Pulmonary atelectasis due to acute endobronchial blood clot impaction is not uncommon in the setting of substantial hemoptysis. Sometimes, life-threatening hypoxemia and hemodynamic changes may occur even with collapse of only one lung. Alterations of pulmonary blood flow distribution with increased pulmonary shunt could contribute to these events. In addition, abnormal negative pleural pressure caused by total lung collapse also plays an important role in these situations. Here we report a case with near-fatal left lung collapse was rescued by immediate chest tube insertion. We would like to discuss the relative pathophysiology of the condition and anesthetic management of patient in such a dangerous situation.