Echocardiography, as a noninvasive hemodynamic evaluation technique, is frequently used in critically ill patients. Different opinions exist regarding whether it can be interchanged with traditional invasive means, such as the pulmonary artery catheter thermodilution (TD) technique. This systematic review aimed to analyze the consistency and interchangeability of cardiac output measurements by ultrasound (US) and TD. Five electronic databases were searched for studies including clinical trials conducted up to June 2019 in which patients’ cardiac output was measured by ultrasound techniques (echocardiography) and TD. The methodological quality of the included studies was evaluated by two independent reviewers who used the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2), which was tailored according to our systematic review in Review Manager 5.3. A total of 68 studies with 1996 patients were identified as eligible. Meta-analysis and subgroup analysis were used to compare the cardiac output (CO) measured using the different types of echocardiography and different sites of Doppler use with TD. No significant differences were found between US and TD (random effects model: mean difference [MD], -0.14; 95% confidence interval, -0.30 to 0.02; P = 0.08). No significant differences were observed in the subgroup analyses using different types of echocardiography and different sites except for ascending aorta (AA) (random effects model: mean difference [MD], -0.37; 95% confidence interval, -0.74 to -0.01; P = 0.05) of Doppler use. The median of bias and limits of agreement were -0.12 and ±0.94 L/min, respectively; the median of correlation coefficient was 0.827 (range, 0.140–0.998). Although the difference in CO between echocardiography by different types or sites and TD was not entirely consistent, the overall effect of meta-analysis showed that no significant differences were observed between US and TD. The techniques may be interchangeable under certain conditions.

The increased intracranial pressure caused by brain edema following traumatic brain injury (TBI) always leads to poor patient prognosis. Aquaporin-4 (AQP-4) plays an important role in edema formation and resolution, which may provide a novel therapeutic target for edema treatment. In this present study, we found that propofol treatment, within a short time, after TBI significantly reduced brain edema in a controlled cortical injury rat model and suppressed in vivo expression of AQP-4. The ameliorating effect of propofol was associated with attenuated expression of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). In addition, the regulatory effect of propofol on AQP-4 expression was investigated in cultured astrocytes. Results showed that propofol could block the stimulatory effect of IL-1β and TNF-α on AQP-4 expression in cultured astrocytes. We also found that both NFκB and p38/MAPK pathways were involved in IL-1β and TNF-α-induced AQP-4 expression and that propofol functions as a dual inhibitor of NFκB and p38/MAPK pathways. In conclusion, treatment with propofol, within a short time, after TBI attenuates cerebral edema and reduces the expression of AQP-4. Propofol modulates acute AQP-4 expression by attenuating IL-1β and TNF-α expression and inhibiting IL-1β and TNF-α induced AQP-4 expression.

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