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)
indication for CVC removal in ESI?
tunnel tract collection, persistant / recurrance ESI, systemic sign, blood C/ST +ve
CRBSI Tx?
empirical Abx (vancomycin 20mg/kg then 500mg post each HD) / cefazolin 20mg/kg post HD + gentamycin 1mg/kg post HD / fortum 1g post HD)
with antibiotics lock (vancomycin 2.5mg/ml or gentamycin 1mg/ml) mix with 5000 unit/ml heparin
if C/ST -ve: stop antibiotics
if bacteremia / fungemia clears:
- CnS: 2wks abx or guidewire exchange
- GNB: 2wks abx or guidewire exchange
- SA: 3 wks abx + CVC removal if TEE -ve
- Candida: 2 weeks abx + CVC removal
- PA: 3wks abx + CVC removal
if bacteremia persists:
- CVC removal + rule out mestatic infection (IE, OM, epidural abscess, septic arthritis) + 4 - 6wks Abx
guidewire exchange only if s/s CRBSI clears and not SA / PA / candida
indication for removal in CRBSI?
septic emboli, septic shock, tunnel tract infection
CVC poor flow causes and Ix and Tx?
early dysfunction:
kinking, edema compressing on catheter (resolve in 24hr), malposition, improper tip, neck position, intracatheter thrombosis
Ix: CXR
Tx: try alteplase 1mg/ml x 2mg +/- filling NS and dwell x 30 - 60min, or try infusion 1mg / lumen / hour
late dysfunction:
fibrin sleeve, mural thrombus: treat by balloon angioplasty to tunnel
Central vein stenosis s/s and Ix and Tx?
limb / neck / face edema, neck collaterals, high VP, prolonged bleeding
Ix by angiogram
Tx by angioplasty, stenting, bypass, AVF ligation
Acute HD URR target / kT/V target and how?
URR 40% esp if urea > 44
BFR 200ml/min, 2 hour Tx time, relatively low efficiency (500 - 600) dialyzer
then aim kT/V > 1.3, assume 3x / week HD
acute HD dialyzate HCO3 setting?
if respi alkalosis / acidosis: aim normal pH with low or high HCO3
if acidosis < 10 HCO3: use HCO3 20-25 to avoid hypoCa, acidification of CSF and lactic acidosis
also consider HCO3 4 from acetate
acute HD dialyzate Na setting?
If Na > 130: aim dNa 140-145, dNA - sNa < 10
If Na < 130:
use CVVH, or correct hypoNa first
or use 100ml/min BFR, lowest dNa setting, HD x 1-2hours
if hyperNa: dNA - sNA < 5 to avoid cerebral edema / spasm,
acute HD dialyzate K setting?
most 2, 2.5 or 3.5 if prone to arrhythmia / on digitalis
acute HD dialyzate Ca setting
1.25, though 1.5 might have less hypotension
acute HD dialyzate Mg setting?
0.375, 0.25 more IDH
hypoMg in HD causes?
TPN, malnorish, PPI, diuretics
acute HD dextrose setting?
5.5, higher 11 has less K removing effect
acute HD PO4 setting?
1.3 if hypoPO4 as can cause respi arrest
or correct PO4 first
acute HD UFR aim?
10ml/kg/h
cause of inflow sucking and Mgt
CVC: tip malposition, fibrin plug
- move neck, AV exchange, urokinase lock, stripping
AVF: improper A needle position low BP AVF vessel spasm inflow stenosis A needle clotting A line kinking access collapse needle too small - redue BFR, check BP, A needle manipulation, evaluate for inflow stenosis
cause of high VP
small V needle
clotting venous bloodline filter
outflow stenosis
improper needle prosition
ekT/v target ?
usually 0.15 lower than spkT/V
stdkT/V target?
2.1
suboptimal kT/V cause and Tx?
poor access
large patient
interruption of HD session
high flux vs low flux benefit?
HEMO: no survival benefit
but if on longer dialysis > 3.7 years survival better, also less CV mortality
European MPO same
chronic HD K setting?
2, 3 unless pre HD hypoK or on digitialis, 1 is associated with cardiac arrest
optimal total cholesterol level?
5.2-6.5
IDH causes?
volume related: - DW too low - high IDWG - short dialyzate time vasoconstriction: - Anti HT - autonomic dysfunction - aneamia - eating during HD - dialyzate temp too high cardiac - diastolic dyfunction - tamponade - MI Others - septicaemia - hemolysis - hemorrhage - air embolism - dialyzer reaction
IDH Drug Px:
midodrine (alpha agonist) before HD (CI if IHD)
sertraline (SSRI)
fludrocortisone if low aldo
type of dialyzer reaction, sym and cause and tx?
type A: IgE related
sym: fever, rash, SOB, abdo pain, diarrhea, cough, running nose
cause: ethylene oxide, AN69 + ACEI, endotoxin / bacteria, heparin, unsubstituded cellulose membrane
type B: complement related
sym: chest pain, back pain
cause: non biocompatible dialyzer membrane
Tx: stop HD, clamp line, H2R / steroid / adrenaline
sym and cause and Tx of hemolysis in HD?
sym: SOB, chest pain, back pain, pot wine blood in venous line
mechanical: tube kinking, small needle under high BFR
dialyzate related:
- too hot
- hypotonic due to insufficient substrate
- chloramine contamination
- copper / zinc / formaldehyde, bleach, fluoride, nitrate, H2O2
Tx: stop HD, clamp line, treat hyperK, anaemia, test dialyzate water
air embolism sym and cause in HD?
sym: LOC, convulsion, chest pain, SOB, arrhythmia, foam in venous bloodline
cause: disconnected tubing with v negative AP
Tx: clamp bloodline, lean on left side with head down
dysequilibrium sym and Tx and Px?
sym: headache, confusion, convulsion
Tx: reduce BFR or stop HD, ? hypertonic saline / manniotol
Px: URR 40% if urea high, dialyzate Na not lower than serum Na > 3
muscle clamp in HD ddx and Tx?
ddx: - vasoconstriction of vessel to muscle - hypoCa - hypoK Tx: - hypertonic saline / D10, massage, nifedipine Px: - stretching, increase dialyzate Na, high dialyzate Mg .5, carnitine, oxazepam, Vit E, NOT quinine
nausea in HD ddx?
dysequilibrium, dialyzer reaction, IDH, gastroparesis
itchiness in HD ddx?
high CaPOt production, PTH high, inadequete kT/V, dialyzer reaction
uremic puruitis Tx?
adequete kT/V, CaPO4 control
ointment, gabapentin (300mg daily), UVB, charcoal 6g/d, Nalfurafine (K opioid agonist), Naltrexone (mu opioid antagonist), FK ointment, acupuncture
RF for HD clotting
low BFR, high Hct, high UFR, access recirculation, blood / lipid infusion, drip chamber
signs of HD clotting
dark blood, black streak in dialuzer, foaming in drip chamber, rapid filling of transducer monitor with blood, teetering (blood in venous line fall back into line segment), clot at inflow dialyzer header
high AP / VP
dialyzer clotted fiber (< 10% grade 1, < 50% grade 2, > 50% grade 3)
agent for anticoagulation in HD?
unfractionated / LMWH, trisodium citrate, direct thrombin inhibitors (argatroban), heparinoid (fondaparinux), prostanoid, nafamostat maleate (synthetic serine protease inhibitor)
heparin S/E?
bleeding, thrombocytopenia (HIT1: time and dose dependent, HIT2: formation of heparin plt factor 4 Ab), allergy, alopecia, osteoporosis, hyperlipidemia, hypoaldosteronism
how to monitor anticoagulation in HD?
APTT (unfractionated)
whole blood partial thromboplastin time (WBPTT): blood + thrombofax to accelerate clot, for unfractionated
activated clotting time: blood + siliceous earth, for unfractionated
activated factor Xa: for LMWH
activated ACT factor Xa
alternative method if bleeding risk high in HD?
heparin free / heparin rinse heparin coated dialyzer high BFR and low UFR smaller area dialyzer citrate containing dialyzate
SLED vs HD?
BFR 200, DFR 100 - 300
indication of CRRT than IHD?
hemodynamic unstability
grossly abnormal biochemistry
large amount of fluid removal (ARDS, APO)
head injury, high ICP
C HD typical BFR and DFR?
BFR = >3x DFR, ~ 150
DFR 20-25ml/kg/h
what is filtration fraction?
UFR / BFR x (1 - hct)
target of fitration fraction in HF?
< 25%
how to maintain fitration fraction?
increase BFR, reduce UFR
predilution mode
CRRT dialyzate setting?
Na 140 (unless trisodium citrate use) K 0, 2, 4 to avoid arrhythmia PO4 0 or 1.3 Ca 1.5 - 1.75 (0 if RCA use + Ca infusion) Mg 0.5 glucose 5.5 room temperature
target of CRRT?
20-25ml/kg/h
aim average urea 16
SLED target?
weekly kT/V 3.9
citrate toxicity sign?
HAGMA, Total Ca / ionized Ca > 2.5
home HD setting?
buttonhole technique alt day HD Duration 6 - 10 hours high flux dialyzer Qb 200 - 300 Qd 100 - 300 Na 135 - 140 K 2 HCO3 28 - 33 PO4 0.32 Ca 1.5
Effect of frequent NHD?
FHN Nocturnal trial: loss of RKF higher if more than 4.5x / week total time > 28 hours
better survival, BP and PO4 control, less LVH
contraindication to NHHD?
patient factor: uncompliance, psychiatric issue
comorbid: seizure, hypoglycemia, IDH
access problem
home environment
predilution and post dilution HDF pros and cons?
predilution: allow lower BFR, reduce fouling, but reduce solute clearance, increase substitution fluid use
post dilution: high solute clearance, use less substituion fluid, but increase clotting and fouling
HDF setting?
access with BFR 350 - 400
dizlyaer high flux > 50ml/hr, high sieving coefficient B2M > 0.6, high SA 1.6-1.8m2
Ultrapure dialyzate (with 2 RO)
UFV 20 - 24L (post dilution), x2 (pre dilution), x1.3 (mixed)
Na, K, Ca, Mg, HCO3 same as HD
heparin anticoagulation given at venous port
clinical benefit of HDF?
less IDH might preserve RKF lower CRP no effect on anaemia, nutrition reduce B2M amyloidosis and CTS CONTRAST: 21L UFV no survival benefit ESHOL: 23-24L UFV improve overall survival
how to estimate plasma volume?
40ml/kg
0.07 x BW x (1 - Hct)
indication of FFP as replacement fluid?
TTP / HUS
high bleeding risk
low pretreatment fibrinogen level
multiple closely space treatment
complication of plasmaphoresis?
vascular acess: hematoma, pneumothorax, retroperitoneal bleed, local infection
procedure: hypotension, coagulopathy, edema, hypersensitivity, hypoK, hypoCa
anticoagulation: bleeding
replacement fluid: anaphylaxis (FFP)
pre-caution of TPE?
stop ACEI 1-2days before TPE
IVIG 100 - 400mg/kg if infection
TPE setting for Anti GBM?
1.5-2 PV x 2 weeks or until Anti GBM -ve and lung hemorrhage subsides
FFP replacement if hemorrhage
TPE setting for TTP?
1 PV daily till plt and LDH normalize / 7 - 10 days,
full FFP replacement
TPE setting for ANCA?
MEPEX: 60ml/kg replacement daily till hemorrhage subside, then alt day for total 2 weeks
TPE indication and setting for SLE?
life threatening SLE: crescentic LN, lung hemorrhage, cerebral lupus, catastrophic APS
1-1.5PV x 7
TPE setting for recurrent FSGS
1-1.5PV x 5
acute confusion in HD patient?
Bleeding: ICH Infraction: CVA, air embolism Metabolic cause: hypogly, hyponatremia, hypercalcemia, dysequilibrium Hypotension: high UF, arrhythmia, MI Infection: CNS Hypertensive encephalopathy Anaphylaxis: dialyzer reaction Aluminium toxicity Drug: antibiotics, antiviral, opiates, anticonvulsant
