NCLEX-RN questions on chronic bronchitis 2

The healthcare provider is caring for a patient who has chronic bronchitis. The patient’s vital signs are stable and the most recent blood gas shows a pH of $7.4$7, point, 4 and $\text{PaCO}_2$start text, P, a, C, O, end text, start subscript, 2, end subscript of $45\,\text{mmHg}$45, start text, m, m, H, g, end text. The patient’s oxygen saturation is noted to be $85\%$85, percent. When considering the oxyhemoglobin dissociation curve, what is the healthcare provider’s estimate of the patient’s partial pressure of oxygen? $\,\text{mmHg}$start text, m, m, H, g, end text .