Understanding Antibiotic Therapy
Bacteriostatic (inhibits)
o inhibits growth of Bacteria by preventing bacteria from multiplying and then hosts defences deal with the small number of bacteria left
Bactericidal (kills)
o kills Bacteria, so eliminates bacteria
Principles of Antibiotic Guidelines
o Specimens for microbiology should be taken prior to the start of empiric Abx treatment.
o In an emergency, at a minimum a set of blood cultures should be taken (meningitis).
o Ensure any history of allergy is documented on the cover of notes and drug kardex prior to commencing antibiotics
o 2 lab specimens should be collected
o In case something happens to the first one (contamination)
o 2 different sticks from 2 different locations
o 12 hours before the results come back
o Patient is started on a broad antibiotic while awaiting test results
Switched to a culture specific antibody when test results return
o Use chlorohexidine to prep site
Principles of Antibiotic Guidelines
o Empiric antibiotics should be reviewed once labs have resulted.
o Empiric therapy should be changed to directed therapy as soon as possible.
o Directed therapy should be the narrowest spectrum antibiotic to adequately cover the pathogens
Definitions
o Pharmacokinetics: Mathematical study of the rate process involved in absorption, distribution, metabolism and excretion
o Pharmacodynamics: Time course of drug effects and other interactions between antimicrobials and the bacterium
Principles of Antibiotic Guidelines
o Pharmacokinetics&Pharmacodynamics issues may necessitate dose adjustments
o Consider compatibility of prescribed Abx interacting with other drugs
o Doses of antibiotics should take into account certain labs and be reviewed regularly.
BUN/ Creatinine; ALT/ AST (Kidneys and Liver respectively)
Renal impairment = give a smaller dose
Body will hold on to the drug longer
o Hang the antibiotic above the saline
Principles of Antibiotic Guidelines
o All antibiotic prescriptions should be reviewed after 48 hours
Determines if the medication is working
o Consideration should be made when appropriate to switch from IV to oral
Fever settled (96-100.4)
WBC returning to normal (5000-10000)
Patient clinically stable (stable vitals)
No gastrointestinal upset
o Patient can go home when they are switched to PO
General Principles of Therapy
o If no improvement within 36-48 hours check adequate dose and /or level of drug should be checked
Therapeutic Drug Monitoring (TDM)
o TDM necessary to ensure therapeutic effectiveness of a drug while ensuring toxic and sub therapeutic doses are avoided.
o TDM is performed on drugs with narrow therapeutic indices such as glycopeptides (vancomycin) and aminoglycosides (gentamicin)
o These drugs may be associated with toxicity so levels should be regularly monitored
General advice on taking levels
o It is important to ensure the levels are taken at the correct time.
o When:
Trough: must be taken immediately before the next due dose.
Peak: one hour after administration of dose.
o Frequency: Levels will be taken more frequently with impaired renal or liver functions
General advice on taking levels
o Action to be taken once levels resulted from lab
If level is within therapeutic range, MD likely to continue current dosing
If level below or above MD will make med dosage changes accordingly
Peak & Trough Values
, o Reference ranges
Vancomycin trough: 10-20 mcg/mL
Vancomycin peak: 25-50 mcg/mL
Gentamycin trough: 0.5-2 mcg/mL
Gentamycin peak: 5-10 mcg/mL
o Toxic: Any value above normal range level
Concentration Dependent Killing
o Increasing or decreasing the concentration of the drug
Time Dependent Killing
o Increasing or decreasing the time period between each dose
Interpretation of Levels
o High trough: increase time between intervals
o Low trough: (subtherpeutic): decreases time between doses; increase dose
o Highpeak: decrease dose
o Low peak: increase dose
Antibiotic Mechanism of Action
o Inhibition of bacterial protein synthesis
o Inhibition of cell membrane synthesis
o Inhibition of cell wall synthesis
o Inhibition of nucleic acid synthesis
Properties of bacterial toxin
o Exotoxin: heat labile (except – enterotoxin of S. aureus)
o Endotoxin: heat stable (up to 250 C)
Structure of Bacteria
o Gram – / +
Gram-positive bacteria: can be compared to a heavy wooden fence, with thick and wide planks, surrounding a yard. Or, perhaps
visualize gram-positive bacteria as a room in a house, which is reinforced by dry walled barriers, complete with 2x4 wooden studs and
foam/fiberglass insulation between the layers of drywall.
Less to manage
Gram-negative bacteria:can be likened to a thin bulletproof Kevlar vest surrounding a security guard. Or, perhaps the gram-negative
bacteria can be compared to a very thin metal armored breastplate, surrounding a Roman warrior or medieval English knight during
battle. It could also be envisaged as a thin chain mail shirt being worn by an ancient militant.
More time management and higher drug concentrations
Chapter 26: Care of Patients with Burns
Hand Hygiene
o Remember Hand Hygiene every time for you and others
Hand Hygiene Guidelines Fact Sheet
o Frequent hand washing is the single best thing people can do to avoid getting sick, from colds and the flu due to germs lurking on surfaces and
in food.
o Improved adherence to hand hygiene (i.e. hand washing or use of alcohol-based hand rubs) has been shown to terminate outbreaks in
health care facilities, to reduce transmission of antimicrobial resistant organisms (e.g. MRSA: methicillin resistant staphylococcus aureus) and
reduce overall infection rates.
o Handwashing with soap and water remains a sensible strategy for hand hygiene in non-health care settings and is recommended by CDC and
other experts.
o The use of gloves does not eliminate the need for hand hygiene. Always wash your hands after removing gloves. Likewise, the use of
hand hygiene does not eliminate the need for gloves. Gloves reduce hand contamination by 70 percent to 80 percent, prevent cross-
contamination and protect patients and health care personnel from infection.
o Handrubs should be used before and after each client just as gloves should be changed before and after each client. When using an
alcohol-based handrub, apply product to palm of one hand and rub hands together, covering all surfaces of hands and fingers, until hands are
dry. Note that the volume needed to reduce the number of bacteria on hands varies by product.
Pathophysiology of Burn Injury
o Skin changes resulting from burn injury
Leads to local & systemic problems
Fluid & Electrolyte Imbalances
Protein losses
Sepsis
Metabolic changes
o Anatomic changes
Skin changes
Prep the family to see how the patient looks now
o Functional changes
Protective barrier against injury and microbial invasion
Helps maintain fluid & electrolyte balance
All burn injuries are painful
o Temperature (Thermoregulation)
They will always be cold and shivering
Skin Assessment
o Size and depth of injury
o Percentage of total BSA affected
o “Rule of nines" using multiples of 9% of total BSA
Groin = 1%
Pathophysiology of Burn Injury
o Anatomic changes
Bacteriostatic (inhibits)
o inhibits growth of Bacteria by preventing bacteria from multiplying and then hosts defences deal with the small number of bacteria left
Bactericidal (kills)
o kills Bacteria, so eliminates bacteria
Principles of Antibiotic Guidelines
o Specimens for microbiology should be taken prior to the start of empiric Abx treatment.
o In an emergency, at a minimum a set of blood cultures should be taken (meningitis).
o Ensure any history of allergy is documented on the cover of notes and drug kardex prior to commencing antibiotics
o 2 lab specimens should be collected
o In case something happens to the first one (contamination)
o 2 different sticks from 2 different locations
o 12 hours before the results come back
o Patient is started on a broad antibiotic while awaiting test results
Switched to a culture specific antibody when test results return
o Use chlorohexidine to prep site
Principles of Antibiotic Guidelines
o Empiric antibiotics should be reviewed once labs have resulted.
o Empiric therapy should be changed to directed therapy as soon as possible.
o Directed therapy should be the narrowest spectrum antibiotic to adequately cover the pathogens
Definitions
o Pharmacokinetics: Mathematical study of the rate process involved in absorption, distribution, metabolism and excretion
o Pharmacodynamics: Time course of drug effects and other interactions between antimicrobials and the bacterium
Principles of Antibiotic Guidelines
o Pharmacokinetics&Pharmacodynamics issues may necessitate dose adjustments
o Consider compatibility of prescribed Abx interacting with other drugs
o Doses of antibiotics should take into account certain labs and be reviewed regularly.
BUN/ Creatinine; ALT/ AST (Kidneys and Liver respectively)
Renal impairment = give a smaller dose
Body will hold on to the drug longer
o Hang the antibiotic above the saline
Principles of Antibiotic Guidelines
o All antibiotic prescriptions should be reviewed after 48 hours
Determines if the medication is working
o Consideration should be made when appropriate to switch from IV to oral
Fever settled (96-100.4)
WBC returning to normal (5000-10000)
Patient clinically stable (stable vitals)
No gastrointestinal upset
o Patient can go home when they are switched to PO
General Principles of Therapy
o If no improvement within 36-48 hours check adequate dose and /or level of drug should be checked
Therapeutic Drug Monitoring (TDM)
o TDM necessary to ensure therapeutic effectiveness of a drug while ensuring toxic and sub therapeutic doses are avoided.
o TDM is performed on drugs with narrow therapeutic indices such as glycopeptides (vancomycin) and aminoglycosides (gentamicin)
o These drugs may be associated with toxicity so levels should be regularly monitored
General advice on taking levels
o It is important to ensure the levels are taken at the correct time.
o When:
Trough: must be taken immediately before the next due dose.
Peak: one hour after administration of dose.
o Frequency: Levels will be taken more frequently with impaired renal or liver functions
General advice on taking levels
o Action to be taken once levels resulted from lab
If level is within therapeutic range, MD likely to continue current dosing
If level below or above MD will make med dosage changes accordingly
Peak & Trough Values
, o Reference ranges
Vancomycin trough: 10-20 mcg/mL
Vancomycin peak: 25-50 mcg/mL
Gentamycin trough: 0.5-2 mcg/mL
Gentamycin peak: 5-10 mcg/mL
o Toxic: Any value above normal range level
Concentration Dependent Killing
o Increasing or decreasing the concentration of the drug
Time Dependent Killing
o Increasing or decreasing the time period between each dose
Interpretation of Levels
o High trough: increase time between intervals
o Low trough: (subtherpeutic): decreases time between doses; increase dose
o Highpeak: decrease dose
o Low peak: increase dose
Antibiotic Mechanism of Action
o Inhibition of bacterial protein synthesis
o Inhibition of cell membrane synthesis
o Inhibition of cell wall synthesis
o Inhibition of nucleic acid synthesis
Properties of bacterial toxin
o Exotoxin: heat labile (except – enterotoxin of S. aureus)
o Endotoxin: heat stable (up to 250 C)
Structure of Bacteria
o Gram – / +
Gram-positive bacteria: can be compared to a heavy wooden fence, with thick and wide planks, surrounding a yard. Or, perhaps
visualize gram-positive bacteria as a room in a house, which is reinforced by dry walled barriers, complete with 2x4 wooden studs and
foam/fiberglass insulation between the layers of drywall.
Less to manage
Gram-negative bacteria:can be likened to a thin bulletproof Kevlar vest surrounding a security guard. Or, perhaps the gram-negative
bacteria can be compared to a very thin metal armored breastplate, surrounding a Roman warrior or medieval English knight during
battle. It could also be envisaged as a thin chain mail shirt being worn by an ancient militant.
More time management and higher drug concentrations
Chapter 26: Care of Patients with Burns
Hand Hygiene
o Remember Hand Hygiene every time for you and others
Hand Hygiene Guidelines Fact Sheet
o Frequent hand washing is the single best thing people can do to avoid getting sick, from colds and the flu due to germs lurking on surfaces and
in food.
o Improved adherence to hand hygiene (i.e. hand washing or use of alcohol-based hand rubs) has been shown to terminate outbreaks in
health care facilities, to reduce transmission of antimicrobial resistant organisms (e.g. MRSA: methicillin resistant staphylococcus aureus) and
reduce overall infection rates.
o Handwashing with soap and water remains a sensible strategy for hand hygiene in non-health care settings and is recommended by CDC and
other experts.
o The use of gloves does not eliminate the need for hand hygiene. Always wash your hands after removing gloves. Likewise, the use of
hand hygiene does not eliminate the need for gloves. Gloves reduce hand contamination by 70 percent to 80 percent, prevent cross-
contamination and protect patients and health care personnel from infection.
o Handrubs should be used before and after each client just as gloves should be changed before and after each client. When using an
alcohol-based handrub, apply product to palm of one hand and rub hands together, covering all surfaces of hands and fingers, until hands are
dry. Note that the volume needed to reduce the number of bacteria on hands varies by product.
Pathophysiology of Burn Injury
o Skin changes resulting from burn injury
Leads to local & systemic problems
Fluid & Electrolyte Imbalances
Protein losses
Sepsis
Metabolic changes
o Anatomic changes
Skin changes
Prep the family to see how the patient looks now
o Functional changes
Protective barrier against injury and microbial invasion
Helps maintain fluid & electrolyte balance
All burn injuries are painful
o Temperature (Thermoregulation)
They will always be cold and shivering
Skin Assessment
o Size and depth of injury
o Percentage of total BSA affected
o “Rule of nines" using multiples of 9% of total BSA
Groin = 1%
Pathophysiology of Burn Injury
o Anatomic changes
