Hemodialysis Flashcards
most appropriate referral to nephrology
stage 3b or 4
rule of 6 in AVF
at least 6 mm in diameter
at least 6 cm of overall needle accessible length
no more than 6 cm below the surface
higher arterial steal phenomenon
side to side anastomososis
advantage of end ro side appeoach
avoidance of venous htn
ideal hd access
high prrimary patency rate instant usability long survival low thrombosis rate low infection rate high blood flow rate patient comfort bathing/hygiene minimize needles minimal cosmetic effect
duration of lack of change on physical examination prognostic of nonmaturation
4 to 6 weeks
most impt monitoring technique
good pe of av shunt
avf has bounding pupsation, inc aneurysm size, does not flatten when arm raised above the head
venous outflow or central venous stenosis
acess placement
gfr < 20
factors influencing effective clearance: small molecules
Small FATmembrane flow (blood/dialysate) area (membrane surface) Time (treatment time) membrane permeability
most impt intrinsic physical feature governing removal
size of molecule
guards against excessive suction on the vascular access
arterial pressure
normal: -20 to 80
gauges resistance to blood return
venous pressure
+ 50 to + 200
affect solute clearance of a hemodialyzer
Increase clearance
- porosity, surface area, hydrophilicity, blood/dialysate flow
decrease clearance
- thickness, molecular weight/size, lipid solubility, protein binding, unstirred layer
varies
-membrane charge
degree to which membrane activates blood components
biocompatibility
min accetable internal fiber diameter
180 mcm
target aluminum level in water
< 10 mg/L
osteomalaciac microcytic anemia, encephalopatjy
direct exposure to this causes hemolysis and methemoglobinemua
chloramine
cardiac arrhythmia and acute death
Fluoride
Hard water syndrome - nausea vomiting weakness flushing labile bp
Excess ca and Mg
target temp of water
77F-100F
quality of dialysis water
lower maximal level of 100 cfu/ml bacteria and a max concn of less than 0.25 eu/ml for endotoxin
action levels
25 cfu
0.125 eu/ml
ultra pure dialysate
bacterial count of less than 0.1 cfu/ml
endotoxin less than 0.03 eu/ml
monitoring of water quality
monthly
post bun sampling
slowing the blood pump to 100 ml/min for 15s, stopping the dialysate flow for 3 mins, drawing sample from dialysate inflow port
clinical conditions with no anticoagulation or reginal anticoagulation
actively bleeding significant risk for bleeding major thrombi static defect major sx within 7 fays intracranial sx 14 days biopsy of visceral organs with 72h pericarditis
Low dose heparin clinical conditions
Major sx beyond 7 days
biopsy if visceral organs beyond 72h
minor sx 8h prior
minor sx within 72h
either low dose or no anticoagulation
major sx 8h prior
to prevent clotting
rinse circuit with heparinized saline
less thrombogenic dialyzer
flush the circuit with 100 to 200 ml 0.9% Nacl every 30 mins
avoid blood or platelet transfusion through circuit
high blood flow rate
limit uf
Mg for persistent intradialytic hypotension
Higher dialysate Mg
Adynamic bone disease
lower dialysate Mg
major complication of bicarbonate dialysate
bacterial contamination and precipitation of Ca and Mg salts
surrogate marker for cardiovascular disease in hd
carotid intimal thickness
reduce plasma isoprostanes and isofurans, markers of oxidative stress and endothelia function
coenzyme q10
surrogates of overall bp status
prehd and post hd bp
htn meds removed poorly with hd
losartan, fosinopril, ramipril, carvedilol, bisoprolol, propranolol
when can false positive hbsag occur
3 weeks
decrease in sbp 20 mmhg or more or a decrease in map of 10 mmhg with clinical events
hypotension
interventions to consider in recurrent intradialytic hypotension
reassess dry wt reduce id Na gain assess id hypoca, hypoK, hypoNg avoid food intake during hd adjust antihtn assess cardiac function cool dialysate extend dialysis time or add sessions sequential Uf or uf remodeling midodrine
measures in dds
- shorter tx times of 1-2h
- lowering blood flow rates to 200-250 ml/min
- Reducing dialysate flow rate, concurrent flow
- dialyzer with small surface area
- Mannitol
pericaridits that occurs within 8 weeks of initiation of hd
uremic pericarditis
dialyzer reaction that occur within 5 to 20 mins and present with pruritus, urticaria, bronchospasm or anaphylactic shock
type A reactions
cause of first use syndrome
IgE antibodies to membrane material or ethylene oxide
Complement mediated, occur later, chest and back discomfort
Type B
chest tightness, back pain, shortness of breath with acute pigmentation of the skin and port wine appearance of the blood in venous line
acute hemolysis
discontinue without blood return
check K, peripheral smear, hgb
screen dialysate and blood tubing for contaminants
foam in venous line
air embolism
tx of air embolism
Stop blood pump clamp venous dialysis line to prevent further air entry administer O2 volume resuscitation keep patient supine
