Do You Need to Starve Before Surgery?

fasting before anesthesiaABC News Photo Illustration
Fasting before anesthesia

Lying in a hospital bed, it can be the most infuriating of responses. You've been suffering for hours in labor or awaiting a major surgery and all you ask for is a bite to eat.

But the nurse says no.

For generations, doctors have put patients on a strict fast before a major surgery. Ten years ago, the recommendation was no food or drink for eight hours before anesthesia. Not even a glass of water.

A toned-down version of the fasting rules even applies to women in labor on the off chance that things go wrong and the mother ends up in surgery.

But a group of researchers in the United Kingdom found evidence that hospitals may not need to be so strict in the maternity ward.

The study in the British Journal of Medicine tracked more than 2,000 mothers in labor. Half followed the traditional liquid diet fast and half were given permission to eat a light meal.

After the births, the study showed no difference in Caesarean rates and no difference in rates of complications if moms were given the chance to eat.

The doctors who led the study hope it will settle a debate in the medical field.

"It's really because it's quite a controversial area," said Dr. Andrew Shennan, a co-author of the study and a professor of obstetrics at King's College in London.

"Over the years there's been a general idea that women should starve during labor," he said.

The traditional fast for women in labor started as a safety precaution in the late 1940s, after doctors reported deaths from pulmonary aspiration in some women who had Caesareans.

Pulmonary aspiration is a nice medical way of describing when someone vomits and then inhales it back into their lungs, which can be quite serious and even cause death.

"When we're awake or when we're asleep we have protective reflexes to keep things out of our airways, but under anesthesia you lose your protective reflexes," said Dr. Craig Palmer, chairman of the Committee on Obstetric Anesthesia for the American Society of Anesthesiologists.

"The steps you would take to minimize the single death of an otherwise healthy woman are pretty dramatic," Palmer said. "We have to protect a lot of people to save one."

During the years, doctors have developed better anesthesia practices, especially for women in labor. Even if women need a Caesarean, doctors say they are far more likely to have local anesthesia that wouldn't require them to "go under."

However, the fasting rules for most patients haven't changed very much.

Why People Can't Eat Before Surgery

"Over the last decade or so, those guidelines have been loosened," said Palmer, who is also a professor of clinical anesthesiology at the University of Arizona in Tucson.

While before, patients could not let anything pass their lips for eight hours, now broth, energy drinks and tea are on the approved list, according to Palmer.

"Now we allow them to take clear liquids by mouth up to two hours before [surgery]," he said.

Women in labor haven't seen much relaxation of the rules either -- at least in the United States. The authors of the study cited that 79 percent of clinicians in the Netherlands allow women to eat during labor, versus 32 percent in the United Kingdom and even less in the United States.

"What we do is women are allowed to have clear liquids during labor, no solid foods, and I would say that's probably the norm in the United States," said Dr. Linda Polley, president of the Society for Obstetric Anesthesia and Perinatology and director of obstetric anesthesia at the University of Michigan Health System in Ann Arbor.

Polley has read multiple studies that show women would feel better if they ate during labor. However, she said she rarely hears complaints about the fasting policy at her hospital.

"I think it is so much part of the culture and so much what patients expect when they come," Polley said.

The study was enough to convince some obstetricians of the merits of allowing food for low-risk women.

"If they want to eat and drink in labor, it doesn't appear to be a problem," said Dr. Soo Downe, director of the Research in Childbirth and Health Group (ReaCH) at the University of Central Lancashire in Preston, England.

"If it makes you feel better, it's probably worth it," she said. Downe wrote an editorial to accompany the study in the British Medical Journal. She said unless the mother is clearly at risk for a complication, doctors could use their judgment and allow a light meal.

Shennan agreed.

"If you are low risk and normal, it's OK to have a light diet or have isotonic fluids that have calories in labor," he said. "But certainly we would not want people to be eating large chunks -- we don't want you to be eating steak and chips."

Will All Doctors Change Fasting Rules?

When it comes to other people awaiting surgery, anesthesiologists come down hard and fast on the rules.

"It's standard practice and it's been fairly well validated that it does reduce the chances for pulmonary aspiration," Palmer said.

But across the board, anesthesiologists and obstetricians said the current study of food during labor was by far the largest they had seen.

"Well, I think it's an important study -- it's the largest study that we have to date," Polley said, "but we have to be careful in how we interpret the results."

Polley said she'd rather to see a study large enough to have more women go through the most critical of scenarios: eating, then needing general anesthesia for a Caesarean and ending up fine in the end. Otherwise, Polley would only change the rules for women who are in the best of circumstances in labor.

"It would have to be women who are not diabetic, who are not obese, whose babies are doing perfectly," Polley said.

But, given the demands of labor, Polley could see the motivation to loosen rules a bit.

"I guess the reason why we're interested in labor in the first place is that we call it labor for a reason, it is difficult, it's hard work, and that's what makes this population different than the typical patient waiting for a procedure," she said.