Hawaii Sen. Daniel Inouye was hospitalized at Walter Reed National Military Medical Center to regulate his oxygen intake, according to his office and ABC News.
"For the most part, I am OK,” Sen. Inouye says in a statement. "However, I am currently working with my doctors to regulate my oxygen intake. Much to my frustration, while undergoing this process, I have to remain in the hospital for my own safety and to allow the necessary observation."
Sen. Inouye, 88, was taken to the George Washington University Hospital where he remained through Sunday. He was transferred to Walter Reed National Military Medical Center, just outside Washington, D.C.
The senator says he hopes to be back on Capitol Hill as soon as doctors will allow. Recently, he was seen using oxygen on the floor of the Senate and has been spotted also using a wheelchair at times.
Sen. Inouye was misdiagnosed with lung cancer and a had a portion of his lung removed, according to his office. After living with this, his office says about nine months ago his doctors recommended using an oxygen supplement.
The senator also uses a wheelchair to preserve his knees, at the advice of his doctors.
"After 50 years of walking the marble floors of the Capitol complex, the marble has taken its toll and he has been advised to avoid long walks on hard surfaces," a spokesperson says.
In November, the senator was taken to Walter Reed after a fall in his apartment and was treated for a minor cut to the back of his head.
Fellow Hawaii Senator Daniel Akaka put out a statement: "I wish my friend, colleague, and brother Dan Inouye a speedy recovery and look forward to his return to the Senate."
Gov. Neil Abercrombie also released this statement: "We are in close touch with Sen. Inouye and his office. He is alert, feisty and ready to get back to work as soon as possible."
Congresswoman-elect Tulsi Gabbard sent her well-wishes: "I join all of Hawaii in wishing Senator Inouye a full and speedy recovery. He is in the best of hands at Walter Reed, and I am confident that he will have a quick return to the U.S. Capitol. I look forward to his continued leadership, as we take on the many challenges facing Hawaii and our nation. My thoughts and prayers are with him and his ohana."