The Relationship Between Hippocampal Volume and Cognition in Patients With Chronic Primary Insomnia

In this study the authors found that hippocampal volume (HV) in primary insomniacs (PI) was negatively correlated with the duration of insomnia and the arousal index. PIs exhibited significantly impaired attention, frontal lobe function, and memory, and their verbal and nonverbal memory scores were positively correlated with HV. These findings suggest that chronic sleep deprivation associated with insomnia impairs memory and frontal lobe function, and that insomnia duration and poor sleep quality contribute to a bilateral reduction in HV.

Apnea-Hypopnea Index Use Among Intensive Care Patients: A Case Series

In this study, the authors review eight cases where the apnea-hypopnea index was determined using ApneaLink™. The authors describe the ApneaLink™ tool as a simple and inexpensive device that determines the apnea hypopnea index with a sensitivity and specificity of 100% and 87.5% respectively. The cases demonstrate that the ApneaLink™ device can be utilized in a variety of clinical situations such as post-operatively and in the ICU. In each of the case studies, the ApneaLink™ device help the authors make better management decisions such as ICU admission after surgery or discharge from the ICU with CPAP. The authors also demonstrate how this device can be used to enhance informed consent.

Obstructive Sleep Apnea, Obesity, and the Development of Acute Respiratory Distress Syndrome

In this study, the authors evaluated weather obstructive sleep apnea could increase the risk of pulmonary complications and ARDS in a cohort of 5584 surgical patients from 22 different hospitals. All patients had at least one risk factor for ARDS. 252 of the patient had OSA and 66% of these patients were obese. After statistical analysis, the authors could not conclude that OSA was a risk factor for ARDS. However, BMI was independently associated with ARDS. Hence, it appears that obese patients, with at least one risk factors for ARDS, are at increase risk of developing this severe pulmonary complication post-operatively.

Low-Grade Albuminuria in Children With Obstructive Sleep Apnea

In conclusion, children with moderate-to-severe obstructive sleep apnea are at significantly higher risk of increased low-grade excretion of albumin in the morning urine as compared with control subjects without obstructive sleep apnea. These findings may reflect altered permeability of the glomerular filtration barrier related to nocturnal hypoxemia and sympathetic activation which are induced by obstructive sleep apnea.

CPAP Versus Oxygen in Obstructive Sleep Apnea

In this four-site, randomized, parallel-group clinical trial, adult patients with significant cardiac risk factors or disease were screened for obstructive sleep apnea (OSA) using the Berlin questionnaire. Following home sleep testing, patients with significant OSA (AHI 15-50events/hour) were randomized to: healthy lifestyle and sleep education (HLSE) alone (control), CPAP with HLSE (Auto-CPAP), or supplemental oxygen with HLSE (2 L/min via nasal prongs). The primary outcome was 24-hour mean arterial pressure.

Of 318 patients who underwent randomization, 281 (88%) were evaluated for ambulatory blood pressure at both baseline and follow-up. Patients randomized to both the CPAP and supplemental oxygen groups had similar reductions in nocturnal hypoxemia. The adjusted 24-hour mean arterial pressure at 12 weeks was significantly lower in the CPAP group than in either the control group (−2.4mmHg; P=0.04) or the supplemental oxygen group (−2.8mmHg; P=0.02).

Comments. In patients with cardiovascular disease or multiple cardiovascular risk factors, the treatment of OSA with Auto-CPAP with HLSE resulted in a significant reduction in blood pressure compared to supplemental oxygen with HLSE or HLSE alone. Despite similar effects on nocturnal hypoxemia, the lack of a beneficial effect of supplemental oxygen suggests that factors such as frequent arousals, hypercapnia, and variation in intrathoracic pressure may play a role in hypertension resulting from OSA. Future pragmatic studies are indicated mechanistic influences of supplemental oxygen (such as high vs. low loop gain or dose-response relationship), and prevention of long-term cardiovascular events.

Alterations in Circulating T-Cell Lymphocyte Populations in Children With Obstructive Sleep Apnea

Pediatric OSA is associated with reduced T reg population and altered Th1:Th2 balance toward Th1 predominance, suggesting a shift to a proinflammatory state. The changes in lymphocytic phenotypes associated with OSA may contribute to the variance in systemic inflammation and downstream morbidities associated with this condition.