Intradialytic Hypotension (IDH) ... what can we do about it?

Hi team,

time for some basic dialysis stuff for revision. I'm revising on intradialytic complications now and one of the commonest complication is IDH (intradialytic hypotension).

Usually occurs for one of three broad reasons:

1) Patient is below dry weight (q.v.)
2) Fluid removal is faster than redistribution can occur (eg, too large weight gains, unstable circulation)
3) Some effect of dialysate/ membrane/ extracorporeal circuit on cardiac output and/or peripheral resistance

... and of course sometimes anti-hypertensive accidentally served in the morning!

What can we do?

1) Advise patient about fluid, salt, etc

2) Review dry weight

3) Consider longer, slower dialysis (unpopular with patients understandably)

4) Consider serial ultrafiltration followed by isovolaemic dialysis (lengthens dialysis again; can be used for a time to get nearer to dry weight)

5) Review haemoglobin (effect of anaemia possibly via cardiac oxygenation)

6) Consider providing oxygen during dialysis

7) Tricks with dialysate:
(a) cooling (causes increased peripheral resistance);
(b) sodium profiling, or ramping, in which the dialysate sodium is altered during dialysis. A higher dialysate Na reduces hypotension (probably by maintaining ECF osmolality) - but reduces Na removal. Start high Na, lower Na later helps (ie linear profiling). Ultrafiltration rate can also be profiled on some machines.

8)Avoid eating and drinking before/during dialysis (reduces peripheral resistance by causing splanchnic vasodilation)

9)Omit hypotensive agents on the morning (or evening) before dialysis

10) Oral midodrine, an a1 adrenergic agonist (I don't think it is available here though)

11) Consider haemofiltration or haemodiafiltration (different membranes, but in the case of haemofiltration, also usually a slower treatment - and possibly with more cooling of blood)