Q.535. When to start R.R.T.?
(B)
Hemodialysis
Q.535. When to start R.R.T.?
A. (1) GFR < 15
ml/min. + Sm. (UK-RAG).
(2) GFR < 6 ml/min. + No
Sm. (UK-RAG).
(3) GFR < 15 ml/min. (physician evaluation) (2006 K/DOQI).
Q.536.What
is the A/V fistula and why is it preferred for hemodialysis?
A. An
AV fistula is surgically created by connecting an a. & v..,
the vein grows larger & is able to handle more bld vol.. Us.
an AV fistula is made in the arm/leg so it’s easily accessible for DX.
After several weeks or m.s, fistula matures mak-ing it ready to use for HDX. In March 2005 the Centers for Medicare & Medicaid (CMS) along with other leaders in kidney care community
launched the Fistula First initiative. This initiative ws started
to support better health for Medicare ptns on DX & lower costs for Medicare
program by incr. No. of HDX ptn.s using fistulas as their HDX access.
The A/V fistula
is considered the “gold standard” access because:
1) It is a connection of the patient’s own artery and
vein so it is all natural.
2) It allows for greater
blood flow resulting in better ttt in less time.
3) It hs a lower infection
rate than (A/V) graft or central venous catheter.
4) It hs less risk of clotting
than (A/V) graft or central venous catheter (CVC).
5) It lasts longer
than arteriovenous (A/V) graft or central venous catheter.
6) Costs
associated é
creating & maintaining fistulae are less thn (A/V) graft or CVC.
Q.537. What are the recommendations for vascular access
creation & follow up?
A. Ptn. should be referred to Nephrologist/Surgeon
é 👉 stage 4 CKD (EBPG, 2007):
Permanent
vascular access (in order of 👍 preference) wrist
AVF, elbow AVF, transposed brachial-basilic v. fistula, AVG of
synthetic material (preferably PTFE) (K/DOQI,
2003).
|
Access type |
Time of creation. |
Effective flow. |
Usage. |
Duration. |
Reference. |
|
AVF. |
6 m. bef.
HD.(GFR<30 ) |
> 600
ml/min. |
>one m. |
>3 y. |
2003
K/DOQI |
|
AV Graft. |
3-6 w. bef. HD. (GFR <30 ) |
> 800 ml/min. |
2-3 w. |
> 2 y. |
2003
K/DOQI |
|
Cuffed Catheter |
At time of HD. |
> 300 ml/min. |
Immediately. |
> 3 w. |
2003
K/DOQI |
Q.538.What are the benefits of early referral
to the Nephrologist?
A. Early referral is mandatory for:
(1)
Slowing Progression rate of CKD.
(2)
Patient counseling & Education.
(3)
Reduction of co-morbid load.
(4)
Choice of dialysis modality.
(5)
Vascular access
creation.
(6)
More compliance to
treatment.
(7)
Pre-emptive transplantation.
(8)
Better outcome of early
dialysis.
(9)
HB.V. vaccination in
pre-DX. 🠊 Good immune response.
(10)
Non-emergent initiation of DX.
(11)
Lower morbidity & improved rehabilitation.
(12)
Less frequent & shorter hospital stays.
(13)
Lower cost.
(14)
Improved survival.
Q.539. How
to prescribe acute hemodialysis? R/
A. RRT in
ARF indicated é: [volume overload refractory to
diuretics, hyperkalemia, metabolic acidosis, uremia & toxic drug overdose].
Once decision of DX. is made, sp. Modality of dialytic support should
be chosen: P.D. or H.D. & H.F., etc. &
DX.
prescription is determined. When Ac. HDX. is chosen as
dialytic support, vasc. access must be established prior to ttt.
Placement of venous cth. shd be
considered. Optimal choice of DX membrane in ARF, is unclear.
Biocompatible membranes is suggested. If water system is
of high quality, high flux biocompatible membranes shd be
used. But, low flux biocompatible membranes or prefilter added to
DX machine shd be used if water system is not of high quality. Dzt.
sol. consists of: [K, Na, HCO3, Ca, Mg, Cl. & gluc.]. Dzt. composition in Ac. HDX is
routinely altered each ttt to correct metab. abn. in ARF. There’s No
fixed Dzt. K+ conc. in Ac. HDX. bec. of
wide variability in s. K+ prior to start of HDX.
Typical K+ in Dzt. for Ac. HDX ranges fr. 2-4 meq/L. Dzt.
bath k+ is deter-mined by both absolute pre-DX. K+ &
rate of rise in the interdialytic period. Rapid rate of rise of s. k may
best be ttt by daily HDX rather thn lowering Dzt. K bath. HDX can 🠊 ventricular
arrhythmias, due to DX-induced K+. They’re associated é num-erous
risk f. e.g. CAD, LVH, digoxin use, systolic
B.P.& advanced age. It’s recomm.: cardiac ptn in Ac. HDX shd be placed on a
cardiac monitor dur. DX.
Dzt Na+🠊 significant
impact on ptn. vol. & hemodynamic status. Dzt HCo3
shd vary é acid-base status. Us. Dzt HCo3 in
ch. HDX = 33-35 meq/L.
High conc. HCo3 shd be used é moderate metabolic acidosis
. Severe acidosis🠊conc. maximized (eg,
40 meq/L)& extended duration of HDX may be
necessary. Ac DX ptn cn also be alkalotic. Severity of alkalosis &
process generating alkalosis Ømain
issues to help determine optimal Dzt HCo3.
It’s recommended adjusting Dzt Ca+ to avoid hyperCa+ or
clinical hypo-Ca+. DX. QB of 400 mL
/minute.
If lower QB is required due to hemodynamic instability, best
modality is unclear, slower solute removal é 6-12
h. (SLED/CCRT), is suggested. U.F. goals in ARF can be
challenging. Target intravascular vol. will guide U.F. goals for I.HDX.
U.F. can intradialytic
Hpt, ttt by 🠋UF
rate by 🠝frequency
of ttt and/or
during
of ttts, as well as Na/UF. profiling & using cool °C Dzt. I.HDX provided at least 3-times/w.
é monitoring of delivered dose of DX to ensure Kt/V of at least 1.2/ttt
. However, more frequent DX may be needed for: intractable hyperk+,
vol. overload, or sev. Hpt.
Q.540.What
are the general considerations of vascular access in chronic H.DX.?
A. Three 👌 main
forms: native A/V fistulas, synth. Grafts & double-lumen tunneled
cuffed cth.. AV fistulas: constructed é
end-to-side v.-to-a. anastomosis between a. & v. Synth. grafts: constructed by
anastomosing synth. conduit betw. a. & v..
Tunneled cuffed cth.: dual lumen, composed of silicone or
polyurethane composites. Fistulas & grafts differ é failure rates,
time to use, patency, complications & perioperative
morbidity. Fistulas: more likely to hv. Iry failure never
provided reliable access for H.DX. Despite this, long-term patency
of mature fistulas is superior to grafts. Common comp.:
fistulas & grafts including: thrombosis, infection, steal, aneurysms, venous
H.T, seroma, H.F.& local bleeding. Thrombosis, infc. &
seromas occ. more freq. é grafts . Iry adv.
of tunneled cth. immediate
access for all ptn.s, but main disadv.: risk of infc., malfunction &
C.V. stenosis. H.DX. AV fistulas: generally associated é 🠋 M.R.
compared to grafts & tunneled cth., while HDX. cth. the worst survival
rates.
A.V
fistulas: preferred over
all other forms of V. acc, due to many benefits. They’re ass. 🠋M.R. & comp. to
grafts & cth.. After fistulae, grafts are next preferred.
Tunneled cth.🠊 least
desirable access & shd be primarily used as intermediate-duration
vasccular access to allow maturation of fistulas or grafts. To achieve a
well-functioning fistula é initiation of DX., timely referral for
surgery is important. Minimum time for fistula
maturation is one m., but may require up
to 6 m.
If neither radiocephalic nor brachiocephalic fistula
is possible, a transposed brachiobasilic shd be
considered. If fistula is not possible, a graft shd be
considered. It’s debatable whether a transposed brachiobasilic
fistula shd be offered before a lower forearm graft. HDX cth.: the least preferred form 😌 of chronic
access.
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