AOBA Anesthesiology flashcards

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

MAC definition

The minimum alveolar concentration of an inhaled anesthetic at which 50% of patients do not move in response to a standardized surgical stimulus, reflecting potency.

Meyer-Overton correlation

The observation that anesthetic potency correlates with lipid solubility: more lipid-soluble agents have lower MAC and greater potency.

Henderson-Hasselbalch equation

pH = pKa + log([A-]/[HA]); it determines the fraction of ionized versus nonionized local anesthetic, affecting onset and duration.

ASA physical status

A classification system ranging from 1 (healthy) to 6 (brain-dead organ donor), with E for emergency, used to assess preoperative comorbidity.

Revised Cardiac Risk Index

Six predictors of perioperative cardiac events: ischemic heart disease, heart failure, cerebrovascular disease, insulin-dependent diabetes, renal insufficiency, and high-risk surgery.

Mallampati classification

A bedside airway assessment (classes I-IV) based on visibility of oropharyngeal structures with the patient seated, phonating, and protruding the tongue.

Preoperative fasting intervals

Clear liquids 2 hours, breast milk 4 hours, infant formula 6 hours, light meal 6 hours, and fatty meal 8 hours before elective anesthesia.

Pin Index Safety System

A cylinder-specific pin configuration that prevents incorrect connection of small gas cylinders to the anesthesia machine yoke.

Diameter Index Safety System

A set of noninterchangeable pipeline connectors that prevents misconnection of gas hoses to wall outlets.

Oxygen flush valve

A bypass valve delivering 100% oxygen at 35-75 L/min directly to the breathing circuit, bypassing the vaporizer; risk of barotrauma.

Capnography waveform phases

Phase I inspiratory baseline, phase II expiratory upstroke, phase III alveolar plateau, and phase IV inspiratory downstroke; end-tidal CO2 approximates PaCO2.

Rapid sequence induction

A technique to secure the airway quickly in patients at risk of aspiration, using preoxygenation, rapid-onset induction agent, and neuromuscular blockade with cricoid pressure.

Difficult mask ventilation predictors

Age >55, BMI >30, edentulous, beard, Mallampati III/IV, limited jaw protrusion, and snoring; these increase the risk of failed mask ventilation.

Laryngeal mask airway

A supraglottic airway device placed over the laryngeal inlet; contraindicated in full stomach, morbid obesity, and low pulmonary compliance.

Laryngospasm treatment

100% oxygen, jaw thrust, gentle positive pressure, and deepening anesthesia; if persistent, succinylcholine 0.5-1 mg/kg IV or 4 mg/kg IM.

Local anesthetic systemic toxicity

A complication of local anesthetic overdose or intravascular injection; treated with airway support, benzodiazepines for seizures, and lipid emulsion 1.5 mL/kg bolus.

Maximum lidocaine dose

4.5 mg/kg without epinephrine and 7 mg/kg with epinephrine; doses above these increase the risk of systemic toxicity.

Epidural test dose

3 mL of lidocaine 1.5% with epinephrine 1:200,000 to detect intravascular or intrathecal catheter placement before initiating epidural anesthesia.

Interscalene block complication

Phrenic nerve palsy occurs in nearly 100% of patients after interscalene brachial plexus block, risking respiratory compromise in those with pulmonary disease.

Mean arterial pressure formula

MAP = (SBP + 2×DBP)/3; a goal of at least 65 mmHg is generally used to maintain organ perfusion during anesthesia.

Stroke volume variation

A dynamic parameter >13% that predicts fluid responsiveness in mechanically ventilated patients with sinus rhythm and adequate tidal volumes.

Oxygen delivery formula

DO2 = cardiac output × CaO2 × 10; normal is approximately 1000 mL/min, and oxygen consumption is about 250 mL/min.

Lung-protective ventilation

Tidal volume 6-8 mL/kg predicted body weight, PEEP 5-10 cm H2O, plateau pressure <30 cm H2O, and driving pressure <15 cm H2O.

One-lung ventilation hypoxemia

Managed by PEEP to the dependent lung, CPAP to the nondependent lung, recruitment maneuvers, and fiberoptic confirmation of tube position.

Cerebral perfusion pressure

CPP = MAP - ICP; a target >60 mmHg is used in neuroanesthesia to maintain cerebral blood flow and avoid ischemia.

Obstetric left uterine displacement

After 20 weeks gestation, displacing the uterus leftward prevents aortocaval compression and preserves venous return and cardiac output.

Pediatric uncuffed endotracheal tube

May be used in children younger than 8 years; size selection based on age and weight, with a leak test to avoid mucosal ischemia.

Sepsis-3 definition

Life-threatening organ dysfunction caused by a dysregulated host response to infection, defined by a SOFA score increase of at least 2 points.

ARDS Berlin criteria

Onset within 1 week, bilateral opacities, PaO2/FiO2 ≤300 with PEEP ≥5 cm H2O, and not fully explained by cardiac failure or fluid overload.

KDIGO AKI criteria

Increase in serum creatinine ≥0.3 mg/dL within 48 hours or urine output <0.5 mL/kg/h for 6 hours.

Neuropathic pain treatment

First-line medications include gabapentinoids, tricyclic antidepressants, and SNRIs; characterized by burning, shooting pain, allodynia, and hyperalgesia.

Opioid-induced hyperalgesia

A paradoxical increase in pain sensitivity with escalating opioid doses, managed by opioid rotation or tapering.

Informed consent elements

Discussion of risks, benefits, alternatives, and the possibility of conversion to general anesthesia, documented before sedation and without coercion.