01Pre-op antibiotics
The surgeon orders them; the anesthesia team usually gives them. For the best reduction in surgical-site infection, the antibiotic should be in the patient ~30 minutes before incision (in peds, where the IV often goes in after induction, give it as soon as the IV is in). Some give a small test dose first and watch the anterior chest for histamine release (redness/urticaria).
| Antibiotic | Adult dose | Peds | Note |
|---|---|---|---|
| Cefazolin (Ancef) | 1–2 g IV | 25 mg/kg | Most common surgical prophylaxis |
| Ampicillin | 1–2 g IV | 25 mg/kg | |
| Clindamycin | 600 mg | 10 mg/kg | |
| Gentamicin | 120 mg (÷ q6h) | 1.5 mg/kg | Give slowly — ototoxicity / tinnitus |
| Metronidazole (Flagyl) | 500 mg q8h | 30 mg/kg/day | |
| Vancomycin | 1 g IV | 10 mg/kg | Give slowly — "red-man" (histamine) |
- Pushing vancomycin fast → red-man syndrome (flushing, hypotension).
02Local anesthetics
Locals block sodium channels to stop nerve transmission. They're used constantly and safely, but each has a toxic dose — and local anesthetic systemic toxicity (LAST) presents first as CNS signs (perioral numbness, tinnitus, metallic taste, seizures) then cardiovascular collapse.
| Local | Max (plain) | Max (with epi) | Onset |
|---|---|---|---|
| Lidocaine | 4.5 mg/kg | 7 mg/kg | 5–15 min |
| Bupivacaine | 2.5 mg/kg | 3 mg/kg | 5–15 min |
| Ropivacaine | 2.5 mg/kg | 2.5–3 mg/kg | 10–20 min |
Adding epinephrine causes local vasoconstriction, which slows absorption — raising the safe maximum and prolonging the block. If you ever dilute locals (e.g., for a block), use preservative-free solutions near nerves.
- Always know the patient's weight and the max dose before locals are injected — toxicity is dose-dependent.