Perspectives in Circulation Today

Some Problem Areas in Wound Healing

No, it's not the macrocirculation, debridements or the choice of antibiotics...

What do you know or do about the following problems? What do they have in common?

Troublesome Infections

• "Critical Colonization" (Kingsley 2003) vs "Clinical Infection" and >100000 organisms.
• Failure to heal with bacterial count >100,000
• Poor penetration of antibiotics into granulation and/or scar tissue(Robson 1974)
• Intracellular foci of bacteria where less susceptible to antibiotics and granulocytes:
  • Osteoblasts (Ahmed 2001), Ellington (2003)
  • Keratinocytes (Mempel 2002), von Eiff (2001)
  • Bovine endothelial cells (Vann 1987), (Hamill 1986)
  • Escape from endosomes to cytoplasm (Shompole 2003)

Post Revascularization and Microcirculation Problems

• Revascularization edema
• Ischemic reperfusion injury (Bolli 1999, Heyndrickx 2006, Movahed 2008)
  • Myocardial stunning
  • Tissue hibernation
  • No flow
  • Cholesterol emboli

  Documentation and Value of Vascular Tests of small vessel disease

• Toe pressures and toe/arm index: Toe pressures may be abnormally low in patients with palpable pulses and neuropathic ulcers(Stevens 1993). Low toe pressures and toe/arm index significantly more common among diabetics than a low ABI (Sahli 2004).
• Abnormal Laser Doppler results early in the course of neuropathic diabetics (Walewski 1997)and diabetics without overt complications(Karnafel 2002). The best locations for perfusion measurement are the most distal, especially the hallex and the base of the little toe. The most valuable parameters of postocclusive hyperemia were maximum response, time to peak flow, and half-time of hyperemia.
• Transcutaneous PO2: Preoperative TcPO2 <=22 and foot/chest <=0.46 indicate severe ischemia requiring bypass (These folks do not have a boot). Postoperative TcPO2 <=22 and foot/chest <= 0.53 indicate revascularization likely to fail. (Lalka 1988)
• Transcutaneous PO2 may be very low in the infected foot and rise appreciably after the infection is controlled.(Pinzur 1993)
• When therapeutic measures to improve the circulation are limited to vascular procedures, microvascular evaluations add no clinical benefit over standard macrovascular tests (Lawall 2000).
• Laser Doppler fluxmetry: preoperative prediction of wound healing of 91.4%, and a predictive value for wound failure of 89%. (Mars 1998)
• The measurement of intracompartmental pressure and tissue oxygen saturation as a guide to need for fasciotomy (Arato 2007).

  Common Features and Comments

  
  Failure to heal may result from all of the above: infection difficult to eradicate, persistent postoperative ischemia and unappreciated small vessel disease. The ability of Staphylococcus to hide within the cells, to subsequently kill cells and to emerge into the extracellular fluid to continue a cellulitic process is one factor leading to failure of standard intravenous therapies to cure osteomyelitis and sepsis. The local injection of antibiotics may increase the local concentration of antibiotic well above the levels achieved by the oral or intravenous routes. And the increased local concentration increases the extracellular/intracellular gradient and the likelihood a bacteriocidal concentration will be achieved within the cell. Locally injected antibiotics, however, may merely pool in the tissues and exit with other drainage. Circulator Boot therapy after the injections does successfully help disseminate the antibiotic throughout the tissues. Dillon reported successful cures of osteomyelitis in 43 consecutive cases (1990). Niezgoda recently reported his success with the same techniques (2008). The combination of a very low TcPO2 and pulsatile flow as documented with a PPG probe (photoelectricplethsmographic probe) may be pathognomonic of a necrotiizing cellulitis. Such findings may constitute a "boot emergency"; the injection of antibiotics into such tissue followed by boot therapy may raise the TcPO2 to acceptable levels within a few hours and prevent tissue breakdown.
  

  Among approved indications for Circulator Boot therapy, the Food and Drug Administration initially approved therapy to increase pre-operative runoff and/or postoperative runoff. Indeed, the concept of improving the visualization of runoff vessels by pneumatic boot therapy prior to the performance of an angiogram was introduced 32 years ago by D'Souza (1976). Dillon reported the significant improvements in ankle blood pressures, arm/ankle indices, Doppler waveform amplitudes, pulse volume measurements (oscillometry indices) and subcutaneous PO2 levels 28 years ago. Many of the case histories on the Circulator Boot website include such vascular data. More recently Gruenes et al (2005) reported that blood flow measured by their Laser Doppler increased in all of their patients by an average of 43%. Williams utilized the Circulator Boot to treat patients with chronic limb ischemia and patients with leg ulcers associated with combined venous and arterial disease (2008, 2008). In the former he documented significant rises in transcutaneous PO2 levels and in the latter, he healed recalcitrant ulcers.

  A tense swollen painful leg in the postoperative period may be associated with the compartment syndrome. Tissue pressure oxygen measurements may indicate need for a fasciotomy.... but boot therapy is easier and does not result in a new wound to heal. If a fasciotomy is done, boot therapy may be useful in closing the wound (Case182)(Case 183).

  What do the above have in common? They all may be associated with indications for therapy with the Circulator Boot.

  Abstracts of all of the authors listed above are found in our website libraries (Literature Menu).

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  Perspectives in Circulation Today

  Volume 3, Number 7

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