Evaluating sleep characteristics in intensive care unit and non-intensive care unit physicians.

Healthcare workers' cognitive performances and alertness are highly vulnerable to sleep loss and circadian rhythms. The purpose of this study was to investigate the changes in sleep characteristics of intensive care unit (ICU) and non-ICU physicians. Actigraphic sleep parameters, Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale and Hamilton Depression Rating Scale were evaluated for ICU and non-ICU physicians on the day before shift-work and on three consecutive days after shift-work. Total sleep time, sleep latency, wakefulness after sleep onset, total activity score, movement fragmentation index, sleep efficiency, daytime naps and total nap duration were also calculated by actigraph. In the ICU physicians, the mean Pittsburgh Sleep Quality Index score was significantly higher than the non-ICU physicians (P = 0.001), however mean Epworth Sleepiness Scale scores were not found significantly different between the two groups. None of the scores for objective sleep parameters were statistically different between the groups when evaluated before and after shift-work (P > 0.05). However in both ICU and non-ICU physicians, sleep latency was observed to be decreased within the three consecutive-day period after shift-work with respect to basal values (P < 0.001). Total sleep time, total activity score and sleep efficiency scores prior to shift-work were significantly different from shift-work and the three consecutive-days after shift-work, in both groups. Working in the ICU does not have an impact on objective sleep characteristics of physicians in this study. Large cohort studies are required to determine long-term health concerns of shift-working physicians.

Atmospheric deposition of polycyclic aromatic hydrocarbons in an urban and a suburban area of Korea from 2002 to 2004.

Atmospheric bulk samples (wet and dry) were collected monthly during 2002 to 2004 from an urban and a suburban area in Korea for assessment of depositional flux and seasonal variations in the concentrations of polycyclic aromatic hydrocarbons (PAHs). PAH depositional flux ranged from 64.1 to 610 microg/m2/y for the urban area and from 65 to 460 microg/m2/y for the suburban area. The fluxes of PAHs measured in this study were comparable with those reported for urban and suburban areas in other countries. The fluxes of particulates and PAHs were higher in winter than in summer, consistent with the greater per capita consumption of fossil fuel in winter than in summer. Ambient temperature played a major role in the seasonal variability in PAH fluxes. Photochemical degradation of PAHs appears to occur during the summer months. The relationship of PAH depositional fluxes with major air pollutants, such as ozone, sulfur dioxide, carbon monoxide, nitrogen dioxide, and presence of particulate matter up to 10 microm in size (PM10), was also investigated. Dominant PAH compounds in both the urban and the suburban locations were benzo[g,h,i]perylene, pyrene, and indeno[1,2,3-c,d]pyrene. Based on the PAH diagnostic ratios and a factor analysis, the major sources of PAHs in the urban and the suburban regions were found to be similar. Diesel exhaust, coal combustion, and gasoline emissions contributed predominantly to atmospheric PAH contamination.