PHAIR - Präoxygenierte Hypokapnische Hyperventilierte Apnoe in der Strahlentherapie

Approximately every 10 of 100 Women suffers breast cancer during their lifetime. Therefore, surgical, medical and radiotherapeutic approaches are combined in the therapy, which is associated with benefits in lifetime but also with raising cardiopulmonary risks. Until today there is a struggle for an optimized treatment paradigm. It was with the introduction of IMRT in 1994 presented a method which has the potential to replace opposing tangential coplanar wedged fields as a standard for the irradiation of the breast and the experiences with the Tomotherapy is also promising. I.e. with IMRT and Tomotherapy irradiation techniques are available that allow the dose distribution in radiotherapy with millimeter precision adjusted to the breast, lung and heart to spare healthy tissues. However, the particular physiological displaceability of healthy and tumurous altered tissues and breathing dependent particular movement of the breast during the irradiation is a substantial obstacle for those precise adjustments. I.e. these innovative techniques can be used with additional information on the breathing motion of the tumor or the organ to be irradiated. These replacement parameters such as the chest wall motion or fluoroscope based motion markers are used for example to an irradiation in a specific respiratory phase (Gating, or a target volume tracking (Tumor Tracking) to be carried out. By contrast, Wong et al. showed in 1999 that practicable tumor fixation is available with apnea and Volhard showed 1908 that breathing is not necessarily associated with ventilation, but continuously ongoing, if enough oxygen is available Thus, this work intends to reduce the deficit of the former apnoeic proceedings, namely the limited apnea time and to look for ways to make apneic radiotherapy possible in curative approaches. Furthermore, this work analyzes the conditions and possibilities of apnea and discussed the progress of science. Therefore it is necessary to introduce the scientific literature of disciplines such as anesthesiology, sports medicine and physiological bases. 
The median time conventional standard BH (SBH) from Eupnoe was 40 sec (SD: ± 14.25) for the control group (group A, n = 6) and 40.3 sec (SD: ± 30.42) for the patients (group B, n = 10). Under hyperventilation (HBH), the controls extended of the BH-time to 105.60 ± 35.33 sec and the patients to 89.10 ± 61.20. With hyperventilation, supplemental oxygen (ohBH), the control group reached 217.20 ± 87.77 sec (confidence interval (CI): 0.79, 0.8) and the patients 164.70 ± 47.33sec (CI : 0.39, 0.4). The volunteers ended their attempt in ohBH with 56 mmHg FeCO2 (SD: ± 13.18), accumulating between T0 and T3 20.3 FeCO2 mmHg (SD: ± 11.61). The patients completed their ohBH on average by 42 mmHg FeCO2 (SD: ± 6.45) and accumulated in relation to the beginning of the experiment, 5.1 mmHg FeCO2 (SD: ± 5.45). The patients accumulated in ohBH as much FeCO2 as in HBH though their BH was doubled. The highest measured heart rate was 123 beats / min in the HBH volunteers. Both groups exceeded the allowed rate of 20 breaths / min. ohBH (p <0.05) during hyperventilation. We found piecemeal changes, for example, individual non-specific changes without violating our security analysis criteria for the measurement of lactate, base excess and pH. 
A key finding of this study is the significant additional increase in the BH´s time, both by hyperventilation and by hyperventilation with oxygen. From a clinical point of view there were no adverse side effects of apnoeic attempts (disorientation, paresthesia) due to decreased carbon dioxide pressures. Our study shows that is possible to perform in a shorter time a complete irradiation of the chest, compared with repetitive BH-maneuvers or Gating We don´t expect any additional side effects caused by reactive oxygen species (ROS), because under physiological conditions and sea level the pressure of oxygen in tissue remains continuous opposed to use of hyperbaric oxygen therapy (HBO). Preoxygenated hyperventilated hypocapnic apnea expanded the BH-time significantly, without adverse side effects or reportable clinical constraints. To the best of our knowledge this is the first demonstration of more than two minutes apnea time in radiation therapy. The demonstrated PHAIR is a clinically relevant, recommendable, safe and feasible technique and could be applied both in BH and in conjunction with gating methods. PHAIR may improve the precision of radiation therapy but further studies are necessary to implement this technique in clinical use.