Effect of a postdischarge virtual ward on readmission or death for high-risk patients: a randomized clinical trial.

IMPORTANCE: Hospital readmissions are common and costly, and no single intervention or bundle of interventions has reliably reduced readmissions. Virtual wards, which use elements of hospital care in the community, have the potential to reduce readmissions, but have not yet been rigorously evaluated. OBJECTIVE: To determine whether a virtual ward-a model of care that uses some of the systems of a hospital ward to provide interprofessional care for community-dwelling patients-can reduce the risk of readmission in patients at high risk of readmission or death when being discharged from hospital. DESIGN, SETTING, AND PATIENTS: High-risk adult hospital discharge patients in Toronto were randomly assigned to either the virtual ward or usual care. A total of 1923 patients were randomized during the course of the study: 960 to the usual care group and 963 to the virtual ward group. The first patient was enrolled on June 29, 2010, and follow-up was completed on June 2, 2014. INTERVENTIONS: Patients assigned to the virtual ward received care coordination plus direct care provision (via a combination of telephone, home visits, or clinic visits) from an interprofessional team for several weeks after hospital discharge. The interprofessional team met daily at a central site to design and implement individualized management plans. Patients assigned to usual care typically received a typed, structured discharge summary, prescription for new medications if indicated, counseling from the resident physician, arrangements for home care as needed, and recommendations, appointments, or both for follow-up care with physicians as indicated. MAIN OUTCOMES AND MEASURES: The primary outcome was a composite of hospital readmission or death within 30 days of discharge. Secondary outcomes included nursing home admission and emergency department visits, each of the components of the primary outcome at 30 days, as well as each of the outcomes (including the composite primary outcome) at 90 days, 6 months, and 1 year. RESULTS: There were no statistically significant between-group differences in the primary or secondary outcomes at 30 or 90 days, 6 months, or 1 year. The primary outcome occurred in 203 of 959 (21.2%) of the virtual ward patients and 235 of 956 (24.6%) of the usual care patients (absolute difference, 3.4%; 95% CI, -0.3% to 7.2%; P = .09). There were no statistically significant interactions to indicate that the virtual ward model of care was more or less effective in any of the prespecified subgroups. CONCLUSIONS AND RELEVANCE: In a diverse group of high-risk patients being discharged from the hospital, we found no statistically significant effect of a virtual ward model of care on readmissions or death at either 30 days or 90 days, 6 months, or 1 year after hospital discharge. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01108172.

Pigeons' memory for time: assessment of the role of subjective shortening in the duration-comparison procedure.

Pigeons were trained in a duration-comparison procedure to peck one key if the comparison duration (c) was 1 sec shorter than a standard duration (s), and another key if c was 1 sec longer than s. During training, the s-c delay was 1 sec, and the total duration of an s-c pair was not predictive of the correct choice. In Experiment 1, during equal-duration pair test trials, pigeons increasingly responded long (i.e., c > s) as the s-c delay was lengthened. In Experiment 2, we demonstrated that s affected long responding on equal-duration test trials, even at the 8-sec s-c delay. In Experiment 3, long responding increased as the s-c delay was lengthened, even when stimulus conditions during the s-c delay differed from those during the intertrial interval (ITI). Additional analyses indicated that it was unlikely that the increase in long responding was due to the pigeons' adding the s-c delay to c and comparing the total against the duration of s. The increase in long responding with an increase in s-c delay is more consistent with subjective shortening of s than with confusion between the s-c delay and the ITI.

Rats' memory for event duration in delayed matching-to-sample with nonspatial comparison response alternatives.

Previous research has suggested that using stationary and moving levers as nonspatial response alternatives can significantly enhance the speed of acquiring a temporal discrimination in rats. In Experiment 1, rats were trained to discriminate 2 and 8s of magazine light illumination by responding to either a stationary lever or a moving lever with a cue light illuminated above it. Rats learned to discriminate event durations at a high level of accuracy after 25 sessions of training. During subsequent delay tests, rats exhibited a strong choose-long bias, indicating that they were timing from the onset of the magazine light until the entry of levers into the chamber. This occurred regardless of whether intertrial intervals and delay intervals were dark or illuminated. On test trials in which the sample was omitted, rats responded as if the short sample had been presented. In Experiment 2, the rats received extensive training with dark and illuminated variable delay intervals (1-4 s). However, they continued to exhibit a tendency to time from the onset of the magazine light until entry of the levers into the chamber. Although the use of stationary/uncued and moving/cued levers as response alternatives enhanced the speed of acquisition of the event duration discrimination in rats, additional procedural modifications will be necessary to prevent rats from timing during the delay interval.

Pigeons' memory for sequences of light flashes when gap duration is an unreliable discriminative cue.

In Experiment 1, pigeons were trained with a 1-sec dark and a 1-sec houselight-illuminated delay interval to discriminate between sequences of two and four flashes of light (feeder illumination). The sequences could be discriminated on the basis of the number of flashes, the number of gaps, or the duration of the gap between flashes. A choose-few bias was obtained at extended dark delays, but not at extended illuminated delays. Pigeons appeared to confuse long dark delays with the longer gap between flashes on few-sample trials. In Experiment 2, additional sample sequences were included that made gap duration an unreliable cue for discriminating between the few and many samples. A significant choose-many bias was obtained at extended dark delay intervals, but no biased forgetting was found at extended illuminated delays. The pigeons appeared to discriminate light flash sequences by relying on multiple temporal features of a sequence rather than using an event switch to count flashes. The biased-forgetting effects observed appear to be due to instructional ambiguity that results from the similarity of the delay interval to features of the flash sequences.

Differential effects of empty and filled intervals on duration estimation by pigeons: tests of an attention-sharing explanation.

Pigeons were trained in a within-subjects design to discriminate durations of an empty interval and a filled interval. Even when different stimuli were used to mark empty intervals and to signal filled intervals, pigeons judged empty intervals to be longer than equal-length filled intervals. This timing difference was not a result of pigeons timing marker duration on empty interval trials. Increasing marker duration did not produce an overestimation of the empty time intervals. It was suggested that this timing difference could be due to a reduction in attention to temporal processing on filled interval trials when visual stimuli are used. Consistent with this hypothesis, it was found that empty intervals were judged longer than filled intervals when testing occurred in a darkened test room, but not when the test room was illuminated. In addition, no timing difference was observed when different auditory stimuli were used as markers for empty intervals and as signals for filled intervals.