Pulmonary edema and blood volume after aneurysmal subarachnoid hemorrhage: a prospective observational study

INTRODUCTION: Pulmonary edema (PED) is a severe complication after aneurysmal subarachnoid hemorrhage (SAH). PED is often treated with diuretics and a reduction in fluid intake, but this may cause intravascular volume depletion, which is associated with secondary ischemia after SAH. We prospectively studied intravascular volume in SAH patients with and without PED. METHODS: Circulating blood volume (CBV) was determined daily during the first 10 days after SAH by means of pulse dye densitometry. CBV of 60-80 ml/kg was considered normal. PED was diagnosed from clinical signs and characteristic bilateral pulmonary infiltrates on the chest radiograph. We compared CBV, cardiac index, and fluid balance between patients with and without PED with weighted linear regression, taking into account only measurements from the first day after SAH through to the day on which PED was diagnosed. Differences were adjusted for age, bodyweight, and clinical condition. RESULTS: In total, 102 patients were included, 17 of whom developed PED after a mean of 4 days after SAH. Patients developing PED had lower mean CBV (56.6 ml/kg) than did those without PED (66.8 ml/kg). The mean difference in CBV was -11.3 ml/kg (95% CI, -16.5 to -6.1); adjusted mean difference, -8.0 ml/kg (95% CI, -14.0 to -2.0). After adjusting, no differences were found in cardiac index or fluid balance between patients with and without PED. CONCLUSIONS: SAH patients developing pulmonary edema have a lower blood volume than do those without PED and are hypovolemic. Measures taken to counteract pulmonary edema must be balanced against the risk of worsening hypovolemia. TRIAL REGISTRATION: NTR1255.