Live blogging ADC Managing Intradialytic Hypotension

Bill is blogging live - here's one article - check out his site for more.

Live blogging ADC Managing Intradialytic Hypotension
By Bill Peckham

Intradialytic Hypotension is experienced at some point by just about every dialyzor. Feeling faint, nauseous, cramping are some of the effects but those are just the tip of the proverbial iceberg, and while these symptoms are bad enough the hidden damage to the body can be of greater consequence.

I'm somewhat knowledgeable on the topic but, writing now, after the session, I realize that there is a lot of it I still need to learn.

Managing Intradialytic Hypotension (IDH): What Works? John Daugirdas, MD, Presiding
4.45 - 6:00pm

4:45
The Role of Frequency and Time in Prevention of IDH
John Daugirdas, MD
"When I was assigned this topic I thought it was a dud because it is obviously true but I thought I would review what we know." Presents the patient characteristics enrolled in the HEMO study, reevaluating data defining IDH interventionally as a change in UFR or Qb during the run; the HEMO study participants experienced IDH during 17% of the runs, 7% cramped. It is tricky to define IDH in terms of BP, however cross comparisons showed that defining IDH in terms of intervention (change in UFR or Qb) indicated that IDH occurred most often when the systolic BP decreased 40%. SBP decreasing by 10% resulted in just 2% of the interventionally defined IDH.

UFR was not hugely relevant in terms of IDH in the HEMO trial, session length had no correlation. Older people had higher incidence of IDH; diabetes also correlated to a 30% increase in IDH among participants of the HEMO study. Predialysis SBP was a major factor. Recognizing that there may be confounding by indication - "If that's the right word. Sometimes statisticians like to use a word we're not sure of the meaning"

Analysis did find a relationship between IDH and mortality but when you look at IDH in terms of starting BP it revealed the BP is confounding the results. Two other studies found that IDH was associated by with survival. High SBP looks to be protective to a point. Changes in SBP during dialysis is revealing.

Myocardial stunning is a frequent occurring event, those that manifest myocardial stunning have wider changes in SBP and low SBP is associated with myocardial stunning. In these events not only does the heart get stunned but the brain gets stunned too and patients may manifest gut ischemia. These impacts could result in more falls particularly in elderly patients.

Among people with residual renal function (RRF) high or aggressive UFR could have a big impact on RRF. Many positive impacts flow from RRF - (wow he is going fast). Aggressive UFR - "challenging dry weight" for instance - can impact RRF, given RRF's value, it should be done with care.

Studies constantly show a strong correlation between high UFR and IDH. Few papers look at frequency and IDH - the FHN did find episodes of IDH disassociated from UFR, perhaps because UFR has less impact during the first two hours.
5:05
How does Diastolic Dysfunction Impact IDH? Roberto Pecoits-Filho, MD

Investigation indicates that perhaps we should expect heart damage in all people who have had a prolonged decline in kidney function prior to starting dialysis. Shows slides revealing myocardial fibrosis (MF) among people starting dialysis. PTH does correlate to MF as does hypovitaminosis aside from issues with PTH.

Systolic dysfunction can occur but diastolic dysfunction is worse and harder to identify. Diagnosing DD is tricky - the optimal exam is the echocardiogram because the ejection fraction may not change. 81% of patients present echo signs of DD and DD is highly prevalent in APPKD. Left atrium enlargement correlates to IDH.

CHF is the prime cause of mortality. Left atrium volume correlates to CHF and IDH correlates LAV thus can IDH can be a marker for who is at risk for CHF given the difficulty in providing regular echo cardiograms...
I need a pause button. I have to stop live blogging to pay attention ... this is very interesting but the info is coming too fast. He covered interventions and additional markers. I think I am missing the implications of the data being presented.

5:25
Has HD Technology Helped To Reduce the Incidence of IDH? Andrew Davenport, MD

Reviewing history of studies of blood volume monitoring, early studies were promising but later RCT undercut the early results. Looking at possible explanations - one is capillary changes during dialysis.

Presents data that dialysate sodium varies greatly and is often not what is expected (WOW! That explains a lot). The machines say one thing but independent testing reveals that the machines lack the sort of accuracy one would want.
I was gobsmacked by Davenport's data on the variabity of sodium among units, among machines, among batches and even during a run using the same batch ... I'll need to revisit this.

http://www.billpeckham.com/from_the_sharp_end_of_the/2011/02/live-blogging-adc-managing-intradialytic-hypotension.html