Our purpose is to explore the effects of commonly used body positions in bed on the intensity of hemodynamic responses to the Valsalva Maneuver in subjects who have mild chronic disorders of the vascular system in which the normal pattern of responses may be altered. The Valsalva Maneuver, forced expiration against a closed glottis, is a normal physiological function performed by everyone many times daily. Within seconds the force of this strain results in marked shifts of cardio- and cerebro-vascular blood flow and pressure. There are clinical situations in which repeated or strenuous performance of the Valsalva is hazardous, particularly for individuals with existing cardiac or cerebo-vascular disease. Although nurses can attempt to decrease the incidence of straining, not all can be eliminated. Efforts aimed at lessening the intensity of this strain on the hemodynamic responses to the Valsalva Maneuver are imperative. Data from year one of this project has shown that body position and gender affect the hemodynamic responses to the Valsalva Maneuver in healthy adults between the ages of 30-55. The major goal is to determine whether the hemodynamic responses to the Valsalva Maneuver change in the same way, as a function of body position, for individuals with: increased body mass and blood volume (overweight), diminished peripheral vasomotor tone (diabetics) and increased peripheral resistance (mild hypertensives) as they do in normal subjects. During years 1 and 2, 50 overweight males, 50 overweight females and 30 diabetic males, 30 diabetic females between the ages of 30-55 will be tested twice in each of five positions (supine, lateral recumbant, 30 and 70 degree upright and chair). In year 3, 50 males and 50 females with mild hypertension will be tested in 3 positions (lateral recumbent, 30 and 70 degree upright). All subjects will be asked to strain by blowing into a pressure-guage meter to a pressure of 40 mmHg, to hold this pressure for ten seconds and to then release the strain. Heart rate and rhythm will be recorded on a cardiac monitor, carotid artery flow velocity recorded using a transcutaneous Doppler flowmeter, and peripheral blood volume recorded using a plethysmograph, prior to, during and following the Valsalva strain and until baseline measures are re-established. Baseline systolic and diastolic blood pressure will be determined; systolic blood pressure will be taken by Doppler technique at five seconds ino the strain, at five seconds after the release of the strain and each minute thereafter until baseline pressure is again reached. This procedure will be completed twice in each position. Data will be analyzed by two factor analysis of variance with repeated measures, time series analysis, and analyses of covariance.
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