Transxiphoid approach without median sternotomy for the repair of atrial septal defects

BACKGROUND: Interest in minimally invasive procedures has recently increased because it results in less surgical trauma, decreased patient discomfort, short hospital stay, reduced costs, and better cosmetic appearance. Based on these facts, we have been using the transxiphoid process approach without sternotomy for the correction of atrial septal defects. METHODS: From July 1996 to January 1997, the xiphoid process window approach was performed in 10 patients with ostium secundum atrial septal defect. Ages ranged from 6 months to 14 years (mean, 5.3 years). In all patients, extracorporeal circulation was carried out by means of cannulation of the femoral artery and both caval veins and of aortic cross-clamping. Videothoracoscopy was used to improve visualization of the aorta. RESULTS: There were no intraoperative or postoperative complications, and in all but 1 patient, extubation was possible while in the operating room. CONCLUSIONS: The xiphoid process window, with no median sternotomy, permitted closure of the atrial septal defects with good results and could be used as a less invasive technique for their correction.     

Pulsus paradoxus in childhood asthma--its prognostic value

One hundred asthmatic children were examined for pulsus paradoxus, a palpable diminution or obliteration of the peripheral pulse during inspiration, while in bronchospasm. Pulsus was measured with a sphygmomanometer and the difference in systolic pressure between inspiration and expiration was noted. Seventy-five children with mild asthma had no palpable pulsus and responded with complete subsidence of symptoms with one or two injections of aqueous epinephrine, 1-1000. Twenty-five children had palpable pulsus ranging from 10 mm to 30 mm. Five patients with pulsus between 10 and 15 mm were admitted to the hospital with status asthmaticus and pneumonia; eight other patients responded to parenteral epinephrine. Twelve children had pulsus of 20 mm or greater and all were hospitalized for uncomplicated status asthmaticus. Pulsus paradoxus may be found in acute exacerbation of childhood asthma and its degree correlates with both the severity and response to bronchodilating agents.     

A study of the transport and permeability properties of the guinea-pig amniotic membrane

1. The simultaneous measurement of the two-way sodium flux across the in vitro amniotic epithelium did not reveal a preferential active movement of sodium in either direction. The amnion is thus unlikely to be the site of formation of amniotic fluid. 2. The permeability of the amniotic epithelium to some non-electrolytes has been measured with isotopes and was found to be generally low in relation to the thinness of the tissue. The permeability to non-electroytes would appear to be depebility to sodium and to non-electrolytes was found to vary with gestational age. The amnion from animals of 61-70 days' gestation was markedly more permanent than those at 50-60 days (term 70 days).     

Strength increase in Ti 35 Wt Pct Nb through step-aging

The room temperature tensile properties of precipitation-hardened Ti?Nb alloys were correlated to the microstructure obtained by aging in the (α+β) phase field. Balanced strength properties with a flow stress of 100 ksi and an elongation to fracture of 4 pct were obtained by means of step aging. The distribution and size of the particles formed by step aging controlled the dislocation-particle interaction. The large α particles precipitated by first aging at 550°C imparted increased ductility while the smaller metastable particles precipitated by subsequent reaging at 400°C conferred a substantial increase in flow stress.     

Hemodialysis-associated hepatitis: report of an epidemic with further evidence on mechanisms of transmission

In the period January-September 1974, 50 cases of hepatitis B infection occurred among a nephrology center's hemodialysis patients and staff. The in-center patient population had an attack rate of 96%. Epidemiologic analysis of risk factors for patients revealed an association between the receipt of intravenous medication and the subsequent development of hepatitis, suggesting that parenteral inoculation was a mode of spread among patients (p equals .008). Nineteen per cent of the staff contracted hepatitis, and all of these personnel had had close contact with patients (p equals .005). The prevalence of hepatitis B infection in staff was related to the failure to use gloves (p less than .01), and accidental needle puncture was associated with the development of clinical hepatitis. These data suggested that disease was transmitted to staff by contact with contaminated blood or close personal contact with patients. Additional data showed that the presence of endogenous antibody protected both patients and staff from antigenemia (p equals .002). These data support the hypothesis that contact with blood is the primary mechanism of spread of hepatitis B in dialysis units, and suggest that, as preventive measures, gloves should be used and antibody-positive staff should dialyze antigen-positive patients.     

Strategies for the selection of log-linear models

In a multidimensional contingency table strategies have been proposed to build log-linear models using either stepwise methods or standardized estimates of the parameters of the saturated model. Brown (1976) proposed a two-step procedure to screen effects and then test a subset of models. Alternate methods of model building are discussed with respect to the final choice of model and with respect to intermediate information available to the data analyst during the selection process.