Monitoring of hypervolemic hemodilution and hypertensive (HHH) therapy in subarachnoid hemorrhage (SAH) patients with pulmonary artery catheter (PAC)

Background

Cerebral arterial vasospasm continues to be a major complication of aneurysmal SAH. Prophylactic HHH therapy may be beneficial reducing delayed ischemia after early aneurysm clipping. Minimal standards of monitoring are not well defined.

The aim of our study was to evaluate the contribution of PAC and cranscranial Doppler (TCD) monitoring during HHH-therapy in patients with SAH after early operative intervention.

Methods

We observed 37 ICU patients with SAH during HHH therapy. All patients received hypervolemic hemodilution therapy aiming for a hematocrit of 33–38%, 10–12 mmHg central venous pressure (or 15–18 mmHg pulmonary wedge pressure), and 160–200 mmHg systolic arterial pressure during the risk period for vasospasm. We evaluated clinical findings, PAC values and mean flow velocity (MFV) on both middle cerebral arteries (MCA).

Results

Outcome correlated with clinical state on admission (Fisher-exact test, P < 0.05). A constantly elevated systemic vascular resistance (SVR) was associated with a good outcome while declining SVR during clinical course with a poor outcome (analysis of variance for repeated measurements, P < 0.05). A successful HHH therapy according to the above hemodynamic criteria did not reduce occurrence of vasospasm (Fisher-exact test). In patients without vasospasm (MFV ≤140 cm/s, n = 16), we were able to develop a multiple regression model that explained 44% of variance of MFV by consideration of SVRI and hematocrit.

Conclusion

SVRI monitoring and manipulation using PAC during HHH therapy may affect outcome positively. An association of MFV with SVRI and hematocrit could be demonstrated.