ABA Anesthesiology 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 one atmosphere preventing movement in 50% of patients exposed to a surgical stimulus; values are additive and reduced by hypothermia, pregnancy, sepsis, and opioids.

Oxygen content formula

Arterial oxygen content equals 1.34 times hemoglobin times arterial oxygen saturation plus 0.003 times arterial oxygen partial pressure; delivery equals cardiac output times content times ten.

Context-sensitive half-time

Time for plasma concentration to fall by half after stopping an infusion; it increases with longer infusions of lipophilic drugs but remains short for remifentanil because of ester hydrolysis.

Poiseuille law

Resistance to laminar flow equals eight times viscosity times length divided by pi times radius to the fourth power; halving radius increases resistance sixteen-fold.

Nernst equation

Equilibrium potential equals 61.5 divided by ion valence times log of outside concentration divided by inside concentration at 37°C; it predicts resting membrane potential.

Henderson-Hasselbalch equation

For a weak acid, pH equals pKa plus log of conjugate base concentration divided by weak acid concentration; it determines the ionized fraction and membrane permeability of drugs.

Preoxygenation

Administration of high inspired oxygen before induction raises alveolar and functional residual capacity oxygen stores, prolonging safe apnea; three minutes of tidal breathing or four vital-capacity breaths are common.

Rapid sequence induction

Technique using a rapidly acting induction agent and neuromuscular blocker, usually succinylcholine 1–1.5 mg/kg or rocuronium 1.2 mg/kg, to secure the airway quickly in patients at aspiration risk.

Macintosh blade

Curved laryngoscope blade whose tip sits in the vallecula and indirectly lifts the epiglottis; it is commonly used for routine direct laryngoscopy in adults.

Spinal anesthesia hypotension

Sympathectomy from neuraxial blockade reduces venous return and systemic vascular resistance; treatment includes vasopressors, intravenous fluids, and atropine when bradycardia accompanies high block.

Malignant hyperthermia treatment

Stop volatile anesthetics and succinylcholine, give dantrolene 2.5 mg/kg intravenously, hyperventilate with 100% oxygen, cool the patient, and treat hyperkalemia and acidosis.

One-lung ventilation

Ventilation of one lung during thoracic surgery; lung-protective settings use tidal volume 4–6 mL/kg predicted body weight, PEEP, and plateau pressure below 30 cm H2O.

Revised cardiac risk index

Predicts major perioperative cardiac events using ischemic heart disease, heart failure, cerebrovascular disease, insulin-requiring diabetes, creatinine above 2 mg/dL, and high-risk surgery.

Perioperative myocardial injury

Troponin elevation above the 99th percentile occurring during or after surgery, with or without ischemic symptoms; it is associated with increased mortality and requires evaluation.

Aortic stenosis anesthesia goals

Maintain sinus rhythm, preload, and systemic vascular resistance while avoiding tachycardia and profound vasodilation; these goals preserve coronary perfusion in fixed left ventricular outflow obstruction.

Cisatracurium elimination

Cisatracurium undergoes Hofmann elimination and ester hydrolysis independent of renal and hepatic function, making it useful in chronic kidney disease and liver failure.

STOP-BANG score

Screening tool for obstructive sleep apnea using snoring, tiredness, observed apnea, pressure, body mass index, age, neck circumference, and gender; score of three or more indicates increased risk.

ARDS Berlin criteria

Acute respiratory failure within one week with bilateral opacities, PaO2/FiO2 of 300 or less with PEEP at least 5 cm H2O, and no primary cardiac explanation.

Septic shock initial fluids

Give 30 mL/kg of intravenous crystalloid for hypotension or lactate of 4 mmol/L or greater, alongside cultures, broad-spectrum antibiotics within one hour, and vasopressors if needed.

KDIGO acute kidney injury

Defined by creatinine rise of at least 0.3 mg/dL within 48 hours, at least 1.5 times baseline within 7 days, or urine output below 0.5 mL/kg/h for 6 hours.

Hyperkalemia emergency treatment

With ECG changes, give intravenous calcium first to stabilize myocardium, then insulin with glucose, albuterol, and bicarbonate as needed; dialysis definitively removes potassium.

Restrictive transfusion threshold

Transfuse most critically ill patients when hemoglobin is below 7 g/dL; a threshold of 8 g/dL is considered for active cardiac ischemia or cardiac surgery.

Local anesthetic systemic toxicity

Caused by excessive local anesthetic absorption or inadvertent intravascular injection; treat by stopping injection, securing airway with oxygen, and giving 20% lipid emulsion.

Lipid emulsion dosing

For local anesthetic systemic toxicity, give 20% lipid emulsion 1.5 mL/kg bolus followed by infusion at 0.25 mL/kg/min; repeat bolus and increase infusion for persistent instability.

Post-dural puncture headache

Positional headache worse upright and relieved supine after dural puncture; conservative treatment includes caffeine, fluids, and analgesics, while epidural blood patch is definitive.

Epidural hematoma signs

Progressive motor weakness, sensory loss, and bowel or bladder dysfunction after neuraxial anesthesia; urgent magnetic resonance imaging and surgical decompression are required to preserve neurologic function.

Interscalene block complication

Ipsilateral phrenic nerve paralysis occurs frequently because the phrenic nerve lies near the brachial plexus; avoid the block in patients with severe pulmonary disease.

ASA physical status

Classification from one to six: one healthy, two mild systemic disease, three severe systemic disease, four constant threat to life, five moribund, and six brain-dead organ donor.

Surgical time-out

Structured pause before incision confirming patient identity, procedure, site, consent, allergies, airway plan, antibiotic prophylaxis, and team concerns; it prevents wrong-site surgery and communication errors.

Capnography confirmation

Persistent end-tidal carbon dioxide waveform after intubation confirms tracheal placement; absence suggests esophageal intubation, disconnection, obstruction, or cardiac arrest.

Root cause analysis

System-focused review after a serious adverse event identifying contributing factors and corrective actions; it aims to prevent recurrence rather than punish individual clinicians.

Informed consent elements

Valid consent requires capacity, disclosure of risks, benefits, and alternatives, patient understanding, and voluntariness; emergency treatment may proceed without consent when delay threatens life.