Monitoring Hypervolemic-hemodilution And Hypertensive Therapy In Subarachnoid Hemorrhage

Abstract

Introduction: Prophylactic hypervolemic-hemodilution-hypertensive (HHH) therapy in subarachnoid hemorrhage (SAH) may be beneficial in reducing delayed ischaemia after early aneurysm clipping. The aim of this study was to assess the correlation among pulmonary artery catheter (PAC) measurements, effectiveness of HHH-therapy and mean flow velocity (MFV) in the middle cerebral artery (MCA) by transcranial Doppler. Methods: We recorded Hunt-Hess classification, hematocrit, hemodynamic and PAC values, bilateral MFV in the MCA and Rankin scale in 37 ICU patients with SAH and no vasospasm (MFV 160 and wedge pressure (PCWP) > 12, moderate when only SBP > 160 or PCWP >12, and ineffective when SBP < 160 and PCWP < 12. Fisher's t test and multiple regression analysis were used for data analysis, p <0.05 was significant. Results: An effective prophylactic HHH-therapy did not reduce occurrence of vasospasm. Outcome did not correlate with clinical state on admission or effectiveness of HHH-therapy. A constantly elevated systemic vascular resistance index (SVRI) was associated with a good outcome while the combination of high MFV in MCA and decline in SVRI with poor outcome (p<0.05). Multiple regression analysis showed that SVRI and hematocrit explained 46% of variance of MFV in patients without vasospasm (MFV <120 cm/s, n=16). Conclusion: Our data demonstrate a correlation among SVRI, hematocrit and MFV. The differences in the outcome between the group where SVRI and MFV where moving in the same directions and the patient group where SVRI and MFV where moving in the opposite direction may be interpreted as early sign of vasospasm and may help to differentiate elevated MFV due to vasospasm (SVRI low) and elevated MFV due to effective HHH therapy (SVRI high). Differences in the outcome between the high and low SVRI may also be due to co-morbidities associated with low vascular resistance in the poor outcome group (e.g. sepsis, SIRS).