Antibiotics in ENT Surgery

1
Antibiotics in ENT Surgery

• Magdy M. Amin RIAD
• Professor of Otolaryngology.
• Ain shames University
• Senior Lecturer in Otolaryngology
• University of Dundee

2
Prophylactic antibiotics

• Prophylaxis with antibiotics has decreased the
  high incidence of wound infection after head and
  neck operations that involve incisions through
  oral or pharyngeal mucosa.
• Prophylactic administration of antibiotics can
  decrease postoperative morbidity, shorten
  hospitalization, and reduce overall costs
  attributable to infections.

3
Prophylactic antibiotics

• Many antibiotics require a single dose given
  within 30 minutes of skin incision to provide
  adequate tissue concentration throughout the
  operation.
• Additional doses during the procedure are
  advisable if surgery is prolonged (i. e, gt4 h),
  major blood loss occurs, or an antimicrobial with
  a short half-life is used

4
The aim of prophylaxis

• The aim of prophylaxis is to augment host defense
  mechanisms at the time of bacterial invasion,.
• Prophylaxis is an attempt to attack organisms
  before they have a chance to induce infection.
• Previous surgery (i. e, scarring) and radiation
  injury decrease host defenses.
• Likewise, certain medical conditions, such as
  diabetes mellitus or HIV, predispose the patient
  to infection because of diminished host response.

5
Choosing an antibiotic for prophylaxis

• Choosing an antibiotic for prophylaxis is
  multi-factorial and should be based on the
  following
• Type of operation
• Kinetics and toxicity of the drugs
• Microbiologic characteristics of the operative
  site
• Antibiotic sensitivities specific to the
  particular hospital environment

6
Choosing an antibiotic for prophylaxis

• If a number of drugs appear equally acceptable
  for prophylaxis, the agent least likely to be
  used for definitive therapy in postoperative
  wound infection should be chosen.
• This strategy should minimize the selection of
  organisms resistant to valuable therapeutic
  agents.

7
Choosing an antibiotic for prophylaxis

• The regimen chosen should be compatible with
  findings from the hospital's infection control
  wound surveillance report.
• This regimen is particularly important in
  hospitals with high incidence of infection with
  methicillin-resistant organisms (eg, S aureus
  MRSA, S epidermidis MRSE) or with newly
  vancomycin-resistant organisms.

8
CLASSIFICATION OF OPERATIONClass Definition

• Clean Operations
• in which no inflammation is encountered .
• The respiratory, alimentary or genitourinary
  tracts are not entered.
• There is no break in aseptic operating theatre
  technique.

9
Non contaminated head and neck surgery

• Non contaminated surgery refers to violation of
  prepared skin only and no mucosal exposure or
  incision (eg, neck dissection, parotidectomy,
  thyroidectomy).

10
Non contaminated head and neck surgery

• Clean surgical procedures are those in which no
  infection exists prior to surgery.
• During surgery, sterility of the wound is
  maintained.
• Following closure of the wound at completion of
  surgery, the wound is never again exposed to
  direct contact with bacteria.
• The risk of postoperative wound infection under
  these circumstances is less than 5.

11
CLASSIFICATION OF OPERATIONClass Definition

• Clean-contaminated Operations
• in which the respiratory, alimentary or
  genitourinary tracts are entered
• but without significant spillage.

12
CLASSIFICATION OF OPERATIONClass Definition

• Contaminated Operations
• where acute inflammation (without pus) is
  encountered.
• or where there is visible contamination of the
  wound.
• Examples include gross spillage from a hollow
  viscus during the operation
• or compound/open injuries operated on within four
  hours.

13
CLASSIFICATION OF OPERATIONClass Definition

• Dirty Operations
• In the presence of pus.
• where there is a previously perforated hollow
  viscus,
• or compound/open injuries more than four hours
  old.

14
PROBABILITY OF WOUND INFECTION BY TYPE OF WOUND
AND RISK INDEX

• Risk
  Index
• 0 1
  2
• Clean 1.0 2.3
  5.4
• Clean-contam. 2.1 4.0 9.5
• Contaminated 3.4 6.8 13.2

15
ENT SURGERY

• Head and neck surgery - A Antibiotic prophylaxis
  is recommended
• Head and neck surgery - clean C Antibiotic
  prophylaxis is not recommended There is no
  evidence of effectiveness from RCTs
• Ear surgery - clean A Antibiotic prophylaxis is
  not recommended There is no evidence of
  effectiveness from RCTs
• Nose or sinus surgery C Antibiotic prophylaxis is
  not recommended There is evidence of no
  effectiveness from RCTs
• Tonsillectomy C Antibiotic prophylaxis is not
  recommended There is no evidence of effectiveness
  of prophylaxis from RCTs. The cited trials are of
  treatment for seven days after tonsillectomy, not
  prophylaxis.

16
ADMINISTRATION OF INTRAVENOUS PROPHYLACTIC
ANTIBIOTICS

• Prophylaxis should be started preoperatively in
  most circumstances
• ideally within 30 minutes of the induction of
  anesthesia.

17
ADMINISTRATION OF INTRAVENOUS PROPHYLACTIC
ANTIBIOTICS

• Antibiotic prophylaxis should be administered
  immediately before or during a procedure.
• Prophylactic antibiotics should be administered
  intravenously.
• The single dose of antibiotic for prophylactic
  use is, in most circumstances, the same as would
  be used therapeutically.

18
ADMINISTRATION OF INTRAVENOUS PROPHYLACTIC
ANTIBIOTICS

• An additional dose of prophylactic agent is not
  indicated in adults, unless there is blood loss
  of up to 1500 ml during surgery or haemodilution
  of up to 15 ml/kg.
• Fluid replacement bags should not be primed with
  prophylactic antibiotics because of the potential
  risk of contamination and calculation errors.

19
Duration of Perioperative Antibiotic Use

• 1. Prophylactic perioperative antibiotics should
  be started prior to skin incision for maximal
  benefit.

20
Duration of Perioperative Antibiotic Use

• 2. There is no advantage to continuation of
  perioperative antibiotics beyond 24 to 48 hours
  postoperatively has ever been demonstrated.

21
Duration of Perioperative Antibiotic Use

• The possible exception to this is metronidazole
• because metronidazole may enter abscess spaces
  better than other antibiotics.
• its prolonged use has been associated with less
  severe postoperative infections in one study.

22
Prophylactic Antibiotic Regimens for Major
Clean-Contaminated

• Clindamycin 600 mg IV within 1 hour of surgery,
  4 additional doses Q6H following surgery.
• The antibiotic may alternatively be given for a
  full 48 hours postoperatively.
• there is no compelling evidence that the
  additional 24 hours confers any additional
  benefit.

23
Prophylactic Antibiotic Regimens for Major
Clean-Contaminated

• 2. Augmentine 1.5 grams IV within 1 hour of
  surgery .
• and 8 additional doses at 6-hour intervals
  following surgery.

24
Prophylactic Antibiotic Regimens for Major
Clean-Contaminated

• 3. Cefazolin 2.0 grams IV within 1 hour of
  surgery.
• and 3 postoperative doses at 8-hour intervals.
  
• This regimen may be extended to a total of 48
  hours postoperatively.

25
Prophylactic Antibiotic Regimens for Major
Clean-Contaminated

• 4. Cefazolin/metronidazole cefazolin 1 gm IV 1
  hour prior to surgery
• then 1 gram IV every 8 hours postoperatively
  for a total of 6 doses.
• and metronidazole 900 mg IV 1 hour prior to
  surgery
• then 900 mg IV every 8 hours postoperatively
  for a total of 6 doses.

26
ENT SURGERYAntibiotic prophylaxis is
recommended in

• A Head and neck surgery (clean-contaminated/cont
  aminated)
• Antibiotic prophylaxis is not recommended in
• A Ear surgery (clean)
• C Head and neck surgery (clean)
• C Nose or sinus surgery
• C Tonsillectomy

27
Contaminated head and neck surgery

• Contaminated surgery refers to transmucosal
  operations (eg, composite resection, glossectomy,
  maxillectomy).
• Saliva contains 108 bacteria per milliliter, 90
  of which are anaerobic. Ninety-six percent of
  wound infections in the head and neck are
  polymicrobial.

28
Contaminated head and neck surgery

• Organisms involving oropharyngeal flora
  included
• anaerobic organisms (Bacteroides, 76)
• gram-negative rods (eg, Escherichia coli and
  Klebsiella, Serratia, and Proteus species)
• gram-positive organisms (ie, Staphylococcus,
  Streptococcus).

29
Contaminated head and neck surgery

• Clindamycin (600 mg PO/IV q8h for 4 doses) is the
  recommended antibiotic to prevent anaerobic wound
  contamination in extensive surgeries of the head
  and neck.
• Appropriate antibiotic choices also include a
  combination of ampicillin and sulbactam (3 g IV
  followed by 1.5 g q8h for 3 doses)
• combination Ancef and Flagyl.
• As an oral mouth rinse, use of clindamycin (75-mg
  caps stirred in 8 oz of tap water) or
  chlorhexidine (Peridex) provides rapid and
  sustained reductions in the concentrations of
  aerobic and anaerobic oral flora.

30
Facial fractures

• Open fractures have an increased incidence of
  infection in the absence of antibiotic
  prophylaxis when compared to closed or open
  fractures treated with prophylactic antibiotics.

31
Facial fractures

• Antibiotic prophylaxis significantly reduce the
  incidence of postoperative infections in facial
  fractures, especially mandible fractures of the
  body.
• The infection rates in zygoma fractures, LeFort
  fractures, and mandibular subcondylar fractures
  are similar.

32
Disadvantages of antibiotics

• It promotes antibiotic resistance and contributes
  to super infection.
• Antibiotic use is also costly and associated with
  allergic reactions, toxic reactions, and adverse
  effects
• The use of antibiotics may encourage laxity of
  good surgical technique.

33
(No Transcript)
34
(No Transcript)
35
Penicillin

• Mechanism of action
• Exerts action on actively dividing cells by
  causing abnormal cell wall development
• Inhibits third stage of cell wall synthesis
• Resistance
• Alterations in penicillin-binding proteins
• Inability to penetrate bacterial cell walls
• Enzymatic hydrolysis of penicillin molecule

36
Penicillin

• Spectrum
• Gram-positive cocci - Group A and group B
  Streptococcus
• Gram-positive bacilli - Corynebacterium
  diphtheriae
• Gram-negative cocci - Neisseria meningitidis
• Gram-negative bacilli - Streptobacillus
  moniliformis
• Anaerobes - Clostridium, Bacteroides,
  Fusobacterium, and Peptostreptococcus species
• Miscellaneous - Treponema pallidum and
  Leptospira, Enterobacter, and Acinetobacter
  species

37
Penicillin

• Adverse reactions
• Hypersensitivity (1-5)
• Irritant properties that affect the peripheral
  nervous system
• Nephropathy - Allergic reaction manifested by
  interstitial nephritis and hypokalemia

38
Cephalosporin

• Mechanism of action
• Inhibits third step of bacterial wall synthesis
• Binds to specific proteins on cell membranes
• Alters cell permeability
• Inhibits protein synthesis
• Releases autolysins
• Resistance - Decrease in bacterial cell wall
  permeability to antibiotics and production of
  beta-lactamase

39
Cephalosporin

• Spectrum
• First generation (eg, Ancef, Keflin, Kefzol) -
  Have the greatest degree of activity against
  gram-positive organisms, such as Staphylococcus
  and Streptococcus (not MRSA) have the same
  coverage against gram-positive, anaerobic, and
  aerobic bacilli as penicillin
• Second generation (eg, Ceclor, Zinacef, Mefoxin)
  - Less active against gram-positive bacteria, but
  have an advantage against Haemophilus influenzae
  organisms and some gram-negative bacilli,
  including Proteus and Enterobacter species
• Third generation (eg, Ceftazidime, Cefotaxime,
  Cefoperazone) - Have the greatest activity
  against gram-negative aerobes, with variable
  activity against Pseudomonas organisms

40
Cephalosporin

• Adverse reactions
• Hypersensitivity - Highest incidence in those
  allergic to penicillin
• Hematologic - Neutropenia, leukopenia, and
  thrombopenia
• GI disturbances - Nausea, vomiting, anorexia, and
  diarrhea
• Reversible renal impairment

41
Erythromycin

• Mechanism of action - Inhibits bacterial protein
  synthesis
• Resistance
• Alteration in protein component of 50s ribosomal
  subunit
• Plasmid-mediated resistance

42
Erythromycin

• Spectrum
• Similar to that of penicillin G
• Effective against Mycoplasma, Legionella, and
  Actinomyces species
• Combined with sulfisoxazole to make Pediazole,
  which is used in the pediatric population
• Effective against H influenzae organisms
• Adverse reactions
• GI disturbances
• Hypersensitivity
• Cholestatic hepatitis

43
Clindamycin

• Mechanism of action Binds to 50s ribosomal
  subunit, thereby inhibiting protein synthesis
• Resistance Similar to that of erythromycin

44
Clindamycin

• Spectrum
• Active against most aerobic and anaerobic
  gram-positive organisms
• Anaerobic gram-negative organisms
• although some staphylococcal organisms have
  developed resistance

45
Clindamycin

• Adverse reactions
• Pseudomembranous colitis
• Mild nausea and diarrhea
• Hypersensitivity
• Leukopenia Transient increase
• Hepatotoxicity (rare)

46
Metronidazole (Flagyl)

• Mechanism of action
• Reduced intracellularly to its active metabolite
  that is bactericidal
• May be administered orally, intravenously, or
  rectally
• Metabolized in the liver and excreted by the
  kidneys

47
Metronidazole (Flagyl)

• Adverse reactions (most of which are dose related
  and are not seen with regular short-term use)
• CNS toxicity
• GI disturbance
• Neutropenia
• Drug fever
• Synergistic alcohol effect
• Prolonged activated partial thromboplastin time
  (aPTT)

48
(No Transcript)
49
(No Transcript)
50
(No Transcript)
51
(No Transcript)
52
(No Transcript)
53
(No Transcript)
54
(No Transcript)
55
(No Transcript)
56
(No Transcript)
57
(No Transcript)