Which patient, among those complaining of shortness of breath, is most likely hypoxic?

The patient most likely to be hypoxic is the 12-year-old female exposed to cold temperatures with an SpO2 of 88%. Hypoxia, or a deficiency in the amount of oxygen reaching the tissues, can be assessed in part through pulse oximetry, which measures arterial oxygen saturation (SpO2).

In this scenario, an SpO2 level of 88% indicates that the patient's blood is not saturated with oxygen at a normal level, which typically should be above 95%. Cold exposure can lead to various physiological effects that may impair breathing and oxygen exchange, contributing to hypoxia.

In contrast, the other patients have SpO2 levels that are generally indicative of adequate oxygenation—95% and above reflect a more sufficient oxygen saturation. The patient with pneumonia still has an SpO2 of 92%, which suggests mild hypoxia; however, it is not as critical as the situation with the child who is much lower at 88%. The 60-year-old male has chronic lung disease, which can affect oxygen saturation; nevertheless, his SpO2 of 90% is still above the threshold seen in the younger patient. Thus, the combination of low SpO2 and the circumstantial exposure puts the