The nurse is reviewing the arterial blood gas (ABG) result for a client currently on a 100% non-rebreather mask. The nurse is able to interpret which of the following results as hypoxemic respiratory failure?
 

Table 9.9 Normal Arterial Blood Gas Values

ABG Value.                                                             Normal Value

pH                                                                             7.35-7.45

PaCO2                                                                                                            35-45 mmHg

HCO3-                                                                         22-26mEq/L

Base excess                                                               -2 to +2

PaO2                                                                            80-95 mmHg

SaO2                                                                            >95%

A. pH 7.44; PaO2 44 mmHg; PaCO2 35 mmHg; HCO3 25 mEq/L; O2 Sat 76%: This set of arterial blood gas (ABG) values is consistent with hypoxemic respiratory failure. Hypoxemic respiratory failure is characterized by a PaO2 less than 60 mmHg, and this client has a PaO2 of 44 mmHg, which is significantly below the normal range of 80-95 mmHg. Despite the fact that the client is on a 100% non-rebreather mask (which should ideally deliver high levels of oxygen), the low PaO2 suggests that oxygenation is not being effectively improved. Additionally, the low O2 saturation of 76% further supports the diagnosis of hypoxemic respiratory failure.

B. pH 7.30; PaO2 80 mmHg; PaCO2 62 mmHg; HCO3 25 mEq/L; O2 Sat 94%: This ABG indicates respiratory acidosis (pH is low, PaCO2 is elevated), but the PaO2 of 80 mmHg is within the normal range, and the O2 saturation of 94% is also normal. Respiratory acidosis with a normal PaO2 would indicate an issue with ventilation (hypoventilation), not hypoxemic respiratory failure. The patient is retaining CO2 but is still oxygenating well, so this result does not indicate hypoxemic respiratory failure.

C. pH 7.35; PaO2 65 mmHg; PaCO2 40 mmHg; HCO3 26 mEq/L; O2 Sat 90%: This result shows a PaO2 of 65 mmHg, which is mildly low but not sufficiently low to meet the criteria for hypoxemic respiratory failure (PaO2 should be below 60 mmHg for this diagnosis). The O2 saturation of 90% is also slightly low but not critically low. This client may have mild hypoxia but is not in respiratory failure based on these values.

D. pH 7.48; PaO2 75 mmHg; PaCO2 41 mmHg; HCO3 28 mEq/L; O2 Sat 93%: In this case, the PaO2 of 75 mmHg is slightly low but still within an acceptable range, and the O2 saturation of 93% is adequate. The elevated pH and normal PaCO2 suggest the presence of respiratory alkalosis (likely caused by hyperventilation). These ABG results are not consistent with hypoxemic respiratory failure, as the oxygen levels are still within a safe range.