Hypotension -- a Post-AVG-Revision (to be continued)

This lady has a Left Arm AVG.
AVG blocked on the normal haemodialysis day, came to ward through ED, had anti-hyperkalemia therapy(resonium 30g, IV 50% Dextrose 50mls and IV Actrapid insulin 10units) and fasted overnight.
AVG revision in the morning, finished at 12pm. Then, start to dialysis. in the end of the dialysis, graft started to bleed a huge amount, spent 30mins pressure, bleeding stopped, but AVG stopped working.
1730, pt went to OT for urgent AVG revision again.
1930, back from recovery, had N/S 600mls in recovery. AVG bruit but frank thrill. BP(110/50mmHg, pt asymptomatic) low range, pt's normal BP around 120~130/60~70mmHg, MO ordered to recheck in 1/2hr.
2000, BP still low (104/50mmHg). MO ordered Gelofusine 500mls over 2hrs.
2030, Recheck BP, still low, AVG bruit but still frank trilll. Increase rate to 500mls over 1 hrs as MO ordered.
2100, 300mls Jelofusion infused. BP even lower (90/40mmHg, still asymptomatic), AVG bruit but very frank thrill....MO, close monitor AVG and BP, review again when Jelofusion finishing. No bleeding since back from recovery.

?Problem: Vascular Colloid Pressure decreased due to blood loss from 2*OT and post dialysis even N/S 600mls. But why Gelofusine as a IV colloids didnt build up BP after infusion?