First, I would be wondering about whether her dry weight is correct. If her dry weight has been set too low and, thus, more fluid is being removed than her circulation is set to permit, then an exaggerated fall in blood pressure or a 'crash' is more likely. Certainly, in the general dialysis population, the removal of too much fluid -- or, and I keep coming back to this point, its removal too quickly -- is the commonest reason why blood pressure might fall or crash during dialysis.
You need to remember that patients change their base weight, just as you and I do. Just as we put on a kilo or two, and then take it off again, so, too, do dialysis patients. We, as the treating team, need to “roll” with these changes and make adjustments accordingly, otherwise we will be caught out by taking off too much fluid -- or taking off too little. No patient sustains the same dry weight, week in, week out. Here, we are constantly looking at BP changes and other signs that might indicate a change in dry weight. This is probably the first thing I would be thinking about.
I am assuming that the BP you have given (140-160), is her pre-dialysis blood pressure. Though a little on the high side, this is not a blood pressure that would be troubling me too much as an entry (pre-dialysis) blood pressure -- I would be more troubled by a blood pressure fall from this level to 94/50 during the dialysis treatment.