Clinical physiology (Oxford, England)
-
Comparative Study Clinical Trial
Cardiac output measured by electric bioimpedance compared with the CO2 rebreathing technique at different exercise levels.
In the lower range of cardiac output (CO, up to 15 l min-1), we found an excellent agreement between CO measured by bioimpedance and carbon dioxide rebreathing techniques. CO estimated by bioimpedance was generally lower. The bioimpedance method had better reproducibility. Both methods seem valuable for non-invasive studies in healthy subjects at work.
-
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). ⋯ 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.