Utilidad de la pulsioximetría en el cribado de enfermedad arterial periférica en pacientes ingresados en servicios de medicina interna

Abstract

IntroductionAnkle-brachial index measured by a continuous wave Doppler device remains as the reference method for office diagnosis of peripheral arterial disease. This method is time consuming, requires an appropriate device and training of the examiner. We evaluated the usefulness of pulse oximetry as an easier method to screen for peripheral arterial disease. MethodsA total of 110 subjects were selected by opportunistic sampling among patients admitted to a general medicine service. Entry criteria were age older than 50years and having an additional cardiovascular risk factor. Patients with known cardiovascular disease were excluded. We measured oxygen saturation (SaO2) by means of a pocket finger tip pulse oximeter at 4limbs. SaO2 was measured at right and left index fingers and great toes with patient lying and after elevating the foot 30cm above the bed. We considered as abnormal a difference in SaO2 greater than 2% between fingers and toes. Brachial index was estimated by means of a handheld Doppler device. ResultsThe prevalence of peripheral arterial disease was 10% (95% confidence interval [CI], 6%-14%). Pulse oximetry has sensitivity 12% (95%CI, 4%-37%), specificity 67% (95%CI, 60%-74%), positive likelihood ratio 0.43 (95%CI, 0.11-1.19), negative likelihood ratio 1.27 (95%CI, 0.91-1.45) and area under the receiving operating characteristics curve 0.75 (95%CI, 0.67-0.82). ConclusionsPulse oximetry showed low accuracy as screening method for peripheral arterial disease. Simpler and more accurate devices than ankle-brachial index measured by Doppler are necessary to ease the screening of peripheral arterial disease.