A 27-year-old man with a hand abscess presents for incision and drainage. Vital signs show BP 128/82 mmHg, HR 92 bpm, RR 16/min, Temp 38.9°C, SpO2 98% on room air. Despite lidocaine injection, he reports severe pain. Local culture grows Staphylococcus aureus with abscess pH of 5.8. He denies prior antibiotic use. Which mechanism best explains the reduced anesthetic effectiveness in this acidic, inflamed tissue environment?
- A)The anesthetic requires alkaline urine for activation
- B)More drug remains ionized and cannot cross the nerve membraneGABARITO
- C)Inflammation causes increased protein binding and reduced potency
- D)The acidic environment irreversibly blocks sodium channels
- E)The drug is degraded too quickly by plasma esterases
Explicação
Local anesthetics are weak bases that must be in the uncharged form to cross the neuronal membrane. In infected acidic tissue, more drug becomes protonated and trapped in the charged form outside the cell, so less reaches the intracellular sodium channel bindi... Ver explicação completa e trilha adaptativa →