The value of mixed venous oxygen saturation as a therapeutic indicator in the treatment of advanced congestive heart failure.

This retrospective study attempted to determine if the mixed venous oxygen saturation (SVO2) is an appropriate therapeutic monitoring parameter in assessing the effectiveness of dobutamine administration in patients with advanced congestive heart failure (CHF). Twelve patients (mean age 56.7 +/- 3.2 years, SEM) with New York Heart Association functional class III or IV (11 patients) received increasing doses of dobutamine with hemodynamic and SVO2 determinations. Dose-dependent hemodynamic improvements occurred with dobutamine administration. The correlation between cardiac output (CO) and SVO2 was poor (r2 = 0.37). One subset of patients (seven patients) had a good correlation (r2 greater than or equal to 0.7), whereas a second subset (five patients) had a weak correlation (r2 less than 0.7) between CO and SVO2. The baseline hemodynamic profile of the latter group demonstrates a trend toward a more seriously ill subset of patients compared to the former group. A parallel relationship between CO and SVO2 may not occur in seriously ill CHF patients. One possible explanation may be a changing oxygen consumption rate in the seriously ill patient, resulting in changes in CO without concomitant changes in SVO2.