US public opinion regarding proposed limits on resident physician work hours

<p>Abstract</p> <p>Background</p> <p>In both Europe and the US, resident physician work hour reduction has been a source of controversy within academic medicine. In 2008, the Institute of Medicine (IOM) recommended a reduction in resident physician work hours. We sought to assess the American public perspective on this issue.</p> <p>Methods</p> <p>We conducted a national survey of 1,200 representative members of the public via random digit telephone dialing in order to describe US public opinion on resident physician work hour regulation, particularly with reference to the IOM recommendations.</p> <p>Results</p> <p>Respondents estimated that resident physicians currently work 12.9-h shifts (95% CI 12.5 to 13.3 h) and 58.3-h work weeks (95% CI 57.3 to 59.3 h). They believed the maximum shift duration should be 10.9 h (95% CI 10.6 to 11.3 h) and the maximum work week should be 50 h (95% CI 49.4 to 50.8 h), with 1% approving of shifts lasting >24 h (95% CI 0.6% to 2%). A total of 81% (95% CI 79% to 84%) believed reducing resident physician work hours would be very or somewhat effective in reducing medical errors, and 68% (95% CI 65% to 71%) favored the IOM proposal that resident physicians not work more than 16 h over an alternative IOM proposal permitting 30-h shifts with ≥5 h protected sleep time. In all, 81% believed patients should be informed if a treating resident physician had been working for >24 h and 80% (95% CI 78% to 83%) would then want a different doctor.</p> <p>Conclusions</p> <p>The American public overwhelmingly favors discontinuation of the 30-h shifts without protected sleep routinely worked by US resident physicians and strongly supports implementation of restrictions on resident physician work hours that are as strict, or stricter, than those proposed by the IOM. Strong support exists to restrict resident physicians' work to 16 or fewer consecutive hours, similar to current limits in New Zealand, the UK and the rest of Europe.</p

Amplitude Reduction and Phase Shifts of Melatonin, Cortisol and Other Circadian Rhythms after a Gradual Advance of Sleep and Light Exposure in Humans

Background: The phase and amplitude of rhythms in physiology and behavior are generated by circadian oscillators and entrained to the 24-h day by exposure to the light-dark cycle and feedback from the sleep-wake cycle. The extent to which the phase and amplitude of multiple rhythms are similarly affected during altered timing of light exposure and the sleepwake cycle has not been fully characterized. Methodology/Principal Findings: We assessed the phase and amplitude of the rhythms of melatonin, core body temperature, cortisol, alertness, performance and sleep after a perturbation of entrainment by a gradual advance of the sleep-wake schedule (10 h in 5 days) and associated light-dark cycle in 14 healthy men. The light-dark cycle consisted either of moderate intensity ‘room ’ light (,90–150 lux) or moderate light supplemented with bright light (,10,000 lux) for 5 to 8 hours following sleep. After the advance of the sleep-wake schedule in moderate light, no significant advance of the melatonin rhythm was observed whereas, after bright light supplementation the phase advance was 8.1 h (SEM 0.7 h). Individual differences in phase shifts correlated across variables. The amplitude of the melatonin rhythm assessed under constant conditions was reduced after moderate light by 54 % (17–94%) and after bright light by 52 % (range 12–84%), as compared to the amplitude at baseline in the presence of a sleep-wake cycle. Individual differences in amplitude reduction of the melatonin rhythm correlated with the amplitude of body temperature, cortisol and alertness

Analysis Method and Experimental Conditions Affect Computed Circadian Phase from Melatonin Data

Accurate determination of circadian phase is necessary for research and clinical purposes because of the influence of the master circadian pacemaker on multiple physiologic functions. Melatonin is presently the most accurate marker of the activity of the human circadian pacemaker. Current methods of analyzing the plasma melatonin rhythm can be grouped into three categories: curve-fitting, threshold-based and physiologically-based linear differential equations. To determine which method provides the most accurate assessment of circadian phase, we compared the ability to fit the data and the variability of phase estimates for seventeen different markers of melatonin phase derived from these methodological categories. We used data from three experimental conditions under which circadian rhythms - and therefore calculated melatonin phase - were expected to remain constant or progress uniformly. Melatonin profiles from older subjects and subjects with lower melatonin amplitude were less likely to be fit by all analysis methods. When circadian drift over multiple study days was algebraically removed, there were no significant differences between analysis methods of melatonin onsets (P = 0.57), but there were significant differences between those of melatonin offsets (P<0.0001). For a subset of phase assessment methods, we also examined the effects of data loss on variability of phase estimates by systematically removing data in 2-hour segments. Data loss near onset of melatonin secretion differentially affected phase estimates from the methods, with some methods incorrectly assigning phases too early while other methods assigning phases too late; missing data at other times did not affect analyses of the melatonin profile. We conclude that melatonin data set characteristics, including amplitude and completeness of data collection, differentially affect the results depending on the melatonin analysis method used

Influence of permanent night work on the circadian rhythm of blood pressure

Abstract. Night workers exercise their labours activities and rest in contrary schedules to the chronobiological standards. This inversion leads the body to several adaptations, including changes in the circadian rhythm of blood pressure (BP). Objectives: To evaluate the BP in individuals who perform work at night, in order to objectively detail the BP circadian rhythm adaptations infixed night workers. Methods: A cross-sectional study enrolling 23 fixed night workers, both genders, was performed, with 24h BP measured with ambulatory blood pressure monitoring (ABPM) during a normal working day. Risk factors, anthropometric and lifestyle information were collected using a standard questionnaire. Results: Ambulatory BP demonstrated a pattern of adaptation to the sleep/activity cycle in all participants. BP dropped during the sleeping period (mean drop: -11.35±6.85) and was higher during the awakening period, reaching the highest results and greater BP variability during the working period. The chronobiological adaptation of the 24h BP was not dependent on sociodemographic or clinical characteristics. In addition, age, male gender, obesity, and those working less time were associated with higher BP mean values. Conclu-sions: The circadian rhythm of BP follows the working circadian profile of the individual.info:eu-repo/semantics/publishedVersio

Plasticity of the Intrinsic Period of the Human Circadian Timing System

Human expeditions to Mars will require adaptation to the 24.65-h Martian solar day-night cycle (sol), which is outside the range of entrainment of the human circadian pacemaker under lighting intensities to which astronauts are typically exposed. Failure to entrain the circadian time-keeping system to the desired rest-activity cycle disturbs sleep and impairs cognitive function. Furthermore, differences between the intrinsic circadian period and Earth's 24-h light-dark cycle underlie human circadian rhythm sleep disorders, such as advanced sleep phase disorder and non-24-hour sleep-wake disorders. Therefore, first, we tested whether exposure to a model-based lighting regimen would entrain the human circadian pacemaker at a normal phase angle to the 24.65-h Martian sol and to the 23.5-h day length often required of astronauts during short duration space exploration. Second, we tested here whether such prior entrainment to non-24-h light-dark cycles would lead to subsequent modification of the intrinsic period of the human circadian timing system. Here we show that exposure to moderately bright light (∼450 lux; ∼1.2 W/m2) for the second or first half of the scheduled wake episode is effective for entraining individuals to the 24.65-h Martian sol and a 23.5-h day length, respectively. Estimations of the circadian periods of plasma melatonin, plasma cortisol, and core body temperature rhythms collected under forced desynchrony protocols revealed that the intrinsic circadian period of the human circadian pacemaker was significantly longer following entrainment to the Martian sol as compared to following entrainment to the 23.5-h day. The latter finding of after-effects of entrainment reveals for the first time plasticity of the period of the human circadian timing system. Both findings have important implications for the treatment of circadian rhythm sleep disorders and human space exploration

Nightly treatment of primary insomnia with prolonged release melatonin for 6 months: a randomized placebo controlled trial on age and endogenous melatonin as predictors of efficacy and safety

&lt;p&gt;Background: Melatonin is extensively used in the USA in a non-regulated manner for sleep disorders. Prolonged release melatonin (PRM) is licensed in Europe and other countries for the short term treatment of primary insomnia in patients aged 55 years and over. However, a clear definition of the target patient population and well-controlled studies of long-term efficacy and safety are lacking. It is known that melatonin production declines with age. Some young insomnia patients also may have low melatonin levels. The study investigated whether older age or low melatonin excretion is a better predictor of response to PRM, whether the efficacy observed in short-term studies is sustained during continued treatment and the long term safety of such treatment.&lt;/p&gt; &lt;p&gt;Methods: Adult outpatients (791, aged 18-80 years) with primary insomnia, were treated with placebo (2 weeks) and then randomized, double-blind to 3 weeks with PRM or placebo nightly. PRM patients continued whereas placebo completers were re-randomized 1:1 to PRM or placebo for 26 weeks with 2 weeks of single-blind placebo run-out. Main outcome measures were sleep latency derived from a sleep diary, Pittsburgh Sleep Quality Index (PSQI), Quality of Life (World Health Organzaton-5) Clinical Global Impression of Improvement (CGI-I) and adverse effects and vital signs recorded at each visit.&lt;/p&gt; &lt;p&gt;Results: On the primary efficacy variable, sleep latency, the effects of PRM (3 weeks) in patients with low endogenous melatonin (6-sulphatoxymelatonin [6-SMT] ≤8 μg/night) regardless of age did not differ from the placebo, whereas PRM significantly reduced sleep latency compared to the placebo in elderly patients regardless of melatonin levels (-19.1 versus -1.7 min; P = 0.002). The effects on sleep latency and additional sleep and daytime parameters that improved with PRM were maintained or enhanced over the 6-month period with no signs of tolerance. Most adverse events were mild in severity with no clinically relevant differences between PRM and placebo for any safety outcome.&lt;/p&gt; &lt;p&gt;Conclusions: The results demonstrate short- and long-term efficacy and safety of PRM in elderly insomnia patients. Low melatonin production regardless of age is not useful in predicting responses to melatonin therapy in insomnia. The age cut-off for response warrants further investigation.&lt;/p&gt

Circadian-Related Sleep Disorders and Sleep Medication Use in the New Zealand Blind Population: An Observational Prevalence Survey

STUDY OBJECTIVES: To determine the prevalence of self-reported circadian-related sleep disorders, sleep medication and melatonin use in the New Zealand blind population. DESIGN: A telephone survey incorporating 62 questions on sleep habits and medication together with validated questionnaires on sleep quality, chronotype and seasonality. PARTICIPANTS: PARTICIPANTS WERE GROUPED INTO: (i) 157 with reduced conscious perception of light (RLP); (ii) 156 visually impaired with no reduction in light perception (LP) matched for age, sex and socioeconomic status, and (iii) 156 matched fully-sighted controls (FS). SLEEP HABITS AND DISTURBANCES: The incidence of sleep disorders, daytime somnolence, insomnia and sleep timing problems was significantly higher in RLP and LP compared to the FS controls (p<0.001). The RLP group had the highest incidence (55%) of sleep timing problems, and 26% showed drifting sleep patterns (vs. 4% FS). Odds ratios for unconventional sleep timing were 2.41 (RLP) and 1.63 (LP) compared to FS controls. For drifting sleep patterns, they were 7.3 (RLP) and 6.0 (LP). MEDICATION USE: Zopiclone was the most frequently prescribed sleep medication. Melatonin was used by only 4% in the RLP group and 2% in the LP group. CONCLUSIONS: Extrapolations from the current study suggest that 3,000 blind and visually impaired New Zealanders may suffer from circadian-related sleep problems, and that of these, fewer than 15% have been prescribed melatonin. This may represent a therapeutic gap in the treatment of circadian-related sleep disorders in New Zealand, findings that may generalize to other countries