[Development of two questionnaires for the assessment of knowledge and self-management in patients with chronic-obstructive pulmonary disease (COPD)]. / Entwicklung zweier Fragebögen zum Krankheitswissen und Umgang mit der Erkrankung für Patienten mit chronisch-obstruktiver Lungenerkrankung (COPD).

INTRODUCTION: As with other chronic diseases, the course of chronic obstructive pulmonary disease (COPD) can be expected to be positively influenced if patients are well informed about their disease and undertake appropriate self-management. Assessments of the level of knowledge and management that are comparable should benefit from structured, systematically developed questionnaires. These, however, have not been published in Germany. METHODS: A total of 310 patients with COPD were recruited from three pneumological practices and one hospital to develop the questionnaires. Based on statistical criteria and content assessments by medical specialists, two questionnaires on knowledge (17 questions) and self-management (25 questions) were developed by selecting and modifying questions from published studies and training programs. In addition, two short versions with 5 and 3 questions were created to enable a quick assessment of the patients' knowledge and self-management. All questionnaires also included a visual analogue scale for self-assessment of knowledge and self-management. The statistical procedures for systematically guided selection comprised correlation and regression analyses. RESULTS: The questionnaires revealed considerable knowledge deficits in many patients and remarkably unsystematic, incoherent knowledge. The extent of this knowledge was negatively correlated with higher age and positively correlated with participation in training programs; this also applied to self-management. Correlations between the answers to the knowledge questions were higher in patients who had participated in training programs. The visual analogue scales for self-assessment of knowledge and management always correlated with the total number of correct answers. DISCUSSION: The questionnaires on knowledge and self-management in patients with COPD could be used in outpatient settings, including by non-medical staff, in order to quickly identify and correct deficits or as a reason to recommend training programs. The short versions and the analogue scales for self-assessment can give at least first hints. Potentially, training programs should focus more on promoting the coherence of knowledge through better understanding, as this presumably favors long-term knowledge. Older patients and those with a low level of education appear to be particularly in need of specially adapted training programs.

Correspondence between Capnovolumetric and Conventional Lung Function Parameters in the Diagnosis of Obstructive Airway Diseases.

BACKGROUND: Capnovolumetry is of interest as a method for the diagnosis of obstructive airway diseases, requiring little cooperation from the patient. OBJECTIVE: To help in the interpretation of capnovolumetric parameters, we aimed to identify their correspondence to conventional lung function indices. METHODS: We studied 978 patients from a diagnostic study with complete functional data and the clinical diagnosis of asthma, chronic obstructive pulmonary disease (COPD), or no respiratory disease. Using path analysis, four capnovolumetric parameters (slope of expiratory phase 3, ratio of slopes of phases 3 and 2, volume of phase 2, and the ratio area/volume of phase 3) previously identified as predictors of airway obstruction in terms of spirometry and body ple-thysmography, were analyzed regarding their relationship to each other and the diagnostic categories of asthma or COPD versus control, or obstruction versus no obstruction. We then identified four lung function parameters showing relationships as much as possible isomorphic to those between capnovolumetric parameters. RESULTS: The four capnovolumetric parameters were related to COPD and obstruction via both direct and indirect influences, but only two of them to asthma. Regarding the correspondence to lung function parameters, the slope of expiratory phase 3 corresponded best to the ratio of residual volume to total lung capacity, the ratio of slopes of phases 3 and 2 to forced expiratory volume in 1 s, the volume of phase 2 to forced expired flow at 50% of vital capacity, and the ratio area/volume of phase 3 to forced vital capacity. CONCLUSIONS: Our results indicated an intricate relationship of capnovolumetric parameters to each other and to airway obstruction, asthma, or COPD. The correspondence to conventional lung function measures seemed to reflect the entities lung hyperinflation, overall ventilatory impairment, bronchoconstriction, and ventilated lung volume, in that order. These findings might be helpful for clinicians in the interpretation of capnovolumetry.

Diagnostic accuracy of capnovolumetry for the identification of airway obstruction - results of a diagnostic study in ambulatory care.

BACKGROUND: One of the known weaknesses of spirometry is its dependence on patients' cooperation, which can only partially be alleviated by educational efforts. Therefore, procedures less dependent on cooperation might be of value in clinical practice. We investigated the diagnostic accuracy of ultrasound-based capnovolumetry for the identification of airway obstruction. METHODS: Consecutive patients from a pulmonary outpatient clinic were included in the diagnostic study. As reference standard, the presence of airway obstruction was evaluated via spirometry and bodyplethysmography. Capnovolumetry was performed as index test with an ultrasound spirometer providing a surrogate measure of exhaled carbon dioxide. Receiver operating characteristic (ROC) analysis was performed using the ratio of slopes of expiratory phases 3 and 2 (s3/s2) ≥ 0.10 as primary capnovolumetric parameter for the recognition of airway obstruction. Logistic regression was performed as secondary analysis to identify further useful capnovolumetric parameters. The diagnostic potential of capnovolumetry to identify more severe degrees of airway obstruction was evaluated additionally. RESULTS: Of 1400 patients recruited, 1287 patients were included into the analysis. Airway obstruction was present in 29% of patients. The area under the ROC-curve (AUC) of s3/s2 was 0.678 (95% CI 0.645, 0.710); sensitivity of s3/s2 ≥ 0.10 was 47.7 (95% CI 42.7, 52.8)%, specificity 79.0 (95% CI 76.3, 81.6)%. When combining this parameter with three other parameters derived from regression analysis (ratio area/volume phase 3, slope phase 3, volume phase 2), an AUC of 0.772 (95% CI 0.743, 0.801) was obtained. For severe airway obstruction (FEV1 ≤ 50% predicted) sensitivity of s3/s2 ≥ 0.10 was 75.9 (95% CI 67.1, 83.0)%, specificity 75.8 (95% CI 73.3, 78.1)%; for very severe airway obstruction (FEV1 ≤ 30% predicted) sensitivity was 86.7 (95% CI 70.3, 94.7)%, specificity 72.8 (95% CI 70.3, 75.2)%. Sensitivities increased and specificities decreased considerably when the combined capnovolumetric score was used as index test. CONCLUSIONS: Capnovolumetry by way of an ultrasound spirometer had a statistically significant albeit moderate potential for the recognition of airway obstruction in a heterogeneous population of patients typically found in clinical practice. Diagnostic accuracy of the capnovolumetric device increased with the severity of airway obstruction. TRIAL REGISTRATION: The study is registered under DRKS00013935 at German Clinical Trials Register (DRKS).