Tehran University of Medical Sciences Archives of Anesthesiology and Critical Care 2423-5849 11 2 2024 11 02 247 255 Alireza Rahat Dahmardeh Department of Anesthesiology and Critical Care, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran. Aliakbar Keykha Community Nursing Research Center, Zahedan University of Medical Sciences, Zahedan, Iran. & Department of Medical-Surgical Nursing, School of Nursing and Midwifery, Zahedan University of Medical Sciences, Zahedan, Iran. 2024 06 08 2024 07 01 Difficult intubation and mechanical ventilation are common causes of pneumothorax in critically ill patients. Patients with chronic respiratory tract disease are at high risk for pneumothorax caused by positive-pressure mechanical ventilation. A timely diagnosis of pneumothorax is critical as it may evolve into tension pneumothorax. In this case report, we report a patient who has a decreased level of consciousness due to opioid overdose. In the emergency room, she underwent mechanical ventilation and became conscious after a naloxone injection. After extubation, she has extensive subcutaneous emphysema. However, her hemodynamic and respiratory status is normal. The chest CT scan showed a large pneumothorax caused by mechanical ventilation. https://aacc.tums.ac.ir/index.php/aacc/article/view/1021