1. Surgical Site Infections

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

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

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

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

6. 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

7. Classification of surgical wounds:
Clean (class 1) %
(class1 D) ….Insertion of prosthetic device
Clean contaminated (class 11) %
Contaminated (class 111 ) %
Dirty (class 1V ) %

8. 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: days of antibiotic therapy,
Removal of indwelling devices( VP or PD)
Rarely require surgical intervention.

9. 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%.

10. 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 mL per day
No evidence of ongoing source of contamination
The patient general condition improve

11. Organ Specific Infections:
Liver abscess:
1. Pyogenic %
2. Parasitic %
3. Fungal %
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.

12. 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.

13. 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.

14. 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

15. 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

16. 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.

17. 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.

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

19. Sepsis

20. 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 minutes before surgery
No longer than 24 hours
Therapeutic concentration to be present throughout the period the wound is open
Asplenic patients

21. 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