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Purpose In stable ventilatory and metabolic conditions, changes in end-tidal carbon dioxide (EtCO.sub.2) might reflect changes in cardiac index (CI). We tested whether EtCO.sub.2 detects changes in CI induced by volume expansion and whether changes in EtCO.sub.2 during passive leg raising (PLR) predict fluid responsiveness. We compared EtCO.sub.2 and arterial pulse pressure for this purpose. Methods We included 65 patients [Simplified Acute Physiology Score (SAPS) II = 57 ± 19, 37 males, under mechanical ventilation without spontaneous breathing, 15 % with chronic obstructive pulmonary disease, baseline CI = 2.9 ± 1.1 L/min/m.sup.2] in whom a fluid challenge was decided due to circulatory failure and who were monitored by an expiratory-CO.sub.2 sensor and a PiCCO2 device. In all patients, we measured arterial pressure, EtCO.sub.2, and CI before and after a fluid challenge. In 40 patients, PLR was performed before fluid administration. The PLR-induced changes in arterial pressure, EtCO.sub.2, and CI were recorded. Results Considering the whole population, the fluid-induced changes in EtCO.sub.2 and CI were correlated (r.sup.2 = 0.45, p = 0.0001). Considering the 40 patients in whom PLR was performed, volume expansion increased CI [greater than or equal to]15 % in 21 'volume responders.' A PLR-induced increase in EtCO.sub.2 [greater than or equal to]5 % predicted a fluid-induced increase in CI [greater than or equal to]15 % with sensitivity of 71 % (95 % confidence interval: 48-89 %) and specificity of 100 (82-100) %. The prediction ability of the PLR-induced changes in CI was not different. The area under the receiver-operating characteristic (ROC) curve for the PLR-induced changes in pulse pressure was not significantly different from 0.5. Conclusion The changes in EtCO.sub.2 induced by a PLR test predicted fluid responsiveness with reliability, while the changes in arterial pulse pressure did not., Author(s): Xavier Monnet [sup.1], Aurélien Bataille [sup.1] [sup.2], Eric Magalhaes [sup.1] [sup.2], Jérôme Barrois [sup.1] [sup.2], Marine Le Corre [sup.1] [sup.2], Clément Gosset [sup.1] [sup.2], Laurent Guerin [sup.1] [sup.2], Christian [...]

Spinal cord injury (SCI) is a debilitating neuropathology with no effective treatment. Magnetic resonance imaging (MRI) technology is the only method used to assess the impact of an injury on the structure and function of the human spinal cord. Moreover, in pre-clinical SCI research, MRI is a non-invasive method with great translational potential since it provides relevant longitudinal assessment of anatomical and structural alterations induced by an injury. It is only recently that MRI techniques have been effectively used for the follow-up of SCI in rodents. However, the vast majority of these studies have been carried out on rats and when conducted in mice, the contusion injury model was predominantly chosen. Due to the remarkable potential of transgenic mice for studying the pathophysiology of SCI, we examined the use of both in and ex vivo 1H-MRI (9.4 T) in two severities of the mouse SCI (hemisection and over-hemisection) and documented their correlation with histological assessments. We demonstrated that a clear distinction between the two injury severities is possible using in and ex vivo 1H-MRI and that ex vivo MR images closely correlate with histology. Moreover, tissue modifications at a remote location from the lesion epicenter were identified by conventional ex vivo MRI analysis. Therefore, in vivo MRI has the potential to accurately identify in mice the progression of tissue alterations induced by SCI and is successfully implemented by ex vivo MRI examination. This combination of in and ex vivo MRI follow-up associated with histopathological assessment provides a valuable approach for further studies intended to evaluate therapeutic strategies on SCI. [ABSTRACT FROM AUTHOR]

Spinal cord injury (SCI) is a debilitating neuropathology with no effective treatment. Magnetic resonance imaging (MRI) technology is the only method used to assess the impact of an injury on the structure and function of the human spinal cord. Moreover, in pre-clinical SCI research, MRI is a non-invasive method with great translational potential since it provides relevant longitudinal assessment of anatomical and structural alterations induced by an injury. It is only recently that MRI techniques have been effectively used for the follow-up of SCI in rodents. However, the vast majority of these studies have been carried out on rats and when conducted in mice, the contusion injury model was predominantly chosen. Due to the remarkable potential of transgenic mice for studying the pathophysiology of SCI, we examined the use of both in and ex vivo (1)H-MRI (9.4 T) in two severities of the mouse SCI (hemisection and over-hemisection) and documented their correlation with histological assessments. We demonstrated that a clear distinction between the two injury severities is possible using in and ex vivo (1)H-MRI and that ex vivo MR images closely correlate with histology. Moreover, tissue modifications at a remote location from the lesion epicenter were identified by conventional ex vivo MRI analysis. Therefore, in vivo MRI has the potential to accurately identify in mice the progression of tissue alterations induced by SCI and is successfully implemented by ex vivo MRI examination. This combination of in and ex vivo MRI follow-up associated with histopathological assessment provides a valuable approach for further studies intended to evaluate therapeutic strategies on SCI.