ABA BASIC flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

MAC

Minimum alveolar concentration at 1 atm that prevents movement in 50% of patients to a standardized surgical stimulus; values are roughly additive among volatile agents.

Henderson-Hasselbalch equation

pH = pKa + log([A−]/[HA]); when pH equals pKa, the drug is 50% ionized. This determines lipid solubility and ion trapping of local anesthetics and opioids.

Poiseuille law

Laminar flow through a tube is proportional to the fourth power of radius and pressure gradient and inversely proportional to viscosity and length; doubling radius increases flow 16-fold.

Oxygen delivery formula

DO2 = cardiac output × arterial oxygen content (CaO2); CaO2 = 1.34 × Hb × SaO2 + 0.003 × PaO2, expressed in mL O2 per dL blood.

Frank-Starling relationship

Increasing ventricular preload stretches sarcomeres and increases stroke volume up to an optimal point; beyond it, further stretch does not augment output.

Right mainstem bronchus anatomy

The right mainstem bronchus is wider, shorter, and more vertical than the left, making right endobronchial intubation and aspiration more likely.

ASA physical status I

A normal healthy patient without systemic disease; examples include nonsmoking, non-obese, healthy adults undergoing elective surgery.

Mallampati class

Airway classification based on visible oropharyngeal structures; class III/IV (only soft palate, base of uvula, or hard palate visible) predicts difficult laryngoscopy.

Succinylcholine dose and duration

1–1.5 mg/kg IV produces paralysis in 30–60 seconds lasting 5–10 minutes; avoid in hyperkalemia risk, burns, denervation, and malignant hyperthermia susceptibility.

Train-of-four ratio

Four supramaximal stimuli at 2 Hz; a ratio ≥0.9 at the adductor pollicis indicates adequate recovery from neuromuscular blockade.

Lipid emulsion for LAST

For local anesthetic systemic toxicity, give 20% lipid emulsion 1.5 mL/kg bolus followed by 0.25 mL/kg/min infusion while supporting airway and circulation.

Methemoglobinemia treatment

Methylene blue 1–2 mg/kg IV reduces methemoglobin; indicated for symptomatic patients or levels >20–30% after oxidant drugs such as benzocaine.

Uncuffed ETT size formula

For children older than 1 year, uncuffed endotracheal tube internal diameter in millimeters is approximately age in years divided by 4 plus 4.

One-lung ventilation settings

Use tidal volume 4–6 mL/kg predicted body weight, PEEP about 5 cmH2O, and keep plateau pressure below 25–30 cmH2O to limit ventilator-induced lung injury.

Left uterine displacement

After 20 weeks gestation, displace the uterus leftward to relieve aortocaval compression and improve venous return and cardiac output during anesthesia.

Heparin for cardiopulmonary bypass

Give heparin 300–400 units/kg before bypass and target an activated clotting time above 400–480 seconds; protamine reverses heparin.

Hyperventilation for increased ICP

Lowering PaCO2 to 30–35 mmHg causes cerebral vasoconstriction and rapidly reduces intracranial pressure; the effect is transient and risks ischemia.

Pediatric fasting intervals

ASA guidelines: clear fluids 2 hours, breast milk 4 hours, infant formula 6 hours, and light meal 6 hours before elective anesthesia.

Dantrolene for malignant hyperthermia

Give 2.5 mg/kg IV, repeat until symptoms are controlled, stop triggering agents, hyperventilate with 100% oxygen, and actively cool the patient.

Surgical safety checklist

WHO three-phase checklist (sign in, time out, sign out) improves teamwork and reduces surgical morbidity and mortality when used consistently.

Capnography confirmation

Continuous end-tidal CO2 waveform is the standard to confirm and monitor endotracheal tube placement; absence suggests esophageal intubation or no perfusion.

Fire triad in airway surgery

Fire requires oxidizer, fuel, and ignition; reduce inspired oxygen to the lowest tolerable FiO2 and avoid nitrous oxide near ignition sources.

Anaphylaxis treatment dose

Epinephrine 10–100 micrograms IV bolus for perioperative anaphylaxis, with fluids and stopping the trigger; intramuscular 0.3–0.5 mg if no IV access.

Informed consent elements

Valid consent requires patient capacity, disclosure of risks, benefits, and alternatives, patient understanding, and a voluntary decision without coercion.

Impaired physician reporting

Suspected impairment that endangers patients should be reported to the state medical board or a physician health program, balancing patient safety and rehabilitation.

DNR order in operating room

Reconfirm code status with the patient or surrogate before anesthesia, because intraoperative events are often treatable and the original order may not apply.

Conflict of interest disclosure

Financial or personal relationships that could bias clinical judgment must be disclosed to patients, institutions, and research oversight bodies.

Revised Cardiac Risk Index

Six predictors: high-risk surgery, ischemic heart disease, heart failure, cerebrovascular disease, insulin-requiring diabetes, and creatinine >2.0 mg/dL.

Perioperative beta-blocker rule

Continue chronic beta-blockers through surgery; do not start high-dose beta-blockers on the day of surgery because it increases stroke and mortality risk.

Perioperative glycemic target

Maintain blood glucose roughly 140–180 mg/dL using insulin; avoid both hyperglycemia and hypoglycemia, which increase morbidity.

Apfel PONV score

Predicts postoperative nausea and vomiting from female sex, nonsmoking status, history of PONV or motion sickness, and postoperative opioids; each adds a point.

Restrictive transfusion threshold

Transfuse when hemoglobin is about 7 g/dL in most stable patients; use 8 g/dL for some cardiac or orthopedic patients based on guidelines.