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.

Continuous cardiac output by femoral arterial thermodilution calibrated pulse contour analysis: comparison with pulmonary arterial thermodilution.

OBJECTIVE: To compare two thermodilution methods for the determination of cardiac output (CO)-thermodilution in the pulmonary artery (COpa) and thermodilution in the femoral artery (COa)-with each other and with CO determined by continuous pulse contour analysis (COpc) in terms of reproducibility, bias, and correlation among the different methods. Good agreement between the methods would indicate the potential of pulse contour analysis to monitor CO continuously and at reduced invasiveness. DESIGN: Prospective criterion standard study. SETTING: Cardiac surgical intensive care unit in a university hospital. PATIENTS: Twenty-four postoperative cardiac surgery patients. INTERVENTIONS: Without interfering with standard hospital cardiac recovery procedures, changes in CO as a result of the postsurgical course, administration of vasoactive substances, and/or fluid administration were recorded. CO was first recorded after a 1-hr stabilization period in the intensive care unit and hourly thereafter for 6 hrs, and by subsequent determinations at 9, 12, and 24 hrs. MEASUREMENTS AND MAIN RESULTS: There were 216 simultaneous determinations of COpa, COa, and COpc. COpc was initially calibrated using COa, and no further recalibration of COpc was performed. COpa ranged from 3.0 to 11.8 L/min, and systemic vascular resistance ranged from 252 to 2434 dyne x sec/cm5. The mean difference (bias) +/-2 SD of differences (limits of agreement) was -0.29+/-1.31 L/min for COpa vs. COa, 0.07+/-1.4 L/min for COpc vs. COpa, and -0.22+/-1.58 L/min for COpc vs. COa. In all but four patients COpc correlated with COa after the initial calibration. Correlation and precision of COpc vs. COa was stable for 24 hrs. CONCLUSIONS: Femoral artery pulse contour CO correlates well with both COpa and COa even during substantial variations in vascular tone and hemodynamics. Additionally, CO determined by arterial thermodilution correlates well with COpa. Thus, COa can be used to calibrate COpc.

Improvement of heart-, lung-, and liver-performance during mechanical circulatory support by the Novacor-system.

OBJECTIVE: Since its clinical introduction, the Novacor left ventricular assist system (LVAS) has proved to be a reliable and safe method for bridging to cardiac transplantation. To find out whether univentricular assistance is sufficient in patients with severe global heart failure, multi organ monitoring using the COLD system was performed. METHODS: In seven patients (mean age 38.8 years), the wearable Novacor system N100 was implanted. Preoperatively, during the first 72 h thereafter and before heart transplantation right and left ventricular cardiac output, right ventricular ejection fraction, pulmonary-, intrathoracic-and total blood volume, extravascular lung water and excretory liver function were monitored by means of double indicator dilution technique with the COLD system. Conventional hemodynamic parameters have also been documented. RESULTS: During left ventricular assistance, both pulmonary and systemic arterial cardiac outputs increased significantly (Student's t-test, P < 0.05). Right ventricular ejection fraction rose from 17 to 26%, preoperatively elevated pulmonary and intrathoracic blood volumes and extravascular lung water fell significantly to normal ranges. Total blood volume remained constant, excretory liver function improved markedly. CONCLUSIONS: Pulmonary cardiac output improves due to the reduced right ventricular afterload by unloading the impaired left ventricle with the Novacor pump. The drop in pulmonary blood volume, intrathoracic blood volume and extravascular lung water also indicates a decrease of pulmonary congestion. Since total blood volume remains unchanged, a volume shift to the systemic circulation is suggested, resulting in an improved splanchnic perfusion as demonstrated by a better excretory liver function. In the absence of primary pulmonary hypertension, treatment of global heart failure with a left ventricular assist device is possible. The COLD system is a useful tool for managing this patient group during the postoperative period.