Early mobilization of mechanically ventilated patients: a 1-day point-prevalence study in Germany.

OBJECTIVES: There is growing evidence to support early mobilization of adult mechanically ventilated patients in ICUs. However, there is little knowledge regarding early mobilization in routine ICU practice. Hence, the interdisciplinary German ICU Network for Early Mobilization undertook a 1-day point-prevalence survey across Germany. DESIGN: One-day point-prevalence study. SETTING: One hundred sixteen ICUs in Germany in 2011. PATIENTS: All adult mechanically ventilated patients. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: For a 24-hour period, data were abstracted on hospital and ICU characteristics, the level of patient mobilization and associated barriers, and complications occurring during mobilization. One hundred sixteen participating ICUs provided data for 783 patients. Overall, 185 patients (24%) were mobilized out of bed (i.e., sitting on the edge of the bed or higher level of mobilization). Among patients with an endotracheal tube, tracheostomy, and noninvasive ventilation, 8%, 39%, and 53% were mobilized out of bed, respectively (p < 0.001 for difference between three groups). The most common perceived barriers to mobilizing patients out of bed were cardiovascular instability (17%) and deep sedation (15%). Mobilization out of bed versus remaining in bed was not associated with a higher frequency of complications, with no falls or extubations occurring in those mobilized out of bed. CONCLUSIONS: In this 1-day point-prevalence study conducted across Germany, only 24% of all mechanically ventilated patients and only 8% of patients with an endotracheal tube were mobilized out of bed as part of routine care. Addressing modifiable barriers for mobilization, such as deep sedation, will be important to increase mobilization in German ICUs.

Effects of psilocybin on time perception and temporal control of behaviour in humans.

Hallucinogenic psilocybin is known to alter the subjective experience of time. However, there is no study that systematically investigated objective measures of time perception under psilocybin. Therefore, we studied dose-dependent effects of the serotonin (5-HT)2A/1A receptor agonist psilocybin (4-phosphoryloxy-N, N-dimethyltryptamine) on temporal processing, employing tasks of temporal reproduction, sensorimotor synchronization and tapping tempo. To control for cognitive and subjective changes, we assessed spatial working memory and conscious experience. Twelve healthy human volunteers were tested under placebo, medium (115 microg/kg), and high (250 microg/kg) dose conditions, in a double-blind experimental design. Psilocybin was found to significantly impair subjects' ability to (1) reproduce interval durations longer than 2.5 sec, (2) to synchronize to inter-beat intervals longer than 2 sec and (3) caused subjects to be slower in their preferred tapping rate. These objective effects on timing performance were accompanied by working-memory deficits and subjective changes in conscious state, namely increased reports of 'depersonalization' and 'derealization' phenomena including disturbances in subjective 'time sense.' Our study is the first to systematically assess the impact of psilocybin on timing performance on standardized measures of temporal processing. Results indicate that the serotonin system is selectively involved in duration processing of intervals longer than 2 to 3 seconds and in the voluntary control of the speed of movement. We speculate that psilocybin's selective disruption of longer intervals is likely to be a product of interactions with cognitive dimensions of temporal processing -presumably via 5-HT2A receptor stimulation.

Unconsciousness.

This paper reviews a theory on the physiological conditions of consciousness. The theory consists of four hypotheses: (1) The occurrence of states of consciousness depends on the formation of higher-order representations that represent the internal state of the brain itself. (2) Higher-order representations are instantiated by the spatio-temporal activity pattern of large-scale neuronal assemblies. (3) The N-methyl-D-aspartate (NMDA) synapse plays a crucial role in the generation of conscious states by implementing the binding mechanism that the brain uses to produce large-scale assemblies. (4) The activation state of the NMDA receptor determines the rate at which representational structures can be built up. Unconsciousness or altered states of consciousness occur if, and only if, NMDA-dependent binding processes are inhibited.