Surgical wound infections may ruin otherwise successful operations, and are associated with extended hospital stay, extra costs, and high mortality rates. In open surgery the wound's exposure to ambient air increases the risk of wound infection via several independent factors. The open surgical wound is subjected to airborne bacterial contamination, desiccation, and heat loss that increase the bacterial load, cause superficial necrosis, and impair tissue oxygenation and cellular immune functions, respectively. The present hypothesis is that topically applied carbon dioxide in the open surgical wound can be used intraoperatively to avoid these risks, and thus help to prevent postoperative wound infection. We also criticize existing methods and describe the theoretical background and supporting evidence for our suggested method. If the hypothesis would prove to be correct in a clinical trial, the new method may be an effective complement, or even an alternative, to antibiotics in preventing surgical site infection.