936 resultados para Respiratory Effort


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BACKGROUND: Cystic fibrosis (CF) is associated with the appearance of serum autoantibodies directed against bactericidal/permeability-increasing protein (BPI). OBJECTIVES: To determine the age-specific seroprevalence rates of anti-BPI-IgG and IgA in a population of patients with CF and to correlate anti-BPI antibody concentrations with microbial respiratory tract colonization and pulmonary function variables at the time of serum sampling and 6 years thereafter. METHODS: Determination of BPI antibodies of the IgG and IgA isotypes using a commercial enzyme-linked immunosorbent assay in sera of a CF serum bank of 1992; correlation of anti-BPI antibody concentrations with age, clinical score, pulmonary function variables in 1992 and 1998, total serum immunoglobulin isotype concentrations and respiratory tract colonization with Pseudomonas aeruginosa and Aspergillus spp. RESULTS: Seventy-one patients (age in 1992, 14.1 +/- 7.5 years) were studied. Reactivities for anti-BPI-IgG and IgA were found in 28 (39%) and 26 (37%) patients, respectively. The seroprevalence of anti-BPI-IgA, but not IgG, increased significantly with age. P. aeruginosa colonization was associated with elevated concentrations of anti-BPI-IgG (P = 0.003) and IgA (P = 0.037). There were significant negative correlations between pulmonary function variables (vital capacity, forced expiratory volume in 1 s) in 1992 and 1998, respectively, and concentrations of anti-BPI-IgG or IgA in a multiple regression analysis. Anti-BPI-IgG, but not IgA, remained significantly associated with P. aeruginosa colonization (P = 0.006) and with reduced vital capacity (P = 0.01) in 1998 after correction for total serum isotype concentration. CONCLUSIONS: Anti-BPI-IgG are strongly associated with concurrent P. aeruginosa colonization and with long term restrictive pulmonary function abnormalities.

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OBJECTIVE: Severe respiratory distress syndrome (RDS) caused by surfactant deficiency is described not only in preterm infants but also in (near-) term babies after caesarean section (CS), especially when carried out before the onset of labour. The aim of the present study was to document the severity of this theoretically avoidable entity in order to improve obstetric and perinatal care. PATIENTS: All neonates admitted to the paediatric intensive care unit of the University Hospital of Bern between 1988 and 2000 with RDS on the basis of hyaline membrane disease (HMD) needing mechanical ventilation (MV) after CS and with a birthweight > or = 2500 g were analysed. HMD was diagnosed when respiratory distress and the typical radiological signs were present. Patients were grouped into elective CS before onset of labour and before rupture of membranes (group 1, n = 34) and patients delivered by emergency CS or CS after onset of labour or rupture of membranes (group 2, n = 22). Analysed indices for severity of illness were duration of stay in intensive care unit and MV, ventilation mode, worst oxygenation index (OI), presence of pulmonary air leak, and systemic hypotension. RESULTS: Mean gestational age (GA) was 37 2/7 weeks in group 1 and 36 2/7 weeks in group 2; no patient had a GA of > or = 39 0/7 weeks. Duration of MV was 4.4 days in group 1 and 3.9 days in group 2. Thirteen patients (38%) of group 1 and 7 (32%) of group 2 had to be managed by rescue high-frequency ventilation. A total of 7 patients had an OI>40. Eight patients (24%) in group 1 and 4 (18%) in group 2 developed a pulmonary air leak. Fourteen neonates (41%) in group 1 had to be supported by catecholamines versus 5 (22%) in group 2. There was one death in group 1. CONCLUSION: Severe RDS on the basis of HMD can also occur in near-term babies after CS; even a fatal outcome can not be excluded. The severity of illness in elective CS without labour may be quite high and is comparable to newborns delivered by CS (after onset of labour and/or rupture of the membranes) who were 1 week younger. No case of HMD was found in our population when CS was carried out after completion of 39 post-menstrual weeks of gestation.

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Six full-term newborn infants are described who suffered from severe adult respiratory distress syndrome (ARDS). The triggering event was intrauterine/perinatal asphyxia in five, and group B streptococcal (GBS) septicemia in three. All had severe respiratory distress/failure and were ventilated mechanically with high concentrations of inspired oxygen and positive end-expiratory pressure. Radiography of the chest showed dense bilateral consolidation with air bronchograms and reduced lung volume. Persistent pulmonary hypertension (PPH) was documented in all cases. The coincidence of ARDS and PPH rendered respiratory management extremely difficult. For this reason high-frequency ventilation was instituted in all patients in order to improve CO2 elimination and induce respiratory alkalosis. Acute complications of respiratory therapy were encountered in five patients (pneumothorax, pulmonary interstitial emphysema, pneumopericardium). Three infants died (irreversible septic shock, progressive severe hypoxemia, and sudden cardiac arrest) after 17, 80, and 175 h of life. Histologic examination of the lungs was possible in all fatal cases and revealed typical changes of acute to subacute stages of ARDS. Three infants survived, the mean time of mechanical respiratory support being 703 h. Two patients were still dependent on oxygen after 1 month of life, and all survivors had increased interstitial markings and increased lung volumes on their chest roentgenograms at this time.

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CONTEXT: Thyroid transcription factor 1 (TITF1/NKX2.1) is expressed in the thyroid, lung, ventral forebrain, and pituitary. In the lung, TITF1/NKX2.1 activates the expression of genes critical for lung development and function. Titf/Nkx2.1(-/-) mice have pituitary and thyroid aplasia but also impairment of pulmonary branching. Humans with heterozygous TITF1/NKX2.1 mutations present with various combinations of primary hypothyroidism, respiratory distress, and neurological disorders. OBJECTIVE: The objective of the study was to report clinical and molecular studies of the first patient with lethal neonatal respiratory distress from a novel heterozygous TITF1/NKX2.1 mutation. Participant: This girl, the first child of healthy nonconsanguineous French-Canadian parents, was born at 41 wk. Birth weight was 3,460 g and Apgar scores were normal. Soon after birth, she developed acute respiratory failure with pulmonary hypertension. At neonatal screening on the second day of life, TSH was 31 mU/liter (N <15) and total T(4) 245 nmol/liter (N = 120-350). Despite mechanical ventilation, thyroxine, surfactant, and pulmonary vasodilators, the patient died on the 40th day. RESULTS: Histopathology revealed pulmonary tissue with low alveolar counts. The thyroid was normal. Sequencing of the patient's lymphocyte DNA revealed a novel heterozygous TITF1/NKX2.1 mutation (I207F). This mutation was not found in either parent. In vitro, the mutant TITF-1 had reduced DNA binding and transactivation capacity. CONCLUSION: This is the first reported case of a heterozygous TITF1/NKX2.1 mutation leading to neonatal death from respiratory failure. The association of severe unexplained respiratory distress in a term neonate with mild primary hypothyroidism is the clue that led to the diagnosis.

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Coronavirus NL63 has been identified as a new member of the coronavirus genus, but its role as a cause of respiratory disease needs to be established. We studied the first episode of lower respiratory tract symptoms in a cohort of healthy neonates. NL63 was identified in 6 (7%) of 82 cases and was as frequent as other coronaviruses (9%). NL63 was recovered at the onset of symptoms and was cleared within 3 weeks in half of the cases. Our data suggests that coronavirus NL63 causes lower respiratory tract symptoms and is acquired in early life.

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This study evaluated the response to increasing levels of neurally adjusted ventilatory assist (NAVA), a mode converting electrical activity of the diaphragm (EAdi) into pressure, regulated by a proportionality constant called the NAVA level. Fourteen rabbits were studied during baseline, resistive loading and ramp increases of the NAVA level. EAdi, airway (Paw) and esophageal pressure (Pes), Pes pressure time product (PTPes), breathing pattern, and blood gases were measured. Resistive loading increased PTPes and EAdi. P(a)(CO)(2) increased with high load but not during low load. Increasing NAVA levels increased Paw until a breakpoint where the Paw increase was reduced despite increasing NAVA level. At this breakpoint, Pes, PTPes, EAdi, and P(a)(CO)(2) were similar to baseline. Further increase of the NAVA level reduced Pes, PTPes and EAdi without changes in ventilation. In conclusion, observing the trend in Paw during a ramp increase of the NAVA level allows determination of a level where the inspiratory effort matches unloaded conditions.

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BACKGROUND: Stress-related hypercoagulability might link job stress with atherosclerosis. PURPOSE: This paper aims to study whether overcommitment, effort-reward imbalance, and the overcommitment by effort-reward imbalance interaction relate to an exaggerated procoagulant stress response. METHODS: We assessed job stress in 52 healthy teachers (49 +/- 8 years, 63% women) at study entry and, after a mean follow-up of 21 +/- 4 months, when they underwent an acute psychosocial stressor and had coagulation measures determined in plasma. In order to increase the reliability of job stress measures, entry and follow-up scores of overcommitment and of effort-reward imbalance were added up to total scores. RESULTS: During recovery from stress, elevated overcommitment correlated with D-dimer increase and with smaller fibrinogen decrease. In contrast, overcommitment was not associated with coagulation changes from pre-stress to immediately post-stress. Effort-reward imbalance and the interaction between overcommitment and effort-reward imbalance did not correlate with stress-induced changes in coagulation measures. CONCLUSIONS: Overcommitment predicted acute stress-induced hypercoagulability, particularly during the recovery period.

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In this paper we first show that the gains achievable by integrating pricing and inventory control are usually small for classical demand functions. We then introduce reference price models and demonstrate that for this class of demand functions the benefits of integration with inventory control are substantially increased due to the price dynamics. We also provide some analytical results for this more complex model. We thus conclude that integrated pricing/inventory models could repeat the success of revenue management in practice if reference price effects are included in the demand model and the properties of this new model are better understood.

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In this paper we analyze a dynamic agency problem where contracting parties do not know the agent's future productivity at the beginning of the relationship. We consider a two-period model where both the agent and the principal observe the agent's second-period productivity at the end of the first period. This observation is assumed to be non-verifiable information. We compare long-term contracts with short-term contracts with respect to their suitability to motivate effort in both periods. On the one hand, short-term contracts allow for a better fine-tuning of second-period incentives as they can be aligned with the agent's second-period productivity. On the other hand, in short-term contracts first-period effort incentives might be distorted as contracts have to be sequentially optimal. Hence, the difference between long-term and short-term contracts is characterized by a trade-off between inducing effort in the first and in the second period. We analyze the determinants of this trade-off and demonstrate its implications for performance measurement and information system design.

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Stenotrophomonas maltophilia (S. maltophilia) is a nonfermentative bacterium, which is naturally resistant against a panel of commonly-used antibiotics. It is frequently isolated from humans with chronic respiratory disease, e.g. cystic fibrosis or chronic obstructive pulmonary disease. In veterinary medicine S. maltophilia is perceived to be a mere coloniser. We herewith report 7 strains of S. maltophilia isolated from animals, of which 5 strains were harvested from 3 horses, a dog and a cat with chronic respiratory disease. The dog isolate showed resistance to trimethoprim / sulphamethoxazole, which was confirmed by detection of the sul 1 gene. Analysis with pulsed field gel electrophoresis revealed that 2 horses, which were boarded in the same clinic but two years apart, harboured the same strain of S. maltophilia. This is indicative of a hospital acquired colonisation / infection, which contradicts involvement in the pre-existing chronic disease.

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The frequency of PRRSV corresponding to live vaccines and wild-type was determined in 902 pigs from North-Western Germany submitted for post-mortem examination. Overall, 18.5% of the samples were positive for the EU wild-type virus. EU genotype vaccine virus was detected in 1.3% and the NA genotype vaccine virus in 8.9% of all samples. The detection of the EU vaccine was significantly higher in pigs vaccinated with the corresponding vaccine (OR=9.4). Pigs vaccinated with NA genotype had significantly higher detection chances for the corresponding vaccine virus when compared to non-vaccinated animals (OR=3.34) animals, however, NA vaccine was also frequently detected in non-vaccinated pigs. Concluding, the dynamics of NA genotype vaccine and EU wild-type virus corresponds with studies on PRRSV spread in endemically infected herds. The potential of spontaneous spread of the NA genotype vaccine should be considered in the planning of eradication programs.

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A retrospective study of 2,146 feedlot cattle in 17 feedlot tests from 1988 to 1997 was conducted to determine the impact of bovine respiratory disease (BRD) on veterinary treatment costs, average daily gain, carcass traits, mortality, and net profit. Morbidity caused by BRD was 20.6%. The average cost to treat each case of BRD was $12.39. Mortality rate of calves diagnosed and treated for BRD was 5.9% vs. .35% for those not diagnosed with BRD. Average daily gain differed between treated and non-treated steers during the first 28 days on feed but did not differ from 28 days to harvest. Net profit was $57.48 lower for treated steers. Eighty-two percent of this difference was due to a combination of mortality and treatment costs. Eighteen percent of the net profit difference was due to improved performance and carcass value of the non-treated steers. Data from 496 steers and heifers in nine feedlot tests were used to determine the effects of age, weaning, and use of modified live virus or killed vaccines prior to the test to predict BRD. Younger calves, non-weaned calves, and calves vaccinated with killed vaccines prior to the test had higher BRD morbidity than those that were older, weaned, or vaccinated with modified live virus vaccines, respectively. Treatment regimes that precluded relapse resulting in re-treatment prevented reduced performance and loss of carcass value. Using modified live virus vaccines and weaning calves 30 days prior to shipment reduced the incidence of BRD.

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Clinical respiratory disease occurs almost every year in fall calves in the McNay Farm herd. Diagnostic procedures have implicated Haemophilus somnus (H. somnus) and bovine respiratory syncyial virus (BRSV) as the infectious agents primarily associated with this disease. Therefore, the 1995 calves were closely monitored after weaning and during the course of a respiratory disease. Serologic evidence indicated the involvement of the same two agents in the pathogenesis of the disease. Also, experimental evidence suggested a role for a preexisting immediate hypersensitivity to H. somnus and the development of this type of response to BRSV. We theorize that the pathogenesis of the clinical disease involved infection with H. somnus, establishment of immediate hypersensitivity in the lungs, viral infection with associated pathologic lesions, and viral exacerbation of the immediate hypersensitivity reaction with resultant clinical signs and tissue damage.

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Switzerland is currently porcine reproductive and respiratory syndrome virus (PRRSV) free, but semen imports from PRRSV-infected European countries are increasing. As the virus can be transmitted via semen, for example, when a free boar stud becomes infected, and the risk of its import in terms of PRRSV introduction is unknown, the annual probability to accidentally import the virus into Switzerland was estimated in a risk assessment. A quantitative stochastic model was set up with data comprised by import figures of 2010, interviews with boar stud owners and expert opinion. It resulted in an annual median number of 0.18 imported ejaculates (= imported semen doses from one collection from one donor) from PRRSV-infected boars. Hence, one infected ejaculate would be imported every 6 years and infect a mean of 10 sows. These results suggest that under current circumstances, there is a substantial risk of PRRSV introduction into Switzerland via imported boar semen and that measures to enhance safety of imports should be taken. The time from infection of a previously negative boar stud to its detection had the highest impact on the number of imported 'positive' ejaculates. Therefore, emphasis should be placed on PRRSV monitoring protocols in boar studs. Results indicated that a substantial increase in safety could only be achieved with much tighter sampling protocols than currently performed. Generally, the model could easily be customized for other applications like other countries or regions or even sow farms that want to estimate their risk when purchasing semen from a particular boar stud.

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Background Molecular methods based on phylogenetic differences in the 16S rRNA gene are able to characterise the microbiota of the respiratory tract in health and disease. Objectives Our goals were (1) to characterise bacterial communities in lower and upper airways of patients with interstitial lung disease (ILD) and (2) to compare the results with the microbiota of patients with Pneumocystis pneumonia (PCP) and normal controls. Methods We examined the upper and lower respiratory tract of 18 patients with ILD of whom 5, 6, and 7 had idiopathic interstitial pneumonia (IIP), non-IIP and sarcoidosis, respectively. In addition, six immune-compromised patients with PCP and nine healthy subjects were included as controls. Exclusion criteria were recent bacterial/viral respiratory tract infection, HIV-positivity and subjects receiving antibiotic therapy. Bronchoalveolar lavage fluid and oropharyngeal swabs were simultaneously collected, and microbiota was characterised by ultra-deep 16S rRNA gene sequencing. Results The microbiota in lower airways of the majority of patients (30; 90%) primarily consisted of Prevotellaceae, Streptococcaceae and Acidaminococcaceae. α and β diversity measurements revealed no significant differences in airway microbiota composition between the five different groups of patients. Comparison of bacterial populations in upper and lower respiratory tract showed significant topographical discontinuities for 7 (23%) individuals. Conclusions IIP, non-IIP and sarcoidosis are not associated with disordered airway microbiota and a pathogenic role of commensals in the disease process is therefore unlikely. Nevertheless, molecular analysis of the topographical microbiota continuity along the respiratory tract may provide additional information to assist management of individual patients.