Transpulmonary thermodilution measurements are not affected by continuous veno-venous hemofiltration at high blood pump flow

Purpose

To assess whether continuous veno-venous hemofiltration (CVVH) with high blood pump flow alters the measurements of cardiac index (CI), global end-diastolic volume indexed (GEDVI), and extravascular lung water indexed (EVLWI) performed by transpulmonary thermodilution.

Methods

Sixty-nine patients were included if they were monitored by a PiCCO2 device and received CVVH through a femoral (n?=?62) or an internal jugular (n?=?7) dialysis catheter. The blood pump flow was set at 250?mL/min (n?=?31) or 350?mL/min (n?=?38) and the filtration flow at 6,000?mL/h. A first set of data was collected with a first transpulmonary thermodilution (TD_on). The blood pump was stopped and the continuous CI derived from pulse contour analysis was recorded (PC_off). A second data set (TD_off) was collected before and a last one (TD_on-last) after restarting the blood pump.

Results

$ {\text{CI}}_{{{\text{TD}}_{\text{on}} }} $ , $ {\text{CI}}_{{{\text{PC}}_{\text{off}} }} $ , $ {\text{CI}}_{{{\text{TD}}_{\text{off}} }} $ , and $ {\text{CI}}_{{{\text{TD}}_{{{\text{on}} - {\text{last}}}} }} $ were not significantly different in patients with a femoral dialysis catheter (3.49?±?0.96, 3.51?±?0.96, 3.51?±?0.99, and 3.44?±?1.00?L?min^?1?m^?2, respectively). This was observed with a blood pump flow at 350?mL/min and at 250?mL/min. In these patients with a femoral dialysis catheter, GEDVI did not significantly change when the blood pump was stopped. EVLWI significantly decreased when the blood pump was stopped but to a non-clinically relevant extent (?0.3?±?0.8?mL/kg). No significant changes in CI, GEDVI, and EVLWI were observed in patients with an internal jugular dialysis catheter over the study period.

Conclusions

CVVH with a high blood flow pump does not alter the transpulmonary thermodilution measurements of CI, GEDVI, and EVLWI.