Spontaneous pneumomediastinum (SPM) is a rare disorder most often affecting young males which is generally self-limiting. Despite the benign prognosis with few complications and little morbidity, it frequently confuses clinicians in primary settings, who may have difficulty differentiating SPM from other serious organ ruptures, especially oesophageal rupture (the so-called Boerhaave syndrome), which may lead to mediastinitis and may be fatal, even with appropriate interventions. An overview of adult SPM is provided, reviewing 17 studies (414 patients), including our clinical experience, and finally an algorithm for diagnosis and management of SPM is proposed, based on the characteristics of SPM.

SPM is a self-limiting disease with mild inflammatory signs. For patients suspicious of SPM, shortened hospitalization for about 2 days with observation alone may be feasible, if their symptoms improve gradually. Otherwise, less invasive procedures, such as esophagram, should be performed immediately. Long-term follow-up is usually unnecessary. We propose a new algorithm for management of SPM based on clinical experience.

Overwork-related disorders, such as cerebrovascular/cardiovascular diseases (CCVD) and mental disorders due to overwork, are a major occupational and public health issue worldwide, particularly in East Asian countries. This report discusses the recent trend of overwork-related disorders in Japan from the perspective of workers’ compensated occupational diseases, as well as the development of a national policy for preventive measures against overwork-related disorders in Japan. Recently, the number of claimed and compensated cases of occupational mental disorders has increased substantially, particularly among young workers, as compared to those of occupational CCVD. In response to these situations and action from society, the Japanese Government passed the “Act on Promotion of Preventive Measures against Karoshi and Other Overwork-Related Health Disorders” in June 2014 to develop a national initiative towards the prevention of overwork-related disorders. Changes in the trend of overwork-related disorders in Japan under a legal foundation and an initiative by the central government should be closely monitored so that other countries can benefit from the experiences.

Napping is one strategy that may assist night shiftworkers to cope with sleepiness and fatigue. However, one potential disadvantage of napping is that awakening from naps is disturbed by sleep inertia, which has also been found to impair performance and/or mood, transiently. The authors examined the effects of the timing and length of a night-shift nap on sleep inertia in a laboratory setting. Twelve male university students (mean +/- SD: 21.6 +/- 2.8 yrs) participated in this 3-day experiment, during which included a simulated night shift (22:00-08:00 h) and subsequent day (11:30-17:30 h) and night sleep (00:00-07:00 h). The simulated night shift was designed to include one of five (four nap/one no-nap) conditions. The napping conditions differed by their timing and duration: 00:00-01:00 h (Early 60 min; E60), 00:00-02:00 h (Early 120 min; E120), 04:00-05:00 h (Late 60 min; L60), 04:00-06:00 h (Late 120 min; L120). Participants completed all the experimental conditions in a counterbalanced order. Rectal temperature (R(T)) was recorded throughout the simulated shift and polysomnography (PSG) was recorded during the nap period. Immediately before and after each nap, participants were required to complete a visual analogue scale (VAS) to assess sleepiness and a visual vigilance test (VVT). During the simulated night shift, a set of tasks (an English transcription task, a performance test battery, and a break) was repeated hourly, except during the periods of napping. For each nap condition, the VAS and VVT (reaction time [RT]; lapses >5 s) results were analyzed by two-way, repeated-measures analysis of variance (ANOVA) (nap [nap versus no-nap] x time point [pre-nap versus post-nap]). PSG and R(T) data were analyzed with one-way repeated-measures ANOVA. Marginally significant interactions were observed for RTs and lapses in VVT for the L60 nap condition (p = .071 and p = .070, respectively). However, those effect sizes were moderate (partial eta(2) = 0.266, 0.268, respectively). Post hoc analyses showed significantly longer RTs (p < .05) and more lapses (p < .05) following the L60 nap compared with no nap. In contrast, there was no significant difference in sleepiness between the L60, or any of the other nap conditions, and the no-nap condition. Our findings suggest the effect of sleep inertia on VVT performance was profound in the L60 condition, although no significant effects on sleepiness were self-reported by VAS. The dissociation between performance and sleepiness might reflect an unstable state where participants cannot perceive decline in their performance. The present findings are significant in terms of occupational safety; the practical implication is that great care is needed when taking a 1-h nap between 04:00 and 05:00 h on the night shift.

This prospective cohort study showed that GERD appears to be a predictive factor for hospitalization due to AECOPD and that severer GERD symptoms may be associated with more frequent AECOPD. Thus, further studies are warranted to evaluate the preventive effect of the therapy for GERD on AECOPD.