Preoxygenation with a 50% Concentration of Oxygen for 15 Minutes might Safely and Feasibly Prolong the Breath-Hold Duration during Radiotherapy: A Pilot Study

Abstract

<h3>Purpose/Objective(s)</h3> Voluntary deep inspiration breath-hold (DIBH) has been wildly used during radiation for thoracic and abdominal tumors. While the main disadvantage of voluntary DIBH is its short duration per single breath-hold. Preoxygenation with a high concentration of oxygen (more than 50%) combined with mechanical hyperventilation induced hypocapnia has been used for prolonging the single breath-hold duration, however, its safety is still a concern. In this study, we aimed to investigate whether simple preoxygenation with a relatively safe oxygen concentration of 50% can feasibly prolong the single breath-hold duration. <h3>Materials/Methods</h3> 12 healthy volunteers aged 21-48 years (6 males and 6 females) without previous cardiovascular diseases were included. The single DIBH duration of room air in resting-state, the single DIBH duration of room air after 5 min, 15 min, and 30 min preoxygenation with 50% concentration of oxygen, respectively, were evaluated and compared using paired t-test. <h3>Results</h3> The mean DIBH duration in room air in resting-state was 51.5 ± 12.97 seconds. Compared with DIBH in room air, after 5, 15, and 30 minutes preoxygenation with 50% concentration of oxygen, the DIBH duration in room air was significantly increased up to 91.9 ± 28.3 (p<0.0001), 115.5 ±25.5 (p<0.0001), and 122.1 ±28.4 seconds (p<0.0001), respectively. Furthermore, compared with 5 minutes of preoxygenation, the DIBH duration after 15 and 30 minutes of preoxygenation was significantly increased with 23.5 ± 9.7 (p<0.0001) and 30.2 ± 13.7 seconds (p<0.0001). Compared with 15 minutes of preoxygenation, the DIBH duration after 30 minutes of preoxygenation was only increased with 6.7 ± 5.4 seconds (p=0.0013). <h3>Conclusion</h3> This pilot study demonstrated that simple preoxygenation with a 50% concentration of oxygen for 15 minutes might safely and feasibly prolong the DIBH duration during radiotherapy. Further studies are warranted to confirm these results and to identify how many cycles of a single breath-hold can be prolonged. This study has been supported by the National Nature Science Foundation of China (82171890 & 81701683), Key Research and Development Projects of Zhejiang Provincial Science and Technology Department (2021C03122), Health Commission of Zhejiang Province (2020KY131), and Zhejiang Provincial Key Discipline of Traditional Chinese Medicine (2017-XK-A32).