Prolonging breath-hold duration in radiotherapy using cognitive engagement.

Purpose/objective: Deep inspiration breath-hold (DIBH) is commonly used in breast cancer radiotherapy to decrease cardiac radiation exposure. Using high-flow nasal oxygen and hyperventilation we achieved voluntary long deep inspiration breath-holds (L-DIBH) exceeding 3 min. Substantial variability in L-DIBH duration among subjects remains, not explained by physical factors. We investigated how cognitive engagement could impact the L-DIBH. Materials/methods: Thirty-six subjects (20 volunteers and 16 patients) each performed 12 L-DIBHs over 4 sessions. During half of the sessions, they were instructed to focus on a mental exercise. Each L-DIBH was preceded by a validated hyperventilation and oxygenation protocol. The baseline DIBH time was calculated by taking the mean of 3 DIBHs. Linear Mixed Models were used to analyse the impact of this exercise on L-DIBH duration. Results: All 36 subjects completed the four sessions, yielding 432 L-DIBHs, including 216 with mental exercises. The mean L-DIBH duration was 152 s overall and 126 s in the patient subgroup. Volunteers outperformed patients. L-DIBH duration increased both within and between sessions, demonstrating a learning effect. The mental exercise increased mean duration by 14,9 s in the full cohort and by 19,0 s among patients. Its relative benefit compared with the between-session learning effect was greatest in those with poorer baseline DIBH times. Conclusion: A simple mental exercise effectively increases voluntary L-DIBH duration, providing a particularly meaningful benefit for participants with lower baseline DIBH times.