Jugular saturation (SjvO2) monitoring was performed in 26 SAH patients to evaluate the incidence of normal (0.56-0.74) and pathological SjvO2 values in this population and to describe its time course in the first 12 days. We also attempt to quantify the influence of systemic and cerebral hemodynamics on SjvO2 and to assess the relationship between cerebral injury volume measured on CT scan and SjvO2. Mean SjvO2 was 0.66 +/- 0.07 (354 samples, median 0.67, range 0.43-0.89). 73% of the observations (259/354) were in the normal range. On serial measurements, we identified only 37/354 (10%) desaturation episodes (D.E.). ICP was significantly higher during low SjvO2 observation (p = 0.008). No statistical differences were noted regarding the influence of MAP, CPP, PaCO2, PaO2 on SjvO2 but during D.E., lower PaCO2 and CPP were more frequently observed. CT scan lesions > 25 ml were associated initially with lower SjvO2 values and with higher values at second CT.