Saline Superior to Soap for Cleaning Open Wounds

Researchers at McMaster University (Hamilton, ON, Canada), McGill University (Montreal, Canada), Sichuan University (Chengdu, China), and other institutions conducted a study involving 2,551 participants at 41 clinical centers in the United States, Canada, Australia, Norway, and India to investigate the effects of different irrigation solutions and irrigation pressures on wound debridement. The majority of patients were men in their 40s with a lower extremity fracture, with the most common reason for injury being involvement in a motor vehicle accident.

The patients were randomly assigned to undergo irrigation with one of three irrigation pressures—high pressure (over 137 kPa), low pressure (34.5–69 kPa), or very low pressure (6.9–13.8 kPa)—and one of two irrigation solutions (castile soap or normal saline). The primary end point of the study was reoperation within 12 months after the index surgery with the intention of promoting wound or bone healing or for the treatment of a wound infection.

The results showed that reoperation occurred in 13.2% of the high-pressure group patients, 12.7% of the low-pressure group, and 13.7% of the very-low-pressure group; reoperation occurred in 14.8% of the soap group and in 11.6% of the saline group. This indicates that while rates of reoperation were higher in the soap group than in the saline group, different irrigation pressures had no influence, a finding that indicates that very low pressure is an acceptable, low-cost alternative for the irrigation of open fractures. The study was published on October 8, 2015, in the New England Journal of Medicine (NEJM).

“There has been a lot of controversy about the best way to clean the dirt and debris from serious wounds with bone breaks,” said lead author Prof. Mohit Bhandari, MD, of the Michael G. DeGroote School of Medicine at McMaster. “All wounds need to be cleaned out—a process known as debridement—but evidence shows that cleaning wounds with soap was not better than just water, which was unexpected.”

“These findings may have important implications for the care of patients with open fractures worldwide, since developing countries deal with a disproportionate number of cases,’’ added study co-author Prof. Edward Harvey, MD, of McGill University. “Most of the time we were using soap and water with a high pressure delivery system to clean the wound, but now we don’t, and that makes the best practice much cheaper.”

Controversy exists regarding the choice of irrigation pressure and solution. While high pressure may be more effective than low pressure in removing particulate matter and bacteria, it does so at the expense of bone damage and a resultant delay in bone healing. Low pressure may avoid bone damage and delayed healing, but at the possible cost of less effective removal of foreign matter and bacteria.

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McMaster University
McGill University
Sichuan University