Hemodynamic monitoring by double indicator dilution technique in patients after orthotopic heart transplantation

STUDY OBJECTIVES A transpulmonary thermal-dye dilution (TDD) technique using cold indocyanine green dye was utilized to monitor cardiac index (CI) and preload in patients after heart transplantation. Preload, determined by intrathoracic blood volume index (ITBVI) and global end-diastolic volume index (GEDVI), was compared to central venous pressure (CVP) and pulmonary artery occlusion pressure (PAOP) and was correlated with stroke volume index (SVI). DESIGN Prospective study. SETTING Cardiac surgery ICU at a university hospital. PATIENTS Forty patients (34 men, 6 women) with a mean (+/- SD) age of 54.4+/-8.5 years after orthotopic heart transplantation. MEASUREMENTS AND RESULTS CI and preload measurements were performed with TDD and pulmonary artery catheters in the ICU at 3, 6, 12, 24, 36, 48, and 72 h postoperatively. The femoral artery CI was compared with the pulmonary artery CI. Changes in the ITBVI, GEDVI, CVP, and PAOP were correlated with changes in the SVI. No difference was found between the femoral and pulmonary arterial CIs (r = 0.98 [bias, 0.35 L/min/m(2)]; p<0.01). There was no statistically significant correlation between changes in the SVI and changes in CVP (r = -0.23,) and PAOP (r = -0.06). However, the ITBVI (r = 0.65; p<0.01) and the GEDVI (r = 0.73; p<0.01) were significantly correlated to changes in the SVI. Changes in the same direction occurred between the SVI and the GEDVI as well as between the SVI and the ITBVI in 76.3% and 71.9% of patients, respectively, while CVP and PAOP also changed in the same direction as SVI in only 35.1% and 36.9% of patients, respectively. CONCLUSION ITBVI and GEDVI are more reliable preload parameters than CVP and PAOP. Even in denervated hearts, ITBVI and GEDVI show significant correlations with SVI. The transpulmonary indicator dilution technique is promising and should be investigated further.