Literature Updates from May 2015

Sedation-Analgesia with Propofol and Remifentanil: Concentrations Required to Avoid Gag Reflex in Upper Gastrointestinal Endoscopy

The work presented by Borrat et al wants to define safe sedation and analgesia guidelines in this case for upper gastrointestinal endoscopy. One of the most stressful moments for the patient is introduction of the endoscopy tube through the mouth and pharynx. Using a sequential statistical approach the concetrations associated with a probability of 0.5 or 0.9 of avoding gag response are estimated and could be used as a starting point for any combination of sedation and analgesia in this situation.

http://www.ncbi.nlm.nih.gov/pubmed/25902320

A Framework for Quantitative Modeling of Neural Circuits Involved in Sleep-to-Wake Transition

Optogenetics has transformed research in the understanding on how neural circuits work. The ability to estimulate single neurons enables the investigators to learn how can influence a predetermined behavior or response. In the present paper Luis de Lecea and his research group proposes a framework to investigate all the circuitry involved in the sleep-wake transitions using the stimulation of single neurons. It is through the knowledge of these mechanisms that we might be able to know how similar or different sedation techniques could be as compared to physiologic sleep and to test if the use of specific drugs to induce sedation might have the same beneficial effects as physiologic sleep.

http://www.ncbi.nlm.nih.gov/pubmed/25767461

Oxalic Acid and Diacylglycerol 36:3 are Cross-Species Markers of Sleep Debt

This work compares metabolic serum profiles from human subjects and experimental rats subjects to similar sleep restriction protocols. They identified numerous significant changes in lipid metabolism between experimental and control groups in both species. Interestingly amongst all changes, a reduction in the metabolites oxalic acid and diacylglycerol 36:3 strongly correlated with sleep restriction across both species. This work provides an overview of the dysfunctional metabolic profile associated with reduced sleep duration and provides potential biomarkers for sleep loss.

http://www.ncbi.nlm.nih.gov/pubmed/25675494

Neuronal Ensembles Sufficient for Recovery Sleep and the Sedative Actions of a2 Adrenergic Agonists

This paper outlines brain regions involved in α-2 adrenergic (α2A) mediated sleep pathways in a mouse model.   By using targeted acute genetic knockdowns of α2A receptors in the locus coeruleus the authors were able to show that the loss of righting reflex and sedation are mediated by α2A agonists but likely involved distinct pathways, and suggesting that LORR is not loss of consciousness but rather a spinal cord inhibitory process. Looking at activated neurons in the hypothalamus they showed a similar pattern of activation between dexmedetomidine-sedated animals and animals in normal recovery sleep.   Targeted reactivation of lateral preoptic neu­rons was sufficient to induce sedation and that GABA inhibition in the same region delayed the sedation caused by dexmedetomidine implying in the involvement of other neuronal subsets in this process.

http://www.ncbi.nlm.nih.gov/pubmed/25706476

Sleep in the Intensive Care Unit

This review article focuses on what is known about sleep in patients admitted to ICU. The etiologies of sleep disruption and circadian rhythm abnormalities in the ICU, tools to measure sleep in critically ill patients, sleep-promoting interventions in the ICU, and sleep disturbances that persist or develop after critical illness are reviewed.

www.atsjournals.org/doi/abs/10.1164/rccm.201411-2099CI

Blood Pressure Regulation, Autonomic Control and Sleep Disordered Breathing in Children

There is mounting evidence that the cardiovascular and autonomic consequences of SDB are not limited to those with OSA, but are also evident in children with PS. The severity of disease and age of onset of autonomic consequences may be important guides for the treatment of SDB.

http://www.ncbi.nlm.nih.gov/pubmed/23850404

Obstructive Sleep Apnea and Hypoxemia are Associated with Advanced Liver Histology in Pediatric Nonalcoholic Fatty Liver Disease

Moderate OSA/hypoxemia is common in pediatric patients with biopsy-proven NAFLD. OSA and the severity/duration of hypoxemia are associated with biochemical and histological measures of NAFLD severity.

http://www.ncbi.nlm.nih.gov/pubmed/24321532

Effects of Partial Tonsillectomy on the Immune Functions of Children with Obstructive Sleep Apnea-Hypopnea Syndrome at Early Stage

The results from the present study indicate that partial tonsillectomy by plasma-mediated temperature-controlled radiofrequency ablation did not impact on the humoral and cellular immunity of children.

http://www.ncbi.nlm.nih.gov/pubmed/24615085