Surgical Site Infections

Definition: Infection of the tissues ,organs or spaces exposed by surgeons during performance of an invasive procedure.

Classification: Incisional: a. Superficial b. Deep Organ/Space

Factors involved: 1.The degree of bacterial contamination of the wound during surgery. 2. The duration of the procedure 3. Host factors

Host factors: a. General: Diabetes Malnutrition Obesity Immune suppression Old age Chronic inflammatory process Smoking Renal failure Anemia Radiation Chronic skin disease

Host factors ……continued, b. Local: Open compared to laparoscopic procedures Poor skin preparation Contamination of the instruments Inadequate antibiotic prophylaxis Prolonged procedures Local tissue necrosis Hypoxia and hypothermia c. Microbial: Prolonged hospitalization leading to nosocomial infections

Classification of surgical wounds: Clean (class 1) 1-2% (class1 D) ….Insertion of prosthetic device Clean contaminated (class 11) 2-10% Contaminated (class 111 ) 3-14% Dirty (class 1V ) 3-20%

Intraabdominal infections: 1. Primary microbial peritonitis: ( Hematogenous dissemination from a distant source) Direct inoculation Ascites Peritoneal dialyses Monomicrobial Rarely require surgical intervention More than 100 WBCs/mL Microbes with a single morphology on Gram stain Treatment: 14-21 days of antibiotic therapy, Removal of indwelling devices( VP or PD) Rarely require surgical intervention.

Intraabdominal Infections…..continued 2. Secondary microbial peritonitis: Peritoneal contamination: a. Perforated viscus b. Inflamed intraabdominal organ. Treatment: 1 Antimicrobial therapy 2 Abscess treatment is drainage Facts: The most morbid form is colonic perforation With source control, mortality 5-6% Without source control, mortality 40% If therapy fails, think of : Abscess formation Presence of anastomosis leak (tertiary peritonitis),mortality here increase to50%.

Diagnosis of intraabdominal abscesses is by CT scan Sites: Pelvic Subdiaphragmatic Subhepatic Paracolic Interloop Abscess treatment: Drainage: a. Percutaneous b. Surgical, for Multiple abscesses Abscess in proximity to a vital structure Ongoing source of contamination(enteric leak) Drain is kept until Cavity collapse Output less than 10-20 mL per day No evidence of ongoing source of contamination The patient general condition improve

Organ Specific Infections: Liver abscess: 1. Pyogenic 80% 2. Parasitic 10% 3. Fungal 10% Pyogenic liver Abscesses: Caused by pyelophlebitis(neglected appendicitis or diverticulitis) Recently, from manipulation of the biliary tree In 50% of cases, no source can be identified Treatment: Less than 1 cm multiple abscesses are treated by Antibiotics for 4-6 weeks Large abscess Drainage.

Organ Specific Infections……continued Splenic Abscess: Rare Same approach as in liver abscesses If recurrent , treated surgically by deroofing or splenectomy. Pancreatic Abscess: Occur in 10-15% of patients with severe pancreatitis and necrosis prognosis depends on Scoring systems CT findings Diagnosis is by CT guided aspiration and positive Gram stain or the presence of gas in the pancreatic bed.

Infections Of Skin And Soft Tissues: Skin Superficial Cellulitis Erysipelas Lymphangitis All are caused by Gram positive cocci and are treated by antibiotics. Furuncles and boils ,may drain spontaneously or surgically.

Aggressive Soft Tissue Infections: Rare Difficult to diagnose Require immediate surgical intervention and administration of antibiotics Failure to do so…..high mortality (80-100%) Even with rapid recognition and intervention mortality rates are high (16-24%) 1. Meleneys synergistic gangrene 2. Rapidly spreading cellulitis 3. Gas gangrene 4.Necrotising faciitis

Aggressive Soft Tissues Infections……continued Predisposing factors: Elderly patients Diabetics Peripheral vascular disease Combination of all The common thread …compromise to the fascial blood supply coupled with introduction of exogenous microbes Streptococcal fasciitis can occur in healthy individuals Patients often develop sepsis or septic shock without an obvious cause

Necrotising Fasciitis….. Continued Sites in order, Extremities Perineum (Fournier gangrene) Trunk Torso Approach: Careful exam for an entry point( small break or sinus ) Drainage of greyish turbid semiperulent material can be expressed (dishwasher pus) Skin changes: Bronze or brawny induration Plebs Crepitus The striking feature is that pain at the site is out of proportion to any of the physical manifestations.

Necrotising Fasciitis….. Continued Treatment: Immediate surgical intervention Exposure and direct visualisation of potentially infected tissue Radical resection During the procedure , Gram stain should be performed on tissue fluid.

Post Op.Nosocomial Infections: 1. Surgical site infections 2. Urinary tract infections 3. Pneumonia 4. Bacteremia

Sepsis

Prophylactic Antibiotics: The use of antibiotics before surgery or dental procedures to prevent bacterial infection Patient selection: a. If the procedure is associated with a considerable risk of infection b. If postop infection would pause a serious hazard to the patient recovery and well- being. Effective Cephalosporins Hospital policies and guidelines Given no more than 30-60 minutes before surgery No longer than 24 hours Therapeutic concentration to be present throughout the period the wound is open Asplenic patients

Post Operative fever: Definition Temperature more than 38.5 C on 2 consequtive post op days or , more than 39 C on any postop day. Fever might be ……benign self limited unrelated to the surgical procedure or, indicative of a surgical complication. Possibilities: 1-2 days Pneumonia or Atelectasis 3-5 days UTI 5-7 days Infected surgical wound (superficial or deep) space infection Organ abscess 5 days to months DVT or PE Anytime Drug fever Febrile nonhemolytic transfusion reaction TRALI Anytime Blood stream infection Phlebitis or cellulitis related to IV lines