Role of prophylactic antibiotic to prevent surgical site infections in clean surgeries

Sulthana Dhilras, J (2013) Role of prophylactic antibiotic to prevent surgical site infections in clean surgeries. Masters thesis, Madurai Medical College, Madurai.


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INTRODUCTION: Surgical site infections are one of the most common hospital acquired infections, which constitute 38% of surgical infections. It creates great burden to the patients by increasing hospital stay by 7-10 days. Also, it increases hospital expenditures creating an economic burden to the patient and country. AIMS AND OBJECTIVES The objective of the study was to evaluate the role of prophylactic antibiotics to prevent surgical site infections in clean and elective surgeries. Surgeries included in the study were: 1. Hernia repair: Open hernioplasty, Laparoscopic hernioplasty. 2. Neck: Thyroid surgeries, Lipoma nape of neck. 3. Breast: Modified radical mastectomy, Excision biopsy. 4. Scrotal surgeries: Hydrocele, Epididymal cyst excision. PROPHYLACTIC ANTIBIOTIC VS NO ANTIBIOTICS: To compare the surgical site infection in two groups of patients, 1. one receiving prophylactic antibiotics (Study group) and 2. the other group without any prophylaxis before surgery. (Control group). ANTIBIOTICS: To compare the surgical site infection in two groups of patients, · one receiving prophylactic antibiotics (Study group) and · the other group without any prophylaxis before surgery. (Control group) REVIEW OF LITERATURE Historical background: As surgeons, though we deal with infections since the dawn of time, our understanding to treat wound infection became clear only after the development of theory of antisepsis and the evolution of germ theory. Many observations made by nineteenth century physicians were crucial in our knowledge regarding the pathophysiology, treatment and prevention of surgical site infections. Louis Pasteur formulated germ theory and elucidated that contagious diseases are caused by specific microbes. With the help of these principles, he pioneered techniques of sterilization. Also, he identified certain organisms responsible for human infections like Staphylococcus, Streptococcus, and pneumococcus. Joseph lister used a solution of carbolic acid, which were used to treat sewage in his times in Europe, to dress the patients. As this reduced the post operative infection incredibly, it was quickly adopted throughout his country. In 1880, Robert Koch, through his experiments identified pathogenic organisms associated with specific disease like cholera and tuberculosis. Charles Mc Burney pioneered the principle of source control (i.e, surgical intervention to eliminate the source and thereby treat the infection) by performing appendicectomy as treatment of appendicitis, which was previously known to be a fatal disease. This was popularised after been performed on the King Edward VII of England, by Sir Frederick Treves. The discovery of effective antimicrobials helped the modern surgeons to treat wound infections in a much better way, during the twentieth century. During world war I, Sir Alexander Fleming, an army medical officer in British Medical Corps identified the first antibacterial agent Penicillin through his works on the natural action of blood against bacteria and sepsis. During his study on influenza virus, in 1928, he noticed a zone of inhibition around Penicillium notatum colony that grew profusely on a plate of Staphylococcus. He then named the substance derived as ‘penicillin’. This subsequently led to the development of hundreds of potent antimicrobial agents against infectious organisms, which set an example for their use as prophylaxis against postoperative wound infection, and became a very crucial component in the treatment of aggressive and potentially fatal surgical wound infections. Prolific advances in the field of clinical microbiology paved way for the discovery of many new anti microbial agents against those microbes. Also the discovery of autochthonous microflora of skin, respiratory tract, alimentary tract helped modern surgeons to enhance their knowledge about the organisms which will be encountered during surgery. However, whether these organisms were pathogenic or non pathogenic remained unclear. With clinical observations made by veteran surgeons, Frank Meleny and William Altemier, the fact that aerobes and anaerobes synergise to cause serious infections (soft tissue infections and intraabdominal sepsis) came into limelight. So the concept that inhabitant microorganisms were not pathogenic to human body was vanished as these organisms have the potential to cause surgical infections when entered into sterile cavity during the time of surgery. Over the few last decades, new ideas of polymicrobial nature of surgical infections were propagated. Aspirates from the peritoneal fluid of patients with perforated viscus or gangrenous appendicitis also showed the presence of aerobes and anaerobes. Trials were conducted to know the effective source control to treat these infections and antimicrobial agents were administered targetting both pathogens and commensals. William osler, one of the pioneers of American Medicine, from his observations noted that patient died due to inflammatory response in the body to a organism. This allowed our insight into the host inflammatory response to infection. It is because of activation of multiple pathways in response to an infection. So many new therapies were formulated tagetting the modified inflammatory response. Exaggerated inflammatory response seems to be the cause of end organ failure and multi organ dysfunction. Thus, treating surgical infections and thereby preventing multi organ failure is one of the challenges faced by surgeons like us. PATHOGENESIS OF INFECTION: Host defences: � Barrier � Microbial flora � Humoral responses � Cellular responses � Cytokine production Defense barriers: � Physical barriers � Chemical barriers � Immunologic barriers Mammalian host possesses intrinsic defense mechanisms that help to prevent invasion of microbes, multiplication of organisms and thereby cause containment of infection. Our host defences are highly regulated system and are very effective in coping the invaders. They include:- 1. Site specific defences (SSD) 2. Systemic defenses Site specific defenses provide protection at tissue level. Systemic defences begin immediately after invasion of pathogen into sterile area of body. Any micro organism will have to face number of barriers in the body. 1. Epithelial barrier 2. Mucosal barrier. Mucosal barriers provided by mucosa of respiratory, gastrointestinal and urogenital system. Host barrier cells prevent invasion of microbes and proliferation by secreting certain substances. Skin commensals adherent to surface preclude virulent organism invasion, thereby forming colonisation resistance. PHYSICAL BARRIERS: Skin: Skin, the largest organ in the body provides most extensive physical barrier. Resident or commensal microflora on the surface of skin block the attachment of pathogens. Some of the endogenous microflora include staphylococcus, streptococcus, corynebacterium, propionibacterium species. Also, Enterococcus faecalis, Enterococcus faecium, Escherichiae coli, Enterobacteriacae and Candida albicans are isolated from skin surface below the umbilicus. Skin diseases can be associated with abnormal proliferation of skin commensals. Respiratory tract: Host defences in respiratory tract help to maintain sterile environment in distal bronchi and alveoli under normal circumstances. Larger particles are trapped in the mucosa of respiratory tract which are later cleared through cough. Smaller particles reaching the lower respiratory tract are cleared by pulmonary macrophages through phagocytosis. Any breach in this process leads to bronchitis or pneumonia. Gastrointestinal tract: Numerous microbes are encountered in many portions of gastro intestinal tract. Places where resident microflora are absent include urogenital, biliary and pancreatic ductal system under normal circumstances. However, in case of inflammation, malignancy, stone formation or catheterisation, microorganisms may proliferate. Vast number of micro organisms are found in oropharynx and colorectal region. But, organisms found in entire gastro intestinal tract are not always from oropharynx. It is because of the following reasons: 1. Highly acidic environment in stomach kills the microbes. 2. Low motility in stomach during initial phases of digestion. Thus, microbial population in stomach accounts to approximately 102 to 103 colony forming units (CFU). But this may be increased during disease states or drug intake. In terminal ileum, microbial proliferation occurs, increasing count to approximately 105 to 108 CFUs. Exponential growth occurs in colon due to its relatively static and hypoxic environment, where aerobic species are outnumbered by anaerobic organisms to approximately 10: 1. FIGURE 1 MICROFLORA IN GASTROINTESTINAL TRACT Part of GIT Microbial population(CFU/ ML) Stomach 102 to 103 Small intestine 105 to 108 Distal colorectum 1011 to 1012 Along with facultative and obligate anaerobes like Bacteroides, Lactobacillus, Clostridium, Fusobacterium and Eubacterium, some aerobic microbes like Escherichia coli, Enterococcus faecalis, Enterococcus faecium, Enterobacteriacae and Candida albicans are also present in the colon. These organisms provide colonisation resistance and prevent the entry of other organisms like Vibrio cholera, Shigella, Salmonella. But when pathology like perforation occur, the commensal organism provide nidus of infection for the pathogens to proliferate. Surprisingly very little host organisms contribute to the intra abdominal infection. When pathogens enter specific body compartments or tissue, defense mechanisms act to eliminate or remove the nidus of infection. Apart from providing physical barrier, certain proteins like 1. Lactoferrin and Transferrin sequester microbial growth factor iron. 2. Fibrinogen in inflammatory fluid trap micro organisms and polymerises to fibrin. 3. Diaphragmatic pumping mechanism on the undersurface of diaphragm help in expunging micro organisms from peritoneal fluid. 4. Omentum, ‘the policeman of abdomen’ serves to limit infection. Immunologic barriers:- Defense mechanisms in tissues of the body ;- a) Resident macrophages regulate cellular host defense. b) Secretion of cytokines is upregulated by substances like TNF – alpha, IL- 1 beta and INF Gamma. When microbes interact with defense mechanisms in body, opsonisation occurs. Extracellular destruction of organisms occur by formation of membrane attack complex and intracellular destruction by formation of phagocytic vacuoles. Complement pathways, both alternate and classical pathways get activated after microbial invasion. Release of complement fragment (C3a, C4a, C5a) increases vascular permeability. When microbial insult occurs, chemotaxis (i.e., attraction of neutrophils to the micro organisms to the site of insult) occurs. This further leads to the influx of inflammatory fluid to the area of insult. Diapedesis of neutrophils occur within minutes and it peaks within a period of hours or days. Response to an infection depends upon several factors: 1) Number of micro organisms entering the body. 2) Proliferation of organisms 3) Virulence of organisms 4) Potency of defense mechanism Invasion of microbes can lead to one of the following possible outcomes. a) Eradication of infection b) Limitation of infection ( purulent infection is the hall mark of chronic infection) c) Locoregional infection (cellulitis, soft tissue infection) d) Systemic infection (bacteremia) Infection is defined as an ‘identification of microorganisms in host tissue or bloodstream, plus an inflammatory response to their presence’. The inflammatory signs of ‘rubor, tumor, calor, and dolor’ are common, at the site of infection. Apart from these local manifestations, certain systemic manifestations like increased pulse rate and respiratory rate, elevated temperature and elevated white blood cell (WBC) count. Above noted systemic manifestations comprise the ‘systemic inflammatory response syndrome ‘(SIRS). Fig 2. Causes of SIRS “Sepsis is not an antibiotic deficiency syndrome” SIRS when it is caused by microbial infection is termed as sepsis and it is mediated by production of a cascade of numerous proinflammatory mediators produced in response to the products of microbial invasion. These products can be a lipopolysaccharide (endotoxin) derived from gram-negative bacteria; or a peptidoglycan and teichoic acid from gram-positive bacteria; multiple fungal cell wall components such as mannan and numerous others. Patients have sepsis if they meet the following clinical criteria for SIRS and have an evident local or systemic infection. Severe sepsis is defined as sepsis along with the occurence of new-onset failure of organs. It is the frequent cause of death in surgical intensive care units, with a very high mortality rate. i.e., when a patient with sepsis needs ventilatory support and is unresponsive to fluid resuscitation or one who requires vasopressors to correct hypotension, is considered to have severe sepsis. Septic shock is a state in which patient has acute circulatory failure which is usually identified by the occurence of persistent hypotension (systolic blood pressure <90 mmHg) inspite of aggressive fluid resuscitation, with no other identifiable causes. It is the severe manifestation of infection. It can occur in approximately 40% of patients with severe sepsis; with a very high mortality rate. PATHOGENS OF INTEREST FOR SURGEONS: 1. BACTERIA These are little organisms which are of great importance for the surgeons, as they form the vast majority of surgical site infections. Cell wall staining: � There are a number of species of bacteria which are identified by a specific staining called Gram’s stain. � This staining imparts specific colour to bacterial cell wall through which it is classified as gram positive and gram negative. a) When they stain blue, they are termed as gram-positive bacteria. b) And when a bacteria stains red, it is termed as gramnegative. Growth characteristics: • Every bacteria have certain specific growth characteristics in its specific media. • Based on a number of some characteristics, bacteria can be further classified. It can be depending on a) Morphological characteristics b) the pattern of multiplication [e.g., single or multiplication in groups of organisms, i.e., in pairs (diplococci) or in clusters (staphylococci), or in chains of organisms. (streptococci). c) and the presence of spores and its location. � Terminal spores � Subterminal spores Gram +ve cocci Gram –ve bacilli Gram-positive bacteria The bacteria that cause surgical site infections are: a) skin commensals � Staphylococcus aureus and � Staphylococcus epidermidis and � Streptococcus pyogenes and These organisms cause infections either alone or in combination with other pathogenic organisms. b) commensals of GIT such as Enterococci faecalis and Enterococci faecium. They have the capability to cause nosocomial infections like respiratory infections, catheter associated infections urinary tract infections (UTIs) and septicaemias in immunologically compromised or chronically debilitated patients. But in healthy individuals, these are of little importance. Gram-negative bacteria: The organisms which a surgeon specially interested among gram negative species include: � E. coli, � Proteus vulgaris and mirabilis � Klebsiella pneumoniae � Serratia marcescens � Pseudomonas aeruginosa, P. fluorescens. � Enterobacter Anaerobic organisms • These organisms are not able to multiply or divide in the presence of atmospheric air. • This is because of the absence of the enzyme catalase, which is important for the metabolism of reactive oxygen species. • They are the predominantly available in many areas of the human body, including oropharynx and colorectum among which flora in oropharynx is different from the one in colorectum. � C. Perfringens � C.difficile � C. tetani � C. Septicum or novyi. � Bacteroides fragilis � Propionibacterium � Fusobacterium spp. Other bacteria of interest to surgeons include: � Mycobacterium tuberculosis � M. avium-intracellulare and M. Leprae. � Nocardia • These are acid fast and are very slow growing bacilli. • They are not easily cultivated in laboratory and need specific culture media to grow which may take several weeks to months. • They are notorious in causing severe pulmonary and extra pulmonary infections which is still prevalent in our country. Viruses: • Though small in their size, they cause wide variety of infections, especially in immunocompromised patients. • Mostly these organisms are intracellular. • They are extremely difficult to cultivate in artificial culture media. • They are usually identified by the presence of DNA and RNA using specific techniques in polymerase chain reactions. Viruses of specific importance for surgeons include: � Hepatitis viruses B and C � Ebstein barr virus � Cytomegalovirus � Herpes simplex virus � Herpes zoster virus. Fungi • Fungi cause a number of nosocomial infections. • They are identified by special staining methods. • This can be � potassium hydroxide � Giemsa � India ink � methenamine silver • These can be present in yeast form, budding forms or can be observed with numerous branching along with septations. • They can cause surgical site infections combined with bacteria. • They cause severe infections in immunocompromised patients. • Fungi of interest to surgeons include: � C. albicans � Mucor � Rhizopus � Absidia spp � Cryptococcus neoformans � Aspergillus fumigates and A. niger, � Coccidioides immitis. SURGICAL SITE INFECTIONS NOMENCLATURE • DEFINITIONS: Earlier, the term, ‘Surgical Wound Infection Task Force’ (SWITF) was used to ascribe surgical site infections. The term ‘SURGICAL WOUND’–was replaced by ‘SURGICAL SITE INFECTION’. This term was formulated by CDC in 1992. Figure-3 Classification of surgical site infection Figure-4 Superficial SSI CATEGORIES OF SSI SSI were categorized into two, 1. Incisional SSI » Superficial » Deep 2. Organ/space SSI. Of surgical infections, 60 to 80% are incisional and the remainder are organ/space infections. SUPERFICIAL SSI A superficial SSI can be defined as ‘An Infection occuring within 30 days of surgery and it involves only the skin and subcutaneous tissue of incision’. It includes: • Purulent aspirate from the site of incision associated with or without positive culture • Local signs of infection and inflammation – pain, tenderness, localised swelling, redness, heat and this is usually followed by FIGURE 5 DEEP INCISIONAL SSI FIGURE 6 DEEP INCISIONAL SSI • deliberate opening of the superficial incision by surgeon, unless the results of culture reports are negative. • Micro organisms obtained from the culture of fluid or tissue taken aseptically from a superficial incision • Diagnosis of superficial infection made by the surgeon Conditions which should not be considered as SSI include: 1. Stitch abscess 2. Episiotomy wound 3. Infection at the site of circumcision in a new born child. 4. Infected burn wound DEEP INCISIONAL SSI Deep incisional SSI can be defined as ‘An Infection that is occurring within 30 days of surgery ( 1yr if an implant is in place) and infection involving deep soft tissues. It usually includes: • Purulent discharge from the site of deep incision. • Fever of 38 degree celsius or More. • Local pain / tenderness at the incision site and incision dehisces spontaneously or is opened deliberately. • Abscess or other evidence of infection which involves the deep incision and found on direct examination / visual / radiological / histological examination. • Diagnosis made by the physician / surgeon. ORGAN / SPACE SSI An organ or space SSI can be defined as ‘An Infection occuring within 30 days ( 1yr of implant ) or Infection involving any other part of the anatomy other than that of the incision site which was opened / manipulated at the time of surgery. It may include : • Purulent aspirate from the organ / space operated which is identified by a drain • Micro organisms from the culture obtained aseptically • Infection identified during reoperation / Histological examination/ imaging. • ORGAN SPACE SSI MASQUERADING INCISIONAL SSI The following organ space surgical site infection pretends to be an incisional SSI. • Imaging studies done to rule out subfascial collection / fistula from hollow organs. • Presumptive usage of systemic antibiotics. • Interventional radiology/ re-operation done. • Trigger the lethal MOF( multi organ failure). FIGURE 7 DEEP/ORGAN SPACE SSI CLASSIFICATION OF SURGICAL WOUND INFECTION: CLASS – I : Clean wound (Expected wound infection rate is 1-3%) Definition:- - Atraumatic wound - There are no signs of inflammation - Gastrointestinal, Respiratory, Genito Urinary, Biliary tracts are not entered. Organisms :-- Staphylococcus aureus, Staphylococcus epidermidis Example:-- Hernia repair, Breast surgeries, Thyroid surgeries. CLASS – II :– Clean contaminated (5-10% expected infection rate) Definition :- Elective operation of GIT, Genito Urinary, respiratory tract have been entered during surgery under controlled conditions Organism:-- Endogenous micro flora of the organ that has been entered Example:-- Cholecystectomy, Elective bowel resection CLASS – III: CONTAMINATED WOUNDS ( Expected infection rate is 15%) Definition :-- traumatic wounds(fresh) any breach in the sterile technique used Gross spillage from Gastrointestinal tract Acute non purulent inflammation Organism :-- Endogenous bacteria Example :- Appendicectomy CLASS - IV DIRTY WOUND (Expected infection rate is 40%) Definition :-- Old traumatic wounds Devitalized tissue Gross purulence Pre existing infection Perforated viscera Example :-- Hartmann's operation for perforated diverticulitis RISK FACTORS: • Rate of SSI is dependent on several variables like 1. Patient 2. Type of surgery 3. Perioperative environment 4. Type of pathogen RISK of SSI = dose of contamination x virulence host resistance CDC SENIC (Study of effect of nosocomial infection control) describes about the predictive index for a surgical site infection. The following four factors are being considered:-- 1) An Abdominal operation 2) An operation that lasts longer than 2 hrs 3) An operation that is contaminated 4) A patient who will have three or more diagnosis at the time of discharge exclusive of wound infection The patients are given a score of 0 or 1 for the above said variables. SENIC SCORE Score % of infection 0 1% 1 3 – 6% 2 9% 3 17% 4 27% NNIS risk index (National Nosocomial Infection Surveillance) NNIS framed the following variables for risk index in surgical site infection. • ASA score – 3 or more • Length of operation – 75th percentile of its duration to a particular surgery • Level of contamination – contaminated/ dirty The risk factors associated with surgical site infection can be: I. ENDOGENOUS FACTORS II. EXOGENOUS FACTORS Endogenous(patient related) factors: This includes: 1. Duration of pre operative stay of a patient in the hospital 2. Presence of any previous infection in patient (I A) 3. History of previous Abdominal operation 4. Age of the patient >50 years or < 1 yr 5. An Obese patient 6. History of Diabetes Mellitus in patient (I B) 7. Immunocompromised state or Malnutrition 8. Altered immune response 9. Usage of Tobacco – (I B) Exogenous (Perioperative factors): The exogenous risk factors which also contribute to surgical site infection include the following: • Prophylactic Antibiotic given to the patient before a surgery or procedure. • Period or length of surgery – if the duration exceeds more than 3hours, additional dose of antibiotic must be given • Ventilation of an operating room • Technique handled by the operating surgeons – usage of cautery cautery, obtaining perfect haemostasis, trauma (IB) • Asepsis and Proper sterilization of instruments • Length and duration of surgical scrub using betadine or alcohol (2-5mts) • Antisepsis of skin (I B) Though removal of hair is controversial in causing SSI, it may contribute to SSI (IA) • Presence of a foreign material in the surgical site • showering of a patient before surgery( I B) • Usage of Surgical drains(guidelines) SURGICAL WOUND SITE SURVEILLANCE: Surveillance of wound site is usually done by a) sterile dressing for 24-48hrs after surgery (IB) b) washing hands before and after changing dressing (IB) c) usage of sterile technique for dressing (II) MEASURES TO PREVENT SSI: FIGURE 8 MEASURES TO PREVENT SSI Pre-operative measures FIGURE 9 PRE OPERATIVE MEASURES PREPARATION OF PATIENT : Before preparing the patient for an elective operation, the following steps must be undertaken. � Identify and treat infections away from the surgical site before operation. � Keep the pre-operative stay as short as possible � Proper control of blood glucose levels � Ask the patient to take a bath before the surgery. � Do not remove hair unless it interferes with operation and if required, remove with electric clippers immediately before operation. � Abstain From any forms of tobacco or alcohol consumption prior to operation � Apply antiseptic agent in concentric circles moving towards periphery. PREPARATION OF THE OPERATING TEAM 1. Nails should be kept clean and short 2. Surgeon should not wear any rings or hand jewellery 3. Preoperative surgical scrub for 5 minutes 4. Scrub the hands till elbows for a surgical hand washing 5. Water should always flow from hands towards elbow after a scrub 6. Always use a towel, gown and gloves which is sterile How to manage when a person in surgical team is infected? � Educate them to report to the team head � Developing well-defined policies concerning patient care � Surgical personnel with draining skin: � Must provide and collect cultures � Abstain from duty, until infection has been subsided � or adequate antimicrobial therapy provided Principles of prophylaxis: Use of multiple methods (physical, chemical, and antimicrobial therapies) or a combination of these to decrease the presence of exogenous factors (surgeon and operating room environment) and endogenous factors (microorganisms) is called prophylaxis. Effective Source control: The primary concept in the treatment of surgical site infections includes: � drainage of pus � wound débridement including infected and devitalized tissue � extrusion of foreign bodies � treatment of the root cause of infection. Prophylactic antibiotic treatment The usage of empirical antibiotics before a surgery or during and sometimes even after a surgery to prevent complications of infections. Therapeutic antibiotic treatment The usage of substances that decrease the growth or multiplication of organisms, which also includes its eradication . Thus, it reduces infection caused not only by a pathogen but also the infection caused by the organism which colonises a gut or skin of the patient. Antibiotic Prophylaxis: Antibiotic prophylaxis was first proposed by Miles and Burk in 1950. Prophylaxis should be planned so that it is administered at the time of induction or skin incision. Because, • after 3 hrs of entry of infectious agent, it becomes very ineffective. • Concentration of organisms > 100,000 / gm of tissue usually exceed the capacity of host defense. • In the body, Humoral or cellular mechanisms defeat bacteria. What are the Principles behind prophylaxis • Always use the antibiotic agent which is likely to cause the probable infection • Use full dose of any antibiotic chosen • Administer the chosen drug prophylactically • If duration of operation is prolonged for more than 3 hrs, give another dose of the chosen antibiotic. • Employ post operative antibiotic, when the risk of infection is increased. “The consensus is that a single dose of antibiotic immediately before an operation is enough and that there are dangers not only to hospital but also to the patients in prolonged course of prophylactic antibiotics. Resistance to antibiotics is related closely to the prolificity with which antibiotics are prescribed” Single dose prophylaxis In 1977, STRACHAN and his colleagues first proposed single dose antibiotic prophylaxis. They proposed single dose of broad spectrum antibiotic prior to surgery without any usage of it after the procedure. Trial of single dose vs no antibiotic: In one of the study conducted, comparison was done between single dose of preoperative antibiotic (cefazolin) against 5 days of post operative treatment of the same. Infection rate of prophylactic group was about 3% and in the other group where post operative antibiotic was given the infection rate was 5%. Trial of Single dose vs. Multiple dose of antibiotics: Comparison was done between patients undergoing Colonic surgery receiving single dose of prophylactic antibiotic against multiple doses of antibiotics. Out of 510 surgeries done in single dose group, infection rate was 4.3% and in the group of 493 patients who received multiple doses of antibiotic, the infection rate was 6.9%. Results of 27 studies conducted were as follows: Single dose Multiple doses operation 510 493 infection 22 34 Rate of infection 4.3% 6.9% Antibiotic prophylaxis and its possible risks? : Patients with a history of allergy, urticaria or pruritic rash, bronchospasm, hypotension, local swelling, laryngeal oedema occurring even after a single dose of penicillin injection have a potential risk of anaphylaxis (type I immediate hypersensitivity). So recommendation of beta-lactams as a prophylactic antibiotic is highly condemnable. For patients with allergy to penicillins or cephalosporins, alternative antibiotics, according to the nature of infection, has been formulated. These are very important as far as the patient’s safety is concerned, failure of which may lead to a disaster. D WHO Model List – 2003 This list contains only 25 essential antibiotics for controlling most of the surgical site infections. For routine use – 19 antibiotics were recommended. For complementary use – 6 have been recommended. NARROW SPECTRUM AGENTS • Gram positive agents include: Penicillin Cloxacillin Erythromycin Clindamycin Vancomycin • Gram negative Gentamycin Ciprofloxacin Spectinomycin Nitrofurantoin Nalidixic acid Ceftriaxone Ceftazidime • EXTENDED SPECTRUM ANTIBIOTICS It includes antibiotics for both Gram + ve and Gram –ve organisms. Ampicillin Amoxycillin Cotrimoxazole Trimethoprim Sulphadiazine Amoxicillin + clavulanic acid Imipenam +cilastatin BROAD SPECTRUM ANTIBIOTICS Doxycyclin Chloramphenicol For Anaerobic infections: • Metronidazole When to administer Antimicrobial prophylaxis ? Administer the antibiotic by an intravenous route How to administer? a) Prophylaxis must be planned such that maximum bactericidal concentration of the agent reaches the serum and the tissues while putting an incision on the skin. b) Also it is important to maintain the serum concentration of the drug till the surgery is over. • Agent • Initiation of 1st dose • Most antibiotics • Within 60 minutes before incision • fluoroquinolone or vancomycin • Within 90-120 minutes before incision Prophylactic Use of Antibiotics Site Antibiotic Alternative (e.g., penicillin allergic) Cardiovascular surgery Cefazolin, cefuroxime Vancomycin Gastroduodenal area Cefazolin, cefotetan, cefoxitin, ampicillinsulbactam Fluoroquinolone Biliary tract with active infection (e.g., cholecystitis) cefaperazone-sulbactam, piptaz and clavulanic acid with ticarcillin Quinolone group with metronidazole or quinolones along with clindamycin Colorectal surgery, obstructed small bowel Cefazolin plus metronidazole, ertapenem, ticarcillin-clavulanate, piperacillin-tazobactam Gentamicin / fluoroquinolone plus clindamycin or metronidazole Head and neck Cefazolin Aminoglycoside plus clindamycin Neurosurgical procedures Cefazolin Vancomycin Orthopedic surgery Cefazolin, ceftriaxone Vancomycin Breast, hernia Cefazolin Vancomycin (Courtesy: Schwartz principles of surgery 9th edition) Timing of Antimicrobial Prophylaxis According to a Prospective Observational study conducted, Consecutive surgical patients were studied over a 1 year period which included 3836 various surgeries performed. All patients received 1.5g cefuroxime as antimicrobial prophylaxis during the study. In all the osteosynthesis operations been done, additional 0.75g cefuroxime at 8 hours and 16 hours after a initial dose of antibiotic. • Doses were adjusted in patients with renal failure. • The exact timing in minutes was recorded. • Incidence rates of SSI were recorded Minutes before incision ssi According to that study, • When antibiotic was administered 0 to 30 minutes before incision, P value was < 0.001. • When the same was administered 60 to 120 minutes before incision, the reported P value was equal to 0.035. • Hence it was concluded that it is better to give prophylaxis half an hour before any surgical procedure. Intra-operative measures to prevent SSI FIGURE 10Intra-operative measures to prevent SSI Ventilation in Operation Theatre • It is very important to maintain ventilation in operative theatres as it is essential step to prevent surgical site infection intra operatively. • There are certain criteria which include: � Air cycles flow inside the theatre must be a minimum of 5 per hour [atleast 3 fresh air] � The recirculated air must pass first through an appropriate filter and then flowed into the operating room. � positive pressure must be maintained in operation theatre with a comparative negative pressure outside the area � Always it is preferable to Keep the door closed unless when needed for passage of persons inside the room. � Always the passage of air must be Air from the ceiling and the exhaust must be near the floor of the theatre. � Except for the surgical operating team, the number of persons inside the theatre must be kept to a minimum. Next is an important point to remember as it is not advisable to use UV rays inside the operating room to prevent infection Cleaning and disinfection of environmental surfaces � When the theatre is soiled or contaminated, use appropriate antiseptic or antibiotic for cleaning before next surgery � Never close the theatre without cleaning after a contaminated or dirty operation. Microbiological Sampling � sampling of the operating room must be performed on a regular basis � surgical instruments must be sterilized periodically according to specific guidelines � Flash sterilization is done for the instruments that must be used immediately after a previous surgery � Never do flash sterilization on a routine basis and it is always advisable to keep an additional set of instruments for emergency purposes. Surgical attire and drapes � Cover the nostrils and mouth using a mask inside the theatre � Until the surgery is over, it is essential to wear a mask. � Cap that is worn must fully cover the hair of the surgeon and assistant. � Gloves used must be sterile. � Gloves are wore after surgical draping � Contaminated or a visibly unsterile surgical gowns must not be worn and always discarded � Strict aseptic technique must be maintained. � It is important to thoroughly wash the wound so that devitalized or dead tissue is effectively debrided. � Foreign body when present must be removed immediately. � Perfect hemostasis must be maintained � It is advisable that a heavily contaminated wound is left open and is allowed to close by secondary intention. � It is essential to maintain wound hygiene. Post-operative care of the incision must be done and kept clean Figure 11 - Wound Surveillance measures Surveillance � standard definitions must be used to define and categorise SSIs � Classification of wound must be done at the end of operation. � Operating surgeon must be informed of the type and classification of infection � Surveillance of the wound may be required even after the discharge of the patient and followed up regularly. • According to Hospital Surgical Surveillance Programme, Strict CDC definitions must be used to classify the wound • Most of the patients are not admitted to the hospital • When discharged in the early post op period, patient must be asked to follow up in the outpatient department till 30 days of surgery • Appropriate number of nurses specially trained to identify infection control must be allotted • Periodical reporting of infection rates must be done. Innovative Strategies to Reduce Infection Within the hospital Environment Though there are studies that show results of decrease in infection rates with the usage of impregnated technologies, it is not been proved beyond doubt of its significance. Thus the impregnated technologies used is of doubtful value. “Antibiotic for the fool is a tool which appears cool. But somebody pays the price as a rule” Postoperative Nosocomial Infections � Postoperative Nosocomial Infections include: � Respiratory infections � Urinary tract infections � Surgical site infections and � Septic episodes. � Nosocomial infections are due to usage of catheters, instrumentation, intra venous and intra arterial access (venflons) and central venous pressure lines. � UTI is confirmed by demonstrating WBCs or bacteria in routine urine examination or a positive test for leukocyte esterase, or a combination of these two. Table- UTI confirmation patients Culture value of organism obtained symptomatic patients >104 CFU/mL asymptomatic individuals >105 CFU/mL � It is important that urinary catheters be removed as quickly as possible within24 to 48 hours, as long as they are ambulant. � Pneumonia may be due to prolonged mechanical ventilation and is due to pathogens common in the hospital atmosphere. � Hospital-acquired pneumonia is diagnosed by the presence of a purulent sputum, leukocytosis, fever of very high grade and chest x-ray changes. � Bronchoalveolar lavage must be done to obtain samples and the material is subjected to Gram's stain and culture to identify the microbes. � Weaning from mechanical ventilation should be done as soon as possible.. � Most patients with intravascular catheter infections are asymptomatic, except for an increase in the blood WBC count. � Presence of the same organism in the blood cultures of a patient obtained from a peripheral site and through the catheter tells the high index of suspicion. � severe sepsis or bacteremia due to gram-negative aerobes or fungi necessitates catheter removal. � Catheter infections due to S. epidermidis can be effectively treated with a 14- to 21-day course of an antibiotic Post operative wound sepsis Post operative wound sepsis continues to account for 14% of adverse events in hospitalized patients Increases Morbidity, Hospital Stay, Expensive Antibiotic use and Wastage of manpower The inability to deliver antibiotics to the under perfused tissue during surgery because of vasoconstriction, hypoxia and shock renders systemic post op antibiotics less effective Prophylactic antibiotics • Patients receiving pre-operative antibiotics had significantly fewer infections than patients receiving antibiotics either too early or postoperatively In order to avoid these problems, rational ANTIBIOTIC prophylaxis is designed to deliver the antibiotics to the undamaged tissue BEFORE CONTAMINATION occurs MECHANISM of PREOPERATIVE ANTIBIOTICS Antibiotics preoperatively diffuse into the peripheral compartment and wound fluid This saturated antimicrobials kill and preventing the invading bacteria and bacterial multiplication GOALS OF ANTIBIOTIC THERAPY 1. To maintain the maximum concentration of agent in the serum and also the tissues which is more than the MIC (minimal inhibitory concentration) by 3-4 times for not less than three quarters of time during surgery. MIC – The minimum concentration of antibiotic to kill 99% of organisms. 2. Use full doses of chosen antibiotic in the DECISIVE period ( The vulnerable period during surgery) CHOICE OF ANTIBIOTIC 1. Maintain effective antibiotic level throughout the procedure 2. Less adverse effects 3. Less interference with anaesthetic drugs 4. Cost effective 5. Broad spectrum to pathogens 6. Less interference with host defense Antibiotics commonly used in the prophylaxis 1. Penicillins 2. Flucloxacillin and methicillin 3. Ampicillin and amoxycillin 4. Mezlocillin and azlocillin 5. Cephalosporins 6. Aminoglycosides 7. Vancomycin 8. Imidazoles 9. Carbapenem 10. quinolones THE ROUTE OF PROPHYLAXIS The route of prophylaxis will depend on the level of contamination. The preference of the surgeon and the reliability of the ancillary care. Both topical and parenteral administration have shown benefit in reducing wound infections when properly administered. TIMING Most consistent timing was achieved with iv administration by the anesthetist just prior to induction of anesthesia or 30 min prior to the incision FOR PROLONGED PROCEDURES Antibiotics should be repeated every 4 hrs Antibiotics should be continued for 24-48 hrs postoperatively in clean contaminated cases For dirty wounds, antibiotics should be continued for 5-7days INDICATIONS 1. Patients undergoing clean operations who are at risk ( ex. Patients undergoing hernia surgery with co- morbidities like diabetes mellitus, hypertension) 2. Prosthesis insertion (mesh repair in hernia surgery, insertion of drain in thyroidectomy or breast surgeries) 3. Clean Contaminated operations 4. contaminated operations TOPICAL ANTIBIOTIC PROPHYLAXIS Topical application consists of instilling antibiotic in the wound upon opening each tissue plane and at frequent intervals throughout the entire operation Only effective when they are constantly present on the surface of the wound ready to tackle the infective organisms Eg., Topical Sulfanilide on open fractures Topical Aminoglycoside In practice, 0.1 % solution of first generation cephalosporin is an excellent choice Aminoglycosides are frequently used but they have two disadvantages a) Systemic absorption leads to toxicity b) Anaerobes cannot be killed regardless of concentrations COMPLICATIONS The most feared complications are anaphylaxis and death Most commonly associated with the b-lactam antibiotics including the penicillins, cephalosporins, carbapenem and monobactam Vancomycin occasionally produces red man syndrome Cephalosporins can occasionally cause hypoprothrombinemia and bleeding. Nephrotoxicity and ototoxicity make aminoglycosides poor choice for prophylaxis They have ability to produce myoneural blockade and apnoea when given concomitantly with muscle relaxants particularly succinyl choline. Figure 12 – Side effects of prophylactic Antibiotics THE KEY TO SUCESSFUL PROPHYLAXIS Prophylaxis should be limited to perioperative administration only. A single perioperative dose or continuous administration if topical antibiotic is chosen Short course prophylaxis will be better Prophylactic antibiotics are not an excuse for poor technique MATERIALS AND METHODS: Source of data: Patients admitted to Govt. Rajaji hospital Madurai from June 2011 to June 2012 for clean general surgical operations were included with the consent obtained from the hospital ethical committee meeting conducted by the board members. Type of study: Prospective interventional study. Sample size: Totally 100 patients were selected. Out of 100, 50 patients were allotted in study group and the remaining 50 in control group. Methods used for allocation: Allocation of patients were done randomly. No specific selection of cases into study or control group was done. Inclusion criteria: Patients who had to undergo the following procedures were included. Hernia repair (open and laparoscopic approaches), breast surgeries (modified radical mastectomy for carcinoma breast and excision biopsies for fibroadenoma breast), neck surgeries (total thyroidectomy for multinodular goitre and hemithyroidectomy for solitary nodular goitre, excision biopsy of lipoma nape of neck) and scrotal surgeries (eversion of sac for hydrocele and excision for epididymal cyst). Administration of prophylaxis: Study Group: Injection Cefotaxim 1g IV was given 30 minutes before operation. Control group: No antibiotics were given pre operatively. • Similar techniques were followed for both groups to rule out any bias. • Strict asepsis were handled for both the groups. • Blinding (which prevents patients from allocation into specific groups) was done again to rule out bias. Exclusion criteria: 1. Patients who are diabetic, hypertensive or consuming medications for any other specific medical conditions 2. Patients who are Immunologically compromised. 3. Patients who are Chronic malnourished. 4. Patients undergoing contaminated or clean contaminated surgeries. 5. History of fever, cough with expectoration. CONCLUSION: According to the results of this study whish evaluated the role of prophylactic antibiotics to prevent surgical site infections in clean surgeries which included hernia repair (both open and laparoscopic), neck surgeries (thyroid surgeries and lipoma), breast surgeries (modified radical mastectomy and fibroadenoma excision) and scrotal surgeries (hydrocele and epididymal cyst excision), the rate of surgical site infection in the group which received prophylactic antibiotic (study group) was 6% and the one which did not receive any antibiotic prior to surgery developed 12% of wound infection rate. This difference in the rate of infection is not significant statistically as the p value was 0.452 (>0.05) obtained by the test of significance (chi square test). Thus we come to a conclusion that for a clean and uncontaminated surgery, the use of antibiotics prophylactically does not cause a significant reduction in the rate of surgical site infection. Also in literature, it is not established that prophylactic antibiotics for clean surgeries in general surgery reduce the infection rate as in clean contaminated and contaminated surgeries where its role is extensively studied and its reduction in rate of surgical site infection is strongly established. Thus to conclude, according to this study performed, prophylactic antibiotics, unless warranted, has no significant role in clean elective surgeries.

Item Type: Thesis (Masters)
Uncontrolled Keywords: prophylactic antibiotic, prevent surgical site infections, clean surgeries.
Subjects: MEDICAL > General Surgery
Depositing User: Devi S
Date Deposited: 02 Jun 2018 16:23
Last Modified: 26 Mar 2020 02:23

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