| Autor: |
E C, Herrman, C F, Knapp, J C, Donofrio, R, Salcido |
| Rok vydání: |
2000 |
| Předmět: |
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| Zdroj: |
Journal of rehabilitation research and development. 36(2) |
| ISSN: |
0748-7711 |
| Popis: |
This study describes alterations in skin perfusion in response to step increases in surface pressure, before and after long-term (5 hr) exposure to pressure-induced ischemia. A provocative test was developed in which surface pressure was increased in increments of 3.7 mmHg until perfusion reached an apparent minimum by a computer-controlled plunger that included a force cell, a laser Doppler flowmeter to determine perfusion, and a thermistor to monitor skin temperature. Force was applied to the greater trochanters of adult male fuzzy rats. Skin perfusion (n=7) initially increased with low levels of surface pressure (up to 13.9+/-1.9 mmHg) and then decreased with further increases in pressure, reaching minimum (zero) perfusion at 58.2+/-3.64 mmHg. After pressure release, reactive hyperemia (3 x normal) was observed, with levels returning to normal within 15-30 min. The provocative test was then applied after a 5-hr ischemic episode (produced by 92 mmHg) and 3 hr of recovery. A comparison of responses between stressed and unstressed skin revealed: elevated (63%) control perfusion levels; loss of the initial increase in perfusion with low levels of increasing pressure; a depression (45%) in the hyperemic response with delayed recovery time; and a decrease (54%) in amplitude of low frequency (1 Hz) rhythms in skin perfusion. Skin surface temperature gradually increased both during the control period and the period of incremental increases in surface pressure (total DT=3.3 degrees C). The results suggest a compromised vasodilator mechanism(s). The provocative test developed in this study may have clinical potential for assessing tissue viability in early pressure ulcer development. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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