Well-being and cerebral oxygen saturation during acute heart failure in humans

Cerebral symptoms and near-infrared spectrophotometry-determined cerebral oxygen saturation (ScO₂) were followed in patients treated for normotensive acute congestive heart failure. The reproducibility and normal range for ScO₂ were established from 39 resting subjects without cardio-respiratory disease: the ScO₂ ranged from 55 to 78% with a coefficient of variation for triple determination of 6%. Patients rated cerebral symptoms on a scale with end-points of 0 (best) and 10 (worst). In eight patients with acute heart failure, arterial oxygen tension increased during decongestive treatment, from 9.1 (4.9-10) to 10.4 kPa (7.3-17); median with range, as did arterial oxygen saturation, from 94 (48-97) to 97% (87-99) (P < 0.02), whereas the mean arterial pressure, heart rate and arterial carbon dioxide tension remained unchanged. The cerebral symptom score improved from 8 (3-10) to 1 (1-9) and the ScO₂ increased from 34 (20-58) to 50% (19-91) (P < 0.02). A ninth patient presented with a silent but massive myocardial infarction: she was cerebrally obtunded with a ScO₂ of 18% and soon died. In patients with normotensive acute heart failure and cerebral symptoms, cerebral oxygen saturation is low and during successful treatment ScO₂ increases with the well-being of the patient.