Inouye spokesman Peter Boylan said Sunday the Hawaii lawmaker remains under observation at Walter Reed National Military Medical Center in Bethesda, Md. The senator was admitted last week to the hospital so that doctors could monitor his oxygen intake.
“At this time, there is no timetable for his release," he added.
Inouye, the chairman of the Appropriations Committee, is also the president pro tempore of the Senate.
Aides last week said that Inouye’s breathing problems were likely related to a surgery he underwent 4 decades ago, in which a portion of his left lung was removed.
Inouye said last week that he planned to return to the Senate after his recovery.