book and course Flashcards
which infusion in critically ill is most likely to cause hyperglycaemia?
adrenaline
Also raised lactate
what has a faster clearance alfentanil or fentanyl? and elimination half life?
fentanyl
the elimination half life of alfentanils is shorter despite having a slower clearance rate.
this is because its Vd is smaller than fentanyl
whats the armitage rule for caudal anaesthesia in paeds?
bupivacaine 0.25%
0.5 ml kg 1 for sacro-lumbar block,
1 ml kg 1 for abdominal block,
1.2 ml kg 1 for mid-thoracic block
what is the bowman principle?
low potency, more drug, quicker onset
what are the properties of a drug that can be used to measure gastric emptying? example?
100% Bio oral availability
zero stomach absorption
rapid GI absorption
paracetamol - well and rapidly absorbed from small inttestine
how is renal clearance calculated?
[U]x V / [P]
check units
what is the best measure of LV contractility?
LV ejection fraction
during exercise what has the biggest influence on increased O2 delivery?
relaxation of pre capillary sphincters - 20 to 30 fold in skeletal blood flow
(cardiac output is only 5-10 fold)
what is the most important factor contributing to increased oxygen delivery in pregancy?
increased venous return (due to increased vasodilation (progesterone) and increased circulatory volume (oestrogen)
leads to increased CO
in giant squid axon what make resting membrane potential less negative?
permeable only to potassium
using nernst
if you increase outside conc of potassium this will make it more similar to inside - hence less negative .
overall increase K OUTSIDE
how is SVR calculated?
SVR = k x (MAP-CVP)/CO
how is O2 conc of venturi mask calculated of entrainment ratio 1:10?
1:10 = 1 of 100%, 9 parts 21%
if 6L/min this will be increased to 60 L by the entrainment
6L = pure
60L = 21%
(6x1.0) + (60x0.21)
when increasing depth on USS, what happens to wave to optimise image?
longer wavelength, lower frequency
can penetrate to a greater depth
why cant n20 cylinder gauge pressure be read as a measure of contents?
the pressure gauge will read SVP at ambient temp regardless of cylinder contents
if CO2 baseline is raised on anaesthetic machine, what is the most immediate action?
increase fresh gas flow - get rid of CO2 and prevent rebreathing
(then replace soda lime)
