Comparison of Carotid Blood Flow Measured by Ultrasound and Cardiac Output in Patients Undergoing Cardiac Surgery.

BACKGROUND: In general, cerebral blood flow accounts for 10-15% of cardiac output (CO), of which about 75% is delivered through the carotid arteries. Hence, if carotid blood flow (CBF) is constantly proportional to CO with high reproducibility and reliability, it would be of great value to measure CBF as an alternative to CO. The aim of this study was to investigate the direct correlation between CBF and CO. We hypothesized that measurement of CBF could be a good substitute for CO, even under more extreme hemodynamic conditions, for a wider range of critically ill patients. METHODS: Patients aged 65-80 years, undergoing elective cardiac surgery were included in this study. CBF in different cardiac cycles were measured by ultrasound: systolic carotid blood flow (SCF), diastolic carotid blood flow (DCF), and total (systolic and diastolic) carotid blood flow (TCF). CO simultaneously was measured by transesophageal echocardiography. RESULTS: For all patients, the correlation coefficients between SCF and CO, TCF and CO were 0.45 and 0.30, respectively, which were statistically significant, but not between DCF and CO. There was no significant correlation between either SCF, TCF or DCF and CO, when CO was <3.5 L/min. CONCLUSIONS: Systolic carotid blood flow may be used as a better index to replace CO. However, the method of direct measurement of CO is essential when the patient's heart function is poor.

[Effects of NaHS on MBP and learning and memory in hippocampus of mice with spinocerebellar ataxia].

Objective: To investigate the effects of exogenous NaHS on myelin basic protein (MBP) and learning and memory of hippocampal neurons in mice with spinocerebellar ataxia type 3 (SCA3) and its therapeutic significance.Methods: Twelve male normal mice were randomly selected as normal control group (NC Group), and 48 SCA3 mice were randomly selected as SCA3 model group (M Group), low dose group (NL Group, 10 µmol/kg), medium dose group (NM Group, 50µmol/kg) and high dose group (NH Group, 100 µmol/kg), 12 rats in each group. The drug treated groups were injected with NaHS intraperitoneally once a day for 4 weeks. The changes of learning and memory ability of SCA3 mice before and after the intervention of different doses of NaHS were determined by Morris water maze, the content of hydrogen sulfide (H2S) in hippocampus was measured by spectrophotometry, the expression of MBP was detected by immunohistochemistry, and the morphological changes of neuron myelin sheath were observed by electron microscope. Results: Compared with the control group, the learning and memory ability of SCA3 mice was decreased significantly (P＜0.05), and the content of H2S in hippocampus was decreased (P＜0.05). After different doses of exogenous NaHS treatment, the learning and memory ability was improved in different degrees (P＜0.05), and the contents of H2S and MBP in hippocampus of SCA3 mice were also improved in different degrees (P＜0.05). Conclusion: Exogenous NaHS may increase the contents of H2S and MBP in the hippocampus of SCA3 mice, which may have a protective effect on the neurons, and then improve the learning and memory ability of SCA3 mice, and provide a new idea for the treatment of SCA3.