PEBC Evaluating Exam flashcards

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

Cardiac output formula

Cardiac output equals heart rate multiplied by stroke volume. In a resting adult it averages about 5 litres per minute and rises during exercise or metabolic demand.

Glomerular filtration rate

GFR is the volume of plasma filtered by the kidneys per unit time. Normal is about 125 mL/min/1.73 m²; creatinine clearance approximates it but overestimates because creatinine is secreted.

Insulin signalling mechanism

Insulin binds a receptor tyrosine kinase and triggers GLUT4 translocation to the membrane of skeletal muscle and adipose cells, increasing glucose uptake and lowering blood glucose.

Henderson-Hasselbalch bicarbonate equation

pH = 6.1 + log([HCO3−]/(0.03 × PaCO2)). It describes the bicarbonate buffer system and is used to classify metabolic versus respiratory acid-base disorders.

Anion gap calculation

Anion gap = Na+ − (Cl− + HCO3−); normal is 8–12 mmol/L. It rises in ketoacidosis, lactic acidosis, renal failure and poisoning by methanol, ethylene glycol or salicylate.

Immunoglobulin classes

IgG crosses the placenta and dominates secondary responses; IgM appears first in primary responses; IgA is secreted in mucosal fluids; IgE mediates type I hypersensitivity; IgD sits on B cells.

Adrenergic receptor effects

Alpha-1 receptors cause vasoconstriction; beta-1 receptors increase heart rate and contractility; beta-2 receptors cause bronchodilation and vasodilation; alpha-2 receptors inhibit presynaptic norepinephrine release.

Gram stain mechanism

Gram-positive bacteria have thick peptidoglycan that retains crystal violet and stain purple. Gram-negative bacteria have thin peptidoglycan and an outer lipopolysaccharide membrane, so they lose dye and stain pink.

Half-life equation

t1/2 = 0.693 × Vd ÷ CL. It is the time for plasma concentration to fall by half during first-order elimination, and about 4–5 half-lives are needed to reach steady state.

Volume of distribution

Vd = amount of drug in the body ÷ plasma concentration. A large Vd indicates extensive distribution into tissues; Vd is used to calculate loading doses.

Clearance at steady state

For a continuous intravenous infusion at steady state, clearance = dose rate ÷ Css. Clearance is the volume of plasma cleared of drug per unit time and sets the maintenance dose.

Oral bioavailability equation

F = (AUC_oral × dose_IV) ÷ (AUC_IV × dose_oral). It is the fraction of an oral dose reaching systemic circulation; F equals 1 for intravenous dosing.

Loading dose formula

Loading dose = (Vd × target concentration) ÷ F. It rapidly raises drug concentration to the therapeutic range, while maintenance dosing replaces eliminated drug.

Michaelis-Menten kinetics

V = Vmax × C ÷ (Km + C). At concentrations well below Km elimination is first-order; well above Km it becomes zero-order, as with phenytoin or ethanol.

Noyes-Whitney dissolution rate

Dissolution rate = (D × A ÷ h) × (Cs − C). Rate increases with surface area, solubility and agitation; dissolution is often rate-limiting for poorly soluble oral drugs.

Prodrug activation examples

Enalapril is hydrolysed to enalaprilat; codeine is O-demethylated to morphine by CYP2D6; clopidogrel is activated by CYP2C19. Prodrugs can improve absorption or target activation.

Warfarin INR targets

Most atrial fibrillation and venous thromboembolism patients target INR 2.0–3.0. A mechanical mitral valve targets 2.5–3.5. Vitamin K reverses over-anticoagulation.

Metformin contraindications

Metformin is first-line for type 2 diabetes but is contraindicated when eGFR is below 30 mL/min/1.73 m². It is held during acute illness and iodinated contrast procedures.

ACE inhibitor adverse effects

ACE inhibitors cause cough from bradykinin accumulation, hyperkalemia, angioedema, hypotension and acute kidney injury. They are contraindicated in pregnancy and require potassium and creatinine monitoring.

Statin myotoxicity

Statins can cause myalgia and rarely rhabdomyolysis. Creatine kinase is checked if muscle symptoms occur. CYP3A4 inhibitors increase exposure to simvastatin and atorvastatin.

Digoxin toxicity

Digoxin has a narrow therapeutic index, with a heart failure target of 0.5–0.9 ng/mL. Toxicity causes nausea, confusion, visual changes and arrhythmias; hypokalemia and renal impairment increase risk.

Acetaminophen antidote

N-acetylcysteine is the antidote for acetaminophen overdose. It replenishes glutathione and is most effective within 8 hours; the Rumack–Matthew nomogram guides treatment decisions.

Opioid overdose antidote

Naloxone is a competitive opioid antagonist used for opioid overdose. It is shorter-acting than many opioids, so repeat doses or an infusion may be required while monitoring respirations.

Aminoglycoside monitoring

Aminoglycosides require peak and trough levels to balance efficacy and toxicity. They cause nephrotoxicity and ototoxicity. Extended-interval once-daily dosing is commonly used.

Health Belief Model

It predicts health behaviour from perceived susceptibility, severity, benefits and barriers, plus cues to action and self-efficacy. It is used to design adherence and screening interventions.

Transtheoretical model stages

The stages are precontemplation, contemplation, preparation, action and maintenance. Behaviour change is staged, and interventions are matched to the patient's current stage.

Number needed to treat

NNT = 1 ÷ absolute risk reduction, where ARR = control event rate − treatment event rate. It is the number of patients treated to prevent one additional adverse event.

Incremental cost-effectiveness ratio

ICER = (cost of intervention − cost of comparator) ÷ (effect of intervention − effect of comparator). It expresses the extra cost per additional unit of health outcome.

Cost-utility analysis

Cost-utility analysis measures outcomes in quality-adjusted life-years (QALYs), combining length and quality of life. Results are reported as cost per QALY gained.

Sensitivity and specificity

Sensitivity = TP ÷ (TP + FN) and measures true-positive detection. Specificity = TN ÷ (TN + FP) and measures true-negative detection. Both are independent of disease prevalence.

Proportion of days covered

PDC = days of medication supplied ÷ days in the observation period. A PDC of 0.80 or more is commonly used to define adherence when analysing pharmacy refill records.

Evidence hierarchy

Systematic reviews and meta-analyses of randomized trials rank highest, followed by randomized trials, cohort studies, case-control studies, case series and expert opinion.