ANTIBIOTICS IN SURGERY

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an overview of the history, uses and effects of antibiotics in surgery.

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ANTIBIOTICS IN SURGERY : 

ANTIBIOTICS IN SURGERY DR TITIGAH BABATUIAMU ABRAHAM

OUTLINE : 

OUTLINE DEFINITIONS HISTORY OF ANTIBIOTICS JUSTIFICATION USES OF ANTIBIOTICS IN SURGERY CLASSIFICATION OF SURGICAL WOUNDS FACTORS TO CONSIDER WHEN SELECTING ANTIBIOTICS DOSING ANTIBIOTICS COMMON ANTIBIOTICS AND THEIR CHARACTERISTICS

DEFINITION : 

DEFINITION ANTIBIOTICS IN SURGERY ARE ANTIBACTERIAL AGENTS USED IN A SURGICAL PATIENT FOR THE PURPOSES OF REDUCING THE RISK OF SURGICAL SITE INFECTION AND/OR TREATING ESTABLISHED INFECTION.

BRIEF HISTORY OF ANTIBIOTICS : 

BRIEF HISTORY OF ANTIBIOTICS 1550- EGYPTIANS DRESSED WOUNDS WITH A MIXTURE OF LARD, HONEY AND LINT. SUCCESSFUL 1988-PYOCYANASE, EFFECTIVE BUT HIGHLY TOXIC, 1910 1929-ALEXANDER FLEMING’S FINDINGS. 1935-SULFONAMIDES 1940- FLOREY AND CHAIN , LARGESCALE PENNICILLIN, OTC. 1955- RESISTANCE

JUSTIFICATION : 

JUSTIFICATION TREATMENT AND PREVENTION OF INFECTION IS A CARDINAL RESPONSIBILITY OF THE SURGICAL TEAM IMPROPER SELECTION OF THE ANTIBIOTIC, DOSAGE, ADMINISTRATION AND DURATION OF ADMINISTRATION CAN BE DELETERIOUS TO THE PATIENT OR INEFFECTIVE.

TYPES OF ANTIBIOTICS : 

TYPES OF ANTIBIOTICS BACTERICIDAL BACTERIOSTATIC

CLASSIFICATION OF SURGICAL WOUNDS : 

CLASSIFICATION OF SURGICAL WOUNDS CLEAN CLEAN CONTAMINATED CONTAMINATED DIRTY

USES OF ANTIBIOTICS IN SURGERY : 

USES OF ANTIBIOTICS IN SURGERY 1. PROPHYLAXIS 2. THERAPEUTIC

PROPHYLAXIS : 

PROPHYLAXIS THE ANTIBIOTIC IS ADMINISTERED BEFORE THE INTENDED SURGICAL PROCEDURE SO THAT AT THE TIME OF THE INCISION, THERE IS ENOUGH ANTIBIOTIC TO PREVENT BACTERIAL PROLIFERATION . IT IS COMMONLY BACTERICIDAL AND GIVEN INTRAVENOUS. NEOMYCIN MAY BE USED IN BOWEL PREPARATION FOR COLONIC SURGERY.

ANTIBIOTIC PROPHYLAXIS GUIDELINES : 

ANTIBIOTIC PROPHYLAXIS GUIDELINES A SINGLE PREOPERATIVE DOSE OF ANTIBIOTIC IS AS EFFECTIVE AS FULL FIVE DAYS COURSE OF THERAPY ASSUMING UNCOMPLICATED PROCEDURE. PROPHYLACTIC ANTIBIOTICS SHOULD BE ADMINISTERED WITHIN 1 HOUR PRIOR TO INCISION, PREFERABLY WITH INDUCTION OF ANESTHESIA. PROPHYLATIC ANTIBIOTICS SHOULD TARGET ANTICIPATED ORGANISMS.

CONTD; : 

CONTD; PROPHYLAXIS SHOULD NOT BE EXTENDED BEYOND 24 HOURS FOLLOWING SURGERY. ONE PREOPERATIVE AND TWO OR THREE POSTOPERATIVE DOSES ARE SUFFICIENT IN CLEAN SURGERY. CONTAMINATED AND DIRTY PROCEDURES SHOULD ADDITIONALLY RECEIVE ADDITIONAL POSTOPERATIVE COVERAGE. DURING PROLONGED PROCEDURES ANTIBIOTIC PROPHYLAXIS SHOULD BE READMINISTERED EVERY 3 HOURS. USE OF ANTIBIOTIC IN PROCEDURES CLASSIFIED AS CONTAMINATED OR INFECTED SHOULD BE USED AS THERAPEUTIC AND NOT PROPHYLACTIC.

CONTD; : 

CONTD; IN TRAUMATICALLY INJURED PATIENTS ANTIBIOTICS CANNOT BE GIVEN BEFORE BACTERIAL CONTAMINATION OCCURS. CEPHALOSPORINS ESPECIALLY CEPHAZOLIN IS 1ST LINE PROPHYLACTIC AGENT FOR MOST SURGICAL PROCEDURES BECAUSE OF THEIR LOW TOXICITY, LONG SERUM HALF LIFE, BROAD SPECTRUM OF ACTIVITY, LOW COST. THIRD GENERATION SHOULD NOT BE USED FOR ROUTINE PROPHYLAXIS BECAUSE THEY PROMOTE THE EMERGENCE OF RESISTANCE.

THERAPEUTIC ANTIBIOTICS : 

THERAPEUTIC ANTIBIOTICS THE AGENT IS GIVEN TO FIGHT INFECTION THAT IS ALREADY ESTABLISHED EG.CONTAMINATED, DIRTY SURGICAL WOUNDS SURGICAL INFECTIONS EG CELLULITIS, SEPTIC ARTHRITIS, SPECIFIC INFECTIONS( TB, SYPHILIS ETC) POST OPERATIVE INFECTIVE COMPLICATIONS EG PNEUMONIA, UTI

FACTORS TO CONSIDER WHEN SELECTING ANTIBIOTICS : 

FACTORS TO CONSIDER WHEN SELECTING ANTIBIOTICS IDENTIFY INFECTING ORGANISM EVALUATE DRUG SENSITIVITY TARGET SITE OF INFECTION EG. CLINDAMYCIN-BONES CF. AMINOGLYCOSIDE – SALMONELLA DRUG SAFETY/ SIDE EFFECT PROFILE PATIENT FACTORS EG IMMUNOCMPROMISED, MALNOURISHED COST

DOSING ANTIBIOTICS : 

DOSING ANTIBIOTICS 1. MIC AND MBC 2. ADME FACTORS THE FREQUENCY DEPENDS ON THE HALF LIFE OF THE DRUG: TO GET A RELATIVELY STABLE PLASMA CONCENTRATION –USUALLY PER 4*T1/2

COMMON ANTIBIOTICS AND THEIR CHARACTERISTICS : 

COMMON ANTIBIOTICS AND THEIR CHARACTERISTICS PENICILLIN, A B- LACTAM MODE OF ACTION: BINDS TO PBP CLASSIFICATION OF PENICILLINS ß-LACTAMASE SENSITIVE EG. PENICILLIN G ß-LACTAMASE RESISTANT EG.FLUCLOXACILLIN AND METHICILLIN BROAD SPECTRUM EG. AMOXYCILLIN ANTIPSEUDOMONAS EG.PIPERACILLIN ADME SPECTRUM ADVERSE EFFECTS

CEPHALOSPORINS : 

CEPHALOSPORINS HAVE B-LACTAMASE RESISTANCE. 1ST GENERATION- HIGH ACTIVITY AGAINST G +VE 4TH GENERATION –HIGHEST ACTIVITY AGAINST G –VE AND B-LACTAMASE ORGANISM

Slide 18: 

SPECTRUM OF ACTIVITY OF CEPHALOSPORINS 1ST-USEFUL FOR SKIN AND SOFT TISSUE INFECTIONS, AGAINST STREPTOCOCCI,STAPH, E.COLI, P MIRABILIS AND K PNEUMONIAE. INFECTIONS AGAINST SURGICAL PROCEDURES 2ND A) ACTIVITY AGAINST H. INFLUENZAE EG. CEFACLOR, CEFAMANDOLE B) AGAINST B.FRAGILIS EG. CEFOXITIN, CEFMETAZOLE FOR EMPIRICAL TREATMENT OF RESPIRATORY INFECTIONS DUE TO S. PNEUMONIAE (SINUSITIS, OTITIS MEDIA, PNEUMONIA), ALSO FOR INFECTIONS IN CHILDREN. FOR MIXED AEROBIC INFECTIONS AND SOFT TISSUE INFECTIONS EG IN DIABETIC PATIENTS. 3RD –INCREASED ACTIVITY AGAINST AEROBIC GRAM –VE BACTERIA EG. ENTEROBACTERIACEAE AND H INFLUENZAE SOME ARE EFFECTIVE AGAINST P.AERUGINOSA EG. CEFTAZIDIME

AMINOGLYCOSIDES : 

AMINOGLYCOSIDES IRREVERSIBLE INHIBITION OF 30S SUBUNIT HIGHLY POLAR, STABLE AGENTS ONLY PARENTERAL EXCEPT NEOMYCIN NEPHROTOXIC, OTOTOXIC NEUROTOXIC. AVOID/ REDUCE FREQUENCY OF DOSING IN RENAL IMPAIRMENT RESERVED FOR SERIOUS Enterobacteriaceae and P. Aeruginosa INFECTIONS NB SPECTRUM = FLUOROQUINOLONES

CLINDAMYCIN : 

CLINDAMYCIN BINDS IRREVERSIBLY TO THE 50S RIBOSOME HIGH PENETRATION INTO TISSUES EXCEPT CSF HAS HIGH ACTIVITY AGAINST ANEROBES, G +VES AND SOME G-VES C. DIFFICILE IS RESISTANT CAN CAUSE PSEUDOMEMBRANOUS COLITIS

CHLORAMPHENICOL : 

CHLORAMPHENICOL BINDS REVERSIBLY TO THE 50S PENETRATES TISSUES VERY WELL-INCLUDING CSF ACTIVE AGAINST G +VE AND G-VE BACTERIA, ANEROBES. MOST ENTROBACTERIAECAE ARE NOW RESISTANT. CAN CAUSE APLASTIC ANEMIA, MARROW SUPPRESSION, GRAY BABY SYNDROME

FLUOROQUINOLONES : 

FLUOROQUINOLONES FLUORINATED FORMS OF NALIDIXIC ACID, INHIBIT DNA GYRASE. HIGHLY ACTIVE AGAINST AGAINSTG-VE ORGANISMS ESPECIALLY ENTEROBACTERICAE AND PSEUDOMONAS. CAN AFFECT GROWING CARTILAGE CAUSING ARTHROPATHY. CF <18YRS, PREGNANT WOMEN CAN CAUSE TENDINITIS AND TENDON RUPTURE.

MACROLIDES : 

MACROLIDES REVERSIBLY INHIBIT 50S SUBUNIT PART OF MEDICAL TREATMENT FOR PEPTIC ULCER. MAY BE USED IN PENICILLIN RESISTANCE

Slide 24: 

Drugs of choice and alternatives for selected common bacterial pathogens

Slide 25: 

Drugs of choice and alternatives for selected common bacterial pathogens

REFERENCES : 

REFERENCES PRIMARY SURGERY VOLUME I, 4TH EDITION. ENCYCLOPEDIA BRITANICA MICROBIOLOGY, INFECTIONS AND ANTIBIOTIC THERAPY, PPT BY ELIZABETH ROSEN ET AL 2002 LECTURE NOTES OF PHARMACOLOGY, KNUST, 2008

THANK YOU : 

THANK YOU ANY QUESTIONS / CONTRIBUTIONS