Mayo investigators reported back in 2001 that people with obstructive sleep apnea had a higher rate of perioperative complications including hypoxia and longer lengths of stay. Since then, there have been other signals that this is a real phenomenon, but perhaps surprisingly, the evidence hasn’t exactly piled up to unequivocally prove the intuitive point. That’s [… read more]
In the face of criticism from insurers and the government for a perceived excessive zeal for profits, and mounting evidence that uncomplicated obstructive sleep apnea (OSA) can be diagnosed at home and managed by primary physicians, you can’t blame sleep specialists for feeling down-in-the-mouth lately. Sushmita Pamidi et al report some brighter news in the [… read more]
Here’s a great example of how weak findings in small, underpowered studies — findings which should be at most viewed as hypothesis-generating — become transmuted into Serious Studies With Important Implications when the lay press give them too much credit. In this case, the Los Angeles Times, Huffington Post, and CNN took the bait after [… read more]
Did you ever wonder what that police officer is really doing while you wait forever in your car for him to write you your ticket? According to new research, it’s possible he’s taking a quick nap. And you’d best save your snarky comment when he brings you the citation: sleepy cops, it turns out, tend to be [… read more]
One thing I thought I knew was that overweight and obesity cause coronary artery disease and make it worse. People with CAD who are obese should lose weight … right? Recent research shows it’s not that simple (although the answer is still “yes, probably”). Did you know about the “obesity paradox?” Or the “lean paradox,” [… read more]
Mah et al followed 11 Stanford varsity basketball players for ~7-10 weeks. During the first ~3 weeks, players maintained their usual sleep schedules. For the next ~6 weeks, they were encouraged to sleep as long as possible each night, with a goal of 10 hours in bed. After the sleep extension period, their shooting accuracy [… read more]
Carter et al followed 244 children in New Zealand from birth to age 3-7. Between ages 3-5, each additional hour of sleep was associated with a 0.48 reduction in BMI, and a 61% reduction in the risk of being obese or overweight by age 7, after controlling for multiple covariates. BMJ 2011;342:d2712. FREE FULL TEXT
Wijesinghe et al randomized and crossed-over 24 people who were recently diagnosed with obesity hypoventilation syndrome to breathe either 100% oxygen or room air for 20 minutes on 2 separate days, while measuring their minute ventilation, expired tidal pCO2, and dead space-to-tidal volume ratio. In 44% of patients, pCO2 increased by at least 4 mm [… read more]
If you spend your nights lying awake worrying about having a heart attack, you’re entirely justified. But you’re probably just making it more likely. Lars Laugsand et al followed 52,610 Norwegian people for 11 years after the subjects completed an initial survey (investigators can do this in Norway, since they’ve got everyone’s health records in [… read more]
Obesity may impose extra burdens on critical care staff (think turning, transport, intubation and central line placement), but reviews suggest people with “ordinary” obesity (BMI 30-39) with have the same mortality from critical illness as overweight or healthy-weight people. In fact, obese people may have a survival advantage, despite possible longer durations of mechanical ventilation and ICU stays. But what about extreme obesity (BMI > [… read more]
Poor people have higher rates of obesity. There are those who believe that’s because the poor lack self-control and discipline, overeating when they should be pulling themselves up by their bootstraps. That hard-core personal responsibility ethic is hard to refute, maybe because it contains a grain of truth, maybe because it lets all us non-poor [… read more]
Non-invasive positive pressure ventilation (NIPPV or NPPV or NIV), overnight or during the day, has not been shown to help most people with stable COPD and daytime hypercarbia. Citing their own previous findings, Dreher, Windisch et al argue that’s because you can’t just use wimpy ordinary settings — you’ve got to crank that sucker to [… read more]
Obesity was named as a risk factor for severe H1N1 influenza during the pandemic. What about for influenza in general? Kwong et al analyzed community survey data in Ontario over 12 influenza seasons, 1996-2008. Severe obesity (BMI >= 35) carried an odds ratio of 2.1 for respiratory hospitalization during flu season. In those with no [… read more]
Drager LF et al. Obstructive Sleep Apnea: An Emerging Risk Factor for Atherosclerosis. CHEST 2011;140:534-542. OSA and CAD review.
Obstructive sleep apnea and other sleep disorders have long been associated with cognitive dysfunction, but so far not in a prospective study. So, Yaffe et al followed 298 older women (~82 years) who had already had polysomnography as part of an osteoporosis study. 105 had sleep disordered breathing (cases), defined as an apnea-hypopnea index >= [… read more]
A minority of people develop central sleep apneas during polysomnography with continuous positive airway pressure titration for obstructive sleep apnea. Others develop central apneas later, discovered on interrogation of their CPAP machine. The fact is, no one knows much about this so-called complex sleep apnea — its natural course, prognosis / risks, and whether or [… read more]
Kuniyoshi et al prospectively observed people admitted to Mayo for myocardial infarction, performing polysomnography and measuring flow-mediated dilation in their brachial arteries. A whopping 69% (45 of 64) were found to have obstructive sleep apnea. Those with moderate to severe OSA had poorer arterial responsiveness, a surrogate marker for subsequent cardiovascular risk, compared to people [… read more]
Teo et al randomized 24 people with newly diagnosed obstructive sleep apnea (AHI > 15) to crossover between nasal and oronasal (full-face) masks during 2 consecutive nights of CPAP titration. The nasal mask had more leaks and people wearing it had more arousals. However, they liked it better than the face mask, and there was [… read more]
Flexible pressure CPAP reduces pressure briefly during expiration, to try to make it more comfortable. Bakker & Marshall meta-analyzed 10 randomized trials in >500 patients testing flexible pressure vs standard CPAP in people with obstructive sleep apnea; there were no differences in compliance or any other outcome. CHEST 2011;139:1322-1330.
Update in sleep medicine 2010. Mokhlesi B, Gozal D. AJRCCM 2011;183:1472-1476. Sleep review.