Does iodine (iodine) wash slow granulation and is normal saline (NS) irrigation more effective than cleaning with gauze for wound dressing management?

Wound Management: Iodine vs. Normal Saline for Wound Cleaning

Normal saline irrigation is preferable to iodine wash for wound dressing management as iodine may potentially slow granulation tissue formation, though evidence is mixed and context-dependent. 1, 2

Effects of Iodine on Wound Healing

• Iodine-based products have been traditionally believed to impair wound healing due to their cytotoxic effects on cells, but recent evidence challenges this assumption 2
• According to the IWGDF guidance, there is insufficient or no evidence to justify the use of iodine-containing dressings in preference to other dressing types 1
• A systematic review found that iodine did not lead to a reduction or prolongation of wound healing time compared with other antiseptic wound dressings 3
• However, vigorous irrigation with any solution may potentially remove protective immunologic cells that enable healing to progress through natural processes, including inflammation and granulation 1

Normal Saline vs. Iodine for Wound Irrigation

• Normal saline is favored as an isotonic solution that does not interfere with the normal healing process 4
• For wound irrigation:
  • Standard saline irrigation alone was not effective in reducing surgical site infections 1
  • When saline was applied with pressure (via syringe), it showed better outcomes (OR 0.35; 95% CI 0.19–0.65) 1
  • Pulse pressure irrigation with saline was superior to standard saline irrigation (OR 0.30; 95% CI 0.08–0.86) 1

Cleaning Methods: Gauze vs. Irrigation

• Thorough irrigation with sterile saline solution is recommended for wound cleaning until no visible debris remains 5
• Pressure irrigation is more effective than standard irrigation or mechanical cleaning with gauze 5
• The World Journal of Emergency Surgery suggests that pressure irrigation is more effective than standard irrigation (odds ratio 0.35,95% CI 0.19–0.65) 5
• Mechanical cleaning with gauze may cause trauma to the wound bed and potentially damage newly forming granulation tissue 5

Practical Recommendations

1. For optimal wound management:

   • Use normal saline irrigation rather than iodine wash for routine wound cleaning 1, 5
   • Apply gentle pressure when irrigating with saline (via syringe) for better outcomes 1, 5
   • Avoid mechanical cleaning with gauze inside wounds when possible, as this may damage granulation tissue 5

2. When to consider iodine products:

   • For short-term use in heavily contaminated wounds 2
   • When infection control is the primary concern rather than promoting granulation 2

3. For promoting granulation tissue:

   • Normal saline irrigation is generally sufficient and less likely to interfere with granulation 4
   • In one study comparing soap and water to povidone-iodine with normal saline, granulation tissue formed after 3.88 ± 1.94 days in the soap group compared to 4.48 ± 2.92 days in the povidone-iodine group, though this difference was not statistically significant (P = 0.391) 6

Important Caveats

• Evidence quality is generally low to moderate in this area 1
• The IWGDF guidance states that in the absence of specific indications, practitioners should use dressings with the lowest acquisition cost that support moist wound healing while controlling exudate 1
• The World Journal of Emergency Surgery notes there are insufficient data to determine the definitive role of saline or povidone-iodine irrigation of wounds to prevent infection 1
• Individual wound characteristics, contamination level, and risk of infection should guide selection of cleaning methods