Hyperventilation and Oxygenation to Prolong Breath Hold in Breast Cancer Irradiation Treatment

Plain-language summary

With the HOBBIT trial, the investigators want to develop a technology that allows volunteers to hold their breath for a long time. This technique will then be taught to patients with breast cancer to be able to hold their breath long-term during the irradiation. After all, research has shown that the heart is in a better position when the patient enters her breath after a deep inhalation, as a result of which there is less unwanted radiation of the heart. To develop this technique the investigators use healthy volunteers, who are asked several times to hold their breath as long as comfortable. Before the respiratory arrest the investigators allow these volunteers to hyperventilate, administer oxygen and cause hyperinflation of the lungs. The volunteers come back four times, on four consecutive days. The first day they receive a short training. Afterwards oxygen is administered for a few minutes while the volunteers are asked to hyperventilate. Afterwards, by using the learned technique, they must hold their breath for as long as possible, comfortably. They should hold their breath 3 times in total with a short break in between. The following days there is always a change in the preparation protocol, compared to the previous study. Different parameters in the protocol will be changed for different groups of volunteers, this is based on randomization. In this way the effect of different parameters in the preparation of the AHS can be investigated. The investigators will use this information to develop a new protocol for extending the duration of breathing to two minutes and thirty seconds for use during radiotherapy treatment. The method for finding the optimal technique is iterative optimization. This method follows a process of development, testing, feedback and redevelopment cycles. Iteratively, these cycles of development use the prior research to further elaborate the most promising discoveries and drop paths that do not produce the desired result. During the development The investigators listen to the input of different people: doctors, nurses, support staff, engineers and the participants, to guarantee the usability of the technique on the radiotherapy device. Once the researchers think they have found a solution that meets all the conditions, a group of untrained volunteers are asked to implement the technique. With this the investigators validate the technique for later use in breast cancer patients.

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