Sleep apnea treatment after stroke (SATS) trial: is it feasible?

Sleep apnea affects more than half of patients with acute ischemic stroke and is associated with poor stroke outcome. This pilot study assessed the feasibility of a randomized, sham-controlled continuous positive airway pressure (CPAP) trial in subjects with acute ischemic stroke. Subjects identified with sleep apnea based on an apnea-hypopnea index≥5 on overnight polysomnography or portable respiratory monitoring within 7 days of onset of stroke symptoms were randomized to receive active or sham CPAP for a 3-month period. Objective usage was ascertained by compliance data cards. Subjects, treating physicians, and outcome assessors were masked to intervention allocation. Among 87 subjects who provided consent, 74 were able to complete sleep apnea screening, 54 (73%) of whom had sleep apnea. Thirty-two subjects agreed to randomization. Of the 15 subjects who commenced active titration, 11 (73%) took the device home, and 8 (53%) completed the 3-month follow-up. Of the 17 subjects who commenced sham titration, 11 (65%) took the sham device home and completed the 3-month follow-up. The median cumulative usage hours over the 90 days were similar in the active group (53 hours; interquartile range, 22-173 hours) and the sham group (74 hours; interquartile range, 17-94 hours), and blinding to subject condition was successfully maintained. This first-ever randomized, sham-controlled trial of CPAP in patients with recent stroke and sleep apnea demonstrates that sham treatment can be an effective placebo.

High prevalence of supine sleep in ischemic stroke patients.

BACKGROUND AND PURPOSE: Sleep apnea is very common after stroke and is associated with poor outcome. Supine sleep is known to exacerbate apneas in the general sleep apnea population. We therefore investigated the pattern of sleep positions in the acute stroke period. METHODS: Inpatients with acute ischemic stroke underwent full polysomnography that included continuous monitoring of sleep positions. Sleep apnea severity was measured using the apnea-hypopnea index (AHI). Stroke severity was measured by the NIH Stroke Scale (NIHSS) at the time of study enrollment by certified study personnel. Percent total sleep time spent in the supine position was calculated and compared by stroke severity based on a median split of NIHSS using a Wilcoxon rank-sum test. RESULTS: Of the 30 patients, the median age was 67. The median AHI was 23 (IQR: 6, 47). Twenty-two patients (73%) had sleep apnea with an AHI >/=5. The vast majority of sleep time among the stroke cases was spent supine, with a median percent sleep time spent supine of 100 (IQR: 62, 100). The majority (63%) of subjects spent no time asleep in any of the nonsupine positions (prone, left, right). Median percent sleep time supine was 100 (IQR: 100, 100) in those with a higher NIHSS and 63 (IQR: 51, 100) in those with a lower NIHSS (P<0.01). CONCLUSIONS: Given the high prevalence of supine sleep identified, research into positional therapy for stroke patients with sleep apnea seems warranted.

Evaluation and environmental correction of ambient CO2 measurements from a low-cost NDIR sensor.

Non-dispersive infrared (NDIR) sensors are a low-cost way to observe carbon dioxide concentrations in air, but their specified accuracy and precision are not sufficient for some scientific applications. An initial evaluation of six SenseAir K30 carbon dioxide NDIR sensors in a lab setting showed that without any calibration or correction, the sensors have an individual root mean square error (RMSE) between ~5 and 21 parts per million (ppm) compared to a research-grade greenhouse gas analyzer using cavity enhanced laser absorption spectroscopy. Through further evaluation, after correcting for environmental variables with coefficients determined through a multivariate linear regression analysis, the calculated difference between the each of six individual K30 NDIR sensors and the higher-precision instrument had an RMSE of between 1.7 and 4.3 ppm for 1 min data. The median RMSE improved from 9.6 for off-the-shelf sensors to 1.9 ppm after correction and calibration, demonstrating the potential to provide useful information for ambient air monitoring.

Identification and treatment of obstructive sleep apnea in adults and children with epilepsy: a prospective pilot study.

OBJECTIVE: To determine the effect of treating obstructive sleep apnea (OSA) on seizure frequency in adults and children with epilepsy in a prospective study. Several case series documented an improvement in seizure control with treatment of coexisting OSA, but published series did not sample a clinic population, were not prospective in design, and did not account for concurrent changes in antiepileptic drug (AED) doses or levels. PATIENTS AND METHODS: Adult patients and the parents of pediatric patients seen in the University of Michigan Epilepsy and Pediatric Neurology Clinics were given validated questionnaires. Thirteen adults (aged 20-56) and 5 children (aged 14-17) were selected for polysomnography (PSG) based on frequency of seizures and risk for OSA. Seizure frequency was compared during 8-week baseline and treatment phases and AED levels were done to document stability in medication levels. RESULTS: Six of 13 adults and 3 of 5 children met PSG criteria for OSA. Three adults and 1 child were treated with continuous positive airway pressure (CPAP), were tolerant of the device, and had no change in AED doses; all four had at least a 45% reduction in seizure frequency during CPAP treatment. One adult was treated with an oral appliance with a reduction in nocturnal seizures only, and 2 adults and 2 children were intolerant of CPAP. CONCLUSIONS: Treatment of OSA in patients with epilepsy may improve seizure control and a large randomized placebo-controlled trial appear warranted.

The evaluation of the extent of transporting or "tracking" an identifiable ignitable liquid (gasoline) throughout fire scenes during the investigative process.

Tests have determined that boots or shoes of individuals at a fire scene do not transport sufficient contaminants ("tracking") through the fire scene to produce a positive laboratory result for the presence of gasoline in a fire scene that was not present at the time of the fire. Questions about the validity of forensic laboratory results have been raised on the basis that low-level gasoline residues detected in the laboratory samples could have been the result of transporting the residue by footwear contaminated from the fire scene ("tracking"). The data collected in this study establish that "tracking" does not lead to false-positive laboratory results. Canines trained and experienced in the detection of trace ignitable liquid residues were also utilized in this study. The canine results confirmed that properly trained canines show a higher sensitivity than do standard ASTM laboratory techniques for fire debris analysis. In a few cases, canines responded to contamination, but laboratory testing (which is the definitive indicator) did not produce positive results.