BackgroundEpidemiological studies have provided inconsistent results on whether intensive care unit (ICU) discharge at night and on weekends is associated with an increased risk of mortality. This systematic review and meta-analysis aimed to determine whether ICU discharge time was associated with hospital mortality.MethodsThe PubMed, Embase, and Scopus databases were searched to identify cohort studies that investigated the effects of discharge from the ICU on weekends and at night on hospital mortality, with adjustments for the disease severity at ICU admission or discharge. The primary meta-analysis focused on the association between nighttime ICU discharge and hospital mortality. The secondary meta-analysis examined the association between weekend ICU discharge and hospital mortality. Odds ratios (ORs) with 95% confidence intervals (CIs) were pooled using a random-effects model.ResultsWe included 14 studies that assessed outcomes for nighttime versus daytime discharges among 953,312 individuals. Of these 14 studies, 5 evaluated outcomes for weekend versus weekday discharges (n = 70,883). The adjusted OR for hospital mortality was significantly higher among patients discharged during the nighttime, compared to patients discharged during the daytime (OR 1.31, 95% CI 1.25–1.38, P < 0.0001), and the studies exhibited low heterogeneity (I 2 = 33.8%, P = 0.105). There was no significant difference in the adjusted ORs for hospital mortality between patients discharged during the weekend or on weekdays (OR 1.03, 95% CI 0.88–1.21, P = 0.68), although there was significant heterogeneity between the studies in the weekday/weekend analysis (I 2 = 72.5%, P = 0.006).ConclusionsNighttime ICU discharge is associated with an increased risk of hospital mortality, while weekend ICU discharge is not. Given the methodological limitations and heterogeneity among the included studies, these conclusions should be interpreted with caution, and should be tested in further studies.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-016-1569-x) contains supplementary material, which is available to authorized users.

Grey–grey separate spatial soliton pairs are predicted in a biased series circuit consisting of two centrosymmetric photorefractive (PR) crystals with the two-photon PR effect. The numerical results show that two grey solitons in a soliton pair can affect each other by the light-induced current. The effects of the intensity of solitary waves and gating lights on the normalized profiles and the dynamical evolutions of solitons are discussed.

No abstract

It is shown theoretically that incoherently coupled bright-dark soliton families can be realized in biased guest-host photorefractive polymers under steady-state conditions. The numerical results show that the soliton families exist irrespective of the polarization of the incident optical beams and that they are stable only in the state of x-polarization.