"
A CLINICAL STUDY ON SURGICAL SITE INFECTIONS"
for a period of 2 years in GMKMCH, Salem
Submitted to
THE TAMIL NADU DR.M.G.R MEDICAL UNIVERSITY, CHENNAI
In Partial fulfillment of the regulations for the award of the degree of M.S. GENERAL SURGERY
GOVERNMENT MOHAN KUMARAMANGALAM MEDICAL COLLEGE, SALEM
MAY 2018
ACKNOWLEDGEMENT
I am extremely grateful to Dr.P.KANAGARAJ.M.D., Dean of Government Mohan Kumaramangalam Medical College Hospital, Salem., for permitting me to utilize the hospital facilities for my Dissertation work.
I express my sincere thanks to the Head of the Department of Surgery, Prof. DR. C. RAJASEKARAN, M.S., for giving me guidance and help in preparing this dissertation .
I am grateful to my Unit Chief Prof. DR. P.SUMATHI, M.S.D.G.O, and Assistant Professors DR. S.SREEDEVI, M.S., DR. M.JEEVANANTHAM, M.S., DR. T.KARTHIKEYAN, M.S., Dr. R.SWAMINATHAN,M.S., Dr. N.JEEVA, M.S., Dr. V.SIVAKUMAR,M.S., for their moral and academic support for my study and their good wishes to make this a successful and relevant study.
I am also grateful to my other Units Chiefs Prof. Dr.A.NIRMALA.,M.S.,D.G.O., Prof. DR. K.VIJAYAKUMAR ,M.S, Prof. DR. K.KESAVALINGAM, M.S., Prof.
DR.RAJ ASHOK,M.S., and Prof.DR.M.RAJASEKAR,M.S.,
I convey my sincere thanks to the Assistant Professor’s, of all the six surgical units for their guidance and contribution to my study.
I cordially thank my parents MR. M.S.KUTTIANNAN AND MRS. C.SAROJA, my Wife Mrs.C.K.PRIYADHARSHINI My Kid, D.LEKHADHAKSHNI my colleagues Dr.T.VARUN, DR.SIVASUBRAMANIAN who have always been there with me whenever I need their help and cooperation.
I also thank my unit CRRI’s for their valuable help. And finally my heartfelt gratitude and sincere thanks to all my Patient’s, who subjected themselves to this study, without them this endeavor would not have been possible at all.
ABSTRACT
Surgical site infection causes considerable morbidity and high cost to the health care system .It is becoming increasingly important in medico-legal aspects.
The discomfort and disability experienced by patients following surgical procedures are increased due to infections. Sometimes life may be endangered.
There are some studies done in our country regarding SSIs. But still more research is required to identify the reasons for SSIs. In elective surgeries, this study may be helpful in reducing the infection rate.
In our study, the surgical site infections developed during pre op hair removal and induction of pre op antibiotic are to be studied. The infections developed during pre op hair removal by shaving and clipping are to be compared.
The comparison between pre op antibiotic given 1 hour before anaesthesia and the same given at the time of induction of anaesthesia will be done.
Even though all the above mentioned techniques are practiced among the surgeons, there is no any high quality randomized studies available to guide proper decision making about appropriate procedure.
An attempt is made in this study to compare various techniques in the pre op hair removal and timing of pre op antibiotics.
Keyword: Superficial SSI, DeepSSI, Antibiotics, Shaving, Clipping
TABLE OF CONTENTS
S.NO TITLE PAGE NO
1 Introduction 1
1.1. Historical Background 1
1.2. An Introduction To Surgical Site Infections 5 2 Classification Of Surgical Site Infections 6
2.1. Incisional SSI 6
2.2. Organ/ Space SSI 6
2.3. Local And Systemic Presentation 9
2.4. Major And Minor Surgical Site Infections 10 3 Risk Factors Of Surgical Site Infections 13 4
Various Manifestations of Surgical Site Infections In Different Scenarios
16
5 Prevention of Surgical Site Infections 28
6
Role Of Pre-Operative Hair Removal In Preventing Surgical Site Infections
35
7
Role Of Pre-Operative Antibiotics In Preventing Surgical Site Infections
42
8 Classification Of Wounds 44
9 Selection And Administration Of Antibiotics 50 10
Recommendations For Specific Categories Of Surgical Procedures
56
11 Materials And Methods 68
12 Observations And Results For Induction Of Pre Op Antibiotic
71
12.1. Sex- Pre op antibiotic 71
12.2. Post op complications- Pre op antibiotic 73
12.3. Types of SSI- Pre op antibiotic 82
12.4. Pus culture- Pre op antibiotic 84
13 Observations And Results For pre op hair removal 86
13.1. Sex- Pre op hair removal 86
13.2. Post op complications- Pre op hair removal 88 13.3. Types of SSI- Pre op hair removal 97
13.4. Pus culture- Pre op hair removal 99
14 Discussions 105
15 Conclusions 107
16 Bibliography 109
17 Patients Proforma 111
LIST OF PICTURES
S.NO TITLE PAGE NO
1 Classification of Surgical Site Infections 6
2 Major Wound Infection And Delayed Healing Presenting As A Faecal Fistula
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3 Minor Surgical Site Infection 11
4 Factors Determining The Development of SSI 15
5 Surgical Site Infection – Abscess 18
6 Surgical Site Infection – Cellulitis 19
7 Surgical Site Infection – Lymphangitis 20
8 Relationship Between SSI And SIRS 21
9 SSI Presenting As Gas Gangrene 23
10 Meleney’s Synergistic Hospital Gangrene 26
11 Fournier’s Gangrene 27
12 SSI – Necrotizing Fascitis 28
13 Pre-Operative Hair Removal With Razor 36
14 Pre-Operative Hair Removal With Clipper 37
15 Comparison Between Shaving And Clipping 39
16 Shaving Vs Trimming 43
LIST OF TABLES
S.NO TITLE PAGE NO
1 Sex Ratio Pre Op Antibiotic 71
2 Fever - Pre Op Antibiotic 74
3 Warmth / Redness - Pre Op Antibiotic 75
4 Pain- Pre Op Antibiotic 76
5 Serous Discharge - Pre Op Antibiotic 77
6 Pus Discharge- Pre Op Antibiotic 78
7 Wound Dehiscence - Pre Op Antibiotic 79
8 Post Op Complications 80
9 Types of SSI - Pre Op Antibiotic 82
10 Pus Culture Organism- Pre Op Antibiotic 84
11 Sex Ratio Pre Op Hair Removal 86
12 Fever - Pre Op Hair Removal 89
13 Warmth / Redness - Pre Op Hair Removal 90
14 Pain- Pre Op Hair Removal 91
15 Serous Discharge Pre Op Hair Removal 92
16 Pus Discharge- Pre Op Hair Removal 93
17 Wound Dehiscence Pre Op Hair Removal 94
18 Post Op Complications - Pre Op Hair Removal 95
19 Types of SSI - Pre Op Hair Removal 98
20 Pus Culture Organism- Pre Op Hair Removal 99
LIST OF CHARTS
S.NO TITLE PAGE NO
1 Sex Ratio- Pre Op Antibiotic 72
2 Post Op Complications- Pre Op Antibiotic 81
3 Types of SSI- Pre Op Antibiotic 83
4 Pus Culture - Pre Op Antibiotic 85
5 Sex Ratio- Pre Op Hair Removal 87
6 Post Op Complications Pre Op Hair Removal 96
7 Types of SSI- Pre Op Hair Removal 98
8 Pus Culture - Pre Op Hair Removal 100
9 Colour plates 101
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1.INTRODUCTION 1.1.HISTORICAL BACKGROUND
Surgical infection, particularly surgical site infection (SSI), has always been a major complication following surgery and it has been documented for 4000–
5000years though it was known since time immemorial. The surgical site infections remained an axiom until it was proved of its etiologic of microorganisms with the discovery of microscope and the development of whole new branch of microbiology.
The Egyptians were the first to have concepts about infection as they were able to prevent putrefaction, which were evident by their mummification skills.
They were the first to use salves and antiseptics to prevent SSIs which they described in their medical papyruses. Though this technique of prophylaxis had also been known earlier by the Assyrians, it was not documented. It was described again independently by the Greeks.
The Hippocratic teachings described the use of products like wine and vinegar to be used as anti-microbials. They were widely used to irrigate open, infected wounds before delayed primary or secondary wound closure. There was a belief common to all these civilisations, and indeed even later to the Romans. It was that, whenever pus got localised in an infected wound, it needed to be drained.
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Galen recognised that this localisation of infection (suppuration) in wounds often showed recovery particularly after drainage. But this dictum was misunderstood by many of his followers who thought that it was the production of pus that was desirable.
In the middle Ages, some practitioners promoted suppuration in wounds by the application of noxious substances, including faeces. It became universal because of the misguided belief that healing could not occur without pus formation. The wrong notion was shattered by Theodoric of Cervia, Ambroise Paré and Guy de Chauliac who observed that clean wounds, closed primarily, could heal without infection or suppuration.
It was in the era of nineteenth century, the understanding of the causes of infection came. Microbes were seen under the micro scope, but it was Koch who laid down the first definition of infective disease.
The Austrian obstetrician Ignac Semmelweis showed that puerperal sepsis can be reduced from over 10% to around 2% by the simple act of hand-washing between cases. He particularly mentioned especially between post-mortem examinations and the delivery suite. But he was ignored by his contemporaries at those times.
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Louis Pasteur was the first to recognise that micro-organisms were responsible for spoiling wine, turning it into vinegar.
Joseph Lister practically applied his knowledge to the reduction of colonising organisms in compound fractures by the use of antiseptics. This allowed surgery without infection post operatively. His toxic phenol spray and principles he laid down on antiseptic surgery soon gave way to aseptic surgery at the turn of the century.
Instead of killing the bacteria in the area of surgical site (antiseptic technique), the conditions under which the surgical procedure was performed were kept free of bacteria (aseptic technique). This technique is still employed in today‘s modern operating theatres.
The concept of a ‗magic bullet‘ (Zauberkugel), which the people believed, that could kill microbes but not their host became a dream come reality with the discovery of sulphonamide chemotherapy in the mid-twentieth century.
The discovery of the antibiotic penicillin is solely attributed to Alexander Fleming, but it was isolated in a pure form by Florey and Chain. The first patient to receive the wonder drug penicillin was Police Constable Alexander in Oxford. He was a victim of severe staphylococcal bacteraemia with metastatic abscesses. After receiving the penicillin, he responded to treatment, made a partial recovery before
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the penicillin ran out, then relapsed and died. There has been a rapid proliferation of antibiotics with broad-spectrum activity.
However, most staphylococci are now gaining resistance to penicillin, whereas streptococci remain sensitive. But streptococci are now seen less commonly in surgical practice. Bacteria developed resistance through the acquisition of β-lactamases, which break up the β-lactam ring in many antibiotics.
The acquisition of extended spectrum β-lactamases (ESBLs) is an increasing concern in some Gram-negative organisms causing surgical site infections. In addition, there is rising resistance of many other bacteria to antibiotics, particularly it is evident with the emergence of methicillin-resistant Staphylococcus aureus (MRSA) and glycopeptide-resistant enterococci (GRE), which are also relevant in general surgical practice. There is a synergy between aerobic Gram-negative bacilli and anaerobic Bacteroides spp. which presents a challenge to SSI prevention, especially abscesses after abdominal surgery.
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1.2. AN INTRODUCTION TO SURGICAL SITE INFECTIONS
Surgical Site Infections Surgical site infections (SSIs) are those infections of the tissues, organs, or spaces that are exposed by surgeons during performance of an invasive procedure.
Some degree of erythema will normally be present at the surgical site normally and it is due to the inflammatory process that causes wound healing. In suspicious cases of surgical site infections, wound erythema can be visible with edges demarcated with ink. If the erythema is expanding, there will be increase in the peri-incisional pain or tenderness or purulent discharge from the wound and then the possibility of infective process is increased and further intervention and treatment should be done to curb the infection.
Infection that occurs following surgery or admission to hospital is termed health care-associated infection (HAI). There are four main groups under the broad term of health care-associated infection:
Respiratory infections (including ventilator-associated pneumonia),
Urinary tract infections (mostly related to urinary catheters),
Bacteraemia (mostly related to indwelling vascular catheters)
Surgical Site Infections.
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2. CLASSIFICATION OF SURGICAL SITE INFECTIONS Surgical Site Infections are classified into two categories:
2.1. Incisional SSIs:
Infectious process those are limited to surgical site.
It is again subdivided into two types:
a) Superficial SSIs:
Infection involving skin and subcutaneous tissues b) Deep SSIs:
Infection involving facial and muscle layers.
2.2. Organ/Space SSIs:
Infectious process that involves any part of the body manipulated during
surgical procedure.
Fig.1 - Classification Of Surgical Site Infections
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SURGICAL SITE INFECTIONS - CRITERIA:
INCISIONAL SSI:
SUPERFICIAL INCISIONAL SSI:
Infection occurring within 30 days of surgery;
+ Infection involves only skin and subcutaneous tissue;
+ at least one of the following must be present:
1. Purulent discharge
2. Organisms isolated from aseptically cultured fluid or tissue.
3. At least one sign of infection: pain or tenderness, localized swelling, redness or heat.
And the incision is deliberately opened by surgeon unless the incision is culture – negative.
4. Diagnosis of SSI by surgeon or attending physician.
DEEP INCISIONAL SSI:
Infection occurring within 30 days of surgery, or within 1 year of operation if implants are in place;
And Infection involves deep soft tissue;
And At least one of the following must be present:
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1. Purulent discharge
2. Deep incision spontaneously dehisces or deliberately opened by a surgeon when the patient has at least one of the following symptoms: fever (>38°C), localized pain or tenderness unless the site is culture negative.
3. Evidence of deep infection on direct examination, during reoperation, or on radiological examinations.
4. Diagnosis of SSI by the surgeon or attending physician.
ORGAN/SPACE SSI:
Infection occurs within 30 days of surgery, or within 1 year of operation if implants are in place;
And Infection involves any part of anatomy that was manipulated during an operation, other than the incision;
And At least one of the following must be present:
1. Purulent drainage that is placed through a stab wound into the organ space 2. Organism isolated from and aseptically cultured fluid or tissue
3. Evidence of deep infection on direct examination, during reoperation, or on radiological examinations
4. Diagnosis of SSI by surgeon or attending physician
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2.3. LOCAL AND SYSTEMIC PRESENTATION
The infection of a wound can be defined as the invasion of organisms through tissues which occurs following a breakdown of local and systemic host defence mechanisms, leading to manifestations like cellulitis, lymphangitis, abscess and bacteraemia.
The infection of caused by most surgical wounds is referred to as superficial surgical site infection (SSSI). The other categories of surgical site infections include deep SSI (infection in the deeper musculofascial layers) and organ space infection (such as an abdominal abscess after an anastomotic leak).
Pathogens resist host defence mechanisms by releasing toxins, which favour their spread through the intact structures of the body, and this is enhanced in anaerobic or frankly necrotic wound tissue.
Clostridium perfringens, which is responsible for gas gangrene, releases toxins in the form of proteases such as hyaluronidase, lecithinase and haemolysin that allows it to spread through the tissues.
Resistance to antibiotics can be acquired by previously sensitive bacteria with the transfer occurring through plasmids. The human body is a home for approximately about 1014 organisms. They can be released into the tissues by surgical procedure, the contamination being most severe when a hollow viscous
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perforates (e.g. faecal peritonitis following a diverticular perforation). Any infection that follows a surgical procedure is termed as primary or secondary.
Classification of sources of infection
■ Primary: Those infections that are acquired from a community or endogenous source (such as that following a perforated peptic ulcer)
■ Secondary or exogenous (HAI): Those infections that are acquired from the operating theatre (such as inadequate air filtration) or the ward (e.g. poor hand- washing compliance) or from contamination at or after surgery (such as an anastomotic leak).
2.4. MAJOR AND MINOR SURGICAL SITE INFECTIONS
A major SSI is defined as a wound that that is active which either discharges significant quantities of pus spontaneously or needs a secondary procedure to drain it. The patient may present with systemic signs such as tachycardia, pyrexia and a raised white count [systemic inflammatory response syndrome (SIRS)].
Major wound infections presents with following features:
■ contains significant quantity of pus
■ warrants delayed return home
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■ Patients are labeled to be systemically ill
Fig.2 – Major wound infection and delayed healing presenting as a faecal Fistula
Minor wound infections may discharge pus or infected serous fluid but they are not associated with excessive discomfort, systemic signs or delay in return home which are the defining features of major wound infections.
Fig.3. Minor surgical site infection
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3. RISK FACTORS OF SURGICAL SITE INFECTIONS
Surgical site infections do not occur in all the individuals who undergo major surgical procedures. There are several factors operating which account for the development of infections in the surgical site. Those factors can be categorized as patient factors, local factors and microbial factors.
Patient factors like older age, immunosuppression, obesity, Diabetes mellitus, Chronic inflammatory process, Malnutrition, Smoking, Renal failure, Peripheral vascular disease, Anaemia, Radiation, Chronic skin disease, Carrier state (e.g., chronic Staphylococcus carriage) are all possible etiological factors in enhancing the probability of surgical site infections.
Local factors attributed to surgical site infections include Open compared to laparoscopic surgery, Poor skin preparation, Contamination of instruments, Inadequate antibiotic prophylaxis, Prolonged procedure, Local tissue necrosis, Blood transfusion, Hypoxia, hypothermia etc.
Microbial factors are the most important factors which are directly related to surgical site infections which includes prolonged hospitalization (leading to nosocomial organisms), Toxin secretion, Resistance to clearance (e.g., capsule formation).
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The degree of contamination of wounds by the microbes during surgery is one of the most important risk factors in developing wound infection is the colonization of bacteria at the surgical site. There is a threshold above which the risk is substantially increased which is 10⁵ colony counts per gram of tissue. If there is presence of foreign body, a much lower count is enough to result in such infection.
Factors that determine whether a wound will become infected:
■ Host response after the surgery
■ Virulence and inoculum of infective agent residing
■ Vascularity and health of tissue being invaded (including local ischaemia as well as systemic shock) by the microbes
■ Presence of dead or foreign tissue in the area of vicinity
■ Presence of antibiotics during the ‗decisive period‘
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Fig.4. Factors determining the development of SSIs
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4. VARIOUS MANIFESTATIONS OF SURGICAL SITE INFECTIONS IN DIFFERENT SCENARIOS
LOCALISED INFECTIONS ABSCESS
An abscess presents all the clinical features of acute inflammation originally which was described by Celsus: calor (heat), rubor (redness), dolour (pain) and tumour (swelling). To these can be added functio laesa (loss of function: if it hurts, the infected part is not used) which was the fifth factor added to signs of acute inflammation. They usually occur following a puncture wound of some kind, which may have been forgotten, as well as surgery, but they can also be metastatic in all tissues following bacteraemia.
Pyogenic organisms, predominantly, Staphylococcus aureus, is the main cause behind tissue necrosis and suppuration.
An abscess is usually surrounded by an acute inflammatory response and a pyogenic membrane which is composed of a fibrinous exudate and oedema and the cells of acute inflammation. Granulation tissue (macrophages, angiogenesis and fibroblasts) is formed later around the suppurative process and it leads to collagen deposition. If it is not drained or resorbed completely, a chronic abscess may be the
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end result. If it is partly sterilised with antibiotics, an antibioma may form without going in for a chronic abscess.
Abscesses contain hyperosmolar material that draws in fluid which increases the pressure and causes intense pain. If they spread, they usually track along planes of least resistance and point towards the skin which is their usual course. Wound abscesses may discharge spontaneously by tracking to a surface, but many a times they need drainage through a surgical incision. Most abscesses relating to surgical wounds take 7–10days to form after the surgical procedure.
As many as 75% of SSIs occur after the patient has left the hospital and should be overlooked by the surgical team.
Abscess cavities need cleaning out after incision and drainage and they are encouraged to heal by secondary intention without any further intervention. All loculi need to be opened and curetted before resolution can occur which should be checked for. Persistent chronic abscesses, if untreated, may lead to sinus or fistula formation.
In a chronic abscess, there is tissue sequestration and later calcification occurs. Certain organisms are commonly associated with chronicity, sinus and fistula formation which are Mycobacterium and Actinomyces.
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Fig.5. Surgical site infection - abscess
Per anastomotic contamination is one of the main causes of an abscess but, in the abdomen, abscesses are more usually the result of anastomotic leakage. An abscess located in a deep cavity such as the pleura or peritoneum may be difficult to diagnose or locate even when there is strong clinical suspicion that it is present but they should always be borne in mind. In such scenarios, plain or contrast radiographs may not be helpful, but ultrasonography, computerized tomography (CT), magnetic resonance imaging (MRI) and isotope scans are all useful and may allow guided aspiration without the need for surgical intervention.
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CELLULITIS AND LYMPHANGITIS
Cellulitis is defined as non-suppurative invasive infection of tissues. There is only poor localisation in addition to the cardinal signs of inflammation.
Spreading surgical site infection presenting in surgical practice is typically caused by organisms such as β-haemolytic streptococci, staphylococci and C. perfringens.
Tissue destruction, gangrene and ulceration may follow, which are caused by release of proteases from these microbes.
Systemic signs (the old-fashioned term toxaemia) are common which include SIRS, chills, fever and rigors.
Fig.6. Surgical site infection - cellulitis
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Lymphangitis is part of a similar process just like cellulitis and it presents as painful red streaks in affected lymphatics. Cellulitis is one which is located at the point of injury. Lymphangitis is more often accompanied by painful lymph node groups in the related drainage area.
Fig.7. Surgical site infection - Lymphangitis
SYSTEMIC INFLAMMATORY RESPONSE AND MULTIPLE ORGAN DYSFUNCTION SYNDROMES (MODS)
Sepsis is defined as one with the systemic manifestation of SIRS, with a documented infection and the signs and symptoms of which may also be caused by multiple trauma, burns or pancreatitis without infection. Serious inciting infection such as surgical site infections, may lead onto SIRS through the release of
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lipopolysaccharide endotoxin from the walls of dying Gram-negative bacilli (mainly Escherichia coli) or other bacteria or fungi. This and other toxins cause the release of cytokines.
Septic manifestations and multiple organ dysfunction syndrome (MODS) are mediated by the release of cytokines and other substances released from polymorphonuclear and phagocytic cells. In its most severe form, MODS may eventually lead onto multiple system organ failure (MSOF).
Fig. 8. Relationship between SSIs and SIRS
.
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DEFINITIONS OF INFECTED STATES
■ SSI is an infected wound or deep organ space
■ SIRS is the body‘s systemic response to an infected wound ■ MODS is the effect that the infection produces systemically
■ MSOF is the end-stage of uncontrolled MODS
BACTERAEMIA AND SEPSIS
Bacteraemia is unusual following superficial SSIs but they are common after deep space SSI. Bacteraemia is important when prosthesis has been implanted, as infection of the prosthesis is a common occurrence. Sepsis which may be accompanied by MODS usually follows anastomotic breakdown.
SPECIFIC WOUND INFECTIONS GAS GANGRENE
This is caused by C.perfringens which is Gram-positive, anaerobic, spore- bearing bacilli that are widely found in nature, particularly in soil and faeces. It is relevant to military and traumatic surgery and colorectal operations and in patients who are immunocompromised, diabetic or have malignant disease who are at
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greater risk, particularly if they have wounds containing necrotic or foreign material, resulting in anaerobic conditions.
Military wounds provide an ideal environment for such infections as the kinetic energy of high-velocity missiles or shrapnel causes extensive tissue damage. The cavitation which follows the passage of a missile causes a ‗sucking‘
entry wound which leaves clothing and environmental soiling in the wound in addition to devascularised tissue. Gas gangrene wound infections are almost always associated with severe local wound pain and crepitus (gas in the tissues, which may also be noted on plain radiographs). Oedema and spreading gangrene occurs because of the release of collagenase, hyaluronidase, other proteases and alpha toxin.
Fig. 9. SSI presenting as Gas Gangrene
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Antibiotic prophylaxis is always given in patients at risk, especially when amputations are performed for peripheral vascular disease with open necrotic ulceration. Once a gas gangrene infection is established, it becomes a surgical emergency and large doses of intravenous penicillin and aggressive debridement of affected tissues are required. The role of hyperbaric oxygen in gas gangrene is controversial.
CLOSTRIDIUM TETANI
This is another anaerobic, terminal spore-bearing, Gram-positive bacterium which is the causative agent of tetanus following implantation into tissues or a wound (which may have been trivial or unrecognised and forgotten).
The spores of Clostridium tetani are widespread in soil and manure, and so the infection is much more common in traumatic civilian or military wounds.
The clinical manifestations of tetanus are mediated by the release of the exotoxin tetanospasmin, which affects myoneural junctions and the motor neurones of the anterior horn of the spinal cord.
A short prodromal period, which has a poor prognosis, leads to spasms in the distribution of the short motor nerves of the face which is eventually followed by the development of severe generalised motor spasms including opsithotonus, respiratory arrest and death.
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A longer prodromal period of 4–5weeks is associated with a comparatively milder form of the disease. Prophylaxis with tetanus toxoid is the best preventative treatment but, in the case of an established infection, minor debridement of the wound needs to be performed and antibiotic treatment with benzylpenicillin provided in addition. The patient may require ventilation in severe forms, which may be associated with a high mortality and the use of anti-toxin using human immunoglobulin is to be considered for both at-risk wounds and established infection. It should be given to all patients with open traumatic wounds who are not immunised.
SYNERGISTIC SPREADING GANGRENE
(SYNONYM: SUBDERMAL GANGRENE, NECROTISING FASCIITIS)
This type of gangrene is not caused by clostridia. It is caused by a mixed pattern of organisms: coliforms, staphylococci, Bacteroides spp., anaerobic streptococci and peptostreptococci have all been implicated, acting in synergy.
Abdominal wall infections are known as Meleney‘s synergistic hospital gangrene and scrotal infection is known as Fournier‘s gangrene.
Patients are almost always immunocompromised with co morbid conditions such as diabetes mellitus. The surgical wound initiating the infection may have
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been minor, but severely contaminated wounds are more likely to be the cause.
Severe wound pain, signs of spreading inflammation with crepitus and smell are all signs indicating that the infection is spreading. If untreated, it will lead to widespread gangrene and MSOF. The subdermal spread of gangrene is always much more extensive than it appears from the point of initial examination.
Fig.10. Meleney’s synergistic hospital gangrene
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Fig.11. Fournier’s gangrene
Broad-spectrum antibiotic therapy must be combined simultaneously with aggressive circulatory support. Locally, there should be wide excision of necrotic tissue followed by laying open of affected areas. The debridement of the affected area may need to be extensive, and patients who survive may need large areas of skin grafting.
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Fig.12. SSI – Necrotizing Fascitis
5. PREVENTION OF SURGICAL SITE INFECTIONS
Protection of surgical patients from infection is the primary consideration throughout the preoperative, peroperative and postoperative phases of hospital care. Bacterial infection of surgical incisions may have a range of results from a simple inconvenience to disaster, from small stitch abscess to massive tissue necrosis, septicaemia and even death. Some of the factors that determine the surgical site infection and its consequences to the patient are beyond the control of surgeons. But others can be well controlled if measures are taken promptly. Those preventive measures against surgical site infection are described in the further pages.
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ASEPTIC MEASURES IN OPERATION THEATRE:
OPERATION THEATRE COMPLEX:
It should be scientifically planned, including barrier system. Its location should be away from the inpatient area and located on the top floor. Operation theatre complex should consist of four zones namely: outer zone, restricted/ clean zone, aseptic zone and disposal zone.
CRITERIA OF AN IDEAL OPERATION ROOM:
It should be big enough for free circulation, having two openings— one towards scrub area and other towards sterile area, openings fitted with swing door and it must be well ventilated, air conditioned by- ―High efficacy positive pressure air filter‖ system.
CLEANING AND DISINFECTION OF OPERATING ROOM:
Cleaning, disinfection and sterilization are the three cornerstones in ensuring operation room asepsis. Cleaning is a form of decontamination which removes organic matter and visible soils that interfere with the action of disinfectant, which reduces the bacterial count and can be done by scrubbing with detergents and rinsing with water. For disinfection Phenol (Carbolic acid 2%) is used, to wash
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floor every day after surgery, mop operating room walls, tables, mats, instrument trolleys, stools followed by a wipe done with 70% alcohol.
ASEPSIS AND ANTISEPSIS
The term asepsis describes all the methods for preventing contamination of wounds and other sites by ensuring that only sterile objects and fluids come into contact with them; by which the risks of airborne contamination are minimized.
Antisepsis is the use of solutions, such as chlorhexidine, iodine or alcohol, for disinfection.
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VARIOUS METHODS USED TO ACHIEVE ASEPSIS INSIDE THE OPERATION THEATRE COMPLEX ARE:
Formaldehyde fumigation
Ultra violet radiation
Good Hand Washing Procedure
Theatre clothing must adhere to the theatre disciplines:
Gowns must be worn in ward areas.
Mask should be changed for each operation and an efficient mask must be capable of arresting low velocity droplets. Surgical antifog masks with flexible nosebands follow the facial contours and retain a high efficiency of filtration.
Eye protection/visors should be utilized.
Tie up long hair and beard should be covered.
Foot wear should be clean and disinfected.
Gloves must always be worn because it protects both surgeon and patient from blood-borne viruses and prevents the wound from becoming contaminated with the surgeon‘s skin flora.
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Theatre air should flow in such a way that airborne microorganisms tend to be carried out rather than in. Ultraclean air systems are advocated in which air is re- circulated through high efficiency particulate air (HEPA) filters. This produces a reduction in circulating microorganisms compared with a conventional system.
SURGEON PREPARATION
1. A surgeon must satisfy certain local occupational health requirements before entering the operating theatre.
2. An initial scrub of 3-5 minutes should be done.
3. Antiseptics like 4% Chlorhexidine gluconate (Hibiscrub), Hexachlorophane (pHisoHex) or Povidone-iodine (Betadine) must be used for hand – washing.
4. Surgeon‘s hands should be completely dried off.
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PREPARATION OF THE PATIENT
1. Longer stay in the hospital increases the risk of woulnd infection. Infections at other sites increase the risk of surgical site infections; therefore we must diagnose and treat pre-existing infections before elective operation.
2. The patient must be transported to theatre in bed directly, after wearing a clean operating gown.
3. If hair removal is to be removed, clippers or depilatory cream can be used.
4. The skin area in the vicinity of the operation site should be prepared, first, with detergent for cleaning and degreasing, then with antiseptic solutions. If the skin is intact, alcoholic solutions of chlorhexidine or povidone-iodine are used rather than aqueous solutions.
Cleaning and disinfection of instruments is another big step in preventing surgical site infections.
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SURGICAL TECHNIQUE:
Postoperative surgical site infection rate is greatly influenced by the surgical techniques. Longer operation predisposes the patient to develop surgical site infections. Operative trauma should be kept as minimum as possible and handling of tissues must be restricted to the level possible.
Incisions made with sharp instruments are less likely to become infected than those produced by cautery; however, cauterization reduces the need for sutures, which itself act as a nidus for infection. Finest suitable ligature should be used during the surgery. Haematomas, necrotic or ischaemic areas are at great risk of causing infections. Prophylactic drains should be avoided in cases where they are not usually necessary because it increases the risk of infection. A necessary drain should be inserted through a separate stab, and it should not be inserted through the main wound. It should be a completely closed system and it should be removed as soon as possible to decrease the chance of ascending infection.
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6. ROLE OF PRE-OPERATIVE HAIR REMOVAL IN PREVENTING SURGICAL SITE INFECTIONS
Hair has long been perceived to lack cleanliness. It can thus interfere with surgical field vision and its removal is related to infection prophylaxis. For these reasons, in the past, patients undergoing surgery routinely had hair removed from the site of the incision, as this was thought to reduce the chance of the surgical site becoming infected.
Appropriate hair removal is a key component of skin preparation. Hair should not be removed unless and until the hair at or around the incision site will interfere with the surgical procedure. Removal of hair from the intended site of surgical incision has traditionally been part of the routine preoperative preparation of patients undergoing surgery.
Hair removal is necessary to facilitate adequate exposure to the surgical site and preoperative skin marking. Furthermore, suturing techniques and the application of wound dressings can become complicated by the presence of hair.
Apart from these practical issues, hair has been associated with the potential to cause surgical site infection (SSI). However, there is also the belief that hair removal might be a factor which increases the risk of SSI by causing microscopic trauma of the skin. So the right method of hair removal is the cornerstone deciding
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whether it will be a causative or a preventive factor for the development of surgical site infections.
Three methods of hair removal are currently used:
Shaving
Clipping
Chemical depilation
Shaving is the commonest and cheapest method of hair removal in the surgical preparation. This method makes use of a sharp blade which is held within the head of a razor and is drawn over the patient‘s skin to cut hair close to the surface of the skin.
Fig.13. Pre operative hair removal with Razor
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During the process of shaving, the skin experiences microscopic cuts and abrasions. It is believed that these microorganisms can enter and colonize these cuts and may contaminate the surgical wound causing post-operative surgical site infections. In addition to their entry through the cuts, abrasions may ooze exudates, which may provide a culture medium for microorganisms. Razor shaving increases the risk of infection by creating micro abrasions that allow the skin - dwelling microorganisms to collect and multiply in those abrasion sites.
Clippers use fine teeth to cut hair close to the patient‘s skin, and they leave short stubble of approximately around one millimetre in length. The heads of clippers can be disposed of or disinfected between patients and this helps to minimise the risks of cross infection. Since clippers do not come into contact with the patient‘s skin they are likely to reduce the risk of cuts and abrasions.
Fig. 14. Pre operative hair removal with clipper
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Surgical clippers available today offer advancements in device technology and they are designed in such a way to provide compliance with professional recommendations and also promote patient safety. Wider blades clip the hair smoothly and as close as possible, thereby avoiding infection-causing nicks and cuts. Disposable, single-use blades prevent cross contamination from happening.
When used in a proper way, electric clippers are less likely to damage the skin and they are associated with lower infection rates. If clipping of hair is done immediately before an operation it is associated with a lower risk of HAI than clipping the night before.
Shaving and clipping most often carried out in operating theatres, anaesthetic rooms, wards or in peoples‘ homes by theatre staff, ward staff, or by patients themselves.
Depilatory creams are the chemicals which have the tendency to dissolve the hair itself. It has its own disadvantages that it is a slower process and it takes a longer time as the cream has to remain in contact with the hair for between 5 and 20 minutes. In addition to the prolonged duration of application, there is a risk of irritant or allergic reactions to the cream and patch tests should be carried out 24 hours before the cream is applied. Chemical depilation is usually carried out on wards or in the home as it requires more time on comparing other two techniques.
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Fig.15.Comparison between shaving and clipping
Hair removal should never take place in the operating theatre as loose hair may contaminate the sterile surgical field and it should be carried out by skilled personnel to prevent abrasion injuries.
To minimize the potential risk of skin trauma, the use of clippers instead of razors has been proposed for preoperative hair removal. Clippers cut the hair as close to the skin as possible without actually touching it, whereas razors involve a sharp blade drawn directly over the skin.
If the presence of hair will interfere with the surgical procedure and removal is in the best interest of the patient, following precautions should be meticulously undertaken:
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• Hair removal should be performed on the day of the surgery, in a location which should be outside the operating or procedure room
• Only the hair interfering with the present surgical procedure should be removed
• Hair is preferably clipped using a single-use electric or battery-operated clipper, or clipper with a reusable head that can be disinfected between patients. Devices are specifically designed for clipping hair in sensitive areas (i.e., for urologic, gynecologic, and obstetric procedures).
Key strategies that we can adopt for changing practice regarding appropriate hair removal include:
• Remove all razors from operating suites and surrounding patient support areas, or eliminate razors from surgical prep kits;
• Institute a policy to avoid shaving surgical sites, or if hair removal is necessary, perform hair removal only with clippers right before surgery
• Institute the placement of electric clippers throughout the areas where hair removal is likely to occur;
• Educate surgeons and clinical staff on appropriate hair removal techniques, and purchasing personnel on appropriate supplies;
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• Implement ―No Shave Zone‖ posters throughout the hospital;
• Standardize documentation of hair removal technique in the preoperative/
operative record to include ―no hair removal, clipper, depilatory,‖
eliminating the razor/shaving option; and
• Educate patients to not shave the surgical site before surgery or develop patient education materials on proper hair removal.
• If clippers are used, nurses can ensure that there are adequate units and supplies based on the daily OR schedule; in addition, nurses can ensure that the clipper units are fully charged and stored in a convenient location.
• If depilatories are used, nurses must remember to assess the patient‘s allergies, test the products on a small area, and keep the products away from the patient‘s eyes and genitalia
7. ROLE OF PRE-OPERATIVE ANTIBIOTICS IN PREVENTING SURGICAL SITE INFECTIONS
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Preoperative antibiotic prophylaxis is defined as the administration of antibiotics before surgery to help prevent the development of surgical site infections.
The use of antibiotic prophylaxis is just one of many actions taken to decrease the rate of surgical site infections. Other such important preoperative actions include basic infection control strategies, instrument sterilization, and a patient's skin preparation (e.g., methicillin-resistant Staphylococcus aureus [MRSA] decolonization, appropriate hair removal, skin antiseptic).
A patient's overall medical condition and perioperative and postoperative management are also important factors included in the prevention of surgical site infections and the outcome of the surgery.
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Fig.16.Shaving Vs Trimming.
HISTORICAL PERSPECTIVE
Following the introduction of antibiotics, early in the 1950s it was reported that the use of antibiotic prophylaxis had either no benefit or a higher infection rate. Moreover, the emergence of resistant strains was also attributed, in part, to such use of antibiotics. In the early 1960s, Burke revealed the critical flaw in previous investigations and clinical failures. Burke administered a single dose of penicillin systemically at different times before and after the inoculation of penicillin-sensitive Staphylococcus aureus in the dermis of guinea pigs.
Administration of antibiotic either shortly before or after the inoculation of organisms resulted in lesions that were histologically identical to lesions induced
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by intradermal inoculation with killed organisms. Delaying the administration of antibiotic by as little as three hours had resulted in lesions identical to those in animals not receiving the antibiotics.
The critical dependence of prophylactic efficacy on timing of administration was soundly established by this and subsequently shown to depend on the presence of peak antibiotic levels in the tissue at a time when the local concentration of microorganisms would otherwise be high. The most common organisms implicated as surgical site infection pathogens are dependent upon the type of wound that is involved in surgical procedure.
8. CLASSIFICATION OF WOUNDS
Clean wounds that are not infected and without inflammation are primarily closed, and do not include the organ systems that are outlined in a clean- contaminated wound.
Clean-contaminated wounds involve the respiratory, alimentary, genital, and urinary tract as long as the tract is entered without unusual forms of contamination.
Contaminated wounds include open, fresh accidental wounds and also those with non-purulent inflammation. Contaminated wounds also include
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procedures in which there are major breaks in sterile technique or gross spillage from the gastrointestinal tract.
Dirty or infected wounds are old traumatic wounds with devitalized tissue or involve existing clinical infection or perforated viscera.
During clean procedures, skin flora such as coagulase- negative staphylococci (e.g., Staphylococcus epidermises) or Staphylococcus aurous are predominant pathogens implicated in surgical site infections. In clean- contaminated procedures, the most commonly found organisms that are causing surgical site infections are skin flora, gram-negative rods, and Enterococci.
In general, the preoperative antibiotic selection is commonly based on the site of infection and most likely pathogens for the type of wound.
The main goal when determining the best antibiotic is to have the narrowest spectrum of activity while still ensuring the most common organisms are targeted.
Additionally, preoperative antibiotics are also chosen based on factors like cost, safety, ease of administration, pharmacokinetic profile, bactericidal activity, and hospital resistance patterns.
By addressing all of these factors during antibiotic selection, surgical site infections are minimized to the best possible way while still maintaining appropriate antimicrobial stewardship practices.
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When addressing antibiotic surgical prophylaxis in the adult population compared with the pediatric population, many of the same antibiotics which are utilized in the adult population are also used in pediatrics (e.g., first-generation and second-generation cephalosporin‘s, vancomycin).
Cefazolin is used most often for surgical prophylaxis except in cases such as known significant beta-lactam allergy, MRSA colonization, or surgical sites with probable organisms that are not covered by cefazolin alone (e.g., appendectomy, colorectal).
In patients requiring only cefazolin for preoperative surgical prophylaxis, clindamycin or vancomycin are also often used as alternatives in those with significant beta-lactam allergies.
In the case of known MRSA colonization, vancomycin is the alternative unless additional antibiotics are required for possible gram-negative or anaerobic organisms. For patients requiring additional microbe coverage (e.g., colorectal), multiple options are to be considered including cefazolin plus metronidazole, cefoxitin, or ertapenem. Additional antibiotics serve according to the options based on specific surgical sites in addition to hospital-specific and patient-specific antibiotic resistance.
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Appropriately administered antibiotic prophylaxis has a great impact on reducing the incidence of surgical wound infection. Prophylaxis is uniformly recommended in cases of clean-contaminated, contaminated and dirty procedures.
The timing in which antibiotic is administered is critical to efficacy. The first dose should always be given before the procedure, preferably within 30 minutes before incision during surgery. Re administration at one to two half-lives of the antibiotic is recommended according to the duration of the procedure.
In general, postoperative administration of antibiotics is not recommended.
Antibiotic selection is influenced solely by the organism most commonly causing wound infection in the specific procedure and also by the relative costs of the particular available agents.
In case of gastrointestinal procedures, oral and intravenous administration of agents with activity against gram-negative and anaerobic bacteria is warranted, as well as mechanical preparation of the bowel is mandated. Cefazolin provides adequate coverage for most other types of surgical procedures.
Postoperative wound infections have an enormous impact on patients' quality of life and they contribute substantially to the financial cost of patients‘ health and care. The potential consequence ranges from increased pain and care of an open wound to sepsis and even death.
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The occurrence of wound infection requires a local inoculum which should be sufficient enough to overcome host defences and establish growth. The process is highly complex and it mainly depends on the interaction of various host, local tissue and microbial virulence factors.
Measures that are intended to prevent wound infection typically attempt to modify the host and local tissue factors and include, for example, preoperative optimization of comorbid illness, control of the operative environment, proper cleansing of the skin and use of aseptic surgical technique which all go hand in hand. Antibiotic prophylaxis is a thing which is only one relatively minor effort among numerous preventive measures, but the efficacy and impact of antimicrobial prophylaxis has clearly been demonstrated to be significant.
Surgical Procedure Classification and Consideration of Risk Factors
To establish a ―prophylaxis indicated‖ status for a given procedure it requires consideration of the likelihood of infection without antibiotics and the morbidity and cost of an infectious complication. The discussion of these issues is facilitated by a taxonomy that helps in classifying a procedure according to the level of microbial contamination routinely associated with that procedure and the likelihood of infection. According to the classification, the incidence of infection ranges widely across classes—less than 2 percent for clean procedures (e.g., breast
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biopsy) to over 40 percent for dirty procedures (colon perforation with diffuse fecal contamination). So it can be said that antibiotic prophylaxis is warranted in all procedures in the categories of clean-contaminated, contaminated or dirty.
There is an argument against antibiotic prophylaxis for clean procedures, based on the intrinsically low rate of infection without antibiotic treatment, but is overly simplistic for several reasons.
For specific clean procedures, infection may be unlikely, but the possibility of morbidity and cost of even infrequent infection can justify the use of prophylaxis. A classic example is the insertion of prosthetic devices, such as heart valves or joints. Though they are clean procedures which constitute approximately 60 percent of all surgical procedures and account for approximately 40 percent of all wound infections, it is estimated that prophylaxis for clean procedures would reduce the overall incidence of wound infection by 17 percent. Abdominal operations and procedures lasting more than two hours and the presence of three comorbid medical conditions are independent and additive risk factors.
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9. SELECTION AND ADMINISTRATION OF ANTIBIOTICS An appropriate prophylactic antibiotic should
(1) Be effective against microorganisms anticipated to cause infection;
(2) Achieve adequate local tissue levels;
(3) Cause minimal side effects;
(4) Be relatively inexpensive, and
(5) Not be likely to select virulent organisms.
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The microbial context of the wound and the hospital environment may be the influential factors but the choice of antibiotic and the coverage should primarily target those organisms known to cause postoperative infection. Species of Staphylococcus may be the causative agent in the majority of procedures that do not violate mucosa or a hollow viscous. In general, a first-generation cephalosporin fulfills these criteria and is regarded as a sufficient antibiotic prophylaxis for the majority of procedures.
For procedures involving the alimentary tract, genitourinary tract and hepatobiliary system, coverage should be additionally influenced by site-specific flora, such as gram-negative and anaerobic microorganisms. In such cases, cefotetan (Cefotan) or cefoxitin (Mefoxin) are considered as suitable agent. For patients with documented allergy to cephalosporins, vancomycin (Vancocin) is an alternative for coverage of Staphylococcus, and metronidazole (Flagyl) or clindamycin (Cleocin) and an aminoglycoside may be used to cover anaerobic and gram-negative organisms, respectively. Aztreonam (Azactam) can be combined with clindamycin in the same setting. A quinolone, such as ciprofloxacin (Cipro), is also effective for coverage of gram-negative organisms.
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The duration of an adequate tissue level of the antibiotic need not exceed the operative period and the duration of administration is extended only in special circumstances, such as gross contamination secondary to a ruptured viscus or severe trauma.
Half-Lives of Selected Antibiotics Commonly Used for Prophylaxis
ANTIBIOTIC HALF-LIFE (HOURS)
Cefazolin (Ancef, Kefzol) 1.8
Vancomycin (Vancocin) 3 to 9
Cefoxitin (Mefoxin) 0.6 to 1
Cefotetan (Cefotan) 3 to 4.6
Aminoglycosides 2
Metronidazole (Flagyl) 8
Clindamycin (Cleocin) 2.4 to 3
Ciprofloxacin (Cipro) 3 to 5
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APPROACHES TO PROPHYLACTIC ANTIMICROBIAL THERAPY:
1. A narrow-spectrum antibiotic: These may be used to treat a known case of sensitive infection; for example, vancomycin for the treatment of MRSA.
2. Combination of broad spectrum antibiotics: These antibiotics are used when the organism is not known or when it is suspected that several bacteria, acting in synergy, may be responsible for the infection. For example during and after any of the emergency surgery requiring opening of perforated or ischaemic bowel, any of the gut organisms may be responsible for the subsequent peritoneal or bacteraemic infection. In this case, a triple regimen which includes a combination of broad spectrum penicillin, an aminoglycoside and Metronidazole, may be used pre and postoperatively to support the patients‘ own body defence.
MECHANISM OF ACTION UTILIZED FOR PROPHYLAXIS OF SSIs Multiple antibiotic classes are now being recommended for use in preoperative antibiotic prophylaxis. The antibiotics utilized are usually bactericidal instead of bacteriostatic. This means that any of the targeted organisms are thus killed instead of just preventing the multiplication of their further growth.
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It should be noted that certain antibiotics can exhibit both bacteriostatic and bactericidal properties depending on the bacterial sensitivity and antibiotic concentration.
For example, Clindamycin is bacteriostatic at lower doses, but once at higher doses, it can exhibit bactericidal properties. In most surgeries, the primary intention is to ensure that the bactericidal concentration has been reached in the blood and tissues before moving onto incision.
ADMINISTRATION OF PROPHYLACTIC ANTIBIOTICS
The majority of preoperative prophylactic antibiotics are administered via intravenously (IV). The initial timing of administration, redosing if applicable, duration of prophylactic therapy, and dosing in obese patients are all important components in the prevention of surgical site infections as well as antimicrobial stewardship. Avoiding unnecessary use of antibiotics helps us to diminish the occurrence of adverse effects and possibility of antibiotic resistance development.
Most of the antibiotics should be given within 60 minutes of a surgical incision.
Exceptions include vancomycin and levofloxacin, which require administration within 120 minutes of the procedural incision because of longer administration times.
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If a patient is already on antibiotics for some other infection before surgery, and it is appropriate for surgical prophylaxis, an extra dose of the antibiotic can be administered within 60 minutes of the incision. If a patient is already receiving vancomycin and has renal failure, cefazolin should be considered before the procedure instead of an extra dose of vancomycin.
Re-dosing antibiotics is an important factor due to the half-life of the particular antibiotic which is being used. Factors such as renal dysfunction and extensive burns may have an impact on the the half-life of an antibiotic. Based on the antibiotics mentioned above, cefazolin and cefoxitin would have to be administered more than once depending on the length of the procedure and also a perioperative dose of cefazolin should be administered again at four hours after the initial preoperative dose while cefoxitin should be administered again two hours later. Re-dosing antibiotics due to significant blood loss or dilution during surgery are other important considerations.
Additional prophylactic antibiotics should not be administered after the surgical incision is closed in clean and clean-contaminated procedures.
This recommendation applies to patients with or without a drain after the surgical site is closed, although there could be procedure-specific exceptions also.
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10. RECOMMENDATIONS FOR SPECIFIC CATEGORIES OF SURGICAL PROCEDURES
Prophylaxis is indicated for all surgical procedures not classified as clean ones. As previously stated, certain risk factors justify the use of prophylaxis for clean procedures as well. The following are the recommendations that provided for specific procedures.
CUTANEOUS AND SUPERFICIAL SOFT TISSUE PROCEDURES
For patients with two or more significant risk factors, prophylaxis is given but not strongly indicated. In traumatic wounds the status of the patient's tetanus vaccination is of importance. Although a single dose of antibiotic is acceptable, mechanical cleansing and adherence to guidelines for open management of wounds created more than 12 hours before treatment are very much essential elements of prophylaxis.
HEAD AND NECK PROCEDURES
For procedures entailing entry into the or pharynx or oesophagus, coverage of aerobic cocci is strictly indicated. Either penicillin or cephalosporin-based prophylaxis is efficient.
Prophylaxis is not indicated for dentoalveolar procedures, but it is warranted in immunocompromised patients undergoing these procedures.
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NEUROSURGICAL PROCEDURES
Prophylaxis is recommended for craniotomy and shunt procedures.
Coverage targets microbes especially S. aureus or Staphylococcus epidermidis.
Various regimens have been assessed, ranging from combinations of cefazolin and gentamicin (Garamycin) to single-agent therapy like cefazolin, vancomycin, piperacillin (Pipracil, Zosyn) and cloxacillin (Cloxapen, Tegapen).
GENERAL THORACIC PROCEDURES
Prophylaxis is routinely used for almost all thoracic procedures. In general, the strength of the recommendation of prophylactic antibiotics is proportionate to the likelihood of encountering high numbers of microorganisms during the procedure.
Pulmonary resection in cases of partial or complete obstruction of an airway is a procedure in which prophylaxis is strictly warranted. Likewise, prophylaxis is also strongly recommended for procedures entailing entry into the esophagus. Although the range of microorganisms encountered in thoracic procedures is extensive, most are sensitive to cefazolin, which is the commonly recommended agent of choice.
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CARDIAC PROCEDURES
Prophylaxis against the microbes S. aureus and S. epidermidis is indicated for patients undergoing cardiac procedures. Although the risk of infection is low, the fear of morbidity of mediastinitis or a sternal wound infection is great. Of particular relevance, cardiopulmonary bypass reduces greatly the elimination of drugs, so additional intraoperative doses typically are not necessary.
The optimal duration of prophylaxis is more than 24 hours, or until invasive lines and chest tubes are removed.
GASTROINTESTINAL TRACT PROCEDURES
Prophylaxis is recommended for most gastrointestinal procedures and the number of organisms and proportion of anaerobic organisms progressively increase along the gastrointestinal tract and so the recommendation depends on the segment of gastrointestinal tract entered during the procedure.
The intrinsic risk of infection associated with procedures entering the stomach, duodenum and proximal small bowel is quite low, however, the predominance of clinical practice involves special circumstances that alter this recommendation. Any context which is associated with decreased gastric acidity is associated with a marked increase in the number of bacteria and the risk of wound infection.
