Research questions and background: This study explores a highly controversial issue of medical care in Germany: the decision to withhold or withdraw mechanical ventilation in critically ill patients. It analyzes difficulties in making these decisions and the physicians' uncertainty in understanding the German terminology of Sterbehilfe, which is used in the context of treatment limitation. Used in everyday language, the word Sterbehilfe carries connotations such as helping the patient in the dying process or helping the patient to enter the dying process. Yet, in the legal and ethical discourse Sterbehilfe indicates several concepts: (1) treatment limitation, i.e., withholding or withdrawing life-sustaining treatment (passive Sterbehilfe), (2) the use of medication for symptom control while taking into account the risk of hastening the patient's death (indirekte Sterbehilfe), and (3) measures to deliberately terminate the patient's life (aktive Sterbehilfe). The terminology of Sterbehilfe has been criticized for being too complex and misleading, particularly for practical purposes. Materials and methods An exploratory study based on qualitative interviews was conducted with 28 physicians from nine medical intensive care units in tertiary care hospitals in the German federal state of Baden-Wuerttemberg. The method of data collection was a problem-centered, semi-structured interview using two authentic clinical case examples. In order to shed light on the relation between the physicians' concepts and the ethical and legal frames of reference, we analyzed their way of using the terms passive and aktive Sterbehilfe. Results Generally, the physicians were more hesitant in making decisions to withdraw rather than withhold mechanical ventilation. Almost half of them assumed a categorical prohibition to withdraw any mechanical ventilation and more than one third felt that treatment ought not to be withdrawn at all. Physicians showed specific uncertainty about classifying the withdrawal of mechanical ventilation as passive Sterbehilfe, and had difficulties understanding that terminating ventilation is not basically illegal, but the permissibility of withdrawal depends on the situation. Conclusions The physicians' knowledge and skills in interpreting clinical ethical dilemmas require specific improvement on the one hand; on the other hand, the terms passive and aktive Sterbehilfe are less clear than desirable and not as easy to use in clinical practice. Fear of making unjustified or illegal decisions may motivate physicians to continue (even futile) treatment. Physicians strongly opt for more open discussion about end-of-life care to allow for discontinuation of futile treatment and to reduce conflic
