Predicting Hypotension During Dialysis in the ICU

Study Overview
=================
Brief Summary
-----------------
Currently, decisions regarding volume management for dialysis sessions in the ICU are made in large part on the nephrologists'/intensivists' overall gestalt. This gestalt is based upon a combination of commonly used measures of circulatory function, the physical exam, fluid balance, estimates of dialysis dry weight, and monitoring changes in relative blood volume status using devices such as the Crit-Line™ III, and central venous pressures. However, these tools perform poorly in predicting the circulatory system's overall response to dialysis. Consequently, episodes of dangerously low blood pressure are still frequently encountered. Better techniques to predict the circulatory system's response to dialysis are much needed. The intent of this study is to test newer metrics of circulatory system function for their ability to predict low blood pressure episodes during dialysis. This is important because it may enable the design of newer treatment strategies created to prevent low blood pressure episodes during dialysis and improve patient outcomes. The investigators overall hypothesis is that newer measures of vascular volume and dynamic indices of fluid responsiveness, previously found to better reflect cardiac preload state than currently used parameters, will better predict low blood pressure episodes during dialysis than current methods.

Official Title
-----------------
Predicting Hypotension During Dialysis in the ICU

Conditions
-----------------
Peridialytic Hypotension

Intervention / Treatment
-----------------
* Procedure: Transpulmonary Thermodilution


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Admitted to OHSU Hospitals ICUs Patient has acute or chronic needs for intermittent hemodialysis support during their ICU stay for any reason other than isolated hyperkalemia Central venous access in place separate from the dialysis catheter, or arteriovenous fistula or graft Two or more organ systems affected by critical illness requiring supportive care as documented in the medical chart. Exclusion Criteria: age younger than 18 years old Weight > 160 kg burns greater than 40% total body surface area known cardiac or vascular aneurysm contraindications to femoral arterial puncture diagnosis of peripheral vascular disease not committed to full support participation in other experimental medication trial within 30 days current atrial or ventricular arrhythmias history of sever CHF- NYHA class >= III, previously documented EF < 30% severe aortic regurgitation anticipated ICU stay < 24 hrs not expected to require dialysis > 48 hours

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| ICU Dialysis Patients<br>Any patient 18 years and older who is admitted to the OHSU Hospitals ICUs with ARF, or End Stage Renal Disease (ESRD) for a diagnosis other than hyperkalemia, as the sole determinant for that level of care, will be invited to participate. The patient must have acute or chronic needs for dialytic support during their ICU stay. | Procedure: Transpulmonary Thermodilution<br>* A PiCCO femoral catheter will be placed and PiCCO parameters will be obtained using transpulmonary thermodilution after continuous dialysis is ordered or just prior to initiation of intermittent dialysis, hourly until either completion of intermittent dialysis or 8 hours of continuous dialysis is completed.<br>* Other names: PiCCO;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| hypotensive episode | A mean arterial pressure of <60 mmHg, a 15% decrease from baseline systolic blood pressure at the start of the dialysis treatment regardless of modality, the need for fluid bolusing >7 mL/kg body weight, or initiation or increase of vasopressor medication in order to maintain MAP >60 mmHg. | during or within one hour post dialysis | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| fluid removal tolerance | Parameters measured will be examined to discriminate between patients that will tolerate fluid removal (UF) during the following 4 hours of dialysis if UF is ordered by physician (no hypotensive events with > 500 mL fluid removal) from those that won't | during the 4 hours following parameter measurement in dialysis | 
| predicted volume of fluid that can be removed without hypotensive events | Parameters measured will be examined to see if they can predict the volume of fluid successfully removed without hypotensive events | during dialysis | 
| mortality in the ICU |  | duration of ICU stay | 
| All cause mortality |  | 30 days | 
| Length of stay in ICU |  | ICU stay duration | 
| Length of stay in hospital |  | duration of hospital stay | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
hemodialysis, dialysis, hypotension, CritLine, PiCCO, Thermodilution, CVVHDF, IHD