The following arterial blood gas (ABG) results indicate?

pH-7.68

PaCO2-30 mmHg

Pa02-81 mmHg HCO3-16.2 mEq/L BE-(+21.2)

02 Sat-91%

A. Metabolic acidosis: The patient’s pH of 7.13 indicates acidemia, and the HCO3- is significantly decreased at 13.2 mEq/L, showing a primary metabolic derangement. The PaCO2 of 38.8 mmHg is within normal limits (35–45 mmHg), suggesting that respiratory compensation has not yet fully occurred. The base excess of -14.5 further supports a significant metabolic acid load. These findings are consistent with metabolic acidosis.

B. Respiratory acidosis: Respiratory acidosis is characterized by elevated PaCO2 (>45 mmHg) due to hypoventilation, which leads to a decreased pH. In this case, the patient’s PaCO2 is normal, indicating that CO2 retention is not the primary cause of acidemia. The primary disturbance is metabolic rather than respiratory.

C. Normal ABG results: Normal arterial blood gas values include pH 7.35–7.45, PaCO2 35–45 mmHg, HCO3- 22–28 mEq/L, and PaO2 80–100 mmHg. In this ABG, the pH is acidotic, HCO3- is low, and base excess is markedly negative, which clearly deviates from normal ranges, indicating a pathological process.

D. Respiratory alkalosis: Respiratory alkalosis is characterized by decreased PaCO2 (<35 mmHg) due to hyperventilation, resulting in an elevated pH. In this ABG, PaCO2 is normal and pH is low, which contradicts the pattern seen in respiratory alkalosis. The acidemia is therefore not caused by a respiratory mechanism.

A. Deep tissue injury: Deep tissue injuries typically present as a localized area of intact or non-intact skin with persistent deep red, maroon, or purple discoloration due to underlying soft tissue damage. They are not usually described as shallow, oozing ulcers with irregular borders, which differentiates them from the findings here.

B. Stage 2 pressure ulcer: Stage 2 pressure injuries involve partial-thickness skin loss with exposed dermis and appear as shallow, open ulcers or blisters. They are usually associated with pressure over bony prominences and do not typically present with irregular borders and chronic oozing on the lower leg, nor with surrounding discoloration related to venous insufficiency.

C. Arterial ulcer: Arterial ulcers are typically located on distal areas such as the toes or lateral ankle and present with well-defined, “punched-out” edges. The wound bed is often pale or necrotic with minimal drainage due to poor blood supply, which contrasts with the oozing, irregular ulcer described.

D. Venous ulcer: Venous ulcers are commonly found on the lower leg and are characterized by shallow depth, irregular borders, and moderate to heavy exudate (oozing). The surrounding tissue often appears discolored or bruise-like due to hemosiderin deposition from chronic venous insufficiency, aligning with the findings.