Pope Francis has completed a ninth night in the hospital, and his condition remains critical but he has no new respiratory crisis as his condition raises speculation he could retire.

"Pope Francis is alert and oxygen is still being administered. His blood values are improving thanks to transfusions. There is an initial slight renal insufficiency. He attended Mass today (February 23," according to the Holy See Press Office.

The pontiff's ninth night in the hospital was peaceful.

He received two units of concentrated red blood cells with beneficial effects, and his hemoglobin levels have risen.

Francis remains alert and well-oriented.

"The complexity of the clinical situation and the necessary time for the pharmacological treatments to show results require that the prognosis remain guarded," said his office.

Pope Francis had a severe breathing crisis on Feb. 22 that required giving him high-flow oxygen and blood transfusions, according to the latest medical report from his doctors at the Gemelli Hospital, Vatican News reported.

The 88-year-old Argentine-born pontiff has been hospitalized since February 14 at Rome's Gemelli Hospital due to breathing difficulties.

The Pope's illness has fueled speculation about a successor for Francis who could retire as did his predecessor Pope Benedit.

While technically speaking, any man of the Roman Catholic faith could be elected to the top position, the successor will likely be one of the 253 cardinals from around the world, the Irish Star reported.

According to tradition after a pope either resigns or passes away a conclave is convened in the Vatican's Sistine Chapel where all 253 cardinals take part in several rounds of voting to determine the next head of the Church.

However, there are rules involved.

One rule is that only 138 of the 253 cardinals will be able to serve as electors in the next conclave. The second rule states that no cardinals over the age of 80 can vote.