Rome Pope John Paul II underwent an operation Thursday to insert a tube in his throat to help him breathe after he was rushed to the hospital with flu symptoms.
The Vatican said in a statement that the 30-minute tracheotomy was a success, adding: "The Holy Father is fine and will spend the night in his regular hospital room."
The statement said the procedure was "elective," suggesting that it wasn't an emergency measure.
Papal spokesman Joaquin Navarro-Valls said the pope on Wednesday started showing signs of the same illness he suffered earlier this month.
"The flu that led to his hospitalization had some complications, including some episodes of difficulty in breathing," the Vatican statement said. The pope, who was hospitalized Feb. 1-10, is now breathing with the help of a respirator, the Italian news agency ANSA reported.
The relapse appeared to have happened quickly. On Wednesday, the pope made his longest public appearance, 30 minutes, since he became ill three weeks ago and was hospitalized at Rome's Gemelli Polyclinic. On Thursday, he was scheduled to attend a meeting on new candidates for sainthood, but instead he returned to the hospital.
The pope, 84, has two full-time personal physicians and specialists who see and treat him at the Vatican. Details of his care are kept secret, but it's widely assumed the Vatican doesn't have the high-tech equipment of a hospital.
Gemelli keeps a suite of rooms open for the pope, who also suffers from Parkinson's disease.
Vatican watchers said there was concern among church leaders because the pope was hospitalized so suddenly.
"The cardinals had no idea anything was wrong, and all of a sudden he was in the hospital," said biographer Andreas Englisch, the author of "The Secret of Karol Wojtyla: John Paul II." He saw the pope earlier in the week and said he "looked surprisingly healthy."