What is the ruling on a female nurse giving injections to men and measuring their blood pressure and sugar, especially if no male nurse is available in the hospital, and is this considered permissible if an alternative is available in other hospitals?

The fundamental principle is that a man should be treated by a male, and a woman by a female, unless there is a necessity, in which case it is permissible for one to treat the other. It is not permissible for a husband to allow a female nurse to view his 'awrah (private parts) except out of necessity. As for measuring blood pressure and sugar, the matter is less stringent. The nurse must wear gloves, and it is not permissible for a man to measure a woman's (blood pressure or sugar) except out of necessity, because the entire body of a woman is considered 'awrah.