The Shulhan Aruch (Orah Haim 328:2) writes (listen to audio recording for precise citation) that when somebody becomes seriously ill on Shabbat such that there is potential danger to his life, there is a Misva to desecrate Shabbat for the sake of assisting him. One who acts quickly to desecrate Shabbat for the sake of patient’s life, the Shulhan Aruch adds, is praiseworthy, whereas one who first goes to consult with a Rabbi is considered a murderer. As the Mishna Berura (Rav Yisrael Meir Kagan of Radin, 1839-1933) explains (listen to audio recording for precise citation), going to consult with a Rabbi delays the treatment, thus increasing the risk of the patient’s death. Therefore, taking time to consult with a Rabbi in the case of a potentially life-threatening condition, instead of immediately doing everything necessary to treat the patient, is considered a grave sin, akin to murder. The Mishna Berura notes in this context the Biblical command "Lo Ta’amod Al Dam Re’echa" (Vayikra 19:16), which forbids standing idly by a fellow Jew in a life-threatening situation. When there is a potential risk to life, one must immediately do everything necessary to protect the person’s life, without any hesitation, even if this entails violating Shabbat.
The Mishna Berura also notes in this context the comment of the Talmud Yerushalmi that if a person takes the time to consult with a Rabbi before desecrating Shabbat to help a dangerously-ill patient, the Rabbi is also at fault. It is a Rabbi’s responsibility to teach his students ahead of time of the obligation to desecrate Shabbat without delay in the case of a dangerously-ill patient, and thus even the Rabbi deserves criticism if he is approached for consultation when such a situation arises.
Hacham Ovadia Yosef, in Me’or Yisrael (vol. 1; listen to audio recording for precise citation), adds that Rabbis must ensure to be well-versed in the Halachot relevant to seriously-ill patients on Shabbat, because when such questions arise, they must be answered immediately. A Rabbi must not begin searching in books to find answers to questions that are brought to him regarding the treatment of life-threatening conditions on Shabbat, and must rather be fluent in these Halachot in advance, lest he cause an unnecessary delay in the patient’s treatment. Additionally, Hacham Ovadia writes, if a Rabbi asked such a question on Shabbat does not know the answer, and a young scholar who is with him has the answer, the other scholar should immediately give the answer. Ordinarily, it is forbidden for a student to answer a question in his Rabbi’s presence, as this is disrespectful. But in the case of a potentially life-threatening situation on Shabbat that is brought to a Rabbi’s attention, any delay could decrease the chances of the patient’s survival, and this serious concern overrides the need to show respect to one’s Rabbi. Therefore, in such a case the student may immediately give the answer.
This discussion underscores the importance of studying Halachot relevant to treating serious medical conditions on Shabbat, even as we hope and pray that these Halachot will always remain theoretical and never become practically relevant.
Summary: It is vitally important for Rabbis to teach their students the laws relevant to treating serious medical conditions on Shabbat, because when such situations arise, any time taken to pose or answer a question could decrease the patient’s chances of surviving. When somebody suffers a potentially life-threatening condition on Shabbat, one should immediately do everything necessary to care for the patient, even if this entails Shabbat desecration, and one should not take the time to consult with a Rabbi.