Intermittent NPWT and Lower Negative Pressures — Exploring the Disparity between Science and Current Practice: A Review

  • Thu, 6/18/09 - 1:55pm
  • 0 Comments
  • 6067 reads
Login to Download
PDF version
Start Page: 
22
End Page: 
28
Author(s): 
Cindy Ahearn, MS, RN, ET, CWCN, FNP-C

Abstract: Negative pressure wound therapy (NPWT) is used to treat a wide and growing range of problematic acute and chronic wounds. Continuous therapy delivered at -125 mm Hg has been routinely recommended, despite consistent research findings suggesting potential advantages to the use of lower pressures and intermittent therapy. To enhance understanding and document the disparity between the body of NPWT science and current practice with respect to negative pressure levels and modes of therapy, a search of the English-language literature from June 1989 through May 2009 was conducted. Thirty-six publications found to contain directly relevant information (in vitro, in vivo, and clinical data) were examined. While lower negative pressures and intermittent therapy were associated in earlier studies with improved microvascular blood flow in porcine wound models and with reduced pain in patients, early system shortcomings discourage adoption of intermittent therapy. Subsequent preclinical studies confirmed the beneficial effects of intermittent therapy compared to continuous therapy on blood flow and granulation tissue formation and lower pressures (-75 mm Hg or -100 mm Hg) compared to higher pressure (-125 mm Hg) on soft tissue blood flow. Considering the available preclinical evidence, reported patient pain, and common use of high-pressure continuous NPWT in clinical practice, high-quality randomized controlled clinical trials must be conducted to help clinicians optimize care.

Key Words: review, intermittent negative pressure wound therapy, low pressure, regional blood flow, granulation tissue




Ms. Ahearn is Director of Clinical Services, Prospera®, Fort Worth, TX. Please address correspondence to: Cindy Ahearn, MS, RN, ET, CWCN, FNP-C, Director of Clinical Services, Prospera®, 2831 Bledsoe Street, Fort Worth, TX 76107; email: cahearn@prospera-npwt.com.






     Negative pressure wound therapy is widely used to treat wounds that do not respond to conventional moist wound healing therapy. Traumatic soft tissue defects and acute and septic wounds were first treated with the method, followed by chronic wounds such as leg ulcers and decubitus ulcers, and more recently, skin grafts, vascular surgery wounds, and burns.1

     Reports from the past two decades of clinical experience, animal research, and in vitro studies describe potential advantages of the use of both intermittent NPWT over continuous therapy and lower negative pressures in general (less than the -125 mm Hg commonly recommended in recent years). In the seminal work of Chariker et al,2 published in 1989, pressures of -60 mm Hg to -80 mm Hg were used to successfully treat patients with enterocutaneous fistulae complicating ventral abdominal wounds. In the frequently cited pig wound model studies of Morykwas et al3 from the late 1990s, researchers observed far superior granulation tissue formation and microvascular blood flow for intermittent therapy compared to continuous therapy. Measurements of blood flow from these same early studies formed the basis for the common pressure recommendation of -125 mm Hg.1

     Throughout the history of NPWT use, clinicians have had to develop treatment strategies that take into account not only the theoretical mechanisms of NPWT, but also the practical realities of what the available systems can deliver. The intermittent setting for NPWT, initially developed to enhance the benefits of treatment, was largely abandoned because of system shortcomings.4 During off times, when pressure dropped to 0 mm Hg, re-expansion of foam dressings used with the system led to pain and disruption of tissue.

References: 

1. Willy C (ed). The Theory and Practice of Vacuum Therapy: Scientific Basis, Indications for Use, Case Reports, Practical Advice. Ulm, Germany: Lindqvist Book-Publishing;2006.
2. Chariker ME, Jeter KF, Tintle TE. Effective management of incisional and cutaneous fistulae with closed suction wound drainage. Contemporary Surg. 1989:34:59–63.
3. Morykwas MJ, Argenta LC, Shelton-Brown EI, McGuirt W. Vacuum-assisted closure: a new method for wound control and treatment: animal studies and basic foundation. Ann Plast Surg. 1997;38:553–562.
4. Webb LX. New techniques in wound management: vacuum-assisted wound closure. J Am Acad Orthop Surg. 2002;10(5):303–311.
5. ECRI Institute. Technology Assessment Draft Report: Negative Pressure Wound Therapy Devices. March 30, 2009. Available at: www.ahrq.gov/clinic/techix.htm. Accessed April 15, 2009.
6. Molnar JA. The science behind negative pressure wound therapy. Ostomy Wound Manage. 2004;50(4A suppl):2–5.
7. Wackenfors A, Sjogren J, Gustafsson R, Algotsson L, Ingemansson R, Malmsjo M. Effects of vacuum-assisted closure on inguinal wound edge microvascular blood flow. Wound Repair Regener. 2004;12(6):600–606.
8. Wackenfors A, Gustafsson R, Sjogren J, Algotsson L, Ingemansson R, Malmsjo M. Blood flow responses in the peristernal thoracic wall during vacuum-assisted closure therapy. Ann Thorac Surg. 2005;79:1724–1731.
9. Lindstedt S, Malmsjo M, Sjogren J, Gustafsson R, Ingemansson R. Impact of different negative pressure levels on myocardial microvascular blood flow. Cardiovasc Revasc Med. 2008;9(1):29–35.
10. Lindstedt S, Malmsjo M, Ingemansson R. The effect of different topical negative pressures on microvascular blood flow in reperfused myocardium during hypothermia. Innovations. 2007;2(5):231–236.
11. Lindstedt S, Malmsjo M, Gesslein B, Ingemansson R. Evaluation of continuous and intermittent myocardial topical negative pressure. J Cardio Med. 2008;9(8):813–819.
12. Philbeck TE, Whittington KT, Millsap MH, Briones RB, Wight DG, Schroeder WJ. The clinical and cost effectiveness of externally applied negative pressure wound therapy in the treatment of wounds in home healthcare Medicare patients. Ostomy Wound Manage. 1999;45(11):41–50.
13. Ilizarov GA. The tension-stress effect on the genesis and growth of tissues: I. The influence of stability of fixation and soft-tissue preservation. Clin Orthop. 1989;238:249–281.
14. Ilizarov GA. The tension-stress effect on the genesis and growth of tissues: II. The influence of the rate and frequency of distraction. Clin Orthop. 1989;239:263–285.
15. Argenta LC, Marks MW. Tissue expansion. In: Georgiade GS, Georgiade NG, Riefkohl R, Barwick WJ (eds). Textbook of Plastic, Maxillofacial and Reconstructive Surgery, 2nd ed, vol 1. Baltimore, MD: Williams and Wilkins;1992:103–113.
16. Ingber DE. Cellular mechanotransduction: putting all the pieces together again. FASEB J. 2006;20(7):811–827.
17. Chen CS, Mrksich M, Huang S, Whitesides GM, Ingber DE. Geometric control of cell life and death. Science. 1997;276(5317):1425–1428.
18. Ingber DE. Fibronection controls capillary endothelial cell growth by modulating cell shape. Proc Natl Acad Sci USA. 1990;87:3579–3583.
19. Huang S, Ingber DE. The structural and mechanical complexity of cell-growth control. Nat Cell Biol 1999;1(5):E131–E138.
20. Ingber DE, Prusty D, Sun Z, Betensky H, Wang N. Cell shape, cytoskeletal mechanics, and cell cycle control in angiogenesis. J Biomech. 1995;28(12):1471–1484.
21. Gupta S, Bates-Jensen B, Gabriel A, Holloway A, Niezgoda JA, Weir D. Differentiating negative pressure wound therapy devices: an illustrative case series. Wounds. 2007;19(1 suppl):1–9.
22. Isago T, Nozaki M, Kikuchi Y, Honda T, Nakazawa H. Effects of different negative pressures on reduction of wounds in negative pressure dressings. J Dermatol. 2003;30:596–601.
23. Shirakawa M, Isseroff R. Topical negative pressure devices: use for enhancement of healing chronic wounds. Arch Dermatol. 2005;141:1449–1453.
24. Krasner D. Managing wound pain in patients with vacuum-assisted closure devices. Ostomy Wound Manage. 2002;48(5):38–43.
25. Etoz A, Ozgenel Y, Ozcan M. The use of negative pressure wound therapy on diabetic foot ulcers: a preliminary controlled trial. Wounds. 2004;16(8):264–269.
26. Price R, Nagarajan M, Srinivasan J. Local anesthetic for change of vacuum-assisted closure dressings. Plast Reconstr Surg. 2007;117(7):237–238.
27. Springhouse Nurse’s Drug Guide, 4th Edition. Springhouse, PA: Springhouse Corp;2002.
28. Bonhom P, Ramundo J. Commentary: surgical wound case studies with the Versatile 1 wound vacuum system for negative pressure wound therapy. J WOCN. 2006;33(2):185–190.
29. Tillery T. The use of gauze-based dressing for NPWT (clinical and financial outcomes). Poster presentation at the Clinical Symposium on Advances in Skin and Wound Care. Las Vegas, NV. October 26–30, 2008.
30. Schwien T, Gilbert J, Lang C. Pressure ulcer prevalence and the role of negative pressure wound therapy in home health quality outcomes. Ostomy Wound Manage. 2005;51(9):47–60.
31. Kirby M. Negative pressure wound therapy. Br J Diabetes Vasc Dis. 2007;7(5):230–234.
32. Sood R. Efficacy of a new negative pressure wound therapy. Oral case study presentation at the John A. Boswick, MD, Burn and Wound Care Symposium. Maui, HI. February 16–20, 2009.
33. Cinat M. A multimodality approach to management of complicated wounds with a new negative pressure wound therapy device. Oral case study presentation at the John A. Boswick, MD, Burn and Wound Care Symposium. Maui, HI. February 16–20, 2009.
34. Kinetic Concepts, LLC Report. Presented at the Bank of America/Merrill Lynch 2009 Health Care Conference. New York, NY. May 12, 2009. Available at: www.veracast.com/webcasts/bas/healthcare09/ id47105193.cfm. Accessed May 13, 2009.
35. Malmsjo M, Ingemansson R, Martin R, Huddleston E. Negative pressure wound therapy using gauze or polyurethane open cell foam: similar effects on wound edge microvascular blood flow. Ann Plast Surg. In press.
36. Malmsjo M, Ingemansson R, Martin R, Huddleston E. Negative pressure wound therapy using gauze or polyurethane open cell foam: similar effects on pressure transduction and wound contraction in an experimental porcine model. Wound Repair Reg. 2009;17:200–205.


































image description image description 




  


  
Post new comment


  



 
 



  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
  • Use  to create page breaks.
More information about formatting options




Image CAPTCHA

 
 
 
Enter the characters shown in the image.