Literature Updates from March 2016

Simulated Night Shift Disrupts Circadian Rhythms of Immune Functions in Humans

This work delineates the normal oscillation and responsiveness of circulating monocytes and T lymphocytes in ten human volunteers over circadian time. Under normal circadian parameters, bimodal cytokine secretion was observed with the night peak caused by an increased responsiveness of monocytes, and the day peak corresponding to a higher absolute number of monocytes. T lymphocytes demonstrated an evening peak caused by both higher cell count and responsiveness. When subjected to a night shift schedule (acute circadian disruption) monocyte and T cells circulating phase was not changed but the responsiveness of both cell types was advanced (earlier expression of cytokine) after stimulation. This suggests that acute changes in sleep-wake cycles alter the cell intrinsic responsiveness to stimulation whereas parameters governing circulation may lag behind.

Chronic Intermittent Hypoxia Alters Local Respiratory Circuit Function at the Level of the preBötzinger Complex

The preBotzinger complex in rats is a respiratory neuronal network driving inspiratory rhythm. Chronic intermittent hypoxia (as is the case in OSA) causes irregular firing of the preBotzinger complex. Dysrhythmia in the preBotzinger complex loosens the coupling of neuronal transmission with XIIn. Lipid peroxidation is increased in both the preBotzinger complex and XIIn as a result of chronic intermittent hypoxia. Treatment with antioxidant can reverse the instability in neuronal coupling caused by the exposure hypoxia. This work demonstrates the effect of hypoxia on rhythmic breathing in a salient neuronal network and provides a possible therapeutic strategy to re-establish rhythmic neuronal connectivity in this pathway.

Adenotonsillectomy Complications: A Meta-Analysis

The most frequent early complications after AT are respiratory compromise and secondary hemorrhage. Based on the current limited evidence, children with OSA appear to have more respiratory complications. Conversely, hemorrhage appears to be more frequent in children without OSA.

Characteristics of Children Under 2 Years of Age Undergoing Tonsillectomy for Upper Airway Obstruction

In children under 2 years, ethnicity seems to be a predictor of OSA severity. African-American, prematurity, daycare and Down syndrome patients were significantly more represented in our study population. PSG is more likely to be requested for syndromic children.

Obstructive Sleep Apnoea in Craniofacial Microsomia: A Systematic Review

According to the literature, OSA is related to CFM. However, as there have been no prospective studies and few studies have presented objective measurements, no definitive conclusions can be drawn.

The Conundrum of Primary Snoring in Children: What are We Missing in Regards to Cognitive and Behavioural Morbidity?

Historically, PS has been considered benign, however there is growing evidence that children with PS exhibit cognitive and behavioural deficits equivalent to children with OSA.

Perioperative Respiratory Complications Following Awake and Deep Extubation in Children Undergoing Adenotonsillectomy

There was no difference in the incidence of perioperative respiratory complications in children undergoing a T&A following an awake vs deep extubation. Only weight ≤14 kg was associated with increased perioperative respiratory complications.

Changes in First Postoperative Night Bispectral Index After Daytime Sedation Induced by Dexmedetomidine or Midazolam Under Regional Anesthesia: A Randomized Controlled Trial

1.111 elderly male patients undergoing TURP under spinal anesthesia were randomized to no sedation, sedation with midazolam, or sedation with dexmedetomidine. Intraoperative sedation and postoperative sleep were measured using BIS monitor. Sleep efficiency following surgery was found to be lowest in the dexmedetomidine group and sleep duration was approximately 240 minutes longer in the midazolam group compared to those who had been sedated with dexmedetomidine.

Genome-Wide Association Analysis Identifies Novel Loci for Chronotype in 100,420 Individuals from the UK Biobank

Using the UK Biobank, genome-wide associations were identified linking sleep-time preference (chronotype) to genes and genetic variants related to circadian rhythm and previously uncharacterized pathways that may relate to circadian rhythm and light sensing. Central nervous system, ocular, and fear-response pathways were implicated. Correlations were noted potentially linking the genetics of chronotype to schizophrenia, educational attainment, and BMI.

The Association Between Nocturnal Cardiac Arrhythmias and Sleep Disordered Breathing: The DREAM Study

697 veterans with suspected sleep disordered breathing were observed for nocturnal arrhythmias during polysomnography. After controlling for age, sex, BMI, and cardiovascular disease, moderate to severe sleep disordered breathing was associated with a two-fold increased risk of nocturnal arrhythmias. Frequency of hypoxic events was positively associated with arrhythmia risk.