Abx, Steroids, & Antiemetics Flashcards
Risk Factors for SSI
DM Smoking Hypothermia Preoperative shaving Skin antisepsis Antimicrobial prophylaxis Inadequate sterilization of instruments Surgical technique
Redosing Time of Ampicillin and Cefazolin
Depends on the abs half life A: 2 hrs C: 4hrs
Redosing Considerations
Normal renal function: creatine clearance is 100 ml/min
- If < 60 ml/min consider adjusted dosing
Blood loss > 1.5L redone Vance half dose, redone all others full dose
Post-op redose limit to 24 hrs
Clean Wound Organism & Abx & Allergy Abx
staphylococcus aureus & coagulase negative staphylococci
Cefazolin
beta lacatam allergy –> clindamycin or vancomycin
Contaminated Wound Organism, Abx, & Allergy Abx
staphylococcus aureus & streptococci
Cefazolin & metronidazole
beta lactam allergy –> clindamycin
Contaminated Oral Organism, Abx, & Allergy Abx
non-bacteroides fragilis, peptostreptococcus & prevotella
Ampicillin/sulbactam
Beta lactam allergy –> clindamycin
Biliary & GI Wound Organism, Abx, & Allergy Abx
staphylococcus aureus & anaerobic gram – rods
Cefazolin & metronidazole
Beta lactam allergy –> clindamycin + aminoglycoside or fluoroquinolone
Cefazolin
1st gen cephalosporin o MOA: beta lactam antimicrobial. Binds to the PBP (pcn-binding proteins) – inhibition of bacterial cell wall synthesis. Bacteriocidal. Dosing: - 2g for healthy adults - 3g > 120kg - 25 mg/kg < 40 kg - IV push over 3-5 min
Vancomycin
broad spectrum abx
o MOA: Inhibits bacterial cell wall synthesis via inhibition of polymerization of peptidoglycans
- Often for pts with MRSA
Dosing:
- 1g over 1 hr
at least 50% should be infused before procedure
Admin time of Abx
Cephalosporins up to 2 min before incision
Vanco & Flagyl 60 min before
Beta Lactam Abxs & Risks
PCNs, cephalosporins, ampicillin
Risk: Allergic reaction
Aminoglycosides
Gentamycin & Streptomycin
Risk: ototoxicity, nephrotoxicity, skeletal muscle weakness
Tetracyclines
Doxycycline
Risk: Hepatotoxicity, Nephrotoxicity
Fluoroquinolones
Ciprofloxacin, Levofloxacin
Risk: GI intolerance
Macrolides
Erythromycin
Risk: P450 inhibition
Vancomycin Infusion
Hypotension with rapid infusion
Red man syndrome
Steven Johnson Syndrome
Gluccocorticoids
Released from adrenal gland.
Potent inhibitors of inflammatory mediators & up-regulate anti-inflammatory mediators. Depress immune system.
Chronic Steroid Therapy Complication
suppression of hypothalamic-pituitary-adrenal axis (HPA)
Hypothalamus: cortico-releasing hormone
anterior pituitary: adrenocorticotropic hormone
adrenal cortex: cortisol
- Assume suppression if they take > 20mg/day of prednisone (or equivalent) for > 3 weeks
(16 mg/day of methylprednisolone, 2 mg/day of dexamethasone, or 80 mg/day of hydrocortisone)
- Body stops normal activation & release of hormones during stress because it has been used to receiving exogenous steroids
Risk of Supra-physiologic Steroid Administration
- HPA suppression
- Impaired wound healing
- friability of skin, superficial blood vessels & other tissues
- risk of fx, infections, GI hemorrhage, ulcer
Risk of Stress Dose Steroid
- Hyperglycemia
- HTN
- Fluid retention
- Increased risk of infection
Steroid Requirement for Minor Surgery
no stress dose – take normal home dose
Steroid Requirement for Moderate Surgery
take normal dose +
50 mg hydrocortisone IV prior to procedure
- Then 25 mg hydrocortisone q8hr for 24 hrs
Steroid Requirement for Major Surgery
take normal dose +
100 mg IV hydrocortisone before induction
- 50mg q8hrs for 24 hrs
- Taper dose by half per day to maintenance level
Steroid Choice
Consider glucocorticoid : mineralocorticoid ratio
- Hydrocortisone 1:1
- If > 100 mg – transition to Methylprednisone G > M
o Cortisol is influence by G
Dexmethasone
synthetic glucocorticoid
Use: PONV, edema/inflammation, post-op pain
Dose: IV 4-12mg
SE: delayed wound healing, HPA axis suppression, hyperglycemia
DOA: up to 72 hrs
All gluccocorticoid
Risk Factors for PONV in adults
female
nonsmoker
hx of PONV/motion sickness
post-op opioids
Risk Factors for PONV in Pediatrics
surgery > 30 min, age > 3, strabismus surgery, hx of PONV
Anesthesia related Risk Factors for PONV
Volatile anesthetics, duration of anesthesia, sugammadex
Central pathway of PONV
stimulation of vestibular system –> central pattern generator (vomiting center) in medulla
Peripheral pathway of PONV
irritation of GI tract –> nucleus tractus solitaries in brainstem –> area postrema at base of fourth ventricle in medulla (CTZ) –> central pattern generator (vomiting center)
Neurotransmitters Involved in PONV
5HT3, D2, H1, M1, Neurokinin 1 via substance P
Ondansteron
5HT3 receptor antagonist. Inhibits serotonin peripherally on vagus nerve & centrally in medulla’s CTZ
• Dose: 4-8 mg
• Use: PONV, chemo N/V
• SE: HA, prolonged QT
Phenothiazines
Promethazine (phenergen) o Antagonizes D2 (CTZ), H1, M1 o Use: PONV & motion sickness o Dose: 6.25-25mg IV o Caution in Parkinson’s & prolonged QT
Butyrophenones
Droperidol o Use: PONV & sedation o Antagonizes D2 (CTZ) o Dose: 0.625 – 1.25 mg IV o Caution in Parkinson’s & prolonged QT
Benzamines
Reglan
o Use: antiemetic, decrease gastric volume, gastroparesis
o Antagonizes D2 (CTZ) & enhances response to ACh in upper GI tract
o Dose: 10 mg IV
o Avoid in GI obstruction & Parkinson’s disease
Diphenhydramine
H1 antagonist.
o Use: hypersensitivities, anaphylaxis, motion sickness, antiemesis, & sedation
o Antagonizes H1 receptors at effector cells in GI tract, BV, & resp tact
o Dose: 10-50 mg IV
o SE: somnolence, hypotension, dry mouth, thickening of bronchial secretions
Scopolamine
o Use: transdermal o Antagonizes M1 receptors o Most effective admin the night before o Can cause sedation o Antisialagogue
