Carefully irrigating and cleaning wounds and surrounding skin is important not only for decreasing risk of infection but also to improve visualization of wound characteristics in preparation for repair. In the multiply injured, obtunded, or sedated patient, meticulous cleaning is even more important. It is not an uncommon scenario to encounter an unconscious patient in the trauma bay, positioned supine with an endotracheal tube and bite-block in the mouth, a nasogastric tube taped in place, and a cervical collar around the neck with dry, crusted blood, dirt, or debris concealing soft tissue injuries. With so many impediments to a thorough examination, cleaning the entire head and neck is critical to avoid missing injuries. This includes hair-bearing scalp and facial hair, where many soft tissue injuries are easily hidden. Hair may need to be shaved or trimmed to adequately clean, assess, and repair injuries. Eyebrows may be trimmed conservatively or shaved if necessary, although it may take 6 months for them to fully regrow.
In most cases, simple antimicrobial cleansers such as chlorhexidine are adequate. Saline alone does little to remove bloody crusts; warm saline is slightly better. Warm saline with dilute peroxide is better still, although studies that show fibroblast and keratinocyte inhibition in vitro with peroxide and povidone-iodine have led to many authors voicing caution regarding their liberal use in open wounds. For most wounds, warm saline under moderate pressure will be adequate for irrigating debris and foreign material. Retained foreign bodies left unrecognized can develop into a significant problem and are a well-known cause of medicolegal action related to repair of traumatic injuries. Fortunately, the limited depth of soft tissue in the face relative to other areas of the body allows for most foreign material to be identified in the course of routine wound exploration.

Imaging is helpful in certain circumstances. Glass is a common foreign body associated with motor vehicle trauma and is easily detected with plain films. However, the utility of these studies is limited to wounds deeper than the immediate subcutaneous fat. Contrary to commonly held assumptions, a negative CT scan result does not rule out a retained foreign body. The radiodensity of substances such as wood, plastic, and vegetative material are so low that imaging frequently misses them. Wood, however, is often visible on magnetic resonance imaging (MRI). An increasing body of literature supports use of ultrasound to detect the presence of radiolucent foreign bodies. Most foreign bodies in the head and neck, however, are discovered in the course of a detailed history, careful
examination, and meticulous wound exploration. Loupe or microscope-assisted magnification is often helpful.
Embedded debris in a wound bed may require gentle scrubbing for complete removal. This must be balanced against the potential for additional disruption of tissue. However, traumatic tattooing can easily occur when pigmented debris left
in the wound bed is subsequently covered by epithelium as
the wound heals. This is most noticeable when debris is left embedded in dermis that has been denuded of epithelium. Judicious use of solvents, such as acetone, may even be necessary to help remove petroleum-based products. Time spent removing debris likely to cause permanent pigmentation will benefit both patient and physician in that delayed treatment of traumatic tattooing is difficult and often has disappointing results.

Source: Cummings Otolaryngology, 6E (2015)