"Not so fast!" the complexity of attempting to decrease door-to-floor time for emergency department admissions.

BACKGROUND: Successful quality improvement is fundamental to high-performing health care systems, but becomes increasingly difficult as systems become more complex. Previous attempts at the University of California, San Francisco (UCSF) Medical Center to reduce door-to-floor (D2F) time -the time required to move an ill patient through the emergency department (ED) to an appropriate inpatient bed-had not resulted in meaningful improvement. An analysis of why attempts at decreasing D2F times in the ED had failed, with attention to contextual factors, yields recommendations on how to decrease D2F time. METHODS: A team of 11 internal medicine residents, in partnership with the Patient Flow Executive Steering Committee, performed a literature review, process mapping, and analysis of the admissions process. The team conducted interviews with medical center staff across disciplines, members of high-performing patient care units, and leaders of peer institutions who had undertaken similar efforts. FINDINGS AND RECOMMENDATIONS: Each of the following three domains-(1) Improving Work Flow, (2) Changing Culture, and (3) Understanding Incentives-is independently an important source of resistance and opportunity. However, the improvement work and understanding of complexity science suggest that all three domains must be addressed simultaneously to effect meaningful change. Recommendations include eliminating redundant and frustrating processes; encouraging multidisciplinary collaboration; fostering trust between departments; providing feedback on individual performance; enhancing provider buy-in; and, ultimately, uniting staff behind a common goal. CONCLUSION: By conceptualizing the hospital as a complex adaptive system, multiple interrelated groups can be encouraged to work together and accomplish a common goal.

Separable substrates for anticipatory and consummatory food chemosensation.

Perception of the smell of a food precedes its ingestion and perception of its flavor. The neurobiological underpinnings of this association are not well understood. Of central interest is whether the same neural circuits code for anticipatory and consummatory phases. Here, we show that the amygdala and mediodorsal thalamus respond preferentially to food odors that predict immediate arrival of their associated drink (FO+) compared to food odors that predict delivery of a tasteless solution (FO-) and compared to the receipt of the drink. In contrast, the left insula/operculum responds preferentially to the drink, whereas the right insula/operculum and left orbitofrontal cortex respond to FO+ and drink. These findings indicate separable and overlapping representation of anticipatory and consummatory chemosensation. Moreover, since ratings of perceived pleasantness of FO+, FO-, and drink were similar, the response in the amygdala and thalamus cannot reflect acquired affective value but rather predictive meaning or biological relevance.

Differential neural responses evoked by orthonasal versus retronasal odorant perception in humans.

Odors perceived through the mouth (retronasally) as flavor are referred to the oral cavity, whereas odors perceived through the nose (orthonasally) are referred to the external world. We delivered vaporized odorants via the orthonasal and retronasal routes and measured brain response with fMRI. Comparison of retronasal versus orthonasal delivery produced preferential activity in the mouth area at the base of the central sulcus, possibly reflecting olfactory referral to the mouth, associated with retronasal olfaction. Routes of delivery produced differential activation in the insula/operculum, thalamus, hippocampus, amygdala, and caudolateral orbitofrontal cortex in orthonasal > retronasal and in the perigenual cingulate and medial orbitofrontal cortex in retronasal > orthonasal in response to chocolate, but not lavender, butanol, or farnesol, so that an interaction of route and odorant may be inferred. These findings demonstrate differential neural recruitment depending upon the route of odorant administration and suggest that its effect is influenced by whether an odorant represents a food.

Taste and olfactory intensity perception changes following left insular stroke.

The authors tested suprathreshold intensity perception of gustatory and olfactory stimuli in a 70-year-old right-handed man following a left posterior insular stroke and compared his results with those of age-matched controls. Both modalities revealed significant differences between left (ipsilateral to lesion) and right (contralateral) ratings of intensity. In both gustation and olfaction, these differences were driven primarily by trends toward increased contralateral sensitivity relative to controls. Intensity changes were most pronounced for unpleasant odors and for tastes perceived strongly as either pleasant (sweet) or unpleasant (salty, bitter). These results show that a left posterior insula lesion may affect taste and olfactory perception similarly by increasing sensitivity contralateral to the lesion. One possible mechanism is release from inhibition at the cortical level.

Experience-dependent neural integration of taste and smell in the human brain.

Flavor perception arises from the central integration of peripherally distinct sensory inputs (taste, smell, texture, temperature, sight, and even sound of foods). The results from psychophysical and neuroimaging studies in humans are converging with electrophysiological findings in animals and a picture of the neural correlates of flavor processing is beginning to emerge. Here we used event-related fMRI to evaluate brain response during perception of flavors (i.e., taste/odor liquid mixtures not differing in temperature or texture) compared with the sum of the independent presentation of their constituents (taste and/or odor). All stimuli were presented in liquid form so that olfactory stimulation was by the retronasal route. Mode of olfactory delivery is important because neural suppression has been observed in chemosensory regions during congruent taste-odor pairs when the odors are delivered by the orthonasal route and require subjects to sniff. There were 2 flavors. One contained a familiar/congruent taste-odor pair (vanilla/sweet) and the other an unfamiliar/incongruent taste-odor pair (vanilla/salty). Three unimodal stimuli, including 2 tastes (sweet and salty) and one odor (vanilla), as well as a tasteless/odorless liquid (baseline) were presented. Superadditive responses during the perception of the congruent flavor compared with the sum of its constituents were observed in the anterior cingulate cortex (ACC), dorsal insula, anterior ventral insula extending into the caudal orbitofrontal cortex (OFC), frontal operculum, ventral lateral prefrontal cortex, and posterior parietal cortex. These regions were not present in a similar analysis of the incongruent flavor compared with the sum of its constituents. All of these regions except the ventrolateral prefrontal cortex were also isolated in a direct contrast of congruent - incongruent. Additionally, the anterior cingulate, posterior parietal cortex, frontal operculum, and ventral insula/caudal OFC were also more active in vanilla + salty minus incongruent, suggesting that delivery of an unfamiliar taste-odor combination may lead to suppressed neural responses. Taken together with previous findings in the literature, these results suggest that the insula, OFC, and ACC are key components of the network underlying flavor perception and that taste-smell integration within these and other regions is dependent on 1) mode of olfactory delivery and 2) previous experience with taste/smell combinations.

Dissociation of neural representation of intensity and affective valuation in human gustation.

We used a 2 x 2 factorial design to dissociate regions responding to taste intensity and taste affective valence. Two intensities each of a pleasant and unpleasant taste were presented to subjects during event-related fMRI scanning. The cerebellum, pons, middle insula, and amygdala responded to intensity irrespective of valence. In contrast, valence-specific responses were observed in anterior insula/operculum extending into the orbitofrontal cortex (OFC). The right caudolateral OFC responded preferentially to pleasant compared to unpleasant taste, irrespective of intensity, and the left dorsal anterior insula/operculuar region responded preferentially to unpleasant compared to pleasant tastes equated for intensity. Responses best characterized as an interaction between intensity and pleasantness were also observed in several limbic regions. These findings demonstrate a functional segregation within the human gustatory system. They also show that amygdala activity may be driven by stimulus intensity irrespective of valence, casting doubt upon the notion that the amygdala responds preferentially to negative stimuli.