Literature Updates from March 2014

Seasonal Trends in Sleep-Disordered Breathing: Evidence from Internet Search Engine Query Data

In this study, internet search engine query data were retrieved from Google Trends over six years from 2012, from USA and Australia.  Authors found statistically significant seasonal effects were found using cosinor analysis in both USA and Australia for “snoring” (p<0.00001 for both countries). Similarly, seasonal patterns were observed for “sleep apnea” in the USA (p=0.001). Magnitude of seasonal effect raged from 5–50%. This indicates that there are significant trends for both snoring and sleep apnea internet search engine queries, with peaks in winter and early spring. Future studies may examine the mechanisms underlying these findings, and whether there is a clinical correlation or not.

Essential Thalamic Contribution to Slow Waves of Natural Sleep

These results demonstrate that the thalamus finely tunes the frequency of slow waves during non-REM sleep and anesthesia, and thus provide the first conclusive evidence that a dynamic interplay of the neocortical and thalamic oscillators of slow waves is required for the full expression of this key physiological EEG rhythm.

Decreased Connectivity Between the Thalamus and the Neocortex During Human Nonrapid Eye Movement Sleep

Results of this study provide evidence of a functional deafferentation of the neocortex during nonrapid eye movement (NREM) sleep in humans. … suggesting that changes in thalamocortical connectivity may act as a universal “control switch” for changes in consciousness that are observed in coma, general anesthesia, and natural sleep

Obstructive Sleep Apnea and Cognitive Impairment: Addressing the Blood-Brain Barrier

An interesting review that addresses the role of blood-brain barrier in OSA. “Studies demonstrate that disruption to the blood-brain barrier (BBB), which is uniquely structured to tightly maintain homeostasis inside the brain, leads to changes in the brain’s microenvironment and affects synaptic plasticity. Cyclical intermittent hypoxia is a stressor that could disrupt the BBB via molecular responses already known to occur in either OSA patients or animal models of intermittent hypoxia.

Typical Sleep Patterns Are Absent in Mechanically Ventilated Patients and Their Circadian Melatonin Rhythm is Evident But the Timing is Altered by the ICU Environment

The authors performed a prospective observational study of 25 mechanically ventilated and sedated patients admitted to a North American ICU. The study investigators evaluated whether circadian and homeostatic processes were functioning normally and appropriately in these patients in order to maintain normal sleep–wake patterns. The authors discovered that these patients appear to have a “free running circadian pacemaker”. The investigators found that EEG activity demonstrated slow wave sleep that was similarly distributed during the 24 hour period of evaluation, indicating absence of changes between wake and sleep states. This study highlights the importance of providing an ICU environment that promotes a normal circadian rhythm.

Nurses Perceptions of Sleep in the Intensive Care Unit Environment: A Literature Review

In this study, the authors hypothesized that frequent assessment by nurses may lead to nursing being the multidisciplinary team members most at risk for impacting the critically ill patients ability to sleep. Through a review of the literature, the authors evaluated the nurses’ knowledge and prioritization of sleep; their understanding of sleep assessment skills and tools; the effects of nursing interventions upon the sleep experience; the implementation of acupuncture a complimentary therapy to aid sleep. 25 articles meet the inclusion criteria as determined by the authors. The authors concluded, “ICU nurses lack a complex understanding of the importance of sleep and interventions needed to promote it.” They site insufficient training and lack of protocols within nursing practice as contributing factors. These important findings can serve as a stimulus to provide nursing with better training and tools to assess and improve sleep in ICU patients.

Bidirectional Relationships Between Sleep Duration and Screen Time in Early Childhood

In this cohort study, a representative sample of 3427 children was obtained from Longitudinal Study of Australian Children. Bidirectional relationships between sleep duration and screen time (TV and Computer) were examined using a cross-lagged models for ages 4, 6 and 8 years. Sleep duration was recorded based on 2 time use diaries maintained by one of the parents on a weekday and weekend day, each. They found that sleep duration was inversely associated with subsequent screen time after two years. Significant associations were observed for children belonging to parents with low education level and extremes of socio-economic status (high and low). Future studies should be targeted to explore the factors resulting in these differences.

Factors Contributing to Cost in Partial Versus Total Tonsillectomy

Previous studies have shown equivalent effectiveness between these two procedures; our study suggests decreased cost and resource utilization with partial tonsillectomy through reduced operative and PACU times and number of postoperative admissions and emergency department visits.

Discharge After Tonsillectomy in Pediatric Sleep Apnea Patients

Patients with an RDI of <5.0, and minimal co-morbidities can be safely discharged home following tonsillectomy for OSAHS. Complications related to sleep apnea were not seen in patients with RDI <11.0, suggesting that patients with an RDI between 5 and 10, who are not obese and have no significant comorbidities may also be sent home after surgery.

The Evaluation of Adenotonsillectomy on TNF-α and IL-6 Levels in Obese Children With Obstructive Sleep Apnea

T&A therapy can improve clinical symptoms and signs but is not a cure for the treatment of obese children with OSA. The inflammation levels of TNF-α and IL-6 changed little. To reduce the risk for excessive daytime sleepiness, supplementary therapies should be introduced for OSA.