis in ischemic compared with nonischemic cardiomyopathy. BACKGROUND: Ischemic myocardium is characterized by increased reliance on aerobic and anaerobic glycolysis. Because glucose utilization by cardiomyocytes is an insulin-mediated process, we hypothesized that diabetes would have a more adverse impact on mortality and progression of heart failure in ischemic compared with nonischemic cardiomyopathy. METHODS: We performed a retrospective analysis of the Studies Of Left Ventricular Dysfunction (SOLVD) Prevention and Treatment trials. RESULTS: In adjusted analyses, diabetes mellitus was strongly associated with an increased risk for all-cause mortality in patients with ischemic cardiomyopathy, (relative risk [RR] 1.37, 95% confidence interval [CI] 1.21 to 1.55; p < 0.0001), but not in those with nonischemic cardiomyopathy (RR 0.98, 95% CI 0.76 to 1.32; p = 0.98). The increased mortality in patients with ischemic cardiomyopathy compared with nonischemic cardiomyopathy was limited to those with ischemic cardiomyopathy and diabetes mellitus (RR 1.37, 95% CI 1.21 to 1.56; p < 0.0001). When patients with ischemic cardiomyopathy and diabetes mellitus were excluded, there was no significant difference in mortality risk between the ischemic and nonischemic cardiomyopathy groups after adjusted analysis (RR 0.99, 95% CI 0.86 to 1.15; p = 0.99). Previous surgical revascularization identified patients within the cohort with ischemic cardiomyopathy and diabetes mellitus, with improved prognosis. CONCLUSIONS: The differential impact of diabetes on mortality and heart failure progression according to the etiology of heart failure suggests that diabetes and ischemic heart disease interact to accelerate the progression of myocardial dysfunction. Evaluation of the potential for revascularization may be particularly important in patients with ischemic cardiomyopathy and diabetes mellitus.


Assuntos
Complicações do Diabetes , Insuficiência Cardíaca/mortalidade , Isquemia Miocárdica/mortalidade , Disfunção Ventricular Esquerda/etiologia , Disfunção Ventricular Esquerda/mortalidade , Estudos de Coortes , Ponte de Artéria Coronária/mortalidade , Feminino , Insuficiência Cardíaca/complicações , Insuficiência Cardíaca/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Isquemia Miocárdica/complicações , Isquemia Miocárdica/cirurgia , Prognóstico , Estudos Retrospectivos , Fatores de Risco , Taxa de Sobrevida , Sístole , Disfunção Ventricular Esquerda/complicações
14.
J Burn Care Rehabil ; 22(3): 203-9, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11403241

RESUMO

Neutrophil recruitment to the lung after thermal injury has been reported by various laboratories. Changes in neutrophil populations in the gut and lung have not been examined simultaneously after burn injury. Mice aged 8 to 10 weeks were anesthetized and subjected to 15% topical scald injury. Animals were sacrificed at 30 minutes and 1, 2, 4, 8, 16, and 32 hours after injury with harvesting of terminal ileum and lung for myeloperoxidase (MPO) assay. Lungs were evaluated after bronchoalveolar lavage and lavage of the vascular bed to remove neutrophils in these compartments. Myeloperoxidase activity was compared between groups of sham-injured and burned animals. Although pulmonary neutrophil recruitment was obvious after scald burn; in the ileum, burned animals showed diminished MPO activity. Histology and bronchoalveolar lavage revealed no evidence of gross organ injury apart from obvious changes in cellular content in the lung. Thermal injury is associated with differential neutrophil movement in the lung and the gut in this model. Pulmonary neutrophil recruitment is confirmed, whereas the gut seems to lose neutrophils as indicated by diminished MPO activity in the initial hours after dorsal scald injury.


Assuntos
Queimaduras/fisiopatologia , Sistema Digestório/fisiopatologia , Pulmão/fisiopatologia , Neutrófilos , Pele/lesões , Animais , Líquido da Lavagem Broncoalveolar/citologia , Citocinas/metabolismo , Modelos Animais de Doenças , Masculino , Camundongos , Peroxidase/metabolismo
15.
N Engl J Med ; 344(18): 1351-7, 2001 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-11333991

RESUMO

BACKGROUND: Black patients with heart failure have a poorer prognosis than white patients, a difference that has not been adequately explained. Whether racial differences in the response to drug treatment contribute to differences in outcome is unclear. To address this issue, we pooled and analyzed data from the Studies of Left Ventricular Dysfunction (SOLVD) prevention and treatment trials, two large, randomized trials comparing enalapril with placebo in patients with left ventricular dysfunction. METHODS: We used a matched-cohort design in which up to four white patients were matched with each black patient according to trial, treatment assignment, sex, left ventricular ejection fraction, and age. A total of 1196 white patients (580 from the prevention trial and 616 from the treatment trial) were matched with 800 black patients (404 from the prevention trial and 396 from the treatment trial). The average duration of follow-up was 35 months in the prevention trial and 33 months in the treatment trial. RESULTS: The black patients and the matched white patients had similar demographic and clinical characteristics, but the black patients had higher rates of death from any cause (12.2 vs. 9.7 per 100 person-years) and of hospitalization for heart failure (13.2 vs. 7.7 per 100 person-years). Despite similar doses of drug in the two groups, enalapril therapy, as compared with placebo, was associated with a 44 percent reduction (95 percent confidence interval, 27 to 57 percent) in the risk of hospitalization for heart failure among the white patients (P<0.001) but with no significant reduction among black patients (P=0.74). At one year, enalapril therapy was associated with significant reductions from base line in systolic blood pressure (by a mean [+/-SD] of 5.0+/-17.1 mm Hg) and diastolic blood pressure (3.6+/-10.6 mm Hg) among the white patients, but not among the black patients. No significant change in the risk of death was observed in association with enalapril therapy in either group. CONCLUSIONS: Enalapril therapy is associated with a significant reduction in the risk of hospitalization for heart failure among white patients with left ventricular dysfunction, but not among similar black patients. This finding underscores the need for additional research on the efficacy of therapies for heart failure in black patients.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , População Negra , Enalapril/uso terapêutico , Insuficiência Cardíaca/tratamento farmacológico , Insuficiência Cardíaca/etnologia , Disfunção Ventricular Esquerda/tratamento farmacológico , População Branca , Adulto , Idoso , Estudos de Coortes , Feminino , Insuficiência Cardíaca/prevenção & controle , Hospitalização/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Mortalidade , Ensaios Clínicos Controlados Aleatórios como Assunto , Volume Sistólico , Resultado do Tratamento , Disfunção Ventricular Esquerda/etnologia , Disfunção Ventricular Esquerda/prevenção & controle
16.
J Trauma ; 50(2): 289-96, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11242294

RESUMO

OBJECTIVE: The purpose of this study was to define the period of time after which delays in management incurred by investigations cause increased morbidity and mortality. The outcome study is intended to correlate time with death from esophageal causes, overall complications, esophageal related complications, and surgical intensive care unit length of stay. METHODS: This was a retrospective multicenter study involving 34 trauma centers in the United States, under the auspices of the American Association for the Surgery of Trauma Multi-institutional Trials Committee over a span of 10.5 years. Patients surviving to reach the operating room (OR) were divided into two groups: those that underwent diagnostic studies to identify their injuries (preoperative evaluation group) and those that went immediately to the OR (no preoperative evaluation group). Statistical methods included Fisher's exact test, Student's T test, and logistic regression analysis. RESULTS: The study involved 405 patients: 355 male patients (86.5%) and 50 female patients (13.5%). The mean Revised Trauma Score was 6.3, the mean Injury Severity Score was 28, and the mean time interval to the OR was 6.5 hours. There were associated injuries in 356 patients (88%), and an overall complication rate of 53.5%. Overall mortality was 78 of 405 (19%). Three hundred forty-six patients survived to reach the OR: 171 in the preoperative evaluation group and 175 in the no preoperative evaluation group. No statistically significant differences were noted in the two groups in the following parameters: number of patients, age, Injury Severity Score, admission blood pressure, anatomic location of injury (cervical or thoracic), surgical management (primary repair, resection and anastomosis, resection and diversion, flaps), number of associated injuries, and mortality. Average length of time to the OR was 13 hours in the preoperative evaluation group versus 1 hour in the no preoperative evaluation group (p < 0.001). Overall complications occurred in 134 in the preoperative evaluation group versus 87 in the no preoperative evaluation group (p < 0.001), and 74 (41%) esophageal related complications occurred in the preoperative evaluation group versus 32 (19%) in the no preoperative evaluation group (p = 0.003). Mean surgical intensive care unit length of stay was 11 days in the preoperative evaluation group versus 7 days in the no preoperative evaluation group (p = 0.012). Logistic regression analysis identified as independent risk factors for the development of esophageal related complications included time delays in preoperative evaluation (odds ratio, 3.13), American Association for the Surgery of Trauma Organ Injury Scale grade >2 (odds ratio, 2.62), and resection and diversion (odds ratio, 4.47). CONCLUSION: Esophageal injuries carry a high morbidity and mortality. Increased esophageal related morbidity occurs with the diagnostic workup and its inherent delay in operative repair of these injuries. For centers practicing selective management of penetrating neck injuries and transmediastinal gunshot wounds, rapid diagnosis and definitive repair should be made a high priority.


Assuntos
Esôfago/lesões , Ferimentos Penetrantes/mortalidade , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Humanos , Tempo de Internação , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Lesões do Pescoço/mortalidade , Estudos Retrospectivos , Fatores de Risco , Ferimentos por Arma de Fogo/mortalidade , Ferimentos Perfurantes/mortalidade
17.
Am J Respir Crit Care Med ; 163(2): 374-8, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11179109

RESUMO

Acute noninvasive ventilation is generally applied via face mask, with modified pressure support used as the initial mode to assist ventilation. Although an adequate seal can usually be obtained, leaks frequently develop between the mask and the patient's face. This leakage presents a theoretical problem, since the inspiratory phase of pressure support terminates when flow falls to a predetermined fraction of peak inspiratory flow. To explore the issue of mask leakage and machine performance, we used a mathematical model to investigate the dynamic behavior of pressure-supported noninvasive ventilation, and confirmed the predicted behavior through use of a test lung. Our mathematical and laboratory analyses indicate that even when subject effort is unvarying, pressure-support ventilation applied in the presence of an inspiratory leak proximal to the airway opening can be accompanied by marked variations in duration of the inspiratory phase and in autoPEEP. The unstable behavior was observed in the simplest plausible mathematical models, and occurred at impedance values and ventilator settings that are clinically realistic.


Assuntos
Cuidados Críticos , Dinâmica não Linear , Respiração com Pressão Positiva/instrumentação , Análise de Falha de Equipamento , Humanos , Máscaras , Modelos Teóricos
19.
Biol Neonate ; 78(4): 308-14, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11093012

RESUMO

Gram-negative sepsis and septic shock remain major causes of morbidity and mortality in the newborn. Respiratory failure is a common feature in neonatal sepsis regardless of the presence or absence of associated pneumonia. In adult animal models, cytokine-induced neutrophil chemoattractant (CINC) is a potent chemoattractant for neutrophils and believed to play a role in endotoxin-induced lung injury. We examined this in a neonatal model. Ten-day-old Sprague-Dawley rats were injected with Salmonella enteritidis endotoxin (ETX) 0.03 mg/kg i.p. and sacrificed at baseline, 30 min, 1, 2, 4, 8 and 16 h post-ETX. Blood was collected by cardiac puncture. After bronchoalveolar lavage, lung tissue was collected and evaluated for neutrophil (polymorphonuclear leukocyte) recruitment by myeloperoxidase assay (MPO). Lung CINC expression was measured by Northern blot and ELISA. Peripheral blood leukocytosis was noted at 1 h (p < 0.001) with counts below baseline at 2 and 4 h. Differential counts revealed neutrophilia at 8 h (p < 0.001). MPO revealed pulmonary PMN recruitment peaking at 1 h (p < 0.05) and CINC RNA and protein expression peaked slightly later at 2 h (p < 0. 001). No overt lung injury was noted by bronchoalveolar lavage cell counts or by histology. Therefore, pulmonary CINC expression and neutrophil recruitment follows LPS exposure in neonatal rats. This may represent priming of the lung tissue and a secondary event may be necessary for injury to occur.


Assuntos
Quimiocinas CXC , Fatores Quimiotáticos/genética , Endotoxemia/metabolismo , Expressão Gênica , Substâncias de Crescimento/genética , Peptídeos e Proteínas de Sinalização Intercelular , Pulmão/metabolismo , Neutrófilos/patologia , Animais , Northern Blotting , Fatores Quimiotáticos/análise , Endotoxemia/patologia , Ensaio de Imunoadsorção Enzimática , Substâncias de Crescimento/análise , Contagem de Leucócitos , Pulmão/química , Pneumopatias/etiologia , Pneumopatias/patologia , Peroxidase/metabolismo , RNA Mensageiro/análise , Ratos , Ratos Sprague-Dawley , Salmonella enteritidis
20.
Air Med J ; 19(2): 38-46, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11010375

RESUMO

The revised guidelines for advanced cardiac life support (ACLS) from the American Heart Association are anticipated in the fall of 2000. Although dramatic changes in the approach to adult basic and ACLS are not anticipated, several controversies and new drugs on the horizon may radically change our approach to emergent cardiac resuscitation. This article features some of the evolving thinking on the emergent treatment of the adult with ventricular fibrillation or ventricular tachycardia, the critical rhythms seen in most cases of acute cardiac distress. Approaches to airway therapy drug administration and new agents also are described.


Assuntos
Reanimação Cardiopulmonar/métodos , Cuidados para Prolongar a Vida/métodos , Taquicardia Ventricular/terapia , Fibrilação Ventricular/terapia , Adulto , Antiarrítmicos/administração & dosagem , Reanimação Cardiopulmonar/tendências , Sistemas de Liberação de Medicamentos , Cardioversão Elétrica , Humanos , Intubação Intratraqueal , Cuidados para Prolongar a Vida/tendências
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