Introduction: A 49-year-old man, former top-athlete had "whoops" with residual tumour and re-resection of a pleomorphic rhabdomyo- sarcoma at the left thigh in 2008 followed by adjuvant radiotherapy. Since 2011 he developed a total of 24 lung metastases. He underwent resection via three right- and two left-sided thoracotomies, one RFA on the right and 8 RFA on the left side, as well as one left-sided stereotactic radiation. Additionally, a single hepatic metastasis was treated by RFA. Palliative chemotherapy (Myocet, Yondelis, Ixoten) proved futile. In spite of increasing technical challenge, another RFA of lung metastasis was scheduled. Case description: For recurrent metastatic disease to the right lung RFA was applied, treating one central lesion and a second subpleural one, both in the upper lobe. The intervention was done in prone position under anaesthesia/intubation. Immediately after turning the patient to supine position he developed tachycardia followed by bradycardia and cardiac arrest. CPR was successful, but dramatic inflow-occlusion was evident. Immediate CT-control showed large amounts of air in the left heart, in the aorta, the coronary arteries and in the subarachnoidal vessels. While applying external pressure to both carotid arteries cardiac massage was continued in Trendelenburg's position, whereupon the inflow-occlusion lessened. Results and conclusions: The patient was transferred to the hyper- baric chamber and had re-compression according to Navy 6 protocol starting one hour after the incident. After hyperbaric oxygen therapy (HBO) he opened his eyes and was able to move both legs. On the next day acute, severe hemorrhage from the endotracheal tube developed. CT- Angiography showed a 2cm bleeding pseudoaneurysm of a subsegmental artery at the site of the central RFA. Coil-embolization stopped the bleeding. Weaning problems necessitated tracheotomy. After further 9 HBO treatments neurology was almost normal. Following uneventful removal of the tracheal cannula the patient was discharged two weeks after RFA. Take-home message: In the palliative setting local treatment of lung metastases can prolong life considerably. Yet multiple interventions may be a risk factor for adverse events. In highly compliant palliative patients with a good performance status severe complications of such measures can be handled.