Mechanisms Mediating Effects of Nitric Oxide on Perifornical Lateral Hypothalamic Neurons

Nitric oxide is a gaseous neurotransmitter that has been implicated in the regulation of sleep. In this study the authors investigated contributions of adenosinergic, GABAergic, and sGC-cGMP signaling mechanisms in mediating nitrergic influences on a major wake-promoting structure, the perifornical-lateral hypothalamic area neurons.

National In-Hospital Morbidity and Mortality Trends After Lumbar Fusion Surgery Between 1998 and 2008

Studying trends in perioperative outcomes in spine surgical patients the authors found that mean patient age and comorbidity burden increased along with significant increases in peri-operative complications including pulmonary and cardiac. These trends highlight the need for appropriate peri-operative services to optimize outcomes in an increasingly morbid and older population of patients undergoing lumbar fusion.

Utilization of Critical Care Services Among Patients Undergoing Total Hip and Knee Arthroplasty: Epidemiology and Risk Factors

The authors sought to identify the incidence and risk factors for the use of critical care services among orthopedic patients and compare the characteristics and outcomes of patients who require critical care services to those who do not. The presence of pulmonary compromise was associated with the highest odds for the use of critical care services (OR 18.44 (16.55, 20.55)).

Pulmonary Hypertension: An Important Predictor of Outcomes in Patients Undergoing Non-Cardiac Surgery

The authors of this article report on perioperative outcomes in a large cohort of patients undergoing non-cardiac surgery, comparing those with and without pulmonary hypertension. They conclude, that in addition to the traditionally known risk factors for outcomes such as coronary artery disease, diabetes mellitus, chronic renal insufficiency, and American Society of Anesthesiology class, the presence of underlying pulmonary hypertension can have a significant negative impact on perioperative outcomes.

A Multisite Randomized Trial of Portable Sleep Studies and Positive Airway Pressure Autotitration Versus Laboratory-Based Polysomnography for the Diagnosis and Treatment of Obstructive Sleep Apnea: The HomePAP Study

This study tests the utility of an integrated clinical pathway for obstructive sleep apnea (OSA) diagnosis and continuous positive airway pressure (CPAP) treatment using portable monitoring devices. A home-based strategy for diagnosis and treatment compared with in-laboratory PSG was not inferior in terms of acceptance, adherence, time to treatment, and functional improvements.

Returning From Oblivion: Imaging the Neural Core of Consciousness

In this elegant study, Långsjö et al. use positron emission tomography (PET) imaging to identify the neuroanatomic sites that are activated during restoration of consciousness (ROC). ROC was tested using two different drugs (dexmedetomidine and propofol), and the study was carefully designed to distinguish between drug-induced epiphenomena and the actual neural correlates associated with ROC. For propofol anesthesia, the dose was decreased and the neural correlates of ROC were identified as the subjects regained consciousness. In contrast, the experiments with dexmedetomidine were performed without changing the drug dose, and gentle tactile and/or verbal stimulation were used to restore consciousness. Because the dose of dexmedetomidine was unchanged, this method allowed the investigators to tease apart the neural correlates associated with the behavioral state change vs. changes due to decreasing drug levels. In both cases, the areas of the brain that were ‘turned on’ during ROC were essentially the same: the anterior cingulate cortex, thalamus, hypothalamus, and brainstem. The implication is that emergence from general anesthesia occurs in a step-wise fashion, where only the activation of arousal-promoting deep brain structures is required for ROC, which apparently precedes the full recovery of neocortical processing.

Hypnotics’ Association With Mortality or Cancer: A Matched Cohort Study

This study sought to estimate the mortality risks associated with specific currently popular hypnotics in a matched cohort design of 10,529 pts who received hypnotic prescriptions and 23,676 matched controls that did not and followed for an average of 2.5 years. They used proportional hazards regression models and also tried to estimate the cancer risks associated with hypnotics. Data were adjusted for age, gender, smoking, body mass index, ethnicity, marital status, alcohol use and prior cancer. They found that pts prescribed any hypnotic had substantially elevated hazards of dying (mostly cardiovascular diseases) compared to those prescribed no hypnotics. Further, those in the upper third of regular hypnotic use had a significant elevation of incident cancer; HR=1.35 and were not attributable to pre-existing disease. The authors concluded that even when prescribed

Effect of Continuous Positive Airway Pressure on the Incidence of Hypertension and Cardiovascular Events in Nonsleepy Patients with Obstructive Sleep Apnea: A Randomized Controlled Trial

In patients with OSA without daytime sleepiness, the prescription of CPAP compared with usual care did not result in a statistically significant reduction in the incidence of hypertension or cardiovascular events. However, the study may have had limited power to detect a significant difference.