Spurious hypoxemia is a very rare but known entity in patients with extreme leukocytosis. There are roughly only 15 cases that have been reported and documented spurious hypoxemia in patients with extreme leukocytosis and improvement in oxygenation with reduction of leukocyte count. There was no attempt to measure plasma oxygen in these case reports. Here we did an experiment to measure plasma oxygen in a patient with chronic lymphocytic leukemia (CLL) with extreme leukocytosis and left lower lobe (LL) community‐acquired pneumonia (CAP) to evaluate spurious hypoxemia.
A 65‐year‐old male with a history of B‐cell CLL diagnosed in October 2007, RAI stage II with baseline leukocyte count of 160 K. who had refused treatment in past, was admitted with LLL CAP with significant hypoxia requiring intubation. The patient's white blood cell (WBC) count increased to 276.9 K with 90% mature lymphocytes, Patient continued to be hypoxic and required 100% FIO2 with very high positive end‐expiratory pressure (PEEP) for oxygenation. Steroids were administered for lympholytic action with no response. Plasmapheresis was ineffective because of the presence of mature lymphocytes, To exclude spurious hypoxemia, plasma oxygen measurement was done along with regular arterial blood gas (ABG) in patient and control. In the patient, regular ABG showed 7.35/41/84/22 (FiO2 100%, PEEP 15, RR 24), and plasma ABG showed 7.38/41/114/24 compared with control, in whom regular ABG showed 7.5/29/72/22 and plasma ABG showed 7.55/27/121 with no significant difference.
Oxygen is delivered to the tissues in 2 forms: bound to hemoglobin (90%–94%) and dissolved in plasma (6%–10%). The plasma oxygenation would not be affected by leukocyte count. Arterial blood was collected in an ABG syringe, placed on ice, and carried to the lab; blood was transferred in different test tubes and spun for 10 minutes. The supernatant was collected in syringe, placed on ice, and taken to the ABG machine for plasma oxygen calculation. For the control, the same test was performed on another patient. Our results failed to demonstrate any significant difference in plasma oxygenation between patient and control. The consumption of oxygen by leukocytes is very fast. The time taken between placing the ABG syringe on ice and the amount of time to transfer the blood from the ABG syringe to the test tube in the lab might be enough for leukocytes to consume significant oxygen. So measuring plasma oxygenation is possible, but it is technically a very difficult test to perform, and spurious hypoxemia can be diagnosed in retrospect with improvement of oxygenation with reduction in leukocyte count.
Measuring plasma oxygen to evaluate true oxygenation of blood in patients with extreme leukocytosis is technically a very difficult test to perform. Spurious arterial hypoxemia can be diagnosed in retrospect with improvement of oxygenation with decrease in WBC count.
V. Ranpura, none; W. Bahou, none.
To cite this abstract:Ranpura V, Bahou W. Measuring Plasma Oxygen to Estimate True Oxygen Content of Blood in Patients with Extreme Leukocytosis: A Case Report. Abstract published at Hospital Medicine 2010, April 8-11, Washington, D.C. Abstract 120. Journal of Hospital Medicine. 2010; 5 (suppl 1). https://www.shmabstracts.com/abstract/measuring-plasma-oxygen-to-estimate-true-oxygen-content-of-blood-in-patients-with-extreme-leukocytosis-a-case-report/. Accessed May 22, 2019.