Surgical Site Infections (SSIs), Antimicrobial Agents, Universal Precautions and Post-exposure Prophylaxis
1.
Introduction
A wound is defined by the Center for Disease Control (CDC) as an interruption
or break in the continuity of the external surface of the body or the surface
of an internal organ, caused by surgical or other forms of injury or trauma.
A surgical site infection (SSI) is clinically defined as presence of pain
at a surgically created wound, which is accompanied by erythema, induration
and local tenderness or presence of purulent discharge at wound site (1).
SSIs are not a modern phenomenon. As early as 14-37AD there is documentary
evidence that Cornelius Celsus (a Roman physician) described the four principal
signs of inflammation and used 'antiseptic' solutions. Another Roman physician,
Claudius Galen (130-200 AD) had such an influence on the management of wounds
that he is still thought of by many today as the ‘father of surgery’.
Surgeons encounter wound infections in two major ways: patients present
with an infection that requires surgical treatment, like drainage of an
abscess; or infection complicates a surgical procedure, e.g. SSI. This problem
was almost universal prior to the development of aseptic surgery in the
last century but, in spite of our more sophisticated understanding of the
nature of infection and an arsenal of antimicrobial agents, SSI still remains
a major surgical problem today.
SSIs have a significant impact on patients, increasing length of hospital
stay, contributing to overuse of hospital stay, contributing to an overuse
of antibiotics and increased associated costs, and contributing to increased
mortality (2).
SSIs are common, comprising about 12% of all hospital-acquired infections.
The rate of infection varies depending on the type of surgery undertaken.
Especially high rates are associated with contaminated surgery, such as
colorectal surgery or delayed surgery to traumatic wounds.
2. Aetiology of SSIs
SSIs are caused by the deposition and multiplication of microorganisms in
the surgical site of a susceptible host. There are a number of ways microorganisms
colonize and cause infection, including: a) direct contact – either from
another patient, transfer from surgical equipment or the hands of the hospital
staff; b) airborne dispersal – surrounding air contaminated with micro-organisms
that deposit onto the wound; and c) self-contamination (also known as endogenous
infection) – physical migration of the patient’s own normal flora which
are present on the skin, mucous membranes or gastrointestinal tract to the
surgical site. Most surgical infection is due to bacterial and, more rarely,
fungal infection. Viruses, such as human immunodeficiency virus (HIV) and
the hepatitis B and C viruses are important to surgeons because they may
contract these diseases from their patients. Due care has to be taken when
managing such patients and infection significantly alters the host response
to other diseases.
The commonest organism causing SSI is Staphylococcus aureus. Other common
causative organisms include other Gram-negative aerobes, Streptococcus spp.
and anaerobes. A study by Erickson et al. in Tanzania showed that S. aureus
was the most common isolate (n=22), followed by E. coli (n=12) and Klebsiella
spp. (n=12) (2). In another observational study in Tanzania,
the overall rate of SSI was 24% among all surgical disciplines; wound classification
associated with infection (dirty-infected wounds) had a risk ratio of 2.8
compared to clean wounds (3). Overall, 144 of the 618 patients
studied developed SSIs, with the most common isolates being S. aureus (37%),
E. coli (11%), and Enterococcus spp. (5%). Especially concerning was the
isolation of one strain of methicillin-resistant S. aureus (MRSA) and three
isolates of vancomycin-resistant Enterococcus. Of the patients with SSIs
in the study, 35% had cultures that yielded no growth or “no clinically
significant organism.” The authors do not specifically mention whether anaerobic
cultures were done, and no obligate anaerobes were identified, so the high
rate of negative cultures may be in part due to failure to identify obligate
anaerobes.
3. Risk factors associated with
SSIs
The likelihood of developing an SSI is influenced by a number of factors.
These factors fall into four major groups, which are: patient factors, anaesthetic
factors, wound status, and surgeon factors.
3.1. Patient factors
General patient characteristics that play a role in SSI include: immunosuppression,
malnutrition, endocrine & metabolic disorders, obesity, age (young and
elderly), malignant disease and others. All these factors have their influence
by lowering host immunity to various infections.
Given the high prevalence of HIV among patients in developing countries,
the impact of HIV on surgical outcomes is a topic of considerable interest.
For example, HIV infection leads to a lower rate of both skin graft survival
(69% vs. 22%) (4), and overall patient survival among burn
victims (for 21-30% burns: 100% mortality versus 50% mortality in HIV negative
patients) (5). Among HIV positive patients undergoing anorectal
procedures, wound healing is poor (6, 7).
A considerable body of research exists on the topic of surgical site infections
and HIV as well. In orthopaedic trauma patients, the risk of postoperative
infection is considerably higher in HIV positive individuals (16.7% versus
5.4%) (8), though in elective orthopaedic cases with intact
skin and use of implants, the rate of infection appears similar between
HIV positive and unaffected individuals (9). Open fractures
in HIV positive patients managed with external fixation are associated with
a higher rate of pin site infection, though the overall infection rate is
favourable in comparison to internal fixation (10). Similar
to the orthopaedic population, HIV positive obstetric patients have a higher
risk of infection; postpartum endometritis is more common with HIV infection
(24% vs. 7%), and among those with HIV and CD4 counts below 400, endometritis
developed in 44% of patients (11).
Despite the body of literature suggesting higher infection rates among orthopaedic
and obstetric patients with HIV, there does not appear to be good evidence
for or against the role of HIV in the development of SSIs after general
surgical procedures. HIV infection does appear to be associated with infectious
skin pathology such as impetigo, folliculitis, furuncles, and carbuncles.
It is biologically plausible that this pathology would predispose HIV infected
individuals to SSIs, and such pathology should be avoided, especially in
patients undergoing clean surgical procedures.
3.2. Anaesthetic factors
There are several peri-operative factors over which the anaesthetist has
control and which are associated with SSIs (12).
Normothermia: the maintenance of peri-operative normothermia may reduce
the incidence of SSIs. The major relation between hypothermia and increased
SSI is thought to be a decrease in subcutaneous tissue perfusion mediated
by vasoconstriction.
Hyperoxia/hypoxia: high inspired oxygen in the peri-operative period confers
some benefit in reducing the incidence of SSI. Hypoxia and shock are associated
with higher rates of SSI.
Normoglycemia: it has been well established that patients with Diabetes
are at increased risk for infections, including SSI. Even in nondiabetic
patients, hyperglycemia is associated with an increased morbidity and mortality.
3.3. Wound status
Wound characteristics which increase the risk of SSI include: presence of
foreign bodies, nonviable tissue in wound, tissue ischemia and haematoma
formation. All of these characteristics provide a fruitful bacterial growing
environment. Other factors known to promote SSIs are a prolonged preoperative
hospital stay (since there is a growing opportunity for the skin to be colonized
by pathogens), a long operation time (as it probably increases the extent
of both tissue trauma and contamination), and poor surgical techniques (see
below).
The risk of SSI varies with the type of surgery. Certain types of surgery
carry a higher risk of contamination than others and have led to the classification
of surgical wounds as “clean”, “clean-contaminated”, “contaminated”, or
“dirty” (Table 1).
Table 1: Classification of the risk of SSI (13)
| Wound Classification | Description | Infective Risk (%) |
| Clean | Uninfected operative wound, no acute inflammation, no entry to internal organs, and no break in aseptic technique. Hernia repair is an example. | <2 |
| Clean - Contaminated | Opening to internal organ but minimal or no spillage of contents. No evidence of infection or major break in aseptic technique. Cholecystectomy and lysis of adhesions are examples. | <10 |
| Contaminated | Opening to internal organs with inflammation or spillage of contents. Major break in aseptic technique. Colectomy for obstruction is an example. | 15-20 |
| Dirty | Purulent inflammation present. Intraperitoneal abscess formation Visceral perforation with peritonitis. Perforated appendicitis is an example. |
~40 |
3.4. Surgeon-related
factors
Factors directly related to surgeon technique include minimizing devitalisation
of tissues (avoiding factors such as tissue tension, crushing, and parallel
or “tram track” scars), adherence to sterile technique, haemostasis to prevent
accumulation of clots in the wound space and prevention of third spaces
by tissue re-approximation.
4. Prevention of SSIs
Prevention is always better than a cure, and thus a careful assessment of
risks related to SSIs is paramount. The goal of SSI management is to prevent
or minimise the risk through careful planning.
The following factors or methods external to the patient are critical to
preventing SSIs: a) Theatre environment and care of instruments; maintenance
of positive pressure ventilation of operating theatre, laminar airflow in
high risk areas, and sterilisation of surgical instruments, sutures etc.
according to guidelines, and b) Surgical team members educated in aseptic
technique; staff with infections excluded from duty and scrubbing up followed
by appropriate sterile attire.
The following section outlines the evidence regarding hair removal, preparation
of the sterile field, and wound closure technique. Prophylactic antibiotic
use is discussed in section 6.
4.1. Decisions regarding
hair removal
Hair removal is commonly performed prior to surgery, yet both the Centers
for Disease Control and Prevention (CDC) and the Norwegian Centre for Health
Technology Assessment recommend against hair removal (14).
The CDC recommends that, if performed, hair removal should be done by clipping
or use of a depilatory cream, rather than by razor. A recent Cochrane Database
of Systematic Reviews identified 11 studies that met criteria for inclusion
in a meta-analysis of hair removal and infections; 3 of these studies compared
shaving with clipping and found that shaving increased surgical site infections
(relative risk 2.02, 95% confidence interval 1.21 to 3.36). Furthermore,
shaving versus clipping leads to more skin trauma even under ideal conditions,
providing further evidence that shaving should be avoided (15).
There were no studies meeting inclusion criteria that compared clipping
of hair to no hair removal. Two studies compared shaving with no hair removal,
and found that shaving increased infection (relative risk 1.59). However
there were relatively few subjects in these two studies and hence the conclusion
did not reach statistical significance.
Evidence from within Africa supports the CDC recommendation against hair
removal. Adeleye et al. recently reported their experience with 17 cranial
procedures on black Africans, in which all of the fields were non-shaved,
and reported no serious complications over a 2 to 6 month follow-up (16).
In conclusion, if hair is to be removed at all, it should be done by clipping
and not by shaving. Furthermore, hair should not routinely be removed except
in cases where the presence of hair interferes with the technical aspects
of the surgery, which is a judgment that is best left to the operating surgeon
within the context of these recommendations.
4.2. Preparation of
the surgical field
Two factors relate to the surgical field—the choice of skin preparation,
and the method of draping. In developing countries, the choice of drapes
has been limited due to cost constraints, whereas in developed countries,
sterile, adhesive iodine-impregnated drapes (commonly known as Ioban) are
available. These adhesive drapes are placed over the skin after preparation
and application of standard side drapes. However, this practice has demonstrated
no benefit in randomized controlled trials. Furthermore, adhesive drapes
without iodine increase SSI rates (relative risk 1.23, p=0.03) (17).
Thus the avoidance of adhesive drapes as an adjunct to standard cloth drapes
is best avoided.
Several methods of skin preparation are available, including chlorhexidine,
iodine, spirit, and over-the-counter soap. Bibbo et al. compared chlorhexidine
and isopropyl alcohol to povidone-iodine in a randomized of 127 patients
undergoing foot surgery and found that chlorhexidine preparation resulted
in a lower rate of culture-positive skin swabs (38% versus 79%) (18).
Chlorhexidine, an antiseptic solution that has been used worldwide since
the 1950s, is a safe and effective product with broad antiseptic activity.
Chlorhexidine gluconate is a water soluble, cationic biguanide that binds
to the negatively charged bacterial cell wall, altering the bacterial cell
osmotic equilibrium and is available in a variety of concentrations (0.5%–4%)
and formulations (with and without isopropyl alcohol or ethanol). Chlorhexidine
(0.05% solution) has broad activity against gram-positive and gram negative
bacteria, facultative anaerobes and aerobes, yeasts, and some lipid-enveloped
viruses, including HIV. Chlorhexidine is not sporicidal (19).
Meier et al., recognizing the scarcity at times of conventional skin preparation
solutions, compared the use of over-the-counter soap followed by methylated
spirit, to the use of iodine (20). The study randomized
200 patients undergoing elective inguinal hernia repair in Nigeria. In group
1, the subject’s skin was prepared by scrubbing with soap and water, blotting
with a sterile towel, and applying spirit. In group 2, skin was prepared
by scrubbing with povidone-iodine then blotting with a sterile towel and
applying povidone-iodine paint. There was no difference in surgical site
infections between groups 1 and 2 (5.1% versus 5.9%, respectively).
To this date, no studies have compared using soap and spirit versus chlorhexidine.
Thus the current evidence supports the use of chlorhexidine for preparation
of the surgical site. If chlorhexidine is not available, scrubbing with
soap followed by painting with spirit (70% alcohol/30% water) appears equally
efficacious as scrubbing and painting with povidone-iodine.
4.3. Wound closure techniques
and use of drains
There is little disagreement that clean wounds should be closed primarily.
However, the choice of whether to close primarily or leave open, contaminated
and clean-contaminated wounds is not as straightforward. If a wound is not
closed primarily (closed at the time of surgery), it can be left open to
heal by secondary intent, or evaluated for closure at a later date (delayed
primary closure, or DPC). DPC of a surgical wound involves placing sterile
dressing over the wound at the conclusion of the case, and then removing
the dressing usually several days later. If the wound bed appears clean
and without devitalized tissue, the wound is then closed with sutures.
One prospective randomized study from Tanzania found that the rate of infection
was higher when clean-contaminated or contaminated wounds were left open,
as opposed to closed (30.2% versus 2.1%) (1). It must be
noted that those subjects in the group whose wounds were left open were
heterogeneous, and included a combination of delayed primary closure (DPC)
and secondary healing techniques. Marion et al. conducted a meta-analysis
of primary versus DPC in complicated appendicitis, and found similar results,
with a lower rate of infection in those wounds closed primarily (relative
risk 0.64, 95% confidence interval 0.46 to 0.91) (21).
The one exception in which DPC might be advisable is in the management of
traumatic wounds. For DPC of traumatic wounds, the same general principles
for DPC of surgical wounds apply: no wound should be closed if grossly contaminated,
and any devitalized tissue should first be debrided. The management of neglected
or chronic wounds by DPC is more complicated. The International Committee
of the Red Cross provides a good overview of DPC in traumatic, neglected,
and contaminated wounds (22).
Decisions surrounding placement of a surgical drain is beyond the scope
of this review. However, in most cases the routine use of surgical drains
should be discouraged, as is discussed in an excellent review by Schein
(23). Schein does note that select situations may be appropriate
for drain placement, including non-collapsible abscesses (rare), high prediction
of fluid leakage (bile, pancreatic juice, or urine), or drainage for a short
duration of an “oozy” surface. One study compared the use of post-mastectomy
drains for 4 days or 10 days, and found a significantly higher rate of infection
among those drains left in place for 10 days (9.5% versus 2.2%) (24),
lending support to Schein’s recommendation of a short duration of drainage.
5. Treatment of surgical site
infections
The following section outlines the diagnosis and surgical treatment of SSIs.
Use of antibiotics is discussed in section 6, and is secondary to adequate
drainage, discussed below.
5.1. Diagnostic criteria
An SSI is defined by both clinical and microbiological examinations. The
isolation of bacteria from the wound alone is not diagnostic for an SSI
without at least clinical evidence of infection (redness, localised swelling,
pain or tenderness, purulent discharge, relative warmth to the touch). Often,
SSIs are diagnosed and treated based on a constellation of signs and symptoms.
However, samples from the wound can also be taken for culture. Pus or, if
appropriate, a tissue biopsy is preferred over simple wound swabs. In patients
where bacteraemia or sepsis is suspected, blood cultures should also be
taken.
5.2. Drainage
“Never let the sun set on an abscess.” This frequently quoted surgical adage
emphasizes the critical importance of timely diagnosis and treatment of
SSIs. Though some SSIs may be limited to cellulitis, one should have a low
threshold for incision and drainage, or reopening, either a portion or all
of the incision, to drain pus if examination suggests the infection is more
then cellulitis.
Special note must also be made of necrotizing fasciitis, which can occur
as a SSI. Signs that suggest necrotizing fasciitis include: a) wounds with
early drainage of clear brown fluid (“dishwater drainage”);
b) wounds in which the subcutaneous fat has a dark brown discoloration;
c) wounds in which normally adherent tissue planes separate easily; d) wounds
in which subcutaneous vessel thrombosis is present.
Any of these signs or the presence of systemic toxicity, suggest a serious
infection, and immediate debridement of all infected tissue is the mainstay
of treatment. This may require debridement of skin, subcutaneous fat, and
possibly muscle. (See Surgery
in Africa, October 2005: Soft-tissue infections)
6. Antibiotics and SSIs
The goals of antibiotic prophylaxis are to achieve inhibitory antibiotic
levels at incision and throughout the procedure in an effort to decrease
the likelihood of developing a SSI. Antibiotics can also play an important
role in the treatment of SSIs.
6.1. Antibiotics for
prophylaxis of SSIs
Animal studies have shown that antibiotic prophylaxis is most effective
in preventing post-surgical infections when administered before the start
of surgery, and pharmacokinetic data suggest administration as near the
time of incision as possible. Classen et al., in a prospective observational
study, monitored the timing of antibiotic prophylaxis in 2847 patients in
“clean” or “clean contaminated” surgery. Using a step-wise logistic regression
model, they found that preoperative antibiotics within two hours of incision
had the lowest rate of infection as compared to antibiotics given after
incision or earlier than two hours prior (25).
In addition to being given preoperatively, prophylactic antibiotics should
not be continued postoperatively. A five-month prospective survey of surgical-site
infections (SSI) conducted in the department of general surgery at Kilimanjaro
Christian Medical Center, Tanzania by Eriksen et al., showed that 77 (19.4%)
of the 397 patients studied developed SSI (2). Twenty-eight
(36.4%) of these infections were apparent only after discharge from hospital.
A surprising eighty-seven percent of the patients who developed SSI had
received antibiotics, the majority having received the antibiotics for several
days. Such a practice is contrary to the current recommendation of a single
preoperative dose, and prolonged inappropriate use of broad-spectrum antibiotics
may contribute to increased emergence of resistance.
The type of surgery (clean, clean/contaminated, contaminated, or dirty)
(see Table 1) also impacts the role of antibiotic
prophylaxis. An understanding of this classification, as well as knowledge
of recommendations for specific procedures, is invaluable in making an appropriate
choice regarding antibiotic prophylaxis. Antibiotic administration in dirty
cases is not considered prophylactic as these cases represent treatment
of infection rather than prophylaxis.
Controversy exists regarding the use of antibiotic prophylaxis for clean
cases. When antibiotic prophylaxis is given, the agent should target S.
aureus, the most common organism causing SSIs in clean cases; cefazolin
is a good choice (26). When bone is incised, the use of
prophylactic antibiotics is clearly recommended (27).
A good choice in this situation, or for cardiothoracic or vascular surgery,
is cefazolin or cefuroxime (or clindamycin or vancomycin for penicillin
allergic) (26). For general surgical clean cases, the
decision is less clear. A Cochrane Database of Systematic Reviews examined
the use of prophylactic antibiotics prior to hernia surgery, and found that
infection rates were lower with use of antibiotics (2.9% versus 3.9%) but
concluded that “antibiotic prophylaxis for elective inguinal hernia repair
cannot be universally recommended” because of overall low infection rates,
a high number needed to treat, and a lack of a large, randomized controlled
trial to prove efficacy (28). Similarly, Osuigwe et al.
studied the use of prophylactic antibiotics for paediatric surgery in a
prospective, randomized, double-blind study of 289 children at a teaching
hospital in Nigeria (29). Patients were randomly assigned
to receive either doses of ampicillin/cloxacillin (Ampliclox) with vitamin
B (Group A, treatment group), or vitamin B only (Group B, placebo group).
The doses were begun at induction and continued for five days postoperatively.
Patients were evaluated for wound infection at postoperative day 5, and
then again at postoperative day 7 to 10 during suture removal. Wound infection
was defined as the presence of erythema, induration, or discharge. Group
A had a 4.3% infection rate compared to 5% in group B, a difference that
was not statistically significant.
For clean-contaminated and contaminated cases, antibiotic prophylaxis is
recommended. Colorectal surgery is the most thoroughly studied type of procedure
in this category, and as such most recommendations are based on studies
involving colorectal surgery. The most commonly encountered organism in
clean-contaminated and contaminated SSIs is still S. aureus, though other
aerobic as well as anaerobic bacteria are also culprits (30).
As such, prophylaxis should be broader than that used for clean cases. Song
et al. reviewed all randomized controlled trials of antibiotic prophylaxis
in colorectal surgery (31). Four of these studies compared
antibiotic regimens to no antibiotics and showed a convincing benefit of
prophylactic antibiotics (odds ratio 0.24, 95% confidence interval 0.13
to 0.43). Further analysis revealed that the most efficacious regimens include
coverage against both aerobic and anaerobic organisms (such as a 2nd or
3rd generation cephalosporin, or gentamicin in combination with metronidazole),
and cited certain regimens inadequate (metronidazole alone, doxycycline
alone, piperacillin alone) (32). Though data from Africa
is limited, differences in efficacy between various 2nd and 3rd generation
cephalosporins appear negligible (33), and choice prophylaxis
with a single-agent 2nd or 3rd generation cephalosporin can probably be
dictated by availability or cost. For penicillin-allergic patients, clindamycin
combined with gentamicin, aztreonam, or ciprofloxacin, or metronidazole
combined with gentamicin or ciprofloxacin are adequate choices (26).
6.2. Antibiotics for
treatment of SSIs
Empiric treatment of an SSI after clean cases should be primarily directed
against S. aureus. Clean-contaminated, contaminated, and dirty cases require
broader empiric coverage to include both aerobic and anaerobic bacteria.
Choices of empiric therapy, against SSIs suspected of being caused by S.
aureus, such as SSIs after clean cases, include cloxacillin or in penicillin-allergic
patients, clindamycin. For SSIs after clean-contaminated, contaminated or
dirty cases, a second- or third-generation Cephalosporin (such as cefuroxime
or ceftriaxone), metronidazole with gentamicin, or amoxicillin/clavulanate,
are all reasonable choices that will provide aerobic and anaerobic coverage.
It is also important to take note that in many surgical operations, patients
will have previously received antibiotic prophylaxis. Prophylaxis can affect
the flora and thus the cause of any subsequent infection. One study of antibiotic
prophylaxis for cardiac surgery compared vancomycin to cefazolin, and found
that SSIs in those receiving cefazolin were more likely to be caused by
methicillin-susceptible S. aureus compared to SSIs in those receiving vancomycin
(3.7% versus 1.3%) (34). As such it is important to determine
the nature of any prior antibiotic therapy; a prudent approach is to choose
a different regimen that the one used for prophylaxis at the time of surgery.
Lastly, it should be re-emphasized that antibiotic administration for SSIs
is secondary to the cornerstone of treatment—which is adequate drainage
of the infection. Additionally, if antibiotic sensitivities are identified,
it may be necessary to tailor antibiotics to the specific strains. Many
surgeons use topical agents such as hydrogen peroxide, 2% acetic acid, or
Dakin’s solution (0.5% sodium hypochlorite), but evidence in support of
this is scant. A review of the evidence regarding Dakin’s solution, for
example, found only three small prospective studies and concluded that there
was no benefit to its use (35). More important is the
frequency of dressing changes when managing SSIs; dressings should be changed
if they appear soiled or are foul-smelling, and must be changed no less
frequently than once daily. Lastly, one should not forget to emphasize the
importance of hand hygiene to the guardian, or any others involved in the
care of the patient, which minimizes cross-contamination.
7. Universal precautions and post-exposure
prophylaxis
Universal precautions mandate that health care providers assume all patients
carry a transmissible infectious disease (such as viral hepatitis or HIV),
and maintain precautions against contracting such infections. The nature
of personal protective equipment is situation-dependent, and may include
gloves, eye protection, a protective gown and/or boots, or a mask. Bodily
fluids, including blood and saliva, as well as airborne particles, are considered
an exposure risk. Testing all patients to identify individuals infected
with transmissible diseases is not feasible, and thus universal precautions
are required (36).
In addition to universal precautions, pre-exposure vaccination against hepatitis
B is recommended. All health care workers potentially coming in to contact
with bodily fluids should be vaccinated against hepatitis B, which is given
as a series of three intramuscular doses. Despite the importance of hepatitis
B vaccination, many health care workers are not vaccinated due to either
not being aware of the vaccine’s efficacy, or being unable to afford the
series of vaccinations (37).
HIV and hepatitis C pose risks to health care providers, and to this date
there are no vaccinations available for pre-exposure prophylaxis. Therefore
prevention relies solely on universal precautions and safe practices, such
as not recapping used needles, using sharps containers appropriately, and
properly passing sharp instruments in theatre (by a sharps container, or
using verbal communication between the surgeon and the scrub nurse).
To this date, there are no known cases of transmission of HIV from a patient
to a health care provider in the operating room. However there are at least
57 documented cases of transmission to health care providers in settings
outside of the operating room (38). Hepatitis C poses
a more serious risk of transmission, which is estimated to be 2% if the
patient is infected with hepatitis C, and the health care provider as been
stuck with a hollow needle (39).
After unintentional exposure, the site should be copiously washed, and consideration
must be given to post-exposure prophylaxis against HIV. If possible, the
patient should be tested for HIV. Factors influencing the choice for or
against HIV post exposure prophylaxis include the type of exposure, whether
the status of the patient is known at the time of exposure, and the availability
of post exposure prophylaxis. The overall risk of transmission from a needle
stick when the patient is HIV positive is estimated at 0.3%; high risk occupational
exposure from an HIV positive patient is defined as a deep puncture with
a hollow needle, a needle that is visibly contaminated, large bore needle,
needle that was place directly in an artery or vein, high viral load of
the patient, or a patient with end-stage disease (40).
Post-exposure prophylaxis should continue for 28 days and include both a
nucleotide reverse transcriptase inhibitor (NRTI) and a protease inhibitor
(PI); in the United Kingdom, the recommended regimen is now Combivir (lamivudine
and zidovudine, both NRTIs) with lopinavir and ritonavir (PIs; supplied
in combination as Kaletra) (Table 2).
Table 2: Possible regimens for post-exposure prophylaxis against HIV (40)
Drug Class |
Examples |
|
Two nucleotide reverse transcriptase inhibitors (NRTIs) AND |
lamivudine and zidovudine (Combivir) tenofovir and emtricitabine (Truvada) tenofovir and lamivudine stavudine and lamivudine |
One protease inhibitor (PI) |
lopinavir |
8. Summary of recommendations
In conclusion, SSIs represent a major cause of morbidity in surgical patients,
affecting only around 2% of patients with clean cases, but upwards of 15-20%
of patients undergoing contaminated cases.
1. To limit the chance of SSIs, one should treat any endocrine or metabolic
disorders in the patient, and optimize nutritional status.
2. Preoperative antibiotics should be given for clean-contaminated and contaminated
cases (second or third generation cephalosporin). For clean cases, the evidence
is mixed, and if given the best choice is a first generation cephalosporin.
The antibiotic should be given before incision, but no longer than 60 minutes
before, and should not be continued for more than 24 hours postoperatively.
Antibiotics for dirty cases represent treatment of infection and thus are
not considered prophylaxis.
3. Body hair need not be removed, and if the surgeon chooses to remove hair,
it should be done by use of clippers or a depilatory agent; shaving causes
an increased chance of wound infections and must be avoided.
4. Chlorhexidine is the best skin preparation agent. Soap followed by iodine,
or 70% alcohol followed by iodone are the next best alternatives.
5. Intraoperatively, patients should retain normothermia, normoglycemia,
and adequate perfusion and oxygenation. The surgeon should minimize tissue
devitalisation, adhere to sterile technique, avoid hematoma formation, and
close potential spaces.
6. Evidence supports closing primarily all wounds, and avoiding drain placement,
or if used, such as in breast surgery, not leaving drains in post-operatively
any longer than necessary.
7. If one suspects an SSI (redness, localised swelling, pain or tenderness,
purulent discharge, relative warmth to the touch), maintain a low threshold
for opening the wound which is the primary treatment. Antibiotics are secondary
to adequate drainage. There are a number of reasonable choices for treating
SSIs, and the choice of an agent should be dictated by culture results when
possible.
8. Surgeons should be familiar with the risks of transmission of HIV, and
the indications for and choices of post-exposure prophylaxis. All surgeons
should be vaccinated against hepatitis B virus.
Jonathan Samuel, M.D., M.P.H.1 & Wakisa Mulwafu, M.D.2
1 University of North Carolina, School of Medicine, Chapel Hill, North Carolina
2 Queen Elizabeth Central Hospital, Blantyre, Malawi
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