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%, p < 0.001) and a shorter in-chamber testing duration (11.85 ± 3.12 min vs. 16.90 ± 3.85 min, p < 0.001). Optimal FVC and FEV1 values were also higher in the intervention group (FVC: 2.95 ± 0.32 L vs. 2.58 ± 0.35 L; FEV1: 2.05 ± 0.25 L vs. 1.70 ± 0.28 L; both p < 0.001), consistent with improved maneuver execution. Post-procedure SAS and SDS scores were lower in the intervention group (SAS: 35.10 ± 7.85 vs. 39.50 ± 8.12, p = 0.015; SDS: 30.05 ± 5.90 vs. 35.80 ± 6.25, p < 0.001). Mild procedure-related adverse events were less frequent in the intervention group (7.3% vs. 24.4%, p = 0.032). The MBCT positivity rate was numerically higher in the intervention group but did not differ significantly between groups (29.3% vs. 17.1%, p = 0.190).

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.