Haemodynamic effects of a fluid challenge with hydroxylethyl starch 130/0.4 (Voluven^®) in patients suffering from symptomatic vasospasm after subarachnoid haemorrhage

Introduction

Patients suffering from symptomatic cerebral artery vasospasm (CAV) after subarachnoid haemorrhage (SAH) develop alterations in sodium and fluid homeostasis, and the effects of fluid infusion are uncertain. Since their fluid management is controversial, we assessed the effect of a single colloid infusion on global haemodynamics and fluid balance.

Methods

In a prospective study, 500 ml of 130/0.4 hydroxylethyl starch (HES) was administered over 30 minutes in patients with CAV after SAH. The mean arterial pressure (MAP), central venous pressure (CVP), fluid balance, cardiac index (CI), intrathoracic blood volume (ITBV), and extravascular lung water (EVLW) were measured immediately before, and 60, 120, 180 and 360 minutes after HES by transpulmonary thermodilution (PiCCO; Pulsion). Patients increasing CI by more than 10% were considered as responders (R), versus nonresponders (NR). Comparisons were made between groups by one-way ANOVA, and at various time points by two-way ANOVA (P < 0.05 significant, mean ± SD).

Results

After HES, the CI changed from -14% to +62%. Considering all patients (n = 20), the CI increased at 60 minutes (4.3 ± 0.7 vs 4.8 ± 0.9 l/m²/min, P < 0.05) but returned to baseline value at 120 minutes (4.6 ± 0.9 l/m²/min) and thereafter. There was no difference in the MAP, CVP, ITBV and EPLW over time. Ten patients were R and 10 were NR. Baseline MAP, CVP, CI, ITBV and EPLW were not different between R and NR. The norepinephrine infusion rate was higher in NR than in R (18 ± 12 vs 6 ± 9 μg/min, P < 0.05). The CI increased in R from 60 to 180 minutes, and returned to baseline at 360 minutes (respectively 4.0 ± 0.6, 5.2 ± 1.1, 4.9 ± 1.1, 4.8 ± 1.0, and 4.2 ± 1.1 l/m²/min). The evolution of fluid balance was different between R and NR: it remained unchanged in R, while it was negative at 360 minutes in NR (-0.60 ± 0.87 vs -0.04 ± 0.47). The MAP, CVP, ITBV and EPLW were not different between R and NR throughout.

Conclusion

By transpulmonary thermodilution, the haemodynamic effects of a short HES infusion were variable and unpredictable. In R, the increase in cardiac output lasted 3 hours. In NR, fluid infusion fluid therapy should be considered with caution, since it may be associated with a negative fluid balance, probably due to cerebral salt wasting. Our data suggest that fluid therapy should be closely monitored in this population of patients with altered homeostasis.