In a client with sudden dyspnea and tachycardia post-fracture, what arterial blood gas parameter suggests a fat embolus?

In the context of sudden dyspnea and tachycardia following a fracture, the identification of a fat embolism is crucial for appropriate management. The correct choice, indicating a normal PaO2 level within the range of 80-100 mm Hg, points towards a specific blood gas disturbance associated with fat embolism.

When fat globules enter circulation, they can cause a variety of pulmonary complications. However, it's not uncommon for patients experiencing fat embolism to exhibit a relatively normal oxygenation status (PaO2) initially, despite significant respiratory distress. This can be attributed to the fact that fat globules primarily lead to ventilation-perfusion (V/Q) mismatch or atelectasis in the lungs rather than outright hypoxemia at first. Thus, a normal range of PaO2 can sometimes be seen in the early stages, indicating that despite the distress, oxygenation has remained adequate.

On the other hand, elevated HCO3 levels might suggest metabolic compensation for a respiratory acidosis or may indicate chronic respiratory issues, which are not specifically aligned with fat embolism. Low Paco2 levels typically relate to hyperventilation or metabolic alkalosis rather than the expected respiratory compromise associated with fat embolism. A decreased pH level is often