Exercise-induced bronchoconstriction assessed by a ratio of surface diaphragm EMG to tidal volume.

Exercise-induced bronchoconstriction (EIB) is usually assessed by changes in forced expiratory volume in 1 s (FEV1 ) which is effort dependent. The purpose of this study was to determine whether the diaphragm electromyogram (EMGdi ) recorded from chest wall surface electrodes could be used to reflect changes in airway resistance during an exercise challenge test and to distinguish patients with EIB from those without EIB. Ninety participants with or without asthma history were included in the study. FEV1 was recorded before and 5, 10, 15, and 20 min after exercise. EIB was defined as an FEV1 decline greater than 10% after exercise. A ratio of root mean square of EMGdi to tidal volume (EMGdi /VT ) was used to assess changes in airway resistance. Based on changes in FEV1 , 25 of 90 participants exhibited EIB; the remainder were defined as non-EIB participants. EMGdi /VT in EIB increased by 124% (19%-478%) which was significantly higher than that of 21% (-39% to 134%) in non-EIB participants (p < 0.001). At the optimal cutoff point (54% in EMGdi /VT ), the area under the ROC curve (AUC) for detection of a positive test was 0.92 (p < 0.001) with sensitivity 92% and specificity 88%. EMGdi /VT can be used to assess changes in airway resistance after exercise and could be used to distinguish participants with EIB from those without EIB.

Application of nomograms to predict overall and cancer-specific survival in patients with chordoma.

BACKGROUND: The survival prediction of patients with chordoma is difficult to make due to the rarity of this oncologic disease. Our objective was to apply a nomogram to predict survival outcomes in individuals with chordoma of the skull base, vertebral column, and pelvis. METHODS: A total of 558 patients with chordoma between 1973 and 2014 were collected from the Surveillance, Epidemiology, and End Results (SEER) database. Independent prognostic factors in patients with chordoma were identified via univariate and multivariate Cox analysis. Then these prognostic factors were incorporated into a nomogram to predict 3- and 5-year overall survival and cancer-specific survival rates. Internal and external data were used to validate the nomograms. Concordance indices (C-indices) were used to estimate the accuracy of this nomogram system. RESULTS: A total of 558 patients were randomly assigned into a training cohort (n = 372) and a validation cohort (n = 186). Age, surgical stage, tumor size, histology, primary site, and use of surgery were identified as independent prognostic factors via univariate and multivariate Cox analysis (all p < 0.05) and further included to establish the nomogram. The C-indices for overall survival and cancer-specific survival prediction of the training cohort were 0.775 (95% confidence interval, 0.770-0.779) and 0.756 (95% confidence interval, 0.749 -0.762). The calibration plots both showed an excellent consistency between actual survival and nomogram prediction. CONCLUSION: Nomograms were constructed to predict overall survival and cancer-specific survival for patients with chordoma of the skull base, vertebral column, and pelvis. The nomogram could help surgeons to identify high risk of mortality and evaluate prognosis in patients with chordoma.