1. Effects of Defecation Strain at Various Bed Reclining Angles on Intrarectal Pressure and Cardiovascular Responses
- Author
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Naoki Nishimura, Tetsuya Fujii, Y. Kuwahara, Satoshi Iwase, Makoto Hirai, Yuuki Shimizu, Rumiko Nishimura, and Mika Imai
- Subjects
Adult ,Male ,Supine position ,medicine.medical_treatment ,Posture ,Blood Pressure ,Strain (injury) ,Electromyography ,Bed rest ,Patient Positioning ,Young Adult ,Abdominal muscles ,Heart Rate ,Reference Values ,Heart rate ,Pressure ,medicine ,Humans ,Defecation ,General Nursing ,Abdominal Muscles ,medicine.diagnostic_test ,business.industry ,Rectum ,medicine.disease ,Blood pressure ,Anesthesia ,business ,Bed Rest - Abstract
BACKGROUND There is no clear information about the optimal bed reclining angle for promoting efficient and safe defecation in bedfast patients. OBJECTIVE The aim of this study was to examine the optimal bed reclining angle for facilitating increases in intrarectal pressure without causing marked cardiovascular changes in order to develop an efficient and safe defecation position for bedfast patients. METHODS Twelve healthy men participated in this study. The subjects were required to strain for 15 seconds at the end stage of inspiration while their bed was reclined at 0° (supine), 15°, 30°, or 60°. During straining, the subjects were asked to maintain (a) an intrarectal pressure of 20 mm Hg or (b) the maximal intrarectal pressure. Intrarectal pressure, blood pressure, heart rate, and abdominal muscle activity (electromyographic activity) were recorded continuously throughout the study period. RESULTS During straining, intrarectal pressure increased with the reclining angle, and a significant linear correlation was detected between the sine of the reclining angle of the bed and intrarectal pressure (η = .57, p < .01). When subjects were straining with the aim of maintaining maximal intrarectal pressure, the extent of the observed changes (delta) in blood pressure and heart rate did not differ significantly across the reclining angles. When subjects were straining with the aim of maintaining an intrarectal pressure of 20 mm Hg, the delta blood pressure decreased as the reclining angle increased 0°: M = 23.7, SD = 15.3 mm Hg, 95% CI [11.9, 35.4]; 15°: M = 25.9, SD = 10.8 mm Hg, 95% CI [17.6, 34.2]; 30°: M = 17.7, SD = 9.4 mm Hg, 95% CI [10.4, 24.9]; 60°: M = 15.5, SD = 9.5 mm Hg, 95% CI [8.1, 22.8]; 15° versus 30°: p < .05; 15° versus 60°: p < .05. The amount of muscle activity observed during straining decreased as the reclining angle increased. DISCUSSION In bedfast patients, it is suggested that higher reclining angles may enable safer and more efficient defecation, because it decreases the amount of muscle activity required to increase the intrarectal pressure and reduces the potentially deleterious effects of straining on the cardiovascular system to develop an efficient and safe defecation position for bedfast patients.
- Published
- 2015