Surgical Infection

Chapter Two

• The classical inflammatory response resulting in the clinical features of infection (the cardinal signs of infection):

• Rubor (redness);• Tumor (swelling);• Dolor (pain);• Calor (heat).

• In acute infection these clinical features may be accompanied by swinging pyrexia, leukocytosis, raised C-reactive protein.

• Resolution: If tissue damage is

minimal, the inflammatory response settles completely and the tissue returns to normal

Spreading infection:

• By direct spread into adjacent tissues;• Along tissue planes, e.g. tendon sheaths;• Via the lymphatic channels, producing the characteristic red lines of lymphangitis and enlarged tender lymph nodes (acute lymphadenitis); or• Via the bloodstream, causing bacteraemia (presence of bacteria in the blood) or septicaemia (presence of propagating organisms in the blood).

• Abscess formation:• Organization: Following acute

inflammation with tissue damage or drainage of an abscess, repair of the tissues is achieved by organization, formation of granulation tissue and fibrosis.

• Chronic inflammation

Management of infection

• Prevention of infection

• Management of established infection

Prevention of infection:

Prophylaxis is always better than cure.

1. The risk of certain complications varies from procedure to procedure

2. Must be started before the operation or procedure and be continued until the risk period has passed

3. Effective and carry very little risk of it.4. To prevent complications that are relatively

common5. To prevent complications that are relatively serious consequences

Principles of prophylaxis:

The following measures are known to reduce infection rates:

• laparoscopic vs. open operations;• skin cleansing/disinfection;• surgical masks and impervious surgical

microfibre gowns;• Preoperative shaving should be

avoided if possible• Avoid hypothermia perioperatively and

ensure supplemental O2 in the recovery

• Prophylactic antibiotics.

Prophylactic antibiotics

If antibiotics are given empirically, they should be used when local wound defenses are not established (the decisive period). Ideally, maximal blood and tissue levels should be present at the time at which the first incision is made and before contamination occurs.

Choice of antibiotics for prophylaxis

• Empirical cover against expected pathogens with local hospital guidelines

• Single-shot intravenous administration at induction of anaesthesia

• Repeat only in prosthetic surgery, long operations or if there is excessive blood loss

• Continue as therapy if there is unexpected contamination

• Benzylpenicillin should be used if Clostridium gas gangrene infection is a possibility

• Patients with heart valve disease or a prosthesis should be protected from bacteraemia caused by dental work, urethral instrumentation or visceral surgery

Antiseptics commonly used in general surgical practice:

Protection against AIDS and hepatitis

• There is no doubt that doctors and nurses risk acquiring hepatitis (especially hepatitis B infection) and AIDS, but the risk is small especially if suitable precautions are taken

• The infectivity of human immunodeficiency virus (HIV) is much less than that of hepatitis B virus

precautions are necessary • avoid 'sharps' injuries• Double gloving• Avoidance of spillage of blood and body

secretions• Labeling suspect blood specimens • Use of disposable equipment• All healthcare workers, including medical

students, are now vaccinated against hepatitis

Tetanus prophylaxis

• Consideration of tetanus prophylaxis depends upon the status of the wound and immunization status of the patient

Prevention of hospital-acquired infections

• Hospital-acquired infections with resistant organisms, e.g. MRSA, cause significant morbidity and mortality and add considerably to the cost of care in severe outbreaks, whole wards may need to be closed

The principles governing prevention of these infections

• strict adherence to hospital antibiotic practice

• always washing hands after examining a patient

• strict aseptic care of intravenous lines• isolation of infected cases

Classifications of wound according to rate of infection

1. Clean

2. Clean – Contaminated

3. Contaminated – Dirty

Management of established infection

• Diagnosis • Antibiotic• Drainage

Diagnosis

• The presence of an infection will be suspected from the clinical picture. Wherever possible, infected material should be obtained for culture before commencing antibiotics

Principles for the use of antibiotic therapy

• Antibiotics do not replace surgical drainage of infection

• Only spreading infection or signs of systemic infection justifies the use of antibiotics

• Whenever possible, the organism and sensitivity should be determined

• Prescribe on basis of culture results and 'most likely organism' while waiting for results

• Certain antibiotics are reserved for serious infections

• Therapeutic monitoring of drug levels may be required, e.g. with aminoglycosides

• Synergistic combinations may be required in some infections, e.g. aminoglycoside, cephalosporin and metronidazole for faecal peritonitis

• In serious infections seek advice from clinical bacteriologist

Antibiotic rotation

Drainage

• Drainage is essential once an abscess has become established and antibiotics play only a secondary role in the management. Traditionally all abscesses were drained surgically but nowadays many, including intra-abdominal abscesses, are drained percutaneously by interventional radiology techniques with CT or ultrasound guidance. Irrespective of approach, radiological or surgical, the principle is the same: the pus should be removed and a track established for free drainage.

The following measures are known to reduce infection rates:

• laparoscopic vs. open operations;• skin cleansing/disinfection;• surgical masks and impervious surgical

microfibre gowns;• Preoperative shaving should be

avoided if possible• Avoid hypothermia perioperatively and

ensure supplemental O2 in the recovery

• Prophylactic antibiotics.

Prophylactic antibiotics

If antibiotics are given empirically, they should be used when local wound defenses are not established (the decisive period). Ideally, maximal blood and tissue levels should be present at the time at which the first incision is made and before contamination occurs.

precautions from AIDS & hepatitis• avoid 'sharps' injuries• Double gloving• Avoidance of spillage of blood and body

secretions• Labeling suspect blood specimens • Use of disposable equipment• All healthcare workers, including medical

students, are now vaccinated against hepatitis

Tetanus prophylaxis

• Consideration of tetanus prophylaxis depends upon the status of the wound and immunization status of the patient

The principles governing prevention of these infections

• strict adherence to hospital antibiotic practice

• always washing hands after examining a patient

• strict aseptic care of intravenous lines• isolation of infected cases

Classifications of wound according to rate of infection

1. Clean

2. Clean – Contaminated

3. Contaminated – Dirty

Management of established infection

• Diagnosis • Antibiotic• Drainage

A 8 years child presenting with facial cellulitis secondary to an odontogenic infection Your supervisor ask you to prescribe an antibiotic coarse for him if the child weight is 30 kg Can you give me the 1st line Tx and the correct dose ?

Thank you

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