Former US president George HW Bush will remain in a Texas hospital through the weekend after experiencing shortness of breath earlier this week.
Family spokesman Jim McGrath said the 90-year-old's condition has improved and doctors are discussing dates for his discharge, but he will remain for now at Houston's Methodist Hospital for observation.
Mr Bush, the oldest living former US president, was taken by ambulance to the hospital on Tuesday for what was reported as a precaution.
Two years ago he spent nearly two months, including Christmas, at the same hospital for treatment of a bronchitis-related cough and other issues.
He suffers from a form of Parkinson's disease that has forced him to rely on a motorised scooter or wheelchair, although in June he celebrated his 90th birthday with a skydive.