Untitled Deck Flashcards
What should be the normal cuff pressure of a tracheostomy?
20–30 cm H2O should be checked every 8–12 hours, or more frequently depending on the clinical picture.
Higher cuff pressures may compress tracheal capillaries, limit blood flow, and predispose to tracheal necrosis (ischaemic damage).
What is the difference between cardiac output and cardiac index?
Cardiac Output = Heart Rate × Stroke Volume. Normal range ~ 4–8 L/min. Cardiac Index = Cardiac Output/Body Surface Area. Normal range ~ 2.5–4 L/min.
What is the physiological role of C-reactive protein?
A pentraxin protein synthesised in the liver. ↑ In response to inflammation. Binds to phosphocholine on the surface of dead/dying cells, which activates the complement system.
Which cardiac structural abnormality may the presence of a right bundle branch block in a young adult indicate?
Atrial septal defect.
What are some of the causes of a raised MCV?
Drugs (e.g. anticonvulsants, antimicrobials, chemotherapy), Reticulocytosis, Alcohol abuse, Megaloblastic anaemia (e.g. pernicious anaemia, B12/folate deficiency), Artefact (e.g. aplasia, myelofibrosis, hyperglycaemia, cold agglutinins), Thyroid (hypothyroidism), Immature bone marrow cells (e.g. myelodysplastic syndrome), Chronic liver disease.
What is the dose of IV salbutamol in treating life-threatening asthma?
Dose: 3–20 mcg/min.
Side effects: tachycardia, arrhythmias, tremors, hyperglycaemia, hypokalaemia, and type B lactic acidosis.
What are the mechanisms of drug-induced hyperkalaemia?
- K+ supplements (e.g. Sando-K, IV fluids with K+),
- Drugs that impair K+ distribution (e.g. beta blockers, arginine, digoxin, suxamethonium),
- Drugs that ↓ renal K+ excretion (e.g. calcineurin inhibitors like tacrolimus and ciclosporin, potassium-sparing diuretics like spironolactone, eplerenone, some antibiotics like trimethoprim),
- Drugs that impact on the RAAS (e.g. NSAIDs, ACE inhibitors, ARBs, heparin).
