Olov Sandberg

Obstructive Sleep Apnea Is a Risk Factor for Death in Patients With Stroke: A 10-Year Follow-up

BACKGROUND Sleep apnea occurs frequently among patients with stroke, but it is still unknown whether a diagnosis of sleep apnea is an independent risk factor for mortality. We aimed to investigate whether obstructive or central sleep apnea was related to reduced long-term survival among patients with stroke. METHODS Of 151 patients admitted for in-hospital stroke rehabilitation in the catchment area of Umeå from April 1, 1995, to May 1, 1997, 132 underwent overnight sleep apnea recordings at a mean (SD) of 23 (8) days after the onset of stroke. All patients were followed up prospectively for a mean (SD) of 10.0 (0.6) years, with death as the primary outcome; no one was lost to follow-up. Obstructive sleep apnea was defined when the obstructive apnea-hypopnea index was 15 or greater, and central sleep apnea was defined when the central apnea-hypopnea index was 15 or greater. Patients with obstructive and central apnea-hypopnea indexes of less than 15 served as control subjects. RESULTS Of 132 enrolled patients, 116 had died at follow-up. The risk of death was higher among the 23 patients with obstructive sleep apnea than controls (adjusted hazard ratio, 1.76; 95% confidence interval, 1.05-2.95; P = .03), independent of age, sex, body mass index, smoking, hypertension, diabetes mellitus, atrial fibrillation, Mini-Mental State Examination score, and Barthel index of activities of daily living. There was no difference in mortality between the 28 patients with central sleep apnea and controls (adjusted hazard ratio, 1.07; 95% confidence interval, 0.65-1.76; P = .80). CONCLUSIONS Patients with stroke and obstructive sleep apnea have an increased risk of early death. Central sleep apnea was not related to early death among the present patients.

Sleep Apnea, Delirium, Depressed Mood, Cognition, and ADL Ability After Stroke

OBJECTIVES: The incidence of sleep apnea and stroke increases with age. The aim of this study was to investigate the presence of sleep apnea after stroke and its relationship to delirium, depressed mood, cognitive functioning, ability to perform activities of daily living (ADLs), and psychiatric and behavior symptoms.

Epidemiology of delirium.

Delirium is one of the most frequent symptoms of disease in the elderly. A large variation of incidence and prevalence data is reported probably due to different patient populations and inconsistent diagnostic criteria. In medical and surgical elderly inpatients recent studies report a prevalence rate of approximately 15% and in postoperative patients the incidence and prevalence rates vary greatly, 7–52%, depending on patient population and clinical setting. In nursing homes the prevalence is even higher and delirium is often combined with dementia. Data supports the statement that delirium is most often found in hospitalized somatically ill elderly patients. As a consequence of the rising number of elderly in hospitals we have to expect an increase in the prevalence and incidence of delirium.

Clinical Profile of Delirium in Older Patients

OBJECTIVE: To examine the prevalence, psychiatric and behavior symptoms, differing symptom profiles, and diurnal variations of delirium in older patients.

Prevalence of dementia, delirium and psychiatric symptoms in various care settings for the elderly.

A prevalence study of psychiatric symptoms was performed in parts of a hospital catchment area in Mid-Sweden. In total 717 patients, aged 75 years and above, who were receiving care in an emergency hospital, three nursing homes, five old peoples homes and two home medical care districts were included. All patients were examined using the OBS-scale (Organic Brain Syndrome Scale). Anxiety (51%), psychomotor slowing (45%), delirium (44%), depressed mood (41%), irritability (40%) and dementia (33%) were the most prevalent psychiatric symptoms or diagnoses in the sample but there were wide differences between the four care settings. The present study shows that the prevalence of dementia, delirium and psychiatric symptoms is high in all types of care settings for the elderly. It also demonstrates the need for psychiatric medical and nursing competence in all types of care for the elderly.

Symptom Profile of Delirium in Older People With and Without Dementia

Clinical profiles of delirium in 717 older people with and without dementia age 75 years and older in 4 different types of care were studied. Delirium and dementia were diagnosed according to DSM-IV criteria. Delirious demented participants (n = 135) had more often had previous delirium episodes and were more often being treated with analgesics compared to delirious participants without dementia (n = 180). The clinical profile of delirium in the participants with dementia was more frequently characterized by aggressivity, latency in reaction to verbal stimuli, restlessness and agitation, delusions, anxiousness, hallucinations, and a poorer orientation and recognition. Delirium among demented participants more often had a fluctuating course during the day and was more common in the evening and at night. In conclusion, clinical profiles of delirium in participants with and without dementia are different, which might indicate a different etiology or pathophysiology, or both, and a need for different treatment strategies. (J Geriatr Psychiatry Neurol 2007;20:166—171)

The thermal properties of an epoxy resin at high pressure and temperature

The thermal conductivity lambda , thermal diffusivity and heat capacity per unit volume has been measured for an epoxy resin, Araldite AW 106, with hardener HV 953 U. Measurements have been carried out at room temperature up to 2.5 GPa and between 300 and 430K at 0.11 and 0.27 GPa. The glass transition temperature and its pressure (P) dependence have been determined. The quantity delta lambda / delta P was found to change abruptly in the temperature region of the glass transition.

Thermal properties of two low viscosity silicon oils as functions of temperature and pressure

The thermal conductivity and the specific heat capacity per unit volume have been measured for two low viscosity grades of Dow Corning 200 fluid (polydimethyl siloxane) in the range 110 to 350 K and under pressures up to 2.0 GPa (20 kbar). Both the quantities studied are found to increase with increasing pressure in the liquid phase. From the measured data the phase diagrams are obtained. The 5 mm2/s (5 cSt) grade fluid does not crystallize, but undergoes a glass transition at 1.0 GPa at room temperature. The 1 mm2/s (1 cSt) grade has a more complicated phase diagram with a partly crystalline phase at low temperatures and pressures and two glass transitions at high temperatures and pressures.

Thermal properties of natural rubber versus temperature and pressure

The thermal conductivity λ and the heat capacity per unit volume ρcp were determined by the transient hot‐wire method at pressures up to 1.0 GPa and in the temperature range 130–340 K. Specimens were cold‐pressed pure rubber and hot‐pressed rubber containing 3.7% sulphur. The vulcanized variety was found to have a higher glass transition temperature Tg at all pressures. Our value of Tg at atmospheric pressure is higher by 23 K than the previously reported values from quasistatic experiments, which can be accounted for by the relaxation time of the excitation mode. The derivative of the transition temperature ∂Tg/∂P was found to decrease with increasing pressure for both samples, as predicted by a recent theory. The thermal‐expansion coefficient was determined under pressure from the temperature response to adiabatic pressurization using the heat‐capacity data.

Thermal properties of some lubricants under high pressure

The thermal conductivity λ, specific‐heat capacity ρcp, and the point of glass transition have been determined for a range of lubricants. These included Santotrac 40; LAD 2201, a naphtenic mineral oil; Oxilube 50/150; and 5P4E, a polyphenyl ether. The thermal properties were determined by a hot‐wire probe method. Pressure was varied from 0–1.5 GPa and the range of temperature covered was in general 20–110 °C although Oxilube was taken down to −24 °C. The thermal conductivities at 1.5 GPa were found to be roughly twice that of the oils at atmospheric pressure. The temperature dependence of the glass formation pressure was found to be quite different for the oils studied. The results obtained will be particularly useful for people studying elastohydrodynamic lubrication.