Relatively few studies have been conducted of the association between air pollution and emergency department (ED) visits, and most of these have been based on a small number of visits, for a limited ...number of health conditions and pollutants, and only daily measures of exposure and response.
A time-series analysis was conducted on nearly 400,000 ED visits to 14 hospitals in seven Canadian cities during the 1990 s and early 2000s. Associations were examined between carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), sulfur dioxide (SO2), and particulate matter (PM 10 and PM2.5), and visits for angina/myocardial infarction, heart failure, dysrhythmia/conduction disturbance, asthma, chronic obstructive pulmonary disease (COPD), and respiratory infections. Daily and 3-hourly visit counts were modeled as quasi-Poisson and analyses controlled for effects of temporal cycles, weather, day of week and holidays.
24-hour average concentrations of CO and NO2 lag 0 days exhibited the most consistent associations with cardiac conditions (2.1% (95% CI, 0.0-4.2%) and 2.6% (95% CI, 0.2-5.0%) increase in visits for myocardial infarction/angina per 0.7 ppm CO and 18.4 ppb NO2 respectively; 3.8% (95% CI, 0.7-6.9%) and 4.7% (95% CI, 1.2-8.4%) increase in visits for heart failure). Ozone (lag 2 days) was most consistently associated with respiratory visits (3.2% (95% CI, 0.3-6.2%), and 3.7% (95% CI, -0.5-7.9%) increases in asthma and COPD visits respectively per 18.4 ppb). Associations tended to be of greater magnitude during the warm season (April - September). In particular, the associations of PM 10 and PM2.5 with asthma visits were respectively nearly three- and over fourfold larger vs. all year analyses (14.4% increase in visits, 95% CI, 0.2-30.7, per 20.6 microg/m3 PM 10 and 7.6% increase in visits, 95% CI, 5.1-10.1, per 8.2 microg/m3 PM2.5). No consistent associations were observed between three hour average pollutant concentrations and same-day three hour averages of ED visits.
In this large multicenter analysis, daily average concentrations of CO and NO2 exhibited the most consistent associations with ED visits for cardiac conditions, while ozone exhibited the most consistent associations with visits for respiratory conditions. PM 10 and PM2.5 were strongly associated with asthma visits during the warm season.
Summary
It is commonly claimed that sleep duration has declined in recent years – over a period coinciding with a marked increase in personal electronics and communications use. The aim of this study ...was to assess change in sleep duration among Canadians from 1998 to 2010, and examine any associations with non‐work‐related screen time. The analysis uses population‐representative data from Statistics Canada's General Social Survey cycles of 1998 and 2010; the respective samples numbered 10 749 and 15 390 individuals. Response rates were 80% in 1998 and 55% in 2010. Respondents were aged 15 years and older, residing in private households in the 10 Canadian provinces. The General Social Survey is administered by computer‐assisted telephone interviewing. Data on sleep duration (excluding naps outside essential sleep time) and recreational screen time were obtained using a 24‐h time‐use diary. Survey weights were applied to adjust for non‐response and non‐landline households. Frequencies (respondent characteristics) and averages (time‐use variables) were estimated by age group and sex. Sleep duration was examined by weighted quartile of screen time. Confidence intervals (95%) were calculated around estimates. Average sleep duration increased from 8.1 h in 1998 to 8.3 h in 2010. Average screen time increased from 140 min in 1998 to 154 min in 2010. Sleep duration and screen time were positively related in both years. The percentage of people averaging less than 6 h sleep decreased from 9.6% in 1998 to 8.6% in 2010. Between 1998 and 2010, increases in screen time did not occur at the expense of sleep duration.
This study compares two North American time-activity data bases: the National Human Activity Pattern Survey (NHAPS) of 9386 interviewees in 1992-1994 in the continental USA with the Canadian Human ...Activity Pattern Survey (CHAPS) of 2381 interviewees in 1996-1997 in four major Canadian cities. Identical surveys and methodology were used to collect this data: random sample telephone selection within the identified telephone exchanges, computer-assisted telephone interviews, overselection of children and weekends in the 24-h recall diary and the same interviewers. Very similar response rates were obtained: 63% (NHAPS) and 64.5% (CHAPS). Results of comparisons by age within major activity and location groups suggest activity and location patterns are very similar (most differences being less than 1% or 14 min in a 24-h day) with the exception of seasonal differences. Canadians spend less time outdoors in winter and less time indoors in summer than their U.S. counterparts. When exposure assessments use time of year or outdoor/indoor exposure gradients, these differences may result in significant differences in exposure assessments. Otherwise, the 24-h time activity patterns of North Americans are remarkably similar and use of the combined data set for some exposure assessments may be feasible.
Heart failure with reduced ejection fraction and obstructive sleep apnea (OSA), 2 states of increased metabolic demand and sympathetic nervous system activation, often coexist. Continuous positive ...airway pressure (CPAP), which alleviates OSA, can improve ventricular function. It is unknown whether this is due to altered oxidative metabolism or presynaptic sympathetic nerve function. We hypothesized that short-term (6-8 weeks) CPAP in patients with OSA and heart failure with reduced ejection fraction would improve myocardial sympathetic nerve function and energetics.
Forty-five patients with OSA and heart failure with reduced ejection fraction (left ventricular ejection fraction 35.8±9.7% mean±SD) were evaluated with the use of echocardiography and 11C-acetate and 11C-hydroxyephedrine positron emission tomography before and ≈6 to 8 weeks after randomization to receive short-term CPAP (n=22) or no CPAP (n=23). Work metabolic index, an estimate of myocardial efficiency, was calculated as follows: (stroke volume index×heart rate×systolic blood pressure÷Kmono), where Kmono is the monoexponential function fit to the myocardial 11C-acetate time-activity data, reflecting oxidative metabolism. Presynaptic sympathetic nerve function was measured with the use of the 11C-hydroxyephedrine retention index. CPAP significantly increased hydroxyephedrine retention versus no CPAP (Δretention: +0.012 0.002, 0.021 versus -0.006 -0.013, 0.005 min(-1); P=0.003). There was no significant change in work metabolic index between groups. However, in those with more severe OSA (apnea-hypopnea index>20 events per hour), CPAP significantly increased both work metabolic index and systolic blood pressure (P<0.05).
In patients with heart failure with reduced ejection fraction and OSA, short-term CPAP increased hydroxyephedrine retention, indicating improved myocardial sympathetic nerve function, but overall did not affect energetics. In those with more severe OSA, CPAP may improve cardiac efficiency. Further outcome-based investigation of the consequences of CPAP is warranted.
http://www.clinicaltrials.gov. Unique identifier: NCT00756366.
The Effects of Continuous Positive Airway Pressure on Myocardial Energetics in Patients With Heart Failure and Obstructive Sleep Apnea Keiichiro Yoshinaga, Ian G. Burwash, Judith A. Leech, Haissam ...Haddad, Chris B. Johnson, Robert A. deKemp, Linda Garrard, Li Chen, Kathryn Williams, Jean N DaSilva, Rob S. B. Beanlands The effect of continuous positive airway pressure (CPAP) on myocardial energetics and left ventricular function was evaluated by echocardiography and 11 C acetate positron emission tomography in patients with heart failure and obstructive sleep apnea. Longer-term CPAP treatment (6 weeks) leads to an improvement in left ventricular systolic function, tends to reduce oxidative metabolism, and leads to an improvement in myocardial efficiency. This indicates an energy-sparing effect of nocturnal CPAP therapy, which may contribute the clinical benefits observed with CPAP therapy in patients with heart failure and obstructive sleep apnea.
To demonstrate that fetal heart rate measured by ultrasound can be successfully captured and monitored throughout the nocturnal polysomnogram.
Fetal heart rate by ultrasound using an abdominal belt ...(Hewlett Packard Fetal Monitor 8040A) was measured during 1 overnight polysomnogram in volunteers in late pregnancy and added to a digitized polysomnography system (Alice 4, Respironics).
In 6 women with a single fetus in their third trimester, the fetal heart rate monitor band only infrequently needed to be readjusted. Fetal kicks and movements resulted in signal loss, usually with subsequent recapture without having to awaken the mother.
Fetal heart rate, 1 of the classic signals of fetal distress, can be added to the nocturnal polysomnogram with minimal disruption of maternal sleep and with signal capture throughout the night.
Time-activity patterns in a panel of 70 patients with COPD (35 males) are compared to an age-matched subgroup from the randomly sampled Canadian Human Activity Pattern Survey. Total time indoors and ...outdoors were similar in both groups but significantly more indoor time in COPD subjects was spent at home than the indoor time of controls, who were more often indoors elsewhere. As part of improving their indoor air at home, COPD subjects were significantly more likely to have air conditioning at home. These results suggest that while outdoor air exposure strategies need not differ in COPD subjects from normals, indoor mitigation strategies should emphasize source pollutant control in the patient's home.
The ability of preoperative quality-of-life and physiologic variables to predict postoperative complications was tested in 117 consecutive patients undergoing thoracotomy for possible or definite ...lung cancer. Preoperatively, quality of life was globally assessed by the QLI and Sickness Impact Profile. Dyspnea was assessed by the Clinical Dyspnea Index and a modified Pneumoconiosis Research Unit question. Spirometry and maximal exercise testing were carried out in 115 and 46 subjects, respectively. Thirty-seven percent experienced at least one respiratory complication (eg, pneumonia, atelectasis prompting bronchoscopy, pulmonary embolism). Twofold or greater increases in respiratory complications were associated with current smoking (p<0.05), cancer as the final pathologic condition (p<0.10), at least moderate dyspnea (p<0.10), FEV1 <60 percent of predicted (p<0.05), ventilatory reserve <25 L (p<0.05), and Vo2max <1.25 L (p<0.05). Twofold increases in the incidence of any complication (respiratory, cardiac, etc) were associated with age ≥75 years (p<0.05) and cancer as the final pathologic condition (p<0.05). We conclude that simple historic information (age, smoking status, cancer status, dyspnea) indicates the risk of postoperative morbidity. General quality-of-life measures were not good predictors of morbidity. Our findings corroborate the few studies supporting the value of Vo2max and suggest that the usefulness of the ventilatory reserve deserves further attention.
Ozone is known to yield hydroxyl radical, which may contribute to ozone-mediated lung injury. In the presence of hydroxyl radical, salicylate is hydroxylated to form 2,3-dihydroxybenzoic acid ...(2,3-DHBA). There is no evidence of enzymatic formation of 2,3-DHBA. We hypothesized that salicylate hydroxylation might be used as a biomarker indicating human exposure to ozone. Healthy, nonsmoking volunteers, 18 to 34 yr of age, were given acetylsalicylic acid (975 mg) or placebo orally 0.5 h before an exposure. Subjects were exposed to ozone (0.12 or 0.4 ppm) or filtered air in an environmental chamber for 2 h, while performing intermittent exercise. Results indicate significant decrements in FVC, FEV1.0, forced expiratory flows at 50% and 75% of FVC, and peak expiratory flow rate, and an increase in airway resistance, after exposure to 0.4 ppm ozone in comparison with air control (p < 0.05). Exposure to 0.4 ppm ozone also resulted in increased symptom numbers and severity (p < 0.05). When subjects were exposed to 0.12 ppm ozone, changes of pulmonary function and symptoms reported were minimal. Plasma concentration of 2,3-DHBA was significantly increased after exposure to 0.12 and 0.4 ppm ozone in comparison with air control (p < 0.05). There was a significant correlation between ozone-induced changes of pulmonary function and normalized salicylate hydroxylation (p < 0.05). The results indicate that exposure to ozone can initiate in vivo production of hydroxyl radical, a potent reactive agent. Salicylate hydroxylation may then serve as a sensitive dosimetric biomarker for ozone exposure, even at subclinical ozone exposure levels.
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