Assessment of Changes in Hemodynamics and Intrathoracic Fluid Using Electrical Cardiometry During Autologous Blood Harvest

Abstract

Objective To evaluate the effect of autologous blood harvest (ABH)-induced volume shifts using electrical cardiometry (EC) in patients with pulmonary artery hypertension secondary to left heart disease. Design Prospective, randomized, controlled trial. Setting A tertiary care hospital. Participants The study comprised 50 patients scheduled to undergo heart valve replacement. Interventions Patients were divided randomly into 2 experimental groups that were distinguished by whether ABH was performed. Blood volume extracted in the test group was replaced simultaneously with 1:1 colloid (Tetraspan; B Braun Melsungen, Melsungen, Germany). Hemodynamic, respiratory, and EC-derived parameters were recorded at predefined set points (T1 [post-induction/pre-ABH] and T2 [20 minutes post-ABH]). Measurements and Main Results Withdrawal of 15% of blood volume in the ABH group caused significant reductions in thoracic fluid content (TFC) (–10.1% [–15.0% to –6.1%]); right atrial pressure (–23% [–26.6% to –17.6%]); mean arterial pressure (–12.6% [–22.2% to –3.8%]); airway pressures: (peak –6.2% [–11.7% to –2.8%] and mean –15.4% [–25.0% to –8.3%]); and oxygenation index (–10.34% [–16.4% to –4.8%]). Linear regression analysis showed good correlation between the percentage change in TFC after ABH and the percentage of change in right atrial pressure, stroke volume variation, autologous blood extracted, peak and mean airway pressures, and oxygen index. Conclusions In addition to its proven role in blood conservation, therapeutic benefits derived from ABH include decongestion of volume-loaded patients, decrease in TFC, and improved gas exchange. EC tracks beat-to-beat fluid and hemodynamic fluctuations during ABH and helps in the execution of an early patient-specific, goal-directed therapy, allowing for its safe implementation in patients with pulmonary hypertension secondary to left heart disease.