Effects of cycle periods and pressure amplitudes of alternating pressure on sacral skin blood flow responses

Fu Lien Wu, Zhi Zheng, Yinyin Ma, Kaixiang Weng, Fuyuan Liao, Yih Kuen Jan

Research output: Contribution to journalArticlepeer-review


Background: There are no guidelines on selecting alternating pressure (AP) configurations on increasing sacral skin blood flow (SBF). Aim: The specific aims were to compare different cycle periods and pressure amplitudes of AP on sacral SBF responses in healthy people to establish the efficacy and safety of the protocols. Methods: Two studies were tested, including the cycle period study (8 2.5-min vs 4 5-min protocols) and the pressure amplitude study (75/5 vs 65/15 mmHg protocols). Sacral SBF was measured using laser Doppler flowmetry (LDF) in 20 participants. AP loads were randomly applied using an indenter through the rigid LDF probe. Each protocol included a 10-min baseline, 20-min AP and 10-min recovery periods. A 30-min washout period was provided. The SBF response was normalized to the baseline SBF of each condition of each participant. Results: For the cycle period study, the 4 5-min cycle protocol partially restored more SBF than the 8 2.5-min cycle protocol at the low-pressure phase (0.87 ± 0.04 vs 0.71 ± 0.03, p < 0.05) and at the high-pressure phase (0.25 ± 0.03 vs 0.19 ± 0.03, p < 0.05). For the pressure amplitude study, the 75/5 mmHg protocol partially restored more sacral SBF than the 65/15 mmHg protocol at the low-pressure phase (0.87 ± 0.1 vs 0.25 ± 0.03, p < 0.05) but not at the high-pressure phase (0.23 ± 0.02 vs 0.21 ± 0.02, non-significant). Conclusion: This study demonstrated that 1) a cycle period of 5 min was better than 2.5 min and 2) a pressure amplitude of 75/5 mmHg was better than 65/15 mmHg. The finding provides insights for selecting the AP configurations for increasing SBF.

Original languageEnglish (US)
Pages (from-to)264-268
Number of pages5
JournalJournal of Tissue Viability
Issue number4
StatePublished - Nov 2020


  • Alternating pressure
  • Support surface
  • Pressure ulcer
  • Blood flow

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Dermatology


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