Objective:

To evaluate whether COMFORT-based nurse–patient communication combined with brief mechanical respiratory training improves the procedural quality of methacholine bronchial challenge testing (MBCT) in patients with suspected cough-variant asthma (CVA).

Approach:

• Study Design: A single-center quasi-experimental study with historical controls, following TREND guidance.
• Participants: Ninety-four adults with suspected CVA were enrolled, with 50 receiving standard instruction and 44 receiving COMFORT-based counseling and respiratory training.
• Outcome Measures: First-attempt success rate, in-chamber testing duration, spirometric maneuver quality, SAS/SDS scores, MBCT positivity, and adverse events.
• Statistical Analysis: Propensity score matching (PSM) was used to reduce temporal confounding.

Key Findings:

• The intervention group had a higher first-attempt success rate (75.6% vs. 24.4%, p < 0.001).
• In-chamber testing duration was shorter in the intervention group (11.85 ± 3.12 min vs. 16.90 ± 3.85 min, p < 0.001).
• Optimal FVC and FEV1 values were 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).
• 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 not significantly different (29.3% vs. 17.1%, p = 0.190).

Interpretation:

The integration of COMFORT-based nurse–patient communication with mechanical respiratory training improved the procedural quality of MBCTs, enhancing maneuver execution and reducing testing duration.

Limitations:

• The study was conducted at a single center, which may limit generalizability.
• The MBCT positivity rate did not show significant differences between groups.

Conclusion:

The combined approach of nurse–patient communication and respiratory training enhances MBCT procedural quality.