Monthly Archives: January 2014

Featured Article

Excessive Daytime Sleepiness Increases the Risk of Motor Vehicle Crash in Obstructive Sleep Apnea

A very interesting retrospective case-series observational study conducted using data from the West Australian Sleep Health Study at a tertiary hospital-based sleep clinic. It describe the incidence rate of motor vehicle crashes (MVCs) in patients with obstructive sleep apnea (OSA); and investigates MVC risk factors in OSA patients. 2673 patients were assessed for suspected sleep disordered breathing. Questionnaire data were collected including age, sex, years of driving, near-misses and MVCs, sleepiness, and consumption of alcohol and caffeinated drinks and an overnight laboratory-based polysomnography was performed.

The authors show that the crash rate was 0.06 MVC/person-year compared with the general community crash rate of 0.02 MVC/person-year. They concluded that untreated OSA was associated with an increased risk of near-misses in men and women and an increased risk of MVCs in very sleepy men. There was a strong association between excessive daytime sleepiness and increased report of near-misses. The data supports the observation that it is those patients with increased sleepiness regardless of OSA severity who are most at risk.

Featured Article

Nocturnal Intermittent Hypoxia is Independently Associated With Pain in Subjects Suffering From Sleep-Disordered Breathing

Obstructive sleep apnea is characterized by both sleep fragmentation and nocturnal recurrent hypoxemia. Experimental fragmentation or deprivation of sleep enhances sensitivity to pain, promotes inflammation, and advances spontaneous pain in healthy humans. The authors hypothesized that nocturnal hypoxemia would be associated with pain reports in subjects suffering from sleep-disordered breathing, independently of sleep fragmentation and inflammation. They examined the association between arterial desaturation and four different types of pain, as well as their composite measure, sequentially adjusted for: clinical characteristics, sleep fragmentation and inflammation. Decreased minimum nocturnal arterial saturation increased the odds for morning headache, headache disrupting sleep, and chest pain while in bed. A decrease in the minimum nocturnal saturation from 92 to 75% approximately doubled the odds for pain. Furthermore, the authors identified that one single-nucleotide polymorphism for the α 1 chain of collagen type XI (COL11A1-rs1676486) gene was significantly associated with headache disrupting sleep, pain disrupting sleep, and pain composite.

The authors concluded that nocturnal arterial desaturation may be associated with an increased pain in subjects with sleep-disordered breathing, independently of sleep fragmentation and inflammation.

Literature Updates, Sleep

Does One Hour of Bright or Short-Wavelength Filtered Tablet Screenlight Have a Meaningful Effect on Adolescents’ Pre-Bedtime Alertness, Sleep, and Daytime Functioning?

In this experimental study, 16 healthy adolescent volunteers were recruited to be exposed to a bright tablet screen, dim screen and a filtered short-wavelength screen for 1hr before their usual bedtime in a within-subjects protocol. Significant effects occurred between bright and dim screens for pre-sleep alertness (GO/NOGO speed and accuracy), although these were minor and may have little clinical significance. However, no significant effects were found for sleep onset latency, slow-rolling eye movements, or the number of SWS and REM minutes in the first two sleep cycles. More studies are required to examine effects of prolonged screen exposure on pre-sleep alertness and morning daytime functioning amongst vulnerable groups such as adolescents.

ICU, Literature Updates

The Association of Pre-Operative STOP-BANG Scores With Postoperative Critical Care Admission

Obstructive sleep apnea is known to be under diagnosed with an estimated 1 in 3 elective surgical patients possible suffering from this disease. Sleep apnea is of concern to the anesthesiologist and critical care physician for a variety of reasons, none the least of which are an associated increase in myocardial infarction, respiratory failure and cardiac arrest. The STOP-BANG questionnaire is an easy to use, well know, validated tool to screen for obstructive sleep apnea. In this study, the authors retrospectively analyzed the association of STOP-BANG score with ICU admission. The authors hypothesized that a high score would be associated with greater ICU admission. After evaluating 5432 patients who underwent elective surgery, 338 (6.2%) were admitted postoperatively to a critical care unit. The authors found that the STOP-BANG score; age; asthma; a history of obstructive sleep apnea; and ASA physical status was independent predictors of ICU admission. With regards to the STOP-BANG questionnaire, A STOP-BANG score of 6 or more was associated with a fivefold increased rate of postoperative critical care unit admission when compared to a score of 2 or less. Therefore, it appears that the STOP-BANG questionnaire could be a useful tool to also stratify patients for ICU admission.

Clinical Pediatric, Literature Updates

A Randomized Trial of Adenotonsillectomy for Childhood Sleep Apnea

As compared with a strategy of watchful waiting, surgical treatment for the obstructive sleep apnea syndrome in school-age children did not significantly improve attention or executive function as measured by neuropsychological testing but did reduce symptoms and improve secondary outcomes of behavior, quality of life, and polysomnographic findings, thus providing evidence of beneficial effects of early adenotonsillectomy.