Question

CASE STUDY 17.5 man was admitted to the emergence A 37-year-old dapartment. He presented with the following symptoms shortness of breath, dizzy, flushed (hyperemic), sweating (diaphoretic), and nauseous. Shortly after being admitted Nood gases were drawn: 7.48 pH 32 mm Hg Рсо, 96 mm Hg ро, 24 mmol/L но, 98% (calculated) S0, 99% ( pulse oximetry oxygen saturation) Spo After a few hours, the patient's symptoms diminished nd he was released from the hospital. Two weeks later, was admitted again to the emergency department with same symptoms. This time, arterial blood was drawn hoth blood gases and CO-oximetry measurements. results were as follows: 7.49 pH 33 mm Hq рCO, 95 mm Hg ро, Hо; 23 mmol/L 98% ( calculated) (reference range, >95 % ) So, 99% (pulse oximetry oxygen saturation) (reference range, >95 % ) Spo Spectrophotometric (CO-oximeter) measurement bemoglobin species: Hb 13.5 g/L OHb 73% (reference range, >95 % ) COH 22% (reference range, <2 %; higher with smokers) MetHb 1% (reference range, <1.5 %) Question 1, Is the patient hypoxic on the first admission to the F 2. Considering the new laboratory data, is this patient nypoxic on the second admission to the ED? 3. Why is there discrepancy between calculated SO SpO2, and O,Hb?

Answer 1

Answer 1) According to the symptoms such as shortness of breath the patient seems hypoxic but the lab results revealed that his SO2 and SpO2 are above normal. Therefore, no patient is not hypoxic on the first admission to the ED.

Answer 2) According to the new lab data, the patient was not hypoxic on the second admission to the ED as the SO2 and SpO2 are above normal again.

Answer 3) These discrepancies between the SO2, SpO2 and O2Hb are occurring because the patient is suffering from a condition called dyshemoglobinemia, in which the structure of hemoglobin is changed so that it does not carry enough oxygen. In this case, the patient is suffering from carboxyhemoglobin (kind of dyshemoglobinemia) which is indicated by a high value of COHb.