An ETCO2 level of 55 mmHg and an arterial oxygen saturation of 88% would indicate what condition?

An ETCO2 level of 55 mmHg, when interpreted alongside an arterial oxygen saturation of 88%, suggests that the patient is in a state of respiratory failure. In healthy adults, normal ETCO2 values are generally between 35 and 45 mmHg. A level of 55 mmHg indicates that there is an accumulation of carbon dioxide, which can occur when ventilation is inadequate, leading to an inability to effectively exhale CO2. Combined with an arterial oxygen saturation of 88%, this demonstrates significant hypoxemia (low oxygen in the blood), further supporting the conclusion of respiratory failure.

In this scenario, the elevated ETCO2 reflects carbon dioxide retention due to compromised respiratory function, while the low oxygen saturation indicates that the body is not receiving sufficient oxygen. Both of these parameters point to a failure in gas exchange, characteristic of respiratory failure rather than hyperventilation, which would show a low ETCO2 due to excessive exhalation of CO2. Hypoxia, while present in this case, is a symptom arising from the underlying issue of respiratory failure, and normal respiration would not correspond with either of these abnormal readings. Thus, the combination of an elevated ETCO2 and low arterial oxygen saturation decisively indicates respiratory failure.