WHY IS THIS IMPORTANT?
Wound infections are a fairly common complication of surgery - and when they occur they are potentially a serious problem for the patient. In addition, treatment of surgical infection costs a great deal of money - consider that expenditure on a national level and it adds a great deal to out health care bill each year. In this study, researchers showed that the utilization of oxygen in high concentrations (80%) is a treatment that costs pennies - but can reduce an expensive complication by a significant amount.

STUDY SUMMARY
Five hundred patients were divided into two groups - all the patients had colorectal surgery and received the same preparation and antibiotics. One group received thirty percent oxygen during the surgery and for two hours after the surgery. The other group received eighty percent oxygen during the surgery and for two hours after the surgery. This oxygen was delivered by a simple mask. While arterial oxygen saturation (a simple measure of oxygen level in the blood) was normal in both groups, the group with the higher oxygen delivery had higher tissue delivery of oxygen - and fifty percent lower infection rates.

CAVEATS
Oxygen is not the same as the air that we breathe. Air is composed of twenty-one percent oxygen as well as nitrogen and other gases. When oxygen is given in higher concentrations such as in this study - it is considered a drug. As with any drug, there are some potential side effects - and these side effects are increased as the oxygen becomes more concentrated. Not every patient can tolerate high levels of oxygen - and there is the potential for damage to the lungs when high concentrations are given for a long period of time.

Oxygen is a drug that should be given under medical supervision - with potential risks and side effects. While it has a lot of potential benefits, care must still be exercised.

WHAT STILL NEEDS TO BE ANSWERED
These results are promising - but the study leaves some questions to be answered:

• First, the duration of oxygen delivery was somewhat arbitrarily chosen to be two hours after surgery. Does it need to be that long? Would giving oxygen for more than two hours show even better results?
• Second, why does it work? It is postulated that oxygen helps to kill bacteria by activating the white blood cells in the immune system - it is these white blood cells that move to the site of injury or infection. Is this the reason for this result?
• Third, are the results applicable to all patients and all surgeries? What about for surgeries that are less complicated than colorectal surgery, or have a reduced chance of infection to begin with? Logically, the benefits should still be there - but this remains to be proven.