A patient at Tottori Prefectural Hospital in Japan suffered severe brain damage after a medical technician mistakenly disconnected the oxygen supply to an ECMO machine for 20 minutes. The error, committed by hospital staff, resulted in a critical interruption of oxygen delivery to the patient. The ECMO machine, used for providing both heart and lung support, was rendered ineffective during this period. Hospital authorities have acknowledged the incident and are investigating the circumstances surrounding the disconnection. The patient’s condition is currently critical, and the long-term prognosis remains uncertain. This incident raises concerns about patient safety protocols and staff training at the hospital, prompting a review of existing procedures.