The Centers for Disease Control (CDC) officially issued guidelines for surgicalsiteinfection (SSI) prevention in 1999, defining SSI and developing a series of SSI prevention measures based on available information and literature. Some of these measures were based on clear evidence-based medical evidence, while others were empirical and left a number of unanswered questions. The subsequent 10 years of clinical practice, after acting according to these guidelines, have resulted in a significant reduction in the incidence of SSI. As a result of extensive research, some remaining issues have been resolved, some concepts have been updated, and some measures have been improved. However, problems remain in clinical practice, with some studies concluding that some of the measures in the guidelines are not sufficiently adherent to be implemented in clinical work, and some studies concluding that the guidelines do not apply to all procedures. Alexander, a renowned surgeon, has analyzed and summarized the results of these studies, and combined them with his own surgical practice to present his views as an update to the SSI guidelines. Our surgical colleagues should pay attention to this. To this end, this update is interpreted to help the majority of surgeons update their knowledge, update their concepts and improve their clinical practice work.
A, reduce contamination (aseptic surgery)
1, the operating room environment: in the operating room air microbial reduction, that high efficiency air particle filter can provide the best operating room environment, while the laminar flow system in the prevention of surgical site infection effect is worse than the high efficiency particle filter. Restrictions on surgical staff activity and meaningless conversations were again emphasized. The role of wearing sterile gloves in preventing surgical site infections has been widely recognized, and in recent years new studies have confirmed this, emphasizing that the use of double-indicator type double gloves can be more effective in preventing surgical site infections.
2, preoperative use of antiseptic froth bath: In the past, it was believed that preoperative bathing with antiseptic could reduce the number of bacteria on the skin, but there was no clear relationship with reducing the incidence of SSI. And the update showed that although the use of chlorhexidine bathing agent was repeatedly shown to reduce the bacteria on the surface of the surgical site, the rate of wound infection was not significantly reduced. It also mentions that the timing of bathing affects the effectiveness of the bathing agent, and that preoperative washing with chlorhexidine soaked bath towels may be more effective. At present, many large hospitals in China have gradually improved their ward facilities and are in a position to implement preoperative bathing. This measure can be promoted in hospitals that are in a position to do so.
3. Hair removal: It has been established in the guidelines that preoperative shaving of the surgical site is associated with a significantly increased risk of SSI compared to the application of hair removal agents or no shaving. It is recommended not to shave the hair preoperatively unless it is around the incision and will interfere with the surgical operation, and if skin preparation is required, it should be done before the start of the procedure, preferably using an electric push knife. Updates suggest that to avoid skin damage, the optimal method is to cut the hair during care. Most studies support the removal of hair immediately prior to surgery. Although this has been recommended in the guidelines as a Class I strong recommendation for implementation, the specific implementation by our surgeons has been less than ideal so far, with many still following traditional practices. Therefore . It is very important to update the concept, which requires all surgeons to accept this view and change from the system, routinely equipped with electric push knife.
4, skin disinfection: the guidelines list alcohol, chlorhexidine, iodine or iodophor, p-chloro-m-xylene phenol and triclosan can be used as preoperative skin disinfectants, and the update proposes the application of alcohol through a summary of recent literature. Chlorhexidine mixed gel preparation for 2 to 3 min scrubbing hard can achieve better results. Li in the surgical site using iodophor-alcohol or chlorhexidine-alcohol system of thorns may be the best method at present. Some large hospitals in China have started to use chlorhexidine and alcohol gel to wash their hands before surgery, while most hospitals have been using iodophor to disinfect the skin for a long time, so the concept needs to be updated. Economic aspects also need to be considered, when the economic conditions are ripe for the gradual use of some new disinfectant agents.
5, surgical film: the use of skin patches containing disinfectants, in the past that there is no advantage. Instead, it is now believed that whether the use of antimicrobial surgical patches can reduce the rate of infection at the surgical site depends on the composition of the patch, the skin preparation, and the adhesion of the patch to the skin at the wound edge. Of these, the technique of the patch is key. The addition of an iodine agent to the patch makes it easier to adhere. The best adhesion is achieved by applying alcohol first, then disinfecting the skin with an alcohol or iodophor solution, allowing it to air dry, and then applying the film. Wound contamination caused by skin microorganisms does not occur when the skin patch is applied correctly to prevent lifting of the skin edge of the incision. Recent studies have suggested that using cyanoacrylate to seal the surgical site can reduce the number of bacteria colonizing the incision, but its ability to reduce infection needs further study.
Second, reduce the impact of contamination (antimicrobial surgery)
1. Sutures: Sutures are one of the major causes of surgical site infections and have been covered in the guidelines, while the update emphasizes the importance of sutures in surgical site infections through more analysis of old and new literature. The properties of various sutures and their ability to fight infection are compared. The update states that the use of braided sutures such as silk sutures can increase infection rates by a factor of 10,000. The use of monofilament sutures compared to multifilament sutures. The incision infection rate is much lower. Because bacteria are less bioadhesive to monofilament sutures, phagocytes are more likely to engulf the bacteria on the surface and inside the suture. The infection rate is lower with continuous sutures than with interrupted sutures. This may be because there is less necrotic tissue at the suture site, more uniform tension distribution, and less suture material left in the wound. Sutures containing antimicrobial substances may be beneficial, but further confirmation in tightly controlled experiments is needed. Some synthetic absorbable sutures are already being used gradually in large hospitals in China. Clinical practice has shown good results, but the extension of the use of these sutures requires a change of concept and economic considerations. It can be used in patients with a high risk of infection first, in order to exchange the minimum cost for the maximum effect.
2, tissue damage and foreign bodies: excessive tissue damage and foreign bodies will increase the incision infection rate. Although there is no clear evidence of increased infection rates with the use of intraoperative electrocoagulation, expert opinion is that electrocoagulation should be used primarily for those prone to bleeding, rather than in all patients, to minimize tissue damage. In addition, multiple layers of sutures to eliminate potential dead spaces can also be effective in preventing wound infection in contaminated areas. For surgical procedures, surgical technique remains the key to affecting incisional infections, and antibiotics and other methods do not fully compensate for poor surgical technique.
3, drainage: drainage is a common technique in surgery, and it has been clear for many years that placing a drain through the incision increases the risk of infection, and the incidence of SSI is lower with the application of closed drainage than with open drainage. In contrast, the results of recent bulk pathology reports and meta-analyses have shown that closed drainage does not show an advantage in reducing the incisional infection rate. Therefore . It should be recognized that drainage serves only to drain fluid from larger potentially dead spaces, but does not prevent infection. This provides the basis for clinical reduction of drain placement and potentially accelerates the patient’s postoperative recovery.
4. Application of prophylactic topical antibiotics: The guidelines for the application of topical prophylactic antibiotics only mention that mupirocin as a topical agent can effectively eliminate Staphylococcus aureus colonized in the nostrils of patients or medical personnel, and that the role of mupirocin in reducing the risk of SSI is to be clarified. The update suggests that topical antibiotics significantly reduce the rate of incisional infections and may be as effective as systemic antibiotics. The combination of topical and systemic antibiotics has a superimposed effect. However, the effect is diminished if the same antibiotic is used. Multiple topical antibiotics were more effective throughout the procedure compared with antibiotic irrigation at the time of incision closure only. However, the optimal interval between doses is unclear. Injecting antibiotics into the incision and maintaining them until the incision is closed, or using antibiotic extended-release materials (which do not need to be removed when the material is biodegradable), may ensure higher drug concentrations. However, there are limited clinical options available.
5, systemic prophylactic antibiotics: perioperative systemic prophylactic antibiotics is the key to prevent incisional infections, although the guidelines have made clear provisions on this issue, but for a variety of reasons, the rate of implementation in accordance with the guidelines is not satisfactory. With the publication of a large amount of research data, some provisions of the original guidelines have been modified and improved in the update.
(1) It is generally accepted that prophylactic antibiotics are not required for clean procedures, but current research data suggest that. However, current research data suggest that prophylactic antibiotics are beneficial for all procedures. The update also includes antibiotic recommendations for relevant procedure types.
(2) The guidelines recommend against the routine use of vancomycin as a prophylactic agent. Instead, the results of numerous studies now show that prophylactic use of vancomycin in certain procedures results in the lowest incisional infection rates. Therefore, prophylactic use of vancomycin is increasingly common and is recommended for prosthetic implantation, sternotomy, and craniotomy procedures. However, the effective dose has not been validated by extensive data.
(3) The timing of antibiotic administration is also clearly required in the update, except for vancomycin and fluoroquinolones. The most effective time of administration for the remaining drugs is within 30 min before incision. Cephalosporins penetrate well into the incision early. Long-acting antibiotics, such as vancomycin and fluoroquinolones, should be administered within 1 to 2 h before incision.
(4) For the dose administered, the update states that the dose administered needs to be adjusted for larger patients. A large number of cases without serious infection have shown that it is not beneficial to give the drug after closing the wound. Therefore, the previous protocol of routinely administering 3 doses of antibiotics should be abandoned. And the additional drug dose needs to be adjusted according to the renal function and drug metabolism rate.
Third, the improvement of the body’s defense function
1. The effect of body temperature: The guidelines have focused on the relationship between hypothermia and SSI. Subsequent studies have confirmed that hypothermia impairs the normal physiological and immune functions of the body and that the immune mechanism is not effective in sterilization, which increases the rate of incisional infection. More studies have shown that hypothermia may be more beneficial than normal body temperature in preventing incisional infections, and that a large number of important immune response mechanisms are enhanced when human body temperature reaches 40°C. Whether moderate hypothermia or normothermia has a synergistic or additive effect with hyperoxia (especially in smokers and diabetics) has not been clarified. Many large hospitals in the country are already equipped with thermal blankets. They play an important role in the resuscitation and treatment of critically ill patients. The insulation during surgery is not ideal, therefore, awareness is the key and attention to detail is very important. In addition to the application of insulation blankets, room temperature, infusion temperature, and rinse fluid temperature need to be maintained. It does not need to be very costly to achieve good results.
2, the role of oxygen inhalation: the previous view did not recommend measures aimed at increasing the oxygen content of the wound to prevent SSI. but in the update, some studies have shown that . An increase in partial pressure of oxygen inhalation from 30% to 80% increased the partial pressure of oxygen at the incision. enhanced bactericidal capacity and reduced the rate and severity of incisional infections. However, not all experiments support this conclusion, and there may be other factors that reduce tissue oxygen partial pressure and thus alter the effect of high oxygen concentrations, including body temperature, blood pressure, smoking, type of anesthesia, population differences, differences in fluid therapy, use of boosters, and type of surgery. It is worth noting that in the past it was thought that compared to open surgery . The risk of SSI in laparoscopic surgery is lower or similar. In recent years, it has been shown that subcutaneous partial pressure of oxygen is significantly lower in patients undergoing laparoscopic surgery than in open surgery, and the incisional infection rate is higher. The optimal concentration and duration of oxygen inhalation has not been determined. The latest recommendation is that oxygen should be administered continuously for at least 2h after closing the incision.
3. Glycemic control: The relationship between glycemic control and SSI has been receiving attention. A consensus has been reached in a large number of studies after 1999. Hyperglycemia is a risk factor for surgical site infection and is independent of diabetes mellitus as a factor. Hyperglycemia impairs a large number of host immune responses, and increased blood glucose levels increase the rate of infection at the incision site. However, there is a risk of hypoglycemia after aggressive treatment with insulin and close monitoring is required. The updated recommended target for blood glucose control is less than 10 mmol/L.
4. Blood transfusion and fluid therapy: It has been recognized in the guidelines that perioperative transfusion of allogeneic blood products containing leukocytes is a clear risk factor for the occurrence of postoperative infections, including the occurrence of SSI. However, because there were more factors influencing the published literature at that time, it was considered at that time that there was no scientific evidence to show any association between reducing blood transfusion to surgical patients and reducing the risk of incision or organ (tissue) SSI occurrence. Therefore, it was proposed that in surgical patients, discontinuation of necessary blood products should not be used as a method of SSI prevention. In contrast, many subsequent reports have shown that postoperative blood transfusions increase the rate of infection, and multifactorial analysis and animal studies have shown that transfusions and infection rates are associated in a dose-related manner. There is evidence that transfusion of blood with de-leukocytes reduces the risk of infection from transfusion. Blood transfusion affects almost every aspect of immune function, most notably macrophage function. Therefore, transfusions in the perioperative period should be done with caution and should be minimized or avoided whenever possible.
Perioperative fluid therapy has received much attention and debate in recent years. It is now clear that intraoperative input of excessive crystalloid fluid can decrease the oxygen content at the incision site, thereby increasing the rate of infection and the severity of infection. Therefore, intraoperative restrictive rehydration is more beneficial than free rehydration.
5. Smoking: A consensus has been reached for many years that smoking is very harmful to postoperative recovery. Smoking can slow down wound healing and may increase the risk of SSI. Smoking increases the rate of infection in surgical incisions through a variety of mechanisms, such as vasoconstriction, which decreases tissue oxygen partial pressure. Whether administering high concentrations of oxygen or heat to smokers reduces the incisional infection rate to the level of nonsmokers is unclear and requires prospective pilot studies. Although quitting jong appears to reduce incisional infection rates, the optimal time to quit smoking is unclear, and available data suggest that quitting for at least 4 weeks is effective.
6. Delayed closure of the incision: The guidelines do not specifically address delayed one-stage closure of the incision and only mention it slightly in the section on postoperative incision care. Delayed closure is only considered when the surgeon believes that the wound may be contaminated or the patient’s condition does not allow for a one-stage closure.
The update uses extensive literature to describe delayed closure of incisions. The results of a recent prospective follow-up study suggest that delayed closure incisions are beneficial for other types of surgery except appendicitis, typhoid ileal perforation, and ileostomy, and are most beneficial for contaminated abdominal incisions, but not for appendicitis surgery and not for patients with open fractures. The benefit of delayed closure incisions was associated with improved blood flow to the incision margins, with a significant increase in blood flow to the wound margins and increased resistance to infection during the first few days.
The concept of delayed closure of the incision has been further confirmed in recent years. It has been further expanded with the use of negative pressure drainage for closure of contaminated wounds, vacuum negative pressure drainage for treatment of open abdominal wounds to assist fascial closure. Or for larger open wounds to drain exudate and accelerate granulation tissue growth.
Delayed closure of highly contaminated wounds is beneficial to promote migration of functional phagocytes to the wound and increasing numbers during the first 5-6 d. Strict adherence to the principles and guidelines described in this article . It is possible to reduce the infection rate of clean-grade surgical incisions to less than 0.5%, clean-contaminated surgical incisions to less than 1.0%, and contaminated surgical incisions to less than 2.0% (including critically ill patients). The following measures should be helpful for clinical work.
1. Follow the guidelines of the Centers for Disease Control and the accreditation body JACO. These include effective aseptic technique, air handling, cleaning of environmental surfaces, sterilization techniques, activities of surgical team members, and surgical gowns.
2. All surgical staff wear double gloves and change gloves immediately if they break during surgery. Use surgical gowns and sterile towel sheets that prevent fluid penetration.
3. Shower with chlorhexidine several hours prior to surgery and the evening before. Clean the surgical site with a chlorhexidine impregnated washcloth before entering the operating room.
4. Trim and remove hair with a hair clipper prior to surgery.
5. Disinfect with a mixture of alcohol and chlorhexidine to reduce microorganisms on the surgical team and patient’s skin. Other effective products including iodophor alcohol may also be used.
6. Apply an antibacterial surgical patch to the surgical site and make it adhere well to the skin.
7. Use suture materials that are resistant to infection.
8.Anti-fire the dead space as much as possible.
9. Minimize trauma to the wound itself and treat the tissue gently. Limit the use of electrocautery and remove as much inactivated tissue as possible.
10.Do not place drains or drainage from the incision.
11. Use prophylactic topical antibiotics such as 0.1% kanamycin or other aminoglycosides (e.g., gentamicin 160 mg/500 ml) and pressure wash with antibiotics several times during the procedure and before closing the incision to remove blood clots and inactivated tissue and to ensure high levels of antimicrobial agents in the tissue. For patients with a subcutaneous fat layer greater than 3 inches (7.5 cm), antibiotics are injected into the wound with a small catheter after closure of the incision and retained for several hours before drainage of fluid by closed drainage.
12. When the nosocomial infection rate exceeds 0.5%, or when a foreign body is implanted, all surgical patients require prophylactic systemic antibiotics according to guidelines.
13.Maintain a deep body temperature greater than or equal to 36°C during the perioperative period.
14.Give sufficient inhaled oxygen concentration to maintain subcutaneous oxygen concentration at approximately 100 mmHg and pulse oxygen over 96%.
15.All diabetic and hyperglycemic patients undergo strict glycemic control (less than 10 mmol/L) during the perioperative period, with some high-risk patients prolonged for 2 to 3 d.
16.Restrict transfusion of blood products.
17. Undergo elective surgery (e.g., abdominoplasty) and quit smoking for at least 4 weeks prior to surgery.
Research on SSI prevention in China is still lacking in a systematic way. In 2006, the Surgical Infection and Critical Illness Group of the Chinese Medical Association’s Surgery Branch proposed guidelines for SSI prevention in China, based on the CDC guidelines and combined with clinical practice in China. Subsequently, a series of studies have been conducted by surgical scholars in China. In comparison with this update, there are still more improvements needed in our surgical practice, many ideas need to be promoted urgently, and some measures need to be researched and improved according to the actual situation in China, so as to develop new guidelines for the prevention of SSI in the midst of distress in line with the national situation.