外科感染与抗生素（英文ppt）surgicalinfection and

SURGICAL INFECTION AND ANTIBIOTICS OUTLINE l Introduction and overview l Definitions and SIRS l Risk factors for surgical infections l Strategies for infection prevention l Peritonitis and intraabdominal abscess l Special infections l Infection risk for the surgeon SURGICAL INFECTION AND ANTIBIOTICS Infection The inflammatory response to the presence of microorganisms SURGICAL INFECTION AND ANTIBIOTICS Sepsis The systemic inflammatory response syndrome in response to infection SURGICAL INFECTION AND ANTIBIOTICS Severe Sepsis Sepsis associated with organ dysfunction, hypoperfusion or hypotension SURGICAL INFECTION AND ANTIBIOTICS Septic Shock Sepsis with hypotension, despite adequate fluid resuscitation, along with the presence of perfusion abnormalities that may include, but are not limited to, lactic acidosis, oliguria, or an acute alteration in mental state SURGICAL INFECTION AND ANTIBIOTICS The Systemic Inflammatory Response Syndrome l Caused by the systemic effects of locally released cytokines l Cytokine release can be triggered by both infectious and noninfectious insults l Provides a conceptual framework for the understanding of ARDS and MODS in the absence of infection SURGICAL INFECTION AND ANTIBIOTICS Systemic Inflammatory Response Syndrome Manifested by two or more of the following: l Temperature 38 C or 90 l Respiratory rate 20 or PCO2 12 K 10% bands SURGICAL INFECTION AND ANTIBIOTICS Multiple Organ Dysfunction Syndrome The presence of altered organ function in an acutely ill patient such that homeostasis cannot be maintained without intervention SURGICAL INFECTION AND ANTIBIOTICS Risk Factors for Surgical Infection l Surgical wound class l SENIC project l NNISS SURGICAL INFECTION AND ANTIBIOTICS Surgical Wound Class l Developed by National Research Council in 1964 l Classifies wounds into one of four classes based on degree of contamination Clean Clean contaminated Contaminated Dirty SURGICAL INFECTION AND ANTIBIOTICS Study on the Efficacy of Nosocomial Infection Control l Published by Haley in 1985 l Utilizes four risk factors to stratify risk Abdominal operation Operation longer than 2 hours Contaminated or dirty wound class Having 3 or more medical diagnoses SURGICAL INFECTION AND ANTIBIOTICS National Nosocomial Infection Surveillance System l Developed by Centers for Disease Control l Uses 3 risk factors ASA score of 3 or greater Operation classed as contaminated or dirty Operation of longer than “T” hours with “T” being operation specific SURGICAL INFECTION AND ANTIBIOTICS Antibiotic prophylaxis lMust be given pre-incision lNo justification for additional dosing lAppropriate pharmacokinetics lBenefits outweigh risks SURGICAL INFECTION AND ANTIBIOTICS Peritonitis and Intraabdominal Abscess Conventional Principles of Management l Control source of contamination l Irrigation of peritoneum with saline l Closure of the abdomen l Close monitoring SURGICAL INFECTION AND ANTIBIOTICS Peritonitis and Intraabdominal Abscess Antibiotic Therapy l Usually empiric l Rarely altered by culture data l Should include anaerobic coverage SURGICAL INFECTION AND ANTIBIOTICS Peritonitis and Intraabdominal Abscess Duration of Antibiotic Therapy l Often empiric e.g. 5,7,10 or 14 days l Often unnecessarily prolonged l Usually not based on clinical parameters SURGICAL INFECTION AND ANTIBIOTIC Peritonitis and Intraabdominal Abscess Duration of Therapy l Patients who are afebrile and with normal WBCs rarely develop further infection if antibiotics are stopped l Approximately 30% of patients who are afebrile but with leukocytosis develop further infection when antibiotics are stopped l Approximately 80% of patients who are still febrile at the conclusion of antibiotics will develop further infection SURGICAL INFECTION AND ANTIBIOTICS Peritonitis and Intraabdominal Abscess Duration of Therapy Summary l Afebrile patients with normal WBC-stop antibiotics l Afebrile patients with leukocytosis-either continue antibiotics or evaluate for residual infection l Febrile patients-evaluate for residual infection SURGICAL INFECTION AND ANTIBIOTICS Special Infections l Fungal infections l Diabetic foot infections l Hand infections l Invasive streptococcal infections l C. dificile infection l Tetanus SURGICAL INFECTION AND ANTIBIOTICS Fungal Infection l Fungal colonization common in ICU l Fungal infection less common l Risk factors for fungal infection Severity of illness (APACHE 20 or ) Intensity of colonization SURGICAL INFECTION AND ANTIBIOTICS Fungal Infection l Diagnosis depends on high index of suspicion l Careful culture of blood, urine, sputum, and drain material l Eye examination important SURGICAL INFECTION AND ANTIBIOTICS Fungal Infection Therapy l Amphotericin B 0.5 mg/kg/day IV for 7-10 days l Fluconazole 400 mg/day po for additional 7 days l Remove central venous catheters SURGICAL INFECTION AND ANTIBIOTICS Diabetic Foot Infection Risk Factors for Foot Problems l Neuropathy l Vascular insufficiency l Altered response to infection SURGICAL INFECTION AND ANTIBIOTICS Diabetic Foot Infections Role of Antibiotics l Antibiotic therapy is an adjunct to overall surgical care l Most infections polymicrobial l 90% are gram + organisms l 50% are gram - organisms l 50% are anaerobes SURGICAL INFECTION AND ANTIBIOTICS Hand Infections l Commonly seen ER condition l 60% trauma 30% human bites 10% animal bites l Most infections result from neglected injury l Antibiotics given early prevent many complications l Reaction to infection determined by anatomic compartments of hand SURGICAL INFECTION AND ANTIBIOTICS Microbiology of Hand Infections l Microbiology depends on type of injury l Staph aureus in 35% l Anaerobes in 35% l 50% of human bites infections are predominantly anaerobic SURGICAL INFECTION AND ANTIBIOTICS Antibiotics in Hand Infections l Coverage should be directed by culture data l In the absence of culture material use broad spectrum penicillin plus B-lactamase inhibitor (e.g. amoxicillin/clavunanate) l Erythromycin a good alternative in penicillin allergic patients SURGICAL INFECTION AND ANTIBIOTICS Hand Infections Management Principles l Immobilization l Splinting l Rest l Elevation l Surgical drainage l Appropriate antibiotics SURGICAL INFECTION AND ANTIBIOTICS Invasive Streptococcal Infections l Include puerperal sepsis, scarlatina maligna, septic scarlet fever, bacteremia, erysipelas, necrotizing soft tissue and fascia infection, gangrene, and myositis l Recent increase in the number and virulence of these infections l Occur mainly in healthy, immunocompetent patients SURGICAL INFECTION AND ANTIBIOTICS Necrotizing Soft Tissue and Fascial Infection l First described by Meleney in 1924 l Preantibiotic era mortality rate 20% l Modern era mortality rate 50% l Increase in virulence? l Decrease in specific immunity? SURGICAL INFECTION AND ANTIBIOTICS Necrotizing Soft Tissue and Fascial Infection Presentation l 80% follow minor trauma l 20% post operative l Initial lesion frequently mild erythema l Swelling, heat, erythema occur rapidly and spread from initial lesion l Systemic toxicity early and severe SURGICAL INFECTION AND ANTIBIOTICS Necrotizing Soft Tissue and Fascial Infection Microbiology l Group A hemolytic strep l Staph Aureus l Enteric organisms including Clostridia species SURGICAL INFECTION AND ANTIBIOTICS Necrotizing Soft Tissue and Fascial Infection Treatment l Aggressive surgical debridement l Initial empiric antibiotic coverage for Staph, Strep, Enterics including Clostridia l Tailor antibiotic coverage to culture results SURGICAL INFECTION AND ANTIBIOTICS Clostridium Dificile Associated Diarrhea l Most common cause of nosocomial diarrhea on surgical units l Variable manifestations including No symptoms Peritonitis, toxic megacolon, perforation, death SURGICAL INFECTION AND ANTIBIOTICS Clostridium Dificile Associated Diarrhea Clinical Criteria for Diagnosis l 3 or more loose stools per day for 2 days without an obvious cause l Previous antibiotic or antineoplastic administration within 6 weeks l Response of the diarrhea to oral vancomycin or metronidazole SURGICAL INFECTION AND ANTIBIOTICS Clostridium Dificile Associated Diarrhea Laboratory Criteria for Diagnosis l C. dificile culture-most sensitive test l C. dificile toxin assay-most specific test l Clinical diagnosis plus positive culture adequate to confirm diagnosis SURGICAL INFECTION AND ANTIBIOTICS Clostridium Dificile Associated Diarrhea Endoscopic Diagnosis l Scope options Rigid proctosigmoidoscope (25 cm) Flexible sigmoidoscope (60 cm) Colonoscopy l If patients do not have pseudomembranes on limited exam, then colonoscopy indicated l Lack of pseudomembranes DO NOT rule out disease SURGICAL INFECTION AND ANTIBIOTICS Clostridium Dificile Associated Diarrhea Severe Disease l Uncommon (0.39% of patients with CDAD) l Indications for operation Signs of peritonitis Signs of organ failure Worsening CT findings l Surgical procedure of choice-Total abdominal colectomy with ileostomy l Mortality rate 36% SURGICAL INFECTION AND ANTIBIOTICS Tetanus l Preventable disease l 100 new cases reported per year in USA SURGICAL INFECTION AND ANTIBIOTICS Tetanus Prophylaxis Guidelines ACS Committee on Trauma General Principles l Guidelines for both general and specific preventive measures are available l Prevention depends upon Adequate immunization of general population Good surgical wound care Passive immunization with tetanus immune globulin-human as indicated SURGICAL INFECTION AND ANTIBIOTICS Infection Risk for the Surgeon l HIV l Hepatitis B l Hepatitis C SURGICAL INFECTION AND ANTIBIOTICS HIV l Risk of infection relatively low (0.3-0.1%) l Universal precautions for all cases l A