Certified Rehabilitation Registered Nurse (CRRN) Practice Exam

Mechanical friction on a wound delays wound healing because it:

1. Promotes blood flow

2. Disrupts granulation tissue

3. Enhances cell migration

4. Stimulates inflammation

The correct answer is: Disrupts granulation tissue

Mechanical friction on a wound delays the healing process primarily because it disrupts granulation tissue. Granulation tissue is formed during the healing process and is crucial for providing a matrix for cells to grow and migrate into the wound area. This tissue is rich in new connective tissue and small blood vessels that proliferate during wound healing. When mechanical friction occurs, it can damage this nascent tissue, leading to a breakdown in the healing process, a re-initiation of the inflammatory response, and potentially a longer duration of wound healing. The other aspects such as blood flow promotion, cell migration enhancement, and inflammation stimulation do not accurately reflect the detrimental impact of mechanical friction. While adequate blood flow is essential for healing, friction typically has the opposite effect, as it can restrict blood flow and nutrient supply to an area. Enhancing cell migration is also not a consequence of friction; rather, friction impedes it by disrupting the healing environment. Although inflammation is a normal part of the healing process, excessive mechanical irritation can lead to chronic inflammation, which further complicates and prolongs wound healing. Thus, the primary factor in the context of this question revolves around the disruption of granulation tissue due to mechanical friction.