The choice of a nasal feeding tube (search) instead of a stomach tube to boost the pope's nutrition indicates his doctors may be expecting the problem to be temporary, medical experts say.

The nose tube may also have been chosen to get the pontiff strong enough for a more invasive procedure to insert a feeding tube in the stomach, the specialists say.

The Vatican said Wednesday the nose tube was intended to "improve the calorie intake and favor an effective recovery of strength," and that the 84-year-old pope was continuing a slow but progressive convalescence.

Pope John Paul II (search) was rushed to Gemelli Polyclinic hospital (search) in Rome twice last month with breathing crises. On Feb. 24, he underwent surgery to insert a tube in his windpipe and ease his breathing. He also suffers from advanced Parkinson's disease.

Feeding tubes are commonly used to help sick or frail people get nutrition, or for patients who have had throat surgery.

In the pope's case, doctors have used a nasogastric tube, a long straw threaded through the nose and into the stomach without anesthetic or sedation. The tube is left in place when it is not being used.

By contrast, a stomach feeding tube, called a percutaneous endoscopic gastrostomy tube, is fitted under sedation and involves punching a hole in the belly. The pencil-sized tube is then permanently connected to the stomach. Neither tube affects normal eating or speaking.

Doctors usually opt for the nose tube if they believe the nutrition problem is temporary or if the patient needs a boost in strength ahead of a stomach tube operation, said Dr. James Underberg of the New York University School of Medicine.

"The maximum time they would leave a nasal tube in would be two weeks," he said.

The nose tube is a temporary measure, experts say, because it is uncomfortable and can cause complications after a while, eroding the nasal passage and causing ulcers and bleeding.

It also can block drainage of the sinuses, leading to sinus infection, or increase the risk of stomach acid flowing back up into the gullet, said Dr. Riji Ayinla, chief of pulmonary disease and critical care at North General Hospital in New York.

A major advantage of feeding tubes is that they reduce the risk of food going to the lungs instead of the stomach, which can lead to pneumonia.