After lifting a heavy object, a 41-yearold man felt a sharp pain in his chest on the right and developed progressing shortness of breath. The man’s condition is severe. His lips and mucosa are cyanotic, respiratory rate – 28/min., pulse – 122/min. Over the right half of the chest, percussion shows tympanitis, while auscultation detects sharply weakened breathing. The II heart sound is accentuated over the pulmonary artery. His blood pressure is 80/40 mm Hg. What primary emergency measure must be taken at the prehospital stage in this case?