i just wanted a baseline, to know how much to spew forth, lol!
bun and creatinine and egfr (estimated glomerular filtration rate, which factors in pt's age) all provide indications of how well the kidneys are functioning.
as the contrast used in the cath is primarily excreted from the kidneys, one of the risks of doing the exam is cin, or contrast-induced nephropathy. this exhibits as a rise in the creatinine post-cath (or, post-exposure to the iodinated contrast).
our mds prefer gfr >60 and creatinine <1.5 ('normal' range may differ, depending on the lab at each hospital).
they give serious pause to performing a cath on a pt with, say a creat. of 1.8 or higher.
always weigh risk vs benefit.
biggest protection for the kidneys in any case is hydration, hydration, hydration! some recommend 1 liter over 6 hr pre-cath, then another liter post-cath (taking care not to overhydrate a pt who has a reduced ejection fraction [ef], say an ef of 30%.)
role of mucomyst in patients with elevated renal function:
article from journal of the american society of nephrology:
some swear by it, some swear at it.
as presented in the two links above, the jury is still out on giving this pre-procedure. nevertheless, our mds do order it if the creat is elevated (cover all the bases!).
pt/ptt/inr: our mds will proceed with cath if inr <1.7.
if the inr is >1.7 risk of bleeding increases (we are going in an artery!).
we use vascular closure devices unless contraindicated (these are deployed under the skin, right on top of the hole made in the artery. e.g.: angioseal, mynx).
heparin, if infusing when the pt arrives to the lab, is turned off and not restarted till 4-6 hr after the case is finished, to allow the body sufficient time to heal over the hole made in the artery.
cbc - mainly i check the wbc
s (if high, why? if the case is an elective one, best to treat any infection first, then perform the cath when the infection is subdued) and the hgb and hct
(if low, why? is pt chronically low or is this new? if pt has a slow gi bleed, for example, and hgb and hct have been dropping over the past week or two, then gets a stent put in and put on plavix =
can cause massive bleeding! again, risk vs benefit, esp. if the case is elective [not an acute mi coming up for cath from the ed] ).
platelets - usually mds will perform the cath if the plt count is >50k. as we puncture the artery, it is important to have adequate platelets for clotting afterwards!
chemistry - yes, normal k+ level is very important (review movement of lytes across the cell membrane) for decreasing risk of dysrhythmias (or sustain of such that happen during the cath. and they do occur, especially if a catheter is put into the left ventricle to measure pressures or do a left ventriculogram [inject contrast in the left ventricle to see how well the walls move]).
hope this has helped.