The French title is pronounced À boo duh soof-luh. The initial A is short, as in 'cat'; the final 'uh' sound is understated.
À bout de soufle means, literally, 'at the end of breath' – or, as we would say in English, 'out of breath'. There is no single-word equivalent in French to the English word that is the answer to this question.
© Haydn Thompson 2017