Fighting Infection in the OROct 28, 2013
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Interviewer: What does it mean to say a surgery went well? Well, one of the big variables in the equation is a controlled surgical site infection. Dr. Harriett Hoff from the University of Utah Medical Center. Her passion is preventing surgical site wound infections, so the first question is in the site of all the things that happens in surgery, how important is that component?
Dr. Harriet Hopf: Hugely important. Surgical site infection is one of the common complications after surgery. It delays the healing time, and it means a longer time in the hospital. It means maybe having more doctor visits. It takes a longer time to get back to work. So if you get a surgical site infection, it's often a devastating complication.
Interviewer: Not only for patients is it bad news but for hospitals it is too, because you've got patients that stay there longer. They don't have as good of outcomes. What are some of the other implications?
Dr. Harriet Hopf: Surgical site infection is actually one of the first things that the centers for Medicaid and Medicare services went after for paper performance metrics. So we are judged on not only our rate of surgical site infection but how well we do all of the things that we do to prevent them. Interestingly enough, the biggest thing that we can do is hand hygiene. So washing your hands is using soap and water, and we do some of that, but we don't have a sink in the room. But the other thing is to use the alcohol gel to clean your hands. So when you touch the patient, you get their bacteria on you. If you alcohol gel your hands immediately, then you're not going to spread that around the room.
Interviewer: So its touch, not necessarily airborne germs in those situations?
Dr. Harriet Hopf: In general, the germs that are being transferred are being transferred by touch. There is potentially some in the air, but that's much less of a problem. The operation room has negative pressure to take the bacteria away from the patient.
Interviewer: What does that mean, negative pressure?
Dr. Harriet Hopf: There is airflow in the operating room that works to sort of pull the bacteria away from the patient and keep stuff from outside the operating room from entering the operating room. So you can feel when you open the door to an operating room, there's a change in pressure when you open the door to an operating room and that helps to keep airborne particles from getting onto the patient.
Interviewer: So I was doing some due diligence before our conversation, and I found it interesting, you just said a lot of it's through hand washing, because that's what I gathered. And that kind of blows me away a little that in today's technologically advanced age, that's kind of the big thing, isn't it? Are there other considerations that are nearly as important?
Dr. Harriet Hopf: There are lots of other considerations. I spend a lot of time on hand hygiene because surprisingly enough people don't wash their hands enough. But other things include, for example, giving antibiotics within an hour before the incision helps to reduce infections by reducing the number of bacteria that is on the skin and in the incision that could cause an infection. Keeping the patient warm turns out to be very important. Operating Rooms are cold. They're cold because the surgeons wear a lot of clothes, and they need to be comfortable to operate. Under anesthesia patients don't manage their temperature very well. Among other things we make them naked. So that they're in a cold environment and they're not necessary naked, but, so there are things that anesthesiologists can do to keep the patient warm.
Interviewer: So what's going on there? Why does keeping them warm versus cold help?
Dr. Harriet Hopf: There's a couple of reasons. Your white cells work better when they're warm. They kill bacteria better. The other thing is when you're cold, it reduces blood flow to your skin to help maintain your core body temperature. And when you reduce blood flow to your skin, you reduce the oxygen level in your skin and you're white cells use oxygen to kill bacteria.
Dr. Harriet Hopf: So when they're cold, they don't get enough oxygen to kill the bacteria. So the things that we do to make sure our patients stay warm in the face of anesthesia and a cold environment, we actually put a blanket on that blows hot air on the patients in the pre-op area. It's actually a great way to warm them up.
Interviewer: Kind of pre-warm them.
Dr. Harriet Hopf: We pre-warm patients, because if you're cold when you go in the operating room, it turns out it get you colder. So we pre-warm patients so that they're warm when they get into that cold environment and they're okay. And then we actually use those blankets during the operation on the part of their body that's not being operated on to keep their body temperature up by adding heat to their system. One more thing that actually works really well, it's not clear exactly who the right patients are to get it, but just giving your patient a higher inspire level of oxygen decreases their risk of surgical infection after a particularly high-risk surgery.
So if you have a high risk, it's easier to fix it, so patients who are cold in the surgery, the best studied, if they get 80% oxygen instead of 30% oxygen, have a reduce risk of infection. So that's a pretty easy thing to do, low risk.
Dr. Harriet Hopf: Everyone is trying to find out now what's the right amount of oxygen, who should get it...
Interviewer: Kind of fine tuning it.
Dr. Harriet Hopf: Fine turning. There's a lot of interest in dressings that can kill the bacteria so that you don't have ongoing bacteria. We give antibiotics. Antibiotics are a double-edged sword. They cause problems. Can we come up with ways to reduce the bacterial load on your skin without causing clostridium difficile colon infections and resistant organisms.
Interviewer: Like it can be great to get rid of the antibiotics entirely if you could.
Dr. Harriet Hopf: It would be lovely. So there is a lot of interest in what kinds of things you could put in the wound that would help kill bacteria. I know a lot of places are now using silver-impregnated dressing. Silver turns out to kill...
Interviewer: The metal silver.
Dr. Harriet Hopf: The metal silver. It's a special kind of the metal silver, but it's pretty good at killing bacteria, so there's a lot of interest in using silver-impregnated dressings on surgical wounds. When I think about how do you get infected, part of it is their bacterial load getting into the wound during the operation. But you always have bacteria on your skin. And you wash them of the surface, but then they come up from the deep levels. So if you put silver on them, then you can keep that level of bacteria down for several days, that can make a big difference.
Interviewer: Interesting. Briefly you had mentioned more risky surgeries. Are there some surgeries that are more likely to develop site infections that others?
Dr. Harriet Hopf: There are. So the higher risk surgeries include, if it's in a contaminated area. So the colon is a great example of, it's got a lot of bacteria in it. They do a lot of things to clean it out. Operations on the face almost never get infected, because there's a great blood supply. We worry about diabetic patients. When their blood sugar is not well controlled, their white cells don't work as well so they're at a higher risk. We worry about patients who have arterial occlusive disease, so if they are having an operation on their leg, and it's not great blood flow to their leg, they don't get as much oxygen. They're at a much higher risk for an infection.
There are some surgeries that have a lower risk of infection, but we spend a lot of time on, so joint replacement, usually hip and knee replacements. They usually have an infection risk of about one percent, between 1% and 5% variable, but...
Interviewer: Pretty good.
Dr. Harriet Hopf: Pretty low rate; however, if you get an infection after you get a metal prosthesis put in your knee, it's devastating. They usually have to take it out, because metal does not resist infection well. So it's a prolonged rehabilitation after that. So there's a lot of interest in getting the surgical site infection rate after knee surgery to zero, or after hip surgery to zero, because it's such a devastating complication. On the other hand, there are some surgeries where yes, you might get an infection, but it's not as devastating. You may have to do some wound care for a few weeks and then it gets better.
So I sort of look at it as there's the high risk, and I'm going to look at things that I can do in the high-risk patients, and I'm going to do it for all of those patients, because it has a big impact, because there are so many patients at risk. And then the low risk patients, where when they get an infection, it just is devastating.
Interviewer: Understood. So we talked a lot about what happens in the operating room, things that you are doing. But patients can actually do things themselves to help prevent these as well. What are some of those things?
Dr. Harriet Hopf: There is some idea that maybe your diet can be helpful. Let's say people who eat a lot of yogurt. There are countries where people eat a lot of yogurt and they have lower risk of surgical site infection, and there is an idea that that might help your personal flora. No studies showing that, but on the other hand, yogurt is not a bad thing to eat. It won't guarantee anything, but... People taking deep breaths after surgery make a big difference. So maintaining your oxygen level in your blood stream is really important.
Interviewer: Breathe from the stomach.
Dr. Harriet Hopf: Right.
Interviewer: What about smoking?
Dr. Harriet Hopf: Smoking is really bad. Smoking acutely, if you smoke a couple of cigarettes, it reduces the oxygen level in your skin by about 40% for an hour. So if you think of a pack a day smoker, their oxygen level in their skin is down 40% all of the time except maybe when they're sleeping. It probably comes back up to normal, so that's a big problem. And we know smokers don't heal well. And a lot of plastic surgeons won't do elective cosmetic surgery on smokers, because they know it's likely to fail.
Interviewer: So if a smoker knew that they had to get surgery, if they stopped smoking just a couple of days before, would that make a difference?
Dr. Harriet Hopf: That's an interesting question. So the answer is no, probably not. It makes probably some difference. But it turns out that there's a lot of affects of smoking that lasts for months after you quit. So you should quit now, just in case you have surgery in the future. There is some benefit of quitting right before surgery that you raise your oxygen levels, but your white cells still aren't working very well. Smoking is one of the biggest risk factors for surgical site infection that we know.
Interviewer: What else? Is there anything else that people should be aware of that they can actually do to help their doctor guarantee that they have a better outcome?
Dr. Harriet Hopf: If they have diabetes, controlling their diabetes is a really important thing. And that's one of the things that we look at. On the day of surgery, not letting themselves get cold before they get there would be helpful. Fluids are another important thing. Drinking enough fluids is really important for getting your blood supply to the wound and helping your body fight infection. A lot of patients now come in on the day of surgery. The anesthesiologist will make you not have anything to eat or drink overnight for safety so we don't want anything in your stomach when you become unconscious.
A lot of patients go home the same day of surgery and may not want to drink that much, but actually drinking fluids, keeping hydrated makes a difference. So that's something that patients can do particularly after surgery. Moving around is really important, kind of getting your blood flowing, but not, if it's particularly abdominal surgery lifting heavy things and stressing the wound, but a little bit of motion really helps with the whole healing process.
Interviewer: So it sounds like a good idea if you're going to be going in for surgery that you can actually as a patient do things. And just ask your doctor a lot of questions I think beforehand.
Dr. Harriet Hopf: Asking questions is always a great idea and finding out what is the risk of your surgery and are there particular things that you can do. And most surgeons can probably tell you things that you can do.
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