3. Historical Aspects
• Pringle 1750 – “Antiseptic”
• Isaac Benedict Prevost 1807 – first proof of
microorganisms as the causation of sepsis.
• Louis Paster 1863 – Putrifaction is caused by
microbes from air.
• Joseph Lister – used antiseptic soln to prevent
putrifaction & demonstrated that pus is a
disaster rather than a sign of healing.
4. • Lister’s technique of sterilization, skin
preparation and washing became –
Foundation of “Antiseptic Surgery”.
• First step in development of
“Asepsis in surgery”.
• Introduction of antibiotics 1940 –
Streptococcal hospital infection disappeared.
• 1950s World wide epidemic of nosocomial
infection by Virulent resistant Staphylococcus.
5. Nosocomial Infection
• Develops during hospitalization
• Neither present nor incubating at the time of
patients admission.
• 50% involve surgical site infection.
6. National Nosocomial Infection Surveillance
(NNIS)
• Current version for SSI risk index scores each
operation by counting the risk factors:
1. Type of wound
2. ASA score of 3,4 or5 (Host defense)
3. Duration of surgery – lasting more than T-hours
7. Surgical site infection
• Postoperative wound developing signs of
inflammation or serous discharge is labeled
as “possibly infected”.
• Cruse et al 1977 classified wounds – 4
categories
1. Clean wound:
• No infection, no break in aseptic technique & no
hollow muscular organ opened.
8. 2. Clean contaminated wound:
Hollow muscular organ opened with minimal
organ spillage.
3. Contaminated wound:
Hollow organ opened with gross spillage, acute
inflammation without pus, traumatic wounds
within 4 hours and major break in aseptic
technique.
10. • Infection in clean wounds – Surveillance &
research.
– < 1% Ideal.
– 1-2% can be acceptable.
– > 2% cause of concern.
• Monthly announcement– Everyone aware of
SSI
– Can reduce by 38% by appropriate feedback.
11. Rate of infection
• Purely a statistic for the surgeon.
• Total DISASTER for the patient.
• Sir Watson Jones 1962 – “Infection of one
clean case in a thousand is a disaster of the
first magnitude”.
• Even slight delay in healing, redness of skin, or
any other sign of wound infection – evidence
of failure.
12. Orthopaedic clean wound
• Too many variables
– Surgery of soft tissues alone or of bones
– With or without implants
– Emergency trauma or planned trauma cases
– Timing of surgery in trauma
– Reaming of medullary canal, primary plating.
– Stable and unstable fixation.
13. Post Operative infection?
• Primary or secondary?
• Possible to predict?
• High risk patients?
• Possible to prevent in best possible operative
conditions?
14. • All operative wounds get contaminated
during surgery – does not mean infection.
• Sources of contamination:
1. Surgeon & his team
2. Air in OT
3. Skin of patient & all OT personnel.
• Conversion of this contamination to
infection is to be avoided.
15. Depends upon:
• Virulence of the organisms
• Degree of contamination
• Presence of dead & devitalized tissue,
implants & suture material.
• Site of operation i.e. bone
• Duration of surgery
• HOST RESPONSE – Immunological status
16. SSI
• Story of germination of a seed in soil.
• 95% of bacteria reach – Via air by direct
sedimentation into the wound or the
instruments.
• Highest conc. – within the circle of surgical
team directly over the wound.
• No of bacteria directly proportional to the
increase in activity and number of the team –
max. at the time of induction, positioning and
extubation/ Closure.
17. • Staphylococcus aureus carrier – 30-50% of
general population.
• Every person sheds ~55,000 skin scales/min. –
10-20% contain live bacteria.
• Increase in shedding:
– Loose cotton scrub suits
– Higher temperature & humidity.
18. Gloves
• In a study of 1209 cases – 141 gloves were
found punctured.
• 18,000 Staph aureus can pass a single
puncture in 20min.
• 3-5 min hand scrub with antiseptic soln. is
essential.
• Double gloves – additional security.
• New cut resistant gloves.
19. Airborne bacteria
• Air handling systems of OT.
• Type of scrub suits worn.
• Air bacterial count in ordinary OT varies from
50 – 500 colony meter cube
• “A Sterile air operating room” &
Concept of “Rapid Unimpeded Down flow of
Filtered Air and Exhaust Ventilated Whole
Body Suit” – Sir John Charnley
20. Microbiological facts:
1. Airborne bacterial contamination is directly
related to number & activity of people in OR.
2. Inversely related to the effectiveness of
personnel garment barrier & no. of air
exchange / hour.
3. Air borne bacteria are agglomerated on
inanimate particles size from 2-10 microns.
4. Almost always gram positive corresponding
to skin flora.
21. Methods of cleaning air
1. Laminar air flow – clean, filtered air with
frequent whole air exchange.
2. Ultraviolet light system
3. Vacuum body exhaust system
4. Garment barrier.
5. HEPA (High Efficacy Particle Air filter) –
removing 99.9% particles larger than 0.3
microns. (Bacteria - .5-10.5)
22. Laminar flow
• Super-high air turn over (400-600) in a laminar
flow room – “Air broom” action.
• Flow – Horizontal or Vertical.
• Conventional OR – 12-25 air exchanges each
hour – Federal standards.
• “Unobstructed” – If not –
positive pressure is generated
• Doors kept closed.
23. • Air temperature – 21.1 to 24.4 C
– Lower temperatures are preferred.
• Humidity: 50%
– Prevent static electricity and
– Decrease perspiration
– Decreased viability of bacteria
24. Garment Barrier
• AORN recommends:
– Pant suit or one piece suit with ankle closure &
shoe covers.
– All hair covered by cap or hood
– Face mask – high microbial filtration efficacy.
• Micro porous textile – disposable/reusable –
use in gown & drape barrier systems.
25. • Standard cotton scrub suit or drapes –
– pore size 100 microns
– Sheds more bacteria
“Cheese grater” effect.
– “Bellows” action
– Wet
26. • Microporous material is superior as:
– Resistance to blood & water
– Abrasion resistant
– Lint free
– Memory free
– High degree of drapability.
• e.g Polypropylene
nonwoven gown.
27. Host defense mechanism
• Skin test score
• Serum albumin level
• Age of the patient
– Prediction regarding susceptibility to infection
• Other factors
– Diabetes, Old age, Obesity, Rh Arthritis,
– Major implant surgery
– AIDS
28. • Protein calorie malnutrition – most imp.
factor.
• Clean wound infection rate in
– Diabetics – 10.5%
– With obesity – 13.5%
– With malnutrition 16.5%
• Polytrauma patients.
• These compromised situations - decision
regarding early operative intervention has to
weigh against possibility of infection.
29. Organisms
• 60% of SSI – Gram +ve bacteria esp. Staph
aureus and epidermidis.
• 20% - Gram –ve bacteria like E.Coli,
Pseudomonas, Klebsiella etc.
• Precise bacteriological diagnosis
– 6 aerobic and anaerobic cultures.
– Enriched media for at least 2 weeks.
30. • 90% of implant surgeries result from
intraoperative contamination.
• 50% of these become clinically evident 3
months after surgery
• Many of these caused by low virulence
organisms like Staph epidermidis and other
anaerobes.
• Steady increase in G –ve bacteria – more
difficult to treat as is resistant Staph aureus.
31. • 2-8 million inoculums of Staph aureus injected
develop infection.
• Only 100 organisms in presence of foreign
body.
• Main reservoir – human body.
• Nasal carriers – 30-50% of general population.
• Glycocalyx biofilms:
– Bacteria get adhered to implant surface.
32. Susceptibility of bone to infection
• Limited soft tissue space
• Blood supply favoring necrosis
• Inadequate mechanism to reabsorb necrotic
bone
• Increased duration of surgery
33. Role of prophylactic antibiotics
• Tengve et al reported
– 16.9% rate of infection with no antibiotics.
– 1.8% with prophylactic antibiotics.
• Antibiotics given before bacterial inoculation
– Inhibit growth of bacteria
• After inoculation
– Prevent overt clinical signs of infection, but
bacteria can always be isolated from the wound.
34. Pathophysiology
• As a response to operative trauma
– Maximum exudation occurs in the first 6 hrs and
– Contamination occurs at the time of surgery
• Antibiotic must be present in the circulation &
into hematoma throughout the operation in
sufficient concentration – to kill these
bacteria.
35. Prophylactic antibiotic
• Started just before surgery
• Ideal conc. in serum during surgery should be
4% of MIC in a healthy individual.
8% in a compromised patient.
• No extra advantage of continuing for 5 or
more days over limited therapy. (Stone et al)
36. Topical antibiotics
• Willson et al 1991 – Topical triple antibiotic
soln.- Neuromycin, polymyxin and bacitracin.
• Bacitracin – allergic rxn so stopped.
• Simple good wash with NS or RL is very
effective.
37. Clinical presentation of postoperative
infection
• 3 types of presentation:
1. Early – within 8 weeks
2. Delayed – 8 weeks – 1 year.
3. Late – after 1 year.
• Early further 4 types (Mukhopadaya)
i. Imminent within 48 hrs
ii. 3-9 days i.e. before suture removal
iii. 10-21st
day and
iv. 3-8 weeks.
38. Classical presentation
• Disproportionate pain
• Fever >102 F
• Wound – signs of local cellulitis
• Mild to moderate serosanguineous discharge.
Seen only when antibiotics and anti
inflammatory are not given.
39. Common presentation
• Severe pain
• Fever not responding to high doses of drugs
• Frank purulent discharge
• Wound already partially opened up due to cut
through sutures.
40. Late infection
• Go home with apparently normal wound
healing
• Return with chronic discharging sinus
• Persistent tachycardia
• Pain not presenting complaint.
41. Diagnosis of infection
• Fever and Leukocytosis – not always helpful.
• Thrombotic index
• “Leukergy” – based on the phenomenon
– WBCs agglomerate in the peripheral blood of
patients with inflammatory disease.
– Percentage of agglomerated cells correlate with
the severity of infection.
– Rapid and inexpensive.
42. • Persistent elevation of ESR –
– Suggests infection
– Neither very sensitive nor specific.
• ESR with CRP
• Results better but still unreliable.
• Bone scan – more accurate.
43. Treatment
• Immediate action.
• Discharging fluid to be sent for –
– Gram staining,
– Culture & sensitivity.
• Broad spectrum antibiotic along with
aminoglycoside started – no relief in 24 hrs –
• Open and debride thoroughly.
• Always better to debride than wait for
antibiotics to act.
44. • Wound always closed by loose intermittent
sutures or by secondary suturing later.
• A well fixed implant can be left as such.
• Loose implant – removal or refixation or
Exfixation.
• Implants once infected needs removal
• Well fixed implant left in place till fracture
unites.
45. • Plate fixation – Early diagnosis and removal –
extensive cortical necrosis.
• Non union is not due to infection but
inadequate fixation.
46. • Sir John Charnley 1982
“Because of the tragic seriousness of post
operative infection, I regard it as our duty to
continue in the future to study to eliminate
post operative infection by any means or
combination of means, whatever, I say
eliminate deliberately because I have not yet
abandoned the hope that some way we’ll
achieve this target”
