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.

Keywords: autologous blood harvest; electrical cardiometry; goal directed therapy; heart valve replacement; thoracic fluid content.