Gökhan M. MUTLU, Jacob I. SZNAJDER

Pseudohypoxemia: interpretation of discrepancies between SaO2 and SpO2

Pulse oksimetre kardiyopulmoner hastalığı olan hastaların değerlendirilmesi ve tedavisinde önemli bir araçtır. Bazı sınırlamaları olsa da, oksijenizasyonun noninvaziv, yeterli ve devamlı olarak ölçümünü sağlar. Psödohipoksemi, aşırı lökositoz ve trombositozu olan hastalarda bildirilen bir durumdur. Pulse oksimetre ile yapılan ölçüm ile arter kan gazında ölçülen oksijen satürasyonu arasında uyumsuzluk olan hastalarda bundan şüphe edilmelidir. Bu durumun tanısını koymak için şüphelenilmesi tedavinin arttırılmasını (oksijen düzeylerinin yükseltilmesi ve mekanik ventilasyon gibi) önlemek için gerekmektedir. Bu derlemede; pulse oksimetrenin prensipleri ve sınırlamaları, psödohipokseminin fizyopatolojisi ve tanısını tartışmaktayız.

Psödohipoksemi: SaO2 ve SpO2 arasındaki uyumsuzlukların yorumu

Pulse oximetry is an important tool in evaluation and management of patients with cardiopulmonary disease. It providesan accurate, continuous, non-invasive measurement of oxygenation, however it has some limitations. Pseudohypoxemia isan artifactual condition that has been reported in patients with extreme leukocytosis and thrombocytosis. It should be suspectedin patients with a discrepancy between oxygen saturation measured by pulse oximetry and that in arterial blood. High level of suspicion is needed to diagnose this condition as not doing so may lead to unnecessary escalation of therapy(i.e., increased levels of oxygen and mechanical ventilation). We provide a review of the principles and limitations of pulseoximetry and discuss the pathophysiology and diagnosis of pseudohypoxemia.

PDF

___

1. Jubran A. Pulse oximetry. In: Tobin MJ (ed). Principles and Practice of Intensive Care Monitoring. New York:McGraw-Hill, 1998: 261-87.
2. Tremper KK, Barker SJ. Pulse oximetry. Anesthesiology 1989; 70: 98-108.
3. Tobin MJ. Respiratory monitoring. JAMA 1990; 264:244-51.
4. Nickerson BG, Sarkisian C, Tremper K. Bias and precision of pulse oximeters and arterial oximeters. Chest 1988;93: 515-7.
5. Morris RW, Nairn M, Torda TA. A comparison of fifteen pulse oximeters. Part I: A clinical comparison; Part II: a test of performance under conditions of poor perfusion.Anaesth Intensive Care 1989; 17: 62-73.
6. Scheller MS, Unger RJ, Kelner MJ. Effects of intravenously administered dyes on pulse oximetry readings.Anesthesiology 1986; 65: 550-2.
7. Cote CJ, Goldstein EA, Fuchsman WH, Hoaglin DC. The effect of nail polish on pulse oximetry. Anesth Analg 1988; 67: 683-6.
8. Barker SJ, Tremper KK. The effect of carbon tjjrionoxide inhalation on pulse oximeter signal detection. Anesthesiology 1987; 67: 599-603.
9. Anderson ST, Hajduczek J, Barker SJ. Benzocaine-induced methemoglqbinemia in adults: accuracy ofpube oximetry with methemoglobinemia. Anesth Analg 1988; 67: 1099-101.
10. Barker SJ, Tremper KK, Hyatt J. Effects of methemoglobinemia on pulse oximetry and mixed-venous oximetry.Anesthesiology 1989; 70: 112-7.
11. Hess CE, Nichols AB, Hunt WB, Suratt PM. Pseudohypoxemia secondary to leukemia and thrombocytosis. N Engl J Med 1979; 301: 361 -3.
12. Gorski TF, Ajemian M, Hussain E, et al. Correlation of pseudohypoxemia and leukocytosis in chronic lymphocytic leukemia. South Med J 1999; 92: 817-9.
13. Charan NB, Marks M, Carualho P. Use of plasma for arterial blood gas analysis in leukemia. Chest 1994; 105: 954-5.
14. Hedeskov CJ, Esmann V. Respiration and glycolysis of normal human lymphocytes. Blood 1966; 28: 163-74.
15. Pachman LM. The carbohydrate metabolism and respiration of isolated small lymphocytes. In vitro studies of normal and phytohemagglutinin stimulated cells. Blood 1967; 30: 691-706.
16. Bird RM, Clements JA, Becker LM. The metabolism of leukocytes taken from peripheral blood of leukemic patients. Cancer 1951; 4: 1009-14.
17. Laszlo J.Energy metabolism of human leukemic lymphocytes and granulocytes. Blood 1967; 30: 151-67.