Enhancing procedural quality and efficiency of methacholine bronchial challenge tests in patients with suspected cough-variant asthma: a quasi-experimental study utilizing nurse-patient communication and respiratory training.

Objective: Methacholine bronchial challenge testing (MBCT) is important for documenting airway hyperresponsiveness in patients with suspected cough-variant asthma (CVA), yet its procedural quality may be compromised by suboptimal patient maneuver execution and procedure-related anxiety. This study evaluated whether COMFORT-based nurse-patient communication combined with brief mechanical respiratory training improves MBCT procedural quality. Methods: This single-center quasi-experimental study with historical controls followed TREND guidance. Ninety-four adults with suspected CVA were sequentially enrolled: 50 controls received standard visual/verbal instruction, and 44 patients received COMFORT-based counseling plus supervised inspiratory/expiratory training before MBCT; one intervention patient dropped out. Propensity score matching (PSM) was used to reduce temporal confounding. Outcomes included first-attempt success rate, in-chamber testing duration, spirometric maneuver quality, SAS/SDS scores, MBCT positivity, and adverse events. Results: In the matched cohort (41 pairs), baseline characteristics were well-balanced after PSM. The intervention group showed a higher first-attempt success rate than the control group (75.6% vs. 24.4%, Conclusion: Integrating empathetic nurse-patient communication with targeted respiratory mechanical training significantly improves the procedural quality of MBCTs. This combined approach improved maneuver execution and first-attempt success and reduced in-chamber testing duration, while requiring additional pre-test preparation time. These findings support a procedural-quality intervention for MBCT rather than evidence of improved diagnostic accuracy or immediate physiological improvement in lung function.