HD Flashcards
indication of starting RRT?
intractable FO / HT refractory hyperK refractory acidosis refractory anaemia unexplained functional decline weight loss or nutritional status deterioration
urgent: neuropathy, encephalopathy, pericarditis, pleuritis, bleeding tendency
benefit of early start RRT?
IDEAL: 9ml vs 7ml no change in QOL or survival
What is extraction ratio?
(inlet - outlet)/ inlet urea concentration
What is clearance?
volumn of blood cleared of solute in certain period of time
relationship of extraction ratio and clearance?
extraction ratio x Qb = clearance
but higher Qb has lower ER
What is K0A
mass transfer area coefficient, clearance at maximal Qb and Qd
depends on area and membrane permeability
as dialyzer clearance
<500ml/min low, >800ml/min high
What is flux
Kuf water permeability, to measure ability to remove large molecule
high flux >20ml/hr, low flux < 8
how to measure spkT/V
stop UFR
slow Qb to 100ml/min, wait 30s
or stop Qd and wait 3min
what is cardiopulmonary recirculation
blood from outlet returns to inlet through heart and lung without going through capillary bed again
usually 5 - 10% less efficient
what is ekT/V
measure post dialysis urea 30min after RRT after urea rebound to calculate kT/V
how to measure residual Kru
urine vol x urine urea / serum urea x (24hr x 60min)
what is stdkT/V
to normalize kT/V so not dependent on number of treatment used
target spkT/V?
3x HD: min 1.2 target 1.4
2x HD: min 1.8 target 2.0
ultrapure dialysis solution requirement?
bacteria < 0.1 cfu / ml
endotoxin < 0.03 eu/ml
aluminium toxicity symptom?
EPO refractory anaemia, dialysis encephalopathy syndrome, bone disease
aluminium source in HD patient?
from aluminium pipe
chloramine toxicity symptoms?
hemolysis
source of chloramine
in water as bacterstatic, increase if depleted carbon bed
fluoride toxicity symptoms?
puruitis, VF, nausea
fluoride source in HD?
depleted deionizer
standard HD dialyzate composition?
Na 135 - 145 K 2 HCO3 26 - 36 Ca 1.25 - 1.75 Mg 0.25 - 0.375 glycose 5.5 acetate 3 - 8
preparation for AVF?
preserve arm veins avoid CVC / IV drip / PPM
Hx: DM / PVD, CHF
P/E palpate pulse, bil arm BP, allen test, edema / collateral vein / size discrepency
Imaging: USG doppler:
- minimal vein 2.5mm, minimal arterial size 1.5mm, arterial / vein dilatation test, mapping
venogram / arteriogram if indicated
AVF sites?
conventional:
- snuffbox
- radiocephalic
- ulnar-basilic
- brachiocephalic
transposed:
- forearm cephalic to proximal radial / brachial
- forarm basilic to radial / brachial
how to assess AVF ready to use?
rule of six: 6 weeks maturation 600ml/min flow < 6mm away from skin surface > 6mm in diameter 6cm length
AVG site?
radio-basilic (straight)
brachial basilic (loop)
brachial axillary
A and V needle position?
inlet: distal, 3cm from anastomotic site, point downstream
outlet: proximal, 5cm (or ?2.5cm) away from inlet, point downstream
buttonhole technique pros and cons?
increase infection and does not prolong AVF survival
how long to press after cannulation AVF?
10min prolonged bleeding (>20min) suggest outflow stenosis
complications of CVC insertion?
arterial puncture pneumothorax / hemothorax arrhythmia, perforation of cardiac chamber, tamponade air embolism retroperitoneal hematoma
Watch out if chest pain / SOB / hypotension after starting HD
delayed complications:
thrombosis, infection, central vein stenosis, AVF
injury to brachial plexus, recurrent laryngeal nerve
care of CVC?
sock catheter hub and connectors in antiseptic x 5min (chlorhexidine >0.5% better than povidone iodine), dried then disconnect
scrubbed with chlorhexidine and covered with dry dressing
avoid bathing
1000 - 5000 unit/ml heparin priming
flush with heparinizaed saline (100unit/ml) before use
vancomyin / gentamycin lock controversal
ES mupirocin ointment reduced CRBSI and cath survival but increase resistance
AVF stenosis features?
P/E: pulse augmentation fail: inflow stenosis
arm elevation fail to collapse: outflow stenosis
occluding access between A and V needle, if AP / VP worsen will suggest inflow / outflow stenosis
HD: increase recirculation > 10%, prolonged bleeding, high AP / VP > 120mmHg if 15G or 150mmHg if 16G
saline dilution
doppler, < 600ml/min for AVF, < 1000ml/min for AVG
intra access pressure: A limb > 75% MAP, V limb > 50% MAP
AVF stenosis Tx?
angioplasty if > 50%, +/- stenting (more in AVG)
AVF thrombosis Px?
DAPT ? warfarin
AVF steal feature?
cold, weakness, numbness extremities
AVF with numbness ddx?
CTS, VPD, neuropathy
AVF steal Tx?
DRIL, banding
AVF pseudoaneurysm s/s?
thin / shinny skin, prolnoged bleeding, ulcer, increasing size suggest impending rupture
AVF pseudoaneurysm Tx?
stenting / surgery
AVF infection Tx?
Abx x 6 weeks, remove if embolic
AVG infection Px and Tx?
prophylactic Abx if dental, genitourinary OT
cover both SA and GNB
remove AFG if within 30 days of placement
CHF with AVF ddx
anaemia, minoxidil / hydralazine without BB use
CVC MSSA ESI Tx?
topical mupirocin / oral Abx nasal decolonization (IN mupirocin bd each nostril x 5 days)