587. Dangerous Illnesses on Shabbos

Shabbos 2:1

Shabbos prohibitions are suspended in the case of a danger to life, the same as other mitzvos. Therefore, we may perform anything necessary for a sick person whose life is in danger, as determined by a doctor. If there is a doubt as to whether Shabbos must be violated for a sick person, it should be violated because Shabbos laws are suspended even in a doubtful case of danger to human life. This is also the case when one doctor says to violate Shabbos and another doctor says that doing so is unnecessary.

Shabbos 2:2

If doctors determine on Shabbos that a patient requires a certain treatment for eight days, we do not delay until nightfall in order to avoid violating two Shabboses for him. Rather, treatment is started immediately, on Shabbos. Even 100 Shabboses may be violated for a patient if that’s what’s called for. As long as someone is dangerously ill - even if there’s just a question as to whether or not he is dangerously ill – if he requires treatment, Shabbos should be violated for him: a lamp may be lit and extinguished for him, animals may be slaughtered for him, we may bake and cook for him, and water may be heated for him, both to drink and for washing. The general rule is that Shabbos should be treated as a weekday for the sake of a patient who is dangerously ill.