The effects of propofol and dexmedetomidine infusion on fluid responsiveness in critically ill patients

BackgroundWe studied the effects of propofol or dexmedetomidine on preload dependency and fluid responsiveness in critically ill patients.MethodsIn the study, we included 91 patients with acute circulatory failure (70 ± 15 y) who received propofol (n = 45 patients, PROP group) or dexmedetomidine (n = 46 patients, DEX group). An initial passive leg-raising (PLR 1) test was performed in all patients to evaluate preload dependency at baseline. Propofol and dexmedetomidine were infused and titrated according to the Richmond Agitation Sedation Scale; the results ranged from −2 to −1, and the bispectral index values ranged from 60–75. A second PLR test (PLR 2) was performed before administration of a 250-mL normal saline fluid challenge over a 5-min period. We obtained central venous pressure and cardiac index (CI) measurements before and after the two PLR tests and volume expansion. An increase of ≥10% in CI during PLR was considered to be a positive test finding that was indicative of preload dependency, whereas an increase of <10% in CI during PLR was considered to be a negative test finding.ResultsAt baseline, 22 of 45 patients had negative PLR 1 in the PROP group, whereas 20 of 46 patients had negative PLR 1 in the DEX group. After propofol or dexmedetomidine sedation, there were significant decreases in CI (−9.5% [±6.6%] versus −16.4% [±8.5%], P < 0.001) in the PROP and DEX groups, respectively. In the PROP group, there were significant increases in CI (+18.4% [±9.5%] versus +10.7% [±12.3%], P < 0.05) induced by PLR 2 compared with that induced by PLR 1. In the DEX group, there were no significant increases in CI (+13.2% [±14.9%] versus +12.8% [±17.7%]) induced by PLR 2 compared with that induced by PLR 1. Although the mean arterial pressure values increased comparably with the volume expansion observed in both groups, the volume expansion resulted in a significantly higher increase in CI compared with the baseline values in the PROP group (3.2 ± 0.8 versus 3.2 ± 0.7 L/min/m2) but not in the DEX group (2.9 ± 0.7 versus 3.1 ± 0.8 L/min/m2, P < 0.05).ConclusionsWe observed that propofol infusion, but not dexmedetomidine infusion, can increase preload dependency and fluid responsiveness in patients with circulatory failure.