A nurse is caring for a patient post-total knee arthroplasty.
Which intervention should be prioritized to prevent deep vein thrombosis (DVT)?

Increased Heart Rate: A rise in heart rate can be seen in both fluid overload and dehydration. In dehydration, tachycardia is a compensatory mechanism: the body increases heart rate to maintain cardiac output despite reduced circulating volume. In fluid overload, the heart may also beat faster because of increased workload and stress on the cardiovascular system, especially if fluid shifts impair effective circulation. In burn patients, tachycardia is often more strongly associated with hypovolemia from fluid loss, but it can signal either condition depending on the broader context.

Decreased Urine Output: Low urine output is a hallmark of dehydration, as the kidneys conserve water in response to reduced circulating volume. In burn patients, this is particularly concerning because it reflects inadequate perfusion and possible progression toward shock. However, decreased urine output can also occur in fluid overload if renal perfusion is compromised by third spacing of fluids or if acute kidney injury develops. Thus, while it most commonly points to dehydration, it is not exclusive to it.

Elevated Blood Urea Nitrogen (BUN): An elevated BUN is strongly consistent with dehydration. When fluid volume is low, renal blood flow decreases, leading to impaired clearance of nitrogenous waste products. This results in a rise in BUN levels. In fluid overload, BUN is not typically elevated unless there is underlying renal dysfunction. Therefore, in this patient, the elevated BUN is a clear indicator of hypovolemia and dehydration.

Decreased Hematocrit: A low hematocrit suggests hemodilution, which occurs when excess fluid dilutes the concentration of red blood cells. This finding is consistent with fluid overload rather than dehydration. In dehydration, hematocrit usually rises due to hemoconcentration. In burn patients, decreased hematocrit may reflect aggressive fluid resuscitation or ongoing capillary leak with fluid shifts back into circulation, leading to dilution of blood components.

Choice A rationale

Incontinence is a significant risk factor for pressure injuries because it exposes the skin to chronic moisture and chemical irritants found in urine and feces. This leads to skin maceration, which softens the tissue and makes it more susceptible to damage from friction and shear. Maintaining a dry environment and using moisture barrier creams are essential nursing interventions. Normal skin pH is slightly acidic, and the alkaline nature of ammonia in urine can disrupt this protective barrier.

Choice B rationale

Immobility is a primary cause of pressure injuries as it results in prolonged pressure over bony prominences. This pressure exceeds the capillary closing pressure, which is approximately 32 mmHg, leading to localized ischemia and tissue hypoxia. If the pressure is not relieved through regular repositioning, the lack of oxygen and nutrients leads to cell death and the formation of an ulcer. Patients who cannot move independently rely entirely on nursing staff to maintain their skin integrity.

Choice C rationale

Malnutrition, specifically a deficiency in protein, vitamins, and minerals, impairs the body's ability to maintain and repair skin tissue. Low serum albumin levels, with a normal range being 3.5 to 5.0 g/dL, are often associated with increased skin fragility and edema. Without adequate nutrition, the inflammatory and proliferative phases of wound healing are compromised, making the skin more likely to break down under minimal stress and making existing injuries much harder to treat or heal.

Choice D rationale

A high protein diet is actually a protective factor rather than a risk factor for pressure injuries. Protein is essential for collagen synthesis and tissue regeneration. Patients at risk for skin breakdown are often prescribed increased protein intake to support the structural integrity of the dermis and epidermis. Therefore, a high protein diet would decrease risk rather than increase it. This choice does not fit the criteria of a factor that places a patient at higher risk.

Choice E rationale

Frequent physical activity increases circulation and ensures regular relief of pressure on tissues, which significantly reduces the risk of developing pressure injuries. Physical activity promotes muscle tone and cardiovascular health, both of which contribute to healthy skin and rapid healing. Unlike immobility, active movement prevents the prolonged ischemia that leads to ulceration. Therefore, this is a protective behavior and does not represent a risk factor for a patient experiencing skin integrity issues or injuries.

Choice F rationale

Decreased sensory perception, often seen in patients with diabetes, spinal cord injuries, or stroke, is a major risk factor for pressure injuries. These patients cannot feel the discomfort or pain caused by prolonged pressure, which is the body's natural signal to shift position. Without this feedback loop, they may remain in one position long enough for significant tissue damage to occur. Normal sensation allows for self-protection, and its loss requires vigilant monitoring and scheduled turning by caregivers.