Which factor contributes to the formation of a pressure injury when a patient’s body slides downward to the foot of the bed?

Choice A rationale:

Shearing force is the primary factor that contributes to the formation of pressure injuries when a patient's body slides downward. It occurs when two surfaces move in opposite directions, causing stress and strain on the tissues between them.

Compression of Tissues: When the patient's body slides downward, the skin and underlying tissues are compressed between the bony prominences (such as the sacrum or heels) and the surface of the bed. This compression restricts blood flow to the area, depriving the tissues of oxygen and nutrients.

Tissue Stretching and Tearing: As the body slides, the skin and underlying tissues are also stretched and pulled in opposite directions. This shearing force disrupts the normal alignment of cells and tissues, leading to microscopic tears and damage.

Impaired Blood Flow: Shearing force further compromises blood flow by stretching and compressing blood vessels. This reduces the delivery of oxygen and nutrients to the tissues, while also hindering the removal of waste products.

Tissue Damage and Necrosis: The combination of compression, stretching, and impaired blood flow leads to cell death and tissue necrosis. This is the hallmark of pressure injuries, which can range from superficial blisters to deep ulcers that extend into muscle and bone.

Factors that Increase Shearing Force: Certain factors can increase the risk of shearing force and pressure injury development, including:

Increased moisture (from sweat or incontinence) Decreased mobility

Poor skin integrity

Malnutrition

Friction from bedsheets

In conclusion, shearing force is the main factor that contributes to pressure injury formation when a patient's body slides downward. It disrupts blood flow, damages tissues, and can lead to significant wounds.

Choice A rationale:

A patient's last bowel movement being 4 days ago does not directly increase their risk of pulmonary embolism (PE). While constipation can be a risk factor for deep vein thrombosis (DVT), which can lead to PE, it is not a significant risk factor on its own.

It's important to assess for other risk factors for DVT, such as immobility, recent surgery, or a history of blood clots, in conjunction with constipation.

Choice C rationale:

A platelet count of 45,000/mm^3 is low (thrombocytopenia), but it does not directly increase the risk of PE.

In fact, a low platelet count can sometimes hinder clot formation. However, it's important to monitor patients with thrombocytopenia for bleeding risks, as they may be more prone to bleeding complications.

Choice D rationale:

While receiving a transfusion of two units of packed red blood cells can increase blood viscosity, which could theoretically slightly increase the risk of PE, it is not a major risk factor.

Patients who receive transfusions are often already at an elevated risk of PE due to other underlying conditions or surgeries. It's essential to assess for other risk factors in these patients.