92:5 We override Shabbos to treat someone with a wound on the outside of his hand or foot, an injury caused by metal, a boil in the rectum, one who was bitten by a leech, a mad dog or a (deadly – OC 328:6) reptile, and one who has a very high fever, even if there is a doubt as to whether or not the patient is in danger of dying. We do not override Shabbos for a regular fever; this should be treated by a non-Jew.
92:6 A person who has high blood pressure lets blood immediately. [Editor’s note: Clearly, bloodletting is not our modern medical treatment for this condition.] If a person had blood let and got a chill, we make a fire to warm him up, even in the summer.