Cardiac Output and Central-Venous Oxygen Saturation in Maintenance Hemodialysis Patients

Oxygen saturation study

Little scientific literature exists to clarify the relationship between blood oxygen levels and cardiovascular function in hemodialysis patients. During the hemodialysis process, blood pressures can vary greatly in some patients. Patients can also have respiratory difficulties and a decrease in cognitive function. This study will monitor the participant’s oxygen status and cardiovascular functioning throughout dialysis to identify patients with low blood oxygen (hypoxia). The research will further examine associations between hypoxia and cardiovascular and arterial functioning using the following measurements.

  • Blood Pressure: Blood pressure will be measured before the start and every 15 minutes throughout the dialysis session by an automated cuff. The cuff will be placed on the non-dialyzing arm of the patient.
  • Heart Rate Variability: Beat-to-beat heart rate (HR) will be recorded using a modified CM5 EGG configuration (Task Force Monitor). The EGG will be collected online at a sampling rate of 1 .000 Hz. The heart rate and the variability of the intervals between successive heart rates will be derived from the EGG signal.
  • Beat-to-Beat Blood Pressure: Beat-to-beat peripheral BP will be derived via finger   plethysmography (Task Force Monitor). A finger cuff will be placed around the non-dialyzing index and middle finger. These cuffs will measure the change in blood pressure from successive beats continuously.
  • Cardiac Output: Cardiac output and stroke volume will be measured continuously for the duration of your dialysis session using the task force monitor. An electrode will be placed around the chest to continuously measure changes in impedance.
  • Relative Blood Volume and Hematocrit: Blood volume and hematocrit (the percentage of cells in your blood) will be measured using a noninvasive device known as a Crit-line In Line Monitor. The Crit-Line non-invasively measures hematocrit, relative blood volume, and oxygen saturation in real A trained staff member of the C-U Dialysis Clinic will add a disposable blood chamber to the dialysis machine. As blood travels through this chamber hematocrit and oxygen saturation are measured by the absorbance and scattering of light. The hematocrit value is then used to estimate the blood volume relative to the start of the dialysis session.