Surgical infection and antibiotics Flashcards
defined by the presence of microorganism in host tissue or the bloodstream
Infection
Systemic manifestation that is noted with individual who has infection e.g rubor, calor, dolor, tachypnea
systemic inflammatory response(SIRS)
documented or suspected infection with SIRS
sepsis
sepsis combined with the presence of new onset organ failure, eg. Pts. w/ oliguria, hypotension
sever sepsis
state of acute circulatory failure identified by the presence of persistent arterial hypotension despite adequate fluid resuscitation
septic shock
occurs 40% in patients with sever sepsis
septic shock
other conditions that causes SIRS
trauma,aspiration,pancreatitis,burn
criteria for systemic inflammatory response syndrome
General variables, altered mental status, inflammatory variables, organ dysfunction, variables, tissue perfusion variables
General variables for SIRS
Fever(core temp g/t 38.3C Hypothermia l/t 36C HR g/t 90bpm Tachypnea altered mental status edema g/t 20ml/kg over 24hrs hyperglycemia in the absence of diabetes
Inflammatory variable for SIRS
WBC g/t 12,000 WBC l/t 4000 bandemia g/t 10% plasma C reactive protein g/t 2 s.d plasma procalcitonin g/t 2 s.d
What are the risk factors for infection?
- Host factors(old age, hyperglycemia)
- Genetics and genomics of trauma and sepsis
- Interactions between the host and therapy
medical conditions known to increase risk of post op infection
- extremes of age
- malnutrition
- obesity
- DM
- prior sire irradiation
- hypothermia
- hypoxemia
- coexisting infection
- corticosteroid therapy
- recent operation in chest and abdomen
- chronic inflammation
- hypercholesterolemia
example of host and therapy interactions
*blood transfusion
-altered leukocyte antigen presentation
-shift to T-helper phenotype
control of blood
*glucose concentration
ways to prevent and treat of surgical infection?
source control
appropriate use of antimicrobial agents
consists of drainage of all purulent material, debridement of all site of infection
source control
- administration of an antimicrobial agents prior to initiation of certain specific typesof surgical procedures to reduce the number of microbes
- 30min- 1 hr prior to incision
prophylaxis
use of an antimicrobial agents when the risk for surgical infection is high
limited to short course of drug (3-5 days)
Emperic therapy
evidence of SIRS should lead the surgeon to initiate what therapy?
empirical antibiotic therapy
initial antimicrobial selection is borad with a later narrowing of agents based on patient response and culture results
de-escalation therapy
therapy guidelines for UTI, given for how many days?
given 3-5 days
therapy guidelines for pneumonia, given for how many days?
given 7-10 days
therapy guidelines for bacteremia, given for how many days?
given 7-14 days
antibiotic therapy for osteomyelitis, endocarditis, or prosthetic infections is given for how many weeks?
6-12 weeks
prophylaxis for cardiovascular and thoracic ]procedure, pulmonary resection, lower limb amputation
first generation cephalosporins
alternative: gentamicin and metronidazole
2nd generation cephalosporins are given for what surgical procedures?
- appendectomy
- colon surgery
- penetrating abdominal trauma
alternative: metro + gentamicin
involves the principles of drug absorption, distribution and metabolism
pharmacokinetics
the percentage of drug dose that reaches the systemic circulation
affected by absorption, intestinal transit time, and degree of hepatic metabolism
bioavailability
reflects clearance and volume
useful to estimate for the interpretation of drug concentration data
half life
derived proportionality constant of no particular physiologic significance that is independent of a drug’s clearance
useful for estimating the plasma drug concentration achievable fronm a given dose
volume of distribution
volume of liquid from which a drug is eliminated per unit of time, whether by tissue, distribution, metabolism, or elimination
clearance
principles in the administration of an antimicrobial agent for prophylaxis
- safety
- appropriate narrow spectrum coverage of relevant pathogens
- little or no reliance on the agent for therapy of infection
- administration within 1 hour before surgery and for a defined brief period thereafter
factors influencing antibiotic choice
-activity against known or suspected pathogen
-disease believed responsible
-distinguish infection from colonization
- narro spectrum coverage most desirable
-antimicrobial resistance pattern
-patient specific pattern
institutional guidelines and restrictions
cell wall active agents
- Beta lactam antibiotics(Penicillins,Cephalosporins,Monobactans,Carbapenems)
- lipoglycopeptides
- Cyclic lipopeptides
- Polymyxins
what drugs are the proteins synthesis inhibitors
- Aminoglycosides
- Tetracyclines
- Oxazolidinones
- Macrolide-lincosamide-steptogramin family(clindamycin)
bind to the bacterial 30s ribosomal subunit, inhibiting protein synthesis.
Aminoglycosides
bind irreversibly to the 30s ribosomal subunit, but unlike aminoglycosides they are bacteriostatic
active against anaerobes
Tetracyclines