LONDON and ROME — The pope “rested well during the night” and woke shortly after 8 a.m. this morning, his 20th day in hospital, as his condition remains stable and his prognosis remains reserved, according to the Vatican.

The pontiff had needed medical intervention amid two episodes of “acute respiratory failure” on Monday, Vatican sources told ABC News.

The pope did not have any episodes of respiratory failure or bronchospasm on Tuesday, according to the Vatican.

Pope Francis has remained “alert, cooperating with therapy and oriented,” the Vatican’s press office, the Holy See, said. He underwent “high-flow oxygen therapy and respiratory physiotherapy” on Tuesday, the Vatican said.

He resumed noninvasive mechanical ventilation overnight into Wednesday morning “as planned,” according to the Vatican.

The pope, 88, was taken off noninvasive mechanical ventilation and resumed receiving supplemental oxygen through a nasal tube, Vatican sources said Tuesday. He was no longer wearing a mechanical ventilation mask, a device that pumped oxygen into his lungs, the sources said.

Wednesday marks Ash Wednesday, the first day of Lent, which is a 40-day season of prayer, fasting and giving. It concludes with Holy Week, which leads to Easter Sunday, the most important day in the Christian calendar.

The Vatican said last week that Cardinal Angelo De Donatis, major penitentiary and delegate of the pope, will replace Pope Francis at Wednesday’s liturgical celebration for Ash Wednesday in Rome.

The Cardinal will read the Homily prepared by the Pope and the text will be released later today, the Vatican said.

Francis, who has led the Catholic Church since 2013, was admitted to Rome’s Gemelli Hospital on Feb. 14 and was diagnosed with bilateral pneumonia. The pontiff had a bronchospasm attack on Friday, church officials said.