ABA ADVANCED Exam flashcards

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

Poiseuille's law

Resistance to laminar flow equals 8 times viscosity times length divided by pi times radius to the fourth power; halving radius increases resistance sixteenfold.

Reynolds number

A dimensionless ratio of inertial to viscous forces; values above roughly 2000 in a tube predict turbulent flow, which increases resistance and depends on density and velocity.

Laplace law for alveoli

Alveolar wall tension and radius determine collapsing pressure: P equals 2T divided by r for a sphere, so smaller alveoli require higher pressure to remain open.

Pulse oximetry ratio

Pulse oximeters compare light absorbance at 660 and 940 nanometers; the ratio of pulsatile red to infrared absorption is calibrated to arterial oxygen saturation.

Phase II capnogram

The steep ascending expiratory upstroke of the capnogram represents transition from anatomic dead space to alveolar gas and normally has a nearly vertical slope.

E-cylinder oxygen volume

A full US E cylinder of oxygen at about 2200 psi contains roughly 660 liters; remaining volume is approximately cylinder pressure in psi times 0.3.

Microshock threshold

Current as low as 100 microamperes delivered directly to myocardium can precipitate ventricular fibrillation, so intracardiac catheters require electrically isolated equipment.

Vaporizer output factors

Output depends on carrier-gas flow, temperature, agent vapor pressure, and back pressure; low flows and high altitude alter delivered concentration compared with calibration conditions.

Context-sensitive half-time

Time for plasma concentration to fall by half after stopping an infusion; it lengthens with infusion duration for lipophilic drugs such as propofol and fentanyl.

MAC definition

Minimum alveolar concentration of inhaled anesthetic at one atmosphere that prevents movement in 50 percent of subjects given a standard surgical stimulus.

Second gas effect

Rapid uptake of a high-concentration gas such as nitrous oxide concentrates remaining alveolar gases, transiently raising the alveolar fraction of a concurrently administered volatile anesthetic.

Diffusion hypoxia

At emergence, nitrous oxide diffuses from blood into alveoli faster than nitrogen enters blood, diluting alveolar oxygen and causing transient hypoxemia unless oxygen is given.

Succinylcholine dose

For adult rapid-sequence induction, succinylcholine 1 to 1.5 milligrams per kilogram intravenously produces paralysis within about 60 seconds and lasts roughly 5 to 10 minutes.

Sugammadex reversal

Sugammadex encapsulates rocuronium or vecuronium; dose is 2 milligrams per kilogram for moderate block, 4 for deep block, and 16 for immediate reversal.

Bupivacaine cardiotoxicity

Bupivacaine binds cardiac sodium channels avidly; overdose can cause refractory ventricular arrhythmias, and treatment includes airway support, benzodiazepines, and intravenous lipid emulsion.

Neostigmine dosing

Neostigmine 0.03 to 0.07 milligrams per kilogram reverses nondepolarizing blockade; coadminister glycopyrrolate 0.2 milligrams per milligram of neostigmine to prevent bradycardia.

Oxygen delivery formula

Oxygen delivery equals cardiac output times arterial oxygen content times 10; normal is about 1000 milliliters per minute, and content depends mainly on hemoglobin and saturation.

Arterial oxygen content

CaO2 equals 1.34 times hemoglobin times SaO2 plus 0.003 times PaO2; dissolved oxygen contributes little, so anemia and desaturation reduce content substantially.

Shunt equation

Shunt fraction equals mixed venous oxygen content minus arterial content divided by mixed venous content minus pulmonary capillary content; it quantifies perfusion without gas exchange.

Cerebral perfusion pressure

Cerebral perfusion pressure equals mean arterial pressure minus intracranial pressure; autoregulation usually keeps cerebral blood flow constant between about 50 and 150 mmHg.

CO2 cerebral reactivity

Cerebral blood flow changes about 3 to 5 percent per mmHg change in PaCO2 within physiologic range; hyperventilation lowers flow and intracranial volume.

A-a gradient

Alveolar-arterial oxygen gradient equals alveolar oxygen minus arterial oxygen; a normal value is roughly age divided by 4 plus 4 on room air.

Renal autoregulation

Renal blood flow is autoregulated between mean arterial pressures of about 80 and 180 mmHg; below that range, glomerular filtration falls and acute kidney injury risk rises.

Henderson-Hasselbalch

pH equals 6.1 plus log of bicarbonate divided by 0.03 times PaCO2; it describes the bicarbonate buffer system and helps classify metabolic versus respiratory acid-base disorders.

Rapid sequence induction

Preoxygenate, apply cricoid pressure if indicated, give induction agent and succinylcholine or high-dose rocuronium, and intubate without positive-pressure ventilation to limit aspiration.

Malignant hyperthermia treatment

Stop triggering agents, call for help, give dantrolene 2.5 milligrams per kilogram intravenously, hyperventilate with 100 percent oxygen, and cool while treating hyperkalemia and arrhythmias.

LAST treatment

Local anesthetic systemic toxicity is treated with airway support, seizure control, and intravenous lipid emulsion 1.5 milliliters per kilogram bolus followed by infusion.

Difficult airway algorithm

After failed tracheal intubation, maintain oxygenation, limit attempts, consider supraglottic rescue, and proceed to emergency invasive airway if ventilation cannot be maintained.

Aspiration risk factors

Risk rises with emergency surgery, full stomach, obesity, diabetes, gastroesophageal reflux, pregnancy, and opioid use; rapid-sequence induction or gastric decompression may be indicated.

Postoperative nausea prophylaxis

Apfel risk factors are female sex, nonsmoking, history of motion sickness or postoperative nausea, and postoperative opioids; multiple prophylactic antiemetics are used for high-risk patients.

Transfusion trigger

In stable postoperative or critically ill adults, restrictive transfusion often uses hemoglobin 7 to 8 grams per deciliter; active bleeding or myocardial ischemia may warrant a higher threshold.

ERAS multimodal analgesia

Enhanced recovery pathways combine regional anesthesia, acetaminophen, nonsteroidal anti-inflammatory drugs when safe, and opioid-sparing regimens to reduce surgical stress and speed recovery.