Update on Treatment of Surgical Infections

Transcription

1 Update on Treatment of Surgical Infections Michael A. West, MD, PhD Department of Surgery University California San Francisco San Francisco, CA, USA Balance of Factors Normally Prevents Infection Bacterial Factors Environmental Factors Host Defenses Virulence Factors: Polysaccharide Capsule of B. fragilis Encapsulated = Abscess Unencapsulated

2 Microbial Synergy = 3 Microbial Synergy in Mixed Infections 100 Mortality (%) E. coli 2 x10 8 plus B. fragilis 2 x10 9 E. coli 2 x Days Oxidative Killing Mechanisms for Destruction of Microbes Note: System REQUIRES molecular Oxygen O 2 e - - O 2 - O 2 superoxide anion SOD O 2 H 2 O 2 H 2 O HOCl 1 O 2 hypochlorus acid MPO H 2 O 2 hydrogen peroxide Fe 2+ Fe 3+ H 2 O singlet oxygen OH + Cl - H + hydroxyl radical H 2 O

3 Diagnosis of Sepsis / Infection Antibiotic Therapy Intravenous ABX should be started within 1 hr of recognition of severe sepsis, after cultures obtained. GRADE 1B/C Initial empiric ABX should include > 1 drug with activity against likely pathogens. GRADE 1B Dellinger RP, et al., Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: Crit Care Med : Antibiotic Therapy Reassess anti-microbial regimen daily to optimize efficacy GRADE 1C Duration of Rx should typically be limited to 7-10 days GRADE 1D Dellinger RP, et al., Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: Crit Care Med :

4 Glue Grant SOP for Antibiotic Administration in Critically Ill Patients with Severe Injury* Clinical Dx Requiring Treat with Antibiotics 1 Site Infection Identified? 1 No Empiric Broad Spectrum Rx 2: Coverage for Gm+ and Gm- aerobes and anaerobes. Consider origin of infection (community vs. hospital), site, suspected pathogens, and local sensitivity Empiric Rx: pip/tazo + vanco, imipenem + vanco, cefipime + flagyl + vanco Intraabdominal Source? No (IAI) Pneumonia? (+Quant Bact.) VAP, HAP, No HCAP Skin/ Skin Structure Infection? (SSSI) No Catheter Infection? (CVCI) > 4 day admit? resist org? No > 4 day admit? resist org? No Nec. Fasc.? Severe SSSI? No Cover Gm- aerobes & anaerobes. Empiric Rx: pip/tazo, carbepenam, or tigecycline.? ± anti-fungal) Cover Gm- and Gm+ aerobes. (MRSA, VRE), Pseudomonas, and Acinetobacter Empiric Rx: vanco or linezolid plus pip/tazo, carbepenam aminoglycoside,or cefepime Cover Gm+ & Gm+ aerobes, & anaerobes. Strep, Staph sp. Empiric Rx: PCN, vanco, pip/tazo, (Note: clinda may inhibit toxin production.] Cover Gm+ aerobes: MSSA, MRSA, Staph epi, Empiric Rx: vanco, linezolid Cover Gm- aerobe & anaerobes. Empiric Rx:: unasyn, ertapenem, moxifloxacin, or cipro/levaquin + metronidazole Cover Gm- aerobe & anaerobes Empiric Rx: unasyn, cefoxitin, ertapenem, moxifloxacin, or fluroquinolone + metronidazole Cover Gm+ (& Gm-) aerobes Empiric Rx: cefazolin, ertapenem, moxifloxacin Cont. * West MA, et al., Patient-Oriented Research Core-Standard Operating Procedures for Clinical Care VII: Guidelines for antibiotic use in the trauma patient. J Trauma. 2008; 65: Source Control Pts with sepsis should be evaluated for focus amenable to source control (e.g., drain abscess, debride necrotic tissue, etc.) as rapidly as possible GRADE 1C Source Control Pts with sepsis should be evaluated for focus amenable to source control (e.g., drain abscess, debride necrotic tissue, etc.) as rapidly as possible (within 6 hours) GRADE 1C Once a focus is identified (e.g., abscess, GI perforation, cholangitis, etc.) source controls measures should be instituted ASAP after resuscitation with least insulting intervention GRADE 1D Dellinger RP, et al., Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: Crit Care Med :

5 Intra-abdominal Surgical Infections Classification of Peritonitis Primary Secondary Tertiary Types of Patients Immunocompromised Pts with Cirrhosis Children Relatively Normal Patients Compromised ICU Patients MODS / MSOF Source of Bacteria Exogenous Endogenous Endogenous # Bacterial Species Single Multiple Multiple Surgery Required Seldom Usually Varies Defect in GI Tract Serosa Muscularis Mucosa Serosa Muscularis Mucosa Mucosa Muscularis Serosa

6 Role of Aerobes and Anaerobes in a Rat Model of Intra-abdominal Sepsis % of subjects 40 % Abscess % Mortality 20 0 E. coli B. fragilis E. coli + B. fragilis Inoculum into Peritoneal Cavity Pathogens in Intra-abdominal Infections Aerobes Escherichia coli* % 38 Anaerobes Bacteroides fragilis* % 24 Streptococcus faecalis 12 Other Bacteroides spp.* 24 Proteus spp. 11 Clostridia 15 Klebsiella spp. 10 Other anaerobes 14 Other Streptococci Other aerobes 9 6 Peptostreptococci Fusobacteria 8 5 Enterobacter spp. 5 Peptococci 5 Pseudomonas aeruginosa Staphylococcus aureus 5 4 Propionibacteria Veillonella 3 2 *E. coli and Bacteroides are the most commonly isolated microorganisms in intra-abdominal infections (Condon et al 1998, p. 657) Adapted from Condon RE et al. Intra-abdominal infections. In: Gorbach LG, Bartlett JG, Blacklow NR, ets. Philadelphia, Pa: W.B. Saunders, Co; Surgical Infection Society (SIS) 2002 Guidelines: Antimicrobial Therapy for Intra-Abdominal Infections 1 Single Agents AM / SBT CTT CEX ERT IMI / CIL MER PIP / TAZ TIC / AMC Combination regimens AMGs (AKN, GENT, NET, TOB) + an antianaerobe AZT + CLIN CXM + MTD CFL + MTD Third/ fourth-generation CEPHs (CPM, CFX, CEF, CTZ, CXO) + an antianaerobe 1 Mazuski JE, Sawyer RG, Nathens AB, et al. for the Therapeutic Agents Committee of the Surgical Infection Society. The Surgical Infection Society guidelines on antimicrobial therapy in intra-abdominal infections: an executive summary. Surg Infect. 2002;3: excerpted from page 165, Table 4.

7 Source Control in the Proximal GI Tract: Influence of Anatomic Location II I III IV Intra-abdominal Sepsis: Treatment Correct the primary pathology!!!? exploratory surgery resect, patch, repair, debride, or drain underlying cause Aggressive resuscitation and monitoring enormous "third space" fluid losses Important role for appropriate antibiotics knowledge of pathogens based on origin of bacterial inoculation Damage Control Laparotomy Focus treatment on immediately life-threatening injuries. Non-life-threatening injuries can be treated at planned reoperation. Avoids hypothermia. Examples: - Pack liver injuries. - Delay bowel anastamoses, stoma - Delay vascular reconstruction IF feasible.

8 Patients Who May Benefit from Damage Control Approach Hemodynamically unstable Coagulopathy Hypothermia (< 35 C) Complex and major visceral injuries Inability to control bleeding Severe acidosis (<7.30) Operative time > 90 minutes Transfusion 10 U PRBC Kourkalis G, Surg Today (2002) 32: Temporary Abdominal Closure Temporary Abdominal Closure (plastic drape, JP drains, sponge) Bogota Bag (sterile plastic sheet sewn to skin) Topical Negative Pressure Therapy (VAC) Admission Intra-abdominal Pressure in ICU Patients Malbrain ML. Incidence and prognosis of intraabdominal hypertension in a mixed population of critically ill patients: A multiple-center epidemiological study. Crit Care Med 2004, 33:

9 Predisposing Factors for IAH after Damage Control Surgery Severe abdominal injuries Spillage of intestinal contents (massive contamination) Intra-abdominal packing for coagulation Massive transfusions with bowel edema and/or congestion Failure to control bleeding with resultant worsening acidosis and coagulopathy Kourkalis G, Surg Today (2002) 32: Percutaneous Drainage for Abdominal Compartment Syndrome Reckard JM, Management of intraabdominal hypertension by percutaneous catheter drainage.j Vasc Interv Radiol. 2005, 16: ACS Treatment Initial Treatment Treatment of underlying cause Supportive care with monitoring Optimized fluid resuscitation Evacuation of intraluminal contents - mechanical or pharmacologic Mechanical ventilation +/- Vasopressors If no response to initial treatment Surgical abdominal decompression Neuromuscular blockade + mechanical ventilation Dialysis An G, Crit Care Med. 2008, 36(4):

10 WSACS Algorithm Decompressive Laparotomy Operating Room Bedside in ICU The downside of late STSG closure of open abdomen Courtesy of CC Cothren, MD, Denver Health Medical Center

11 Complicated (Severe) Skin and Soft Tissue Infections Classification of SSTIs Superficial Uncomplicated infections Cellulitis Impetiginous lesions Furuncles Simple abscesses Can be treated by surgical incision and drainage alone Complicated Deep soft tissue infections May require surgical intervention Infected ulcers Infected burns Major abscesses Significant underlying disease state, which complicates response to treatment FDA. Available at: Accessed June 14, Severe* Soft Tissue Infections (* severe = requires surgical intervention to treat) Extensive tissue destruction High mortality rate Mixed aerobic and anaerobic gram-negative and gram-positive bacteria Recognize early and treat promptly Surgical Rx: debride all necrotic tissue May require amputation Worry about reconstruction later

12 Soft Tissue Gas on Radiographs: Fournier Gangrene External Appearances Can Be Deceiving! Aggressive (appropriate) Debridement is Cornerstone of Soft Tissue Surgical Treatment

13 Necrotizing Infection of Extremity Completed Debridement - often large open wounds Vacuum-Assisted Wound Closure (VAWC) Suliburk JW. Vacuum-Assisted Wound Closure Achieves Early Fascial Closure of Open Abdomens after Severe Trauma. J Trauma 2003, 55:

14 Microbiology of Necrotizing Soft Tissue Infections Polymicrobial most common Staphylococus aureus Anaerobic streptococci Aerobic gram-negative bacilli Bacteroides fragilis-- unusual Monomicrobial Streptococcus pyogenes Streptococcus viridans Clostridium sp. Rare monomicrobial Aspergillus Vibrio vulnificans Summary: Management of Surgical Infection Surgical infection/ sepsis recognition. Initiate antibiotics, resuscitation, and source control early! Surgical infections usually polymicrobial. Debridement, repair, resection are most important principles of surgical intervention. Damage control is not just for trauma. High index of suspicion for IAH / ACS. Broad applications for negative pressure therapy. THE END Thank You