Preventing a hospital infection.

You've finally shed those 50 extra pounds you picked up after the birth of your third daughter. And you did it in only four months, a real accomplishment, you think, for someone 35 years old. On this diet regimen, you didn't exercise much, just cut your calories to 600 a day. You've been a little tired lately, but your clothes fit great.

Then the unexpected happens. At your routine six-month checkup your obstetrician discovers a mass around one of your ovaries. A diagnostic laparoscopy shows an endometrioma (a large mass of endometrial tissue). It is too involved to be removed by simple laparoscopy, using a laser. You have to undergo surgery.

Now, five days after surgery, they're talking Greek, saying something about your blood work being abnormally low. Your albumin, one of your blood proteins, is only 2.5. Your total lymphocyte count, a measure of your immunity, is only 1,000. And, of all things, your incision has become infected and you've developed pneumonia.

What went wrong? Why are you suddenly seriously ill? Perhaps that low-calorie diet wasn't such a good idea after all. While malnutrition isn't the only thing that can make you more vulnerable to infection, it is one factor over which you have some control.

What statistics don't tell. Statistics tell us if you're admitted to the hospital, you have a one in 20 chance of getting a hospital-acquired (or nosocomial) infection. If that happens, your hospital stay will be prolonged by about four days and will be more costly. Not only that, you have a one in 20 chance of dying from that infection.

What statistics don't always tell us is that many of these infections are preventable, just by being in the healthiest possible condition when you're admitted to the hospital and by being aware of simple infection prevention and control practices.

It's helpful to think of infection as a chain of events. For an infection to occur, there must be three links in this chain. The first link is a source of infection. Microorganisms, or germs, are present everywhere in the environment, and especially in a hospital. Practically any microorganism can cause infection if the conditions are right.

Second, there must be a way for the infection to spread. The most common way this occurs in the hospital setting is when caregivers forget to wash their hands or change their gloves between patients.

Third, there must be a person who is susceptible to infection. Healthy individuals aren't as likely to get an infection as persons whose immune systems are compromised for one reason or another. And of course, people who are admitted to the hospital are usually not healthy.

A person's defenses become compromised because of age (the very young and the very old are particularly susceptible), chronic illness (such as diabetes or cancer), as a result of an invasive procedure (such as surgery or having a catheter inserted), medications (such as steroids), obesity, or malnutrition.

The malnutrition factor. A person doesn't have to look skinny to be malnourished, however. Whenever a person loses more than two pounds per week, even if that person is obese, he or she loses body proteins in addition to fat. While the word "malnutrition" evokes images of emaciated children in underdeveloped countries on the evening news, it is important to recognize that 40 to 60 percent of patients admitted to American hospitals are malnourished to some degree. Even a patient who hasn't eaten a well-balanced diet for as few as 10 days (while undergoing diagnostic tests and/or surgery in the hospital, for example) can have nutritional deficiencies.

When a person is malnourished, the body produces less antibodies and lymphocytes (a type of white blood cell), placing the person at a higher risk of developing an infection. And when a person is injured or ill as well as malnourished, the body responds by using both fats and proteins for energy. The more protein lost, the more compromised that person becomes.

Common hospital infections. Recognizing that approximately one third to one half of all nosocomial infections can be prevented, most U.S. hospitals have well-developed infection prevention and control programs in place. In the hospital setting, infection control measures are directed at interrupting the transmission of infection through procedures such as handwashing between patient contacts, wearing protective apparel such as gloves, masks, and gowns when contact with blood or other body fluids is likely, and using sterile techniques when performing invasive procedures such as the insertion of an TV line or a urinary drainage catheter.

Urinary tract infections are the most common type of nosocomial infections, accounting for nearly 40 percent of all nosocomial infections. Four out of five urinary tract infections are associated with the presence of a catheter in the bladder. While such catheters are often necessary, the longer the catheter remains in place, the more likely a person is to get an infection. Females and older persons (particularly those over age 70) are at greater risk.

Surgical wound infections are the second most common nosocomial infection. Surgical incisions don't heal as well in persons who are malnourished. In addition, 70 percent of all nosocomial infections occur in patients who have had surgical procedures. This is largely because these persons have had tubes or other devices placed in their urinary and respiratory tracts.

Pneumonia is the third most common and the most costly nosocomial infection. It is also the most common cause of death in persons with protein-calorie malnutrition. Not only is the malnourished person's immune system compromised, but he or she is less capable of clearing respiratory secretions and is more likely to have abnormalities in the "mechanics" of breathing.

More than a century ago Florence Nightingale wisely said that infection is something that people are generally so afraid of that they frequently engage in the very practice they ought to avoid. And with our sophisticated supertechnology, it's easy to overshadow the basics such as good nutrition and simple precautionary measures. Granted, not all nosocomial infections can be prevented, but a key ingredient in their prevention is the steps you take.

What you can do. Here are 10 ways you can help prevent a nosocomial infection:

1. Avoid contact with anyone who has a communicable disease, especially if you are planning to enter the hospital.

2. Follow your doctor's advice with regard to receiving the flu or pneumonia vaccine. Vaccines aren't just for children.

3. When your doctor prescribes antibiotics, take the full course as prescribed, rather than stopping when you feel better.

4. If you need to lose weight, do so, but don't cut calories below 1,200 a day. Diet under the supervision of a physician, especially if you're scheduled to enter the hospital. Malnutrition increases the likelihood of getting an infection, and the severity and outcome of that infection-particularly when you're a patient in a hospital.

5. If you're having surgery, enter the hospital as close to the date of your scheduled surgery as possible. Your chances of getting an infection are greater if you're hospitalized several days prior to surgery, because you're exposed to more microorganisms.

6. If you smoke, quit, or stop smoking two weeks in advance of surgery. This helps your lungs adapt better to the effects of anesthesia. Some doctors even refuse to perform elective surgery on patients who continue to smoke.

7. After surgery, take 5 to 10 deep breaths and cough every hour to expand your lungs. This helps to prevent pneumonia.

8. If necessary, remind caregivers to wash their hands or to change their gloves when going from one patient to another or one body site to another.

9. Avoid contaminating yourself, such as by touching your IV catheter site, urinary catheter, or other tubes. These devices are essential to providing care during hospitalization. Most of these devices do not become infected, but they can cause problems if not cared for properly.

10. Ask to be weighed on admission to the hospital and twice per week throughout your hospitalization. This is particularly important if you have to be in the hospital for an extended period of time, if you have had nothing by mouth or receive a clear liquid diet or standard IV glucose for more than five days. Remember, a bottle of plain glucose has less calories than a candy bar. Question your doctor or nurse should you not receive a meal tray for more than two days, if you're not receiving nutrition by another source (such as tube feedings or special IV feedings). There may be a legitimate reason for this (such as diagnostic tests), but such open communication makes you a partner in your own health care.

Roberta L. Messner, R.N., Ph.D., C.P.H.Q., is quality management nursing coordinator at the Veterans Administration Medical center in Huntington, West Virginia. William Wheeler, M.D., a surgeon and a professor or surgery, has published widely in medical journals.