Hemodynamic Monitoring during Erythrocytapheresis in Sickle Cell Disease Patients Using Impedance Cardiography

BACKGROUND: Erythrocytapheresis procedures are increasingly used in the treatment of severe acute complications of sickle cell disease (SCD). Some patients who undergo erythrocytapheresis experience dizziness during or after the procedure. There is no data in literature for hemodynamic monitoring of cardiac index (CI) and systemic vascular resistance index (SVRI) during erythrocytapheresis. We have previously shown that impedance cardiography (ICG) and invasive measures of CI by thermodilution techniques are significantly correlated in children.

OBJECTIVES: We wanted to evaluate changes in CI and SVRI using ICG and to correlate these with systolic blood pressure (SBP) measurements in SCD patients while undergoing erythrocytapheresis.

METHODS: Thirty one SCD patients who had 70 consecutive erythrocytapheresis procedures were included in this IRB approved study. ICG measurements (CI, SVRI, and blood pressure) were taken pre-erythrocytapheresis, 30 minutes after initiation of the procedure, one hour into erythrocytapheresis, and at the end of the procedure. ICG measurements were repeated in symptomatic patients before and after intervention with fluid administration.

RESULTS: We evaluated hemodynamic data on 31 SCD patients, average age 12.8±5.2 years and 56% are female. SBP decreased below the base line during 33 procedures and increased above the baseline during 37 procedures. Among patients who had a decrease in SBP, 28/33 (84%) had decreased CI. Among them 22/28 (78%) had increased SVRI. Among patients who had an increase in SBP, 5/37 (14%) had increased CI. Among them 4/5 (80%) also had increased SVRI. Using paired t test, the changes in CI (P <0.001) and SVRI (P=0.0002) comparing to baseline are statistically significant. CI is negatively correlated with change in SVRI (Pearson correlation coefficient −0.8).

CONCLUSIONS:In summary, the hemodynamic changes during erythrocytapheresis are probably multifactorial in origin and may include a combination of SVRI and CI changes. Confirmation of these findings may allow early intervention in some patients and minimize the risk of developing overt clinical symptoms during erythrocytapheresis.