整型外科: 傷口的負壓照護如何設定?
Q:傷口的負壓照護如何設定?
A: 75-125mmHg (100-169cmH2O)
真空輔助傷口癒合療法（Vaccum Assisted Clossure；VAC）是臨床上常被運用來治療感染性傷口的方式。它的原理是以在傷口附近製造負壓環境來達到廓清細菌、增加血流與血管增生與促進肉芽組織生成來幫助傷口的癒合。然而負壓的壓力該設定多少呢？卻常是一個困擾大家的議題。
負壓是開越大越好嗎？還是說有一定的閾值呢？如果有一定的閾值的話，那要多大的負壓才能夠達到我們想要廓清細菌和促進傷口癒合的效果呢？
之前的動物實驗研究裡已經告訴我們，使用125mmHg的負壓與500mmHg的負壓相較，使用125mmHg的負壓增加血流和肉芽組織增生的能力都會比較好，但是125mmHg和500mmHg之間實在差太多了，這當中會不會有更適合的負壓大小呢？今天選的這篇研究——Role of different negative pressure values in the process of infected wounds treated by vacuum-assisted closure: an experimental study.——就運用動物實驗的方法給了我們答案。
負壓是開越大越好嗎？還是說有一定的閾值呢？如果有一定的閾值的話，那要多大的負壓才能夠達到我們想要廓清細菌和促進傷口癒合的效果呢？
之前的動物實驗研究裡已經告訴我們，使用125mmHg的負壓與500mmHg的負壓相較，使用125mmHg的負壓增加血流和肉芽組織增生的能力都會比較好，但是125mmHg和500mmHg之間實在差太多了，這當中會不會有更適合的負壓大小呢？今天選的這篇研究——Role of different negative pressure values in the process of infected wounds treated by vacuum-assisted closure: an experimental study.——就運用動物實驗的方法給了我們答案。
本篇研究在6隻豬上製造了36個傷口，並使這些傷口都感染相同數量的金黃色葡萄球菌（staphylococcus aureus）。研究者將這36個傷口分為六組，分別是對照組：只有使用紗布覆蓋傷口，並沒有使用負壓裝置的，以及五組實驗組：
（1）使用真空輔助傷口敷料覆蓋傷口卻沒有使用負壓的
（2）使用真空輔助傷口敷料覆蓋傷口並使用75mmHg的負壓的
（3）使用真空輔助傷口敷料覆蓋傷口並使用150mmHg的負壓的
（4） 使用真空輔助傷口敷料覆蓋傷口並使用225mmHg的負壓的
（5） 使用真空輔助傷口敷料覆蓋傷口並使用300mmHg的負壓的。
之後研究者會在第一次手術後的第3、5、7、9天施行換藥時，並同時收集檢體做分析。
（1）使用真空輔助傷口敷料覆蓋傷口卻沒有使用負壓的
（2）使用真空輔助傷口敷料覆蓋傷口並使用75mmHg的負壓的
（3）使用真空輔助傷口敷料覆蓋傷口並使用150mmHg的負壓的
（4） 使用真空輔助傷口敷料覆蓋傷口並使用225mmHg的負壓的
（5） 使用真空輔助傷口敷料覆蓋傷口並使用300mmHg的負壓的。
之後研究者會在第一次手術後的第3、5、7、9天施行換藥時，並同時收集檢體做分析。
研究結果顯示，四組有使用負壓的組別，從第3天開始，傷口上的細菌數量與沒有使用負壓的組別和對照組在統計上都有顯著意義上的減少。在第3天和第5天時，使用負壓75、150和225mmHg的組別新生微血管的數目有明顯的上升，同時使用負壓150mmHg的組別，有著最多的新生微血管的產生。相反的，使用負壓300mmHg的組別，新生微血管的數目反而還比對照組跟沒有使用負壓的組別來得少。但到第七天時，負壓150mmHg的新生血管數量反而是和對照組及沒有使用負壓的組別差不多的，至於負壓300mmHg的組別新生血管的數量還是比對照組與沒有使用負壓的組別少，儘管如此使用負壓75、150mmHg的組別，它們長出來的新生血管是發展得較為良好，管徑也較大的。至於與傷口癒合相關的細胞（collagen）和相關因子(VEGF與bFGF)研究裡可以發現，使用負壓75mmHg跟負壓150mmHg的組別，它們的數量都是最多的！
因此，這篇的作者做出結論，當我們使用75-150mmHg的負壓時，傷口的癒合速度應該是最好的。
這篇研究在2017年時也被引用進European Wound Management Association（EWMA）的建議中，EWMA參考了其他研究建議VAC的壓力值最好設定在-75~-125mmHg之間，但仍須考量病人對於疼痛忍受的程度、傷口組織灌流良好與否及滲液的多寡來做調整！
結論：使用VAC時，負壓的設定值應設定在-75~-125mmHg中為當，太大的負壓值，反而有可能沒有辦法達到預期的效果喔！
參考文獻：https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1742-481X.2012.01008.x
Role of different negative pressure values in the process of infected wounds treated by vacuum-assisted closure: an experimental study.
Int Wound J. 2013 Oct;10(5):508-15 Epub 2012 May 29. Zhou M1, Yu A, Wu G, Xia C, Hu X, Qi B.
Abstract
Vacuum-assisted closure (VAC) device is widely used to treat infected wounds in clinical work. Although the effect of VAC with different negative pressure values is well established, whether different negative pressures could result in varying modulation of wound relative cytokines was not clear. We hypothesise that instead of the highest negative pressure value the suitable value for VAC is the one which is the most effective on regulating wound relative cytokines. Infected wounds created on pigs' back were used to investigate the effects of varying negative pressure values of VAC devices. Wounds were treated with VAC of different negative pressure values or moist gauze, which was set as control. The VAC foam, semiocclusive dresses and moist gauze were changed on days 3, 5, 7 and 9 after wounds were created. When changing dressings, tissues from wounds were harvested for bacteria count and histology examination including Masson's trichrome stain and immunohistochemistry for microvessels. Western blot was carried out to test the expression of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Results showed that on days 3 and 5 the number of bacteria in wounds treated by VAC with 75, 150, 225 and 300 mmHg was significantly decreased compared with that in wounds treated by gauze and 0 mmHg pressure value. However, there was no difference in wounds treated with negative pressure values of 75 , 150, 225 and 300 mmHg at any time spot. Immunohistochemistry showed that more microvessels were generated in wounds treated by VAC using 75 and 150 mmHg negative pressure comparing with that using 225 and 300 mmHg on days 3 and 5. However this difference vanished on days 7 and 9. Morphological evaluation by Masson's trichrome staining showed increased collagen deposition in VAC of 75 and 150 mmHg compared with that in VAC of 225 and 300 mmHg. Western blot showed that the expression of VEGF and bFGF significantly increased when the wounds treated with 75 and 150 mmHg negative pressure values compared with the wounds treated with 225 and 300 mmHg on day 5. Treatment using VAC with different negative pressure values more than 75 mmHg has similar efficiency on reducing bacteria in the infected wound. VAC with negative pressure values of 75 and 150 mmHg promote wound healing more quickly than other pressure values. Moreover, comparing with vigorous negative pressure, relatively moderate pressures contribute to wound healing via accelerated granulation growth, increased angiogenic factor production and improved collagen fibre deposition. Further study of this model may show other molecular mechanisms.
KEYWORDS: Different negative pressure values; VAC; Vacuum-assisted closure; Wound healing
PMID: 22640026
DOI: 10.1111/j.1742-481X.2012.01008.x
Role of different negative pressure values in the process of infected wounds treated by vacuum-assisted closure: an experimental study.
Int Wound J. 2013 Oct;10(5):508-15 Epub 2012 May 29. Zhou M1, Yu A, Wu G, Xia C, Hu X, Qi B.
Abstract
Vacuum-assisted closure (VAC) device is widely used to treat infected wounds in clinical work. Although the effect of VAC with different negative pressure values is well established, whether different negative pressures could result in varying modulation of wound relative cytokines was not clear. We hypothesise that instead of the highest negative pressure value the suitable value for VAC is the one which is the most effective on regulating wound relative cytokines. Infected wounds created on pigs' back were used to investigate the effects of varying negative pressure values of VAC devices. Wounds were treated with VAC of different negative pressure values or moist gauze, which was set as control. The VAC foam, semiocclusive dresses and moist gauze were changed on days 3, 5, 7 and 9 after wounds were created. When changing dressings, tissues from wounds were harvested for bacteria count and histology examination including Masson's trichrome stain and immunohistochemistry for microvessels. Western blot was carried out to test the expression of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Results showed that on days 3 and 5 the number of bacteria in wounds treated by VAC with 75, 150, 225 and 300 mmHg was significantly decreased compared with that in wounds treated by gauze and 0 mmHg pressure value. However, there was no difference in wounds treated with negative pressure values of 75 , 150, 225 and 300 mmHg at any time spot. Immunohistochemistry showed that more microvessels were generated in wounds treated by VAC using 75 and 150 mmHg negative pressure comparing with that using 225 and 300 mmHg on days 3 and 5. However this difference vanished on days 7 and 9. Morphological evaluation by Masson's trichrome staining showed increased collagen deposition in VAC of 75 and 150 mmHg compared with that in VAC of 225 and 300 mmHg. Western blot showed that the expression of VEGF and bFGF significantly increased when the wounds treated with 75 and 150 mmHg negative pressure values compared with the wounds treated with 225 and 300 mmHg on day 5. Treatment using VAC with different negative pressure values more than 75 mmHg has similar efficiency on reducing bacteria in the infected wound. VAC with negative pressure values of 75 and 150 mmHg promote wound healing more quickly than other pressure values. Moreover, comparing with vigorous negative pressure, relatively moderate pressures contribute to wound healing via accelerated granulation growth, increased angiogenic factor production and improved collagen fibre deposition. Further study of this model may show other molecular mechanisms.
KEYWORDS: Different negative pressure values; VAC; Vacuum-assisted closure; Wound healing
PMID: 22640026
DOI: 10.1111/j.1742-481X.2012.01008.x
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