Minimizing preparation time for repeated prolonged deep-inspiration breath holds during breast cancer irradiation using pre-oxygenation with high-flow nasal oxygen and voluntary hyperventilation

Objectives: Deep inspiration breath-holds (DIBHs) reduce heart and lung toxicity during breast cancer radiotherapy. Consecutive DIBHs are stressful, time-consuming, and leads to position changes. To facilitate the introduction of pre-oxygenation using high-flow nasal oxygen (HFNO) and hyperventilation to prolong DIBHs (L-DIBHs), we examined the effect of hyperventilation time on the duration of L-DIBHs. Additionally, to minimize total treatment time, the feasibility of several successive L-DIBHs was examined.

Methods: Our previous protocol imposed 3 min of hyperventilation at 16 breaths per minute with pre-oxygenation using HFNO, in prone position. In the first phase, the effect of hyperventilation time on the length of the L-DIBH was investigated. The aim of the second phase was to investigate the feasibility of shorter preparation times before the second and third L-DIBH in the case of 3 consecutive L-DIBHs of at least 2 minutes.

Results: There is a positive but weak correlation between preparation time and L-DIBH duration. With either 3 minutes 30 seconds or 6 minutes 20 seconds (depending on fitness) of voluntary hyperventilation duration, 93% of subjects could hold 3 consecutive L-DIBHs for over 2 minutes. The median duration of the third and last L-DIBH was 3 minutes 17 seconds (SD 1 min 4 seconds).

Conclusion: A weak relationship exists between the hyperventilation time and L-DIBH duration. Repeating L-DIBHs with shorter preparations is achievable, resulting in a shorter total treatment time required.

Advances in knowledge: It is possible to perform repeated L-DIBHs for breast cancer irradiation using HFNO and hyperventilation.