Inherent in the remote organ injury caused by sepsis is a profound maldistribution of microvascular blood flow. Using a 24-h rat cecal ligation and perforation model of sepsis, we studied O(2) transport in individual capillaries of the extensor digitorum longus (EDL) skeletal muscle. We hypothesized that erythrocyte O(2) saturation (SO(2)) levels within normally flowing capillaries would provide evidence of either a mitochondrial failure (increased SO(2)) or an O(2) transport derangement (decreased SO(2)). Using a spectrophotometric functional imaging system, we found that sepsis caused 1) an increase in stopped flow capillaries (from 10 to 38%, P < 0.05), 2) an increase in the proportion of fast-flow to normal-flow capillaries (P < 0.05), and 3) a decrease in capillary venular-end SO(2) levels from 58.4 +/- 20.0 to 38.5 +/- 21.2%, whereas capillary arteriolar-end SO(2) levels remained unchanged compared with the sham group. Capillary O(2) extraction increased threefold (P < 0.05) and was directly related to the degree of stopped flow in the EDL. Thus impaired O(2) transport in early stage sepsis is likely the result of a microcirculatory dysfunction.

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Objective:To evaluate the possible role of the default mode network (DMN) in consciousness and assess the diagnostic or prognostic potential of DMN connectivity measures in the assessment of a patient group lacking cognitive awareness.Methods: DMN connectivity was established using independent component analysis of restingstate fMRI data in patients with reversible (n ϭ 2) and irreversible (n ϭ 11) coma following cardiac arrest and compared to healthy controls (n ϭ 12).Results: A present and intact DMN was observed in controls and those patients who subsequently regained consciousness, but was disrupted in all patients who failed to regain consciousness. Conclusions:The results suggest that the DMN is necessary but not sufficient to support consciousness. Clinically, DMN connectivity may serve as an indicator of the extent of cortical disruption and predict reversible impairments in consciousness. Neurology ® 2012;78:175-181 GLOSSARY BOLD ϭ blood oxygenation level-dependent; DMN ϭ default mode network; FOV ϭ field of view; GCS ϭ Glasgow Coma Scale; GOS ϭ Glasgow Outcome Scale; ICA ϭ independent component analysis; PCC ϭ posterior cingulate cortex; SSEP ϭ somatosensory evoked potential; TE ϭ echo time; TR ϭ repetition time; VS ϭ vegetative state.Coma represents a state of unarousable psychological unresponsiveness with a total absence of awareness of both self and environment. 1 Currently, there are few tools available to adequately assess the cerebral function in this patient population, making prediction of future outcome particularly challenging. However, a growing body of research has shown that fMRI can reveal important insights into brain function and connectivity and may be well suited for the prognostication of comatose patients in a clinical setting. [2][3][4] Recently, increasing attention has been directed at investigating the default mode network (DMN) which includes cortical regions that characterize the baseline state of the brain thought to relate to unconstrained, spontaneous cognition, or stimulus-independent thoughts. 5-7 The DMN is comprised of several cortical areas including the posterior cingulate cortex/precuneus, medial prefrontal cortex, and bilateral temporoparietal junctions. 8,9 The proposed role of the DMN in internal mental processes and cognition has made it an attractive candidate as the neural correlate of the stream of consciousness. 10 -12 As such, the DMN may provide important insights into the cerebral function of patients with impaired states of consciousness such as coma. Altered connectivity in the DMN has been reported in case studies and case series of impaired consciousness including vegetative state (VS), 13 coma, 14 and brain death. 15 From the Graduate Program in Neuroscience (L.

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Background: Refractory status epilepticus (RSE) is defined as continued seizures after 2 or 3 antiepileptic drugs have failed. Several intravenous agents have been used for RSE; however, problems occur with their toxicity and/or effectiveness. Objective: To report our experience with inhalational anesthesia (IA) in patients who were refractory to other antiepileptic drugs. Design, Setting, and Participants: Retrospective review during a 4-year period of patients with RSE treated with isoflurane and/or desflurane. Main Outcome Measure: Efficacy of IA on therapy in terminating RSE. Results: Seven patients (4 male) aged 17 to 71 years received 7 to 15 (mean, 10) antiepileptic drugs in addition to IAs. The IAs were initiated after 1 to 103 (mean, 19) days of RSE and were used for a mean ± SD 11±8.9 days.