Assisted venous drainage, venous air, and gaseous microemboli transmission into the arterial line: an in-vitro study.

The objective of this study was to examine the interaction of cardiopulmonary bypass venous air with assisted venous drainage, focusing on its production of gaseous microemboli in the arterial line. An in-vitro recirculating cardiopulmonary bypass circuit containing fresh whole bovine blood was monitored with a pulsed-doppler microbubble detector. Air of specific amounts was injected into the venous line and gaseous microemboli counts were obtained distal to the arterial filter. Data was recorded for unassisted drainage, vacuum-assisted drainage, and centrifugal pump-assisted drainage. Centrifugal pump-assisted drainage produced over 300 microbubbles in one minute distal to the arterial filter when venous air was introduced into the circuit. Of these, 220 were greater than 80 microns in size. Vacuum-assisted drainage produced no microbubbles when the same amount of venous air was introduced into the circuit. However, vacuum-assisted drainage did produce some microbubbles in the arterial line when a stopcock was left open on the venous line for 30 seconds. Unassisted drainage produced no microbubbles at all levels of venous air entrainment. Air becomes entrained in the venous line from a variety of sources. In a typical gravity-drained situation, the air remains whole and is dissipated in the venous reservoir by buoyancy and filtration. In an assisted-drainage situation, the air is subjected to additional forces. The air is subjected to a greater degree of negative pressure and, with centrifugal pump assisted drainage, is subjected to kinetic energy imparted by the cones or vanes of the pump. The kinetic energy from the centrifugal pump appears to break the air into small bubbles which become suspended in the blood, passing through the reservoir, oxygenator, and arterial filter. In a clinical setting, these bubbles would be passed into a patient's arterial system.

A polysomnographic study of sleep disturbance in community elderly with self-reported environmental chemical odor intolerance.

Subjective sleep complaints and food intolerances, especially to milk products, are frequent symptoms of individuals who also report intolerance for low-level odors of various environmental chemicals. The purpose of the present study was to evaluate the objective nature of nocturnal sleep patterns during different diets, using polysomnography in community older adults with self-reported illness from chemical odors. Those high in chemical odor intolerance (n = 15) exhibited significantly lower sleep efficiency (p = .005) and lower rapid-eye-movement (REM) sleep percent (p = .04), with a trend toward longer latency to REM sleep (p = .07), than did those low in chemical intolerance (n = 15), especially on dairy-containing as compared with nondairy (soy) diets. The arousal pattern of the chemical odor intolerant group differed from the polysomnographic features of major depression, classical organophosphate toxicity, and subjective insomnia without objective findings. The findings suggest that community elderly with moderate chemical odor intolerance and minimal sleep complaints exhibit objectively poorer sleep than do their normal peers. Individual differences in underlying brain function may help generate these observations. The data support the need for similar studies in clinical populations with chemical odor intolerance, such as multiple chemical sensitivity patients and perhaps certain veterans with "Persian Gulf Syndrome."

Stress, coping, and injuries in male and female high school basketball players.

Past research has identified a positive relationship between life-event stress and football injuries, but research in other sports has yielded more ambiguous results. It seems, then, that the relation of life stress and injury may be sport-specific and that different sports must be studied separately before such a relationship is assumed. The present investigation examined the relationships among life-event stress, coping skills, social support, and injuries of male and female high school basketball players. Contrary to the hypothesis, the number of days missed due to injury was not significantly related to life-event stress. As expected, the injury measure was negatively correlated with both the coping-skills and social-support variables, but these correlations did not reach statistical significance. Recommendations for research are discussed.