ABSTRACT
INTRODUCTION: Ankle-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. METHODS: A total of 110 subjects were selected by opportunistic sampling among patients admitted to a general medicine service. Entry criteria were age older than 50 years 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 4 limbs. SaO2 was measured at right and left index fingers and great toes with patient lying and after elevating the foot 30 cm 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. RESULTS: The 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). CONCLUSIONS: Pulse 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.
Subject(s)
Mass Screening/methods , Oximetry/methods , Oxygen/blood , Peripheral Arterial Disease/diagnosis , Aged , Aged, 80 and over , Ankle Brachial Index/methods , Female , Humans , Likelihood Functions , Male , Middle Aged , Peripheral Arterial Disease/epidemiology , Prevalence , ROC Curve , Sensitivity and SpecificityABSTRACT
Introducción El índice tobillo-brazo medido mediante Doppler es la prueba recomendada en el cribado de la enfermedad arterial periférica, pero requiere un equipo adecuado y un entrenamiento específico del examinador. En este estudio hemos evaluado la utilidad de la pulsioximetría como un método diagnóstico más fácil y sencillo para realizar este cribado. Métodos Se estudiaron 110 individuos, seleccionados mediante muestreo oportunístico entre los pacientes ingresados en el servicio de medicina interna. Se incluyeron pacientes mayores de 50años de edad con al menos un factor de riesgo cardiovascular adicional. Se excluyeron pacientes con enfermedad cardiovascular conocida. Se midió la saturación arterial de oxígeno (SaO2) con un pulsioxímetro digital de bolsillo en las 4extremidades, con el paciente en decúbito supino y tras elevar los miembros inferiores 30cm sobre el plano horizontal. Se consideró anormal una diferencia de SaO2mayor del 2% entre los miembros superiores y los inferiores. Se determinó el índice tobillo-brazo mediante un Doppler portátil. Resultados La prevalencia de enfermedad arterial periférica fue del 10% (intervalo de confianza [IC] al 95%, 6-14%). La pulsioximetría tuvo una sensibilidad del 12% (IC95%, 4-37%), una especificidad del 67% (IC95%, 60-74%), una razón de verosimilitud positiva de 0,43 (IC95%, 0,11-1,19), una razón de verosimilitud negativa de 1,27 (IC95%, 0,91-1,45) y un área bajo la curva operador-receptor de 0,75 (IC95%, 0,67-0,82).Conclusiones La pulsioximetría digital tuvo escasa precisión en el diagnóstico de la enfermedad arterial periférica. Es necesario buscar sistemas de diagnóstico alternativos al índice tobillo-brazo para identificar pacientes con enfermedad arterial periférica (AU)
Introduction Ankle-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. Methods A 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. Results The 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).Conclusions Pulse 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 (AU)
Subject(s)
Humans , Oximetry , Peripheral Arterial Disease/diagnosis , Mass Screening , Sensitivity and SpecificityABSTRACT
BACKGROUND: Upper arm automated blood pressure devices are widely available and could be used to estimate the ankle-brachial index. METHODS: We conducted a trial to determine the equivalence of ankle-brachial index estimated by an upper arm blood pressure measuring device as index method compared to the handheld Doppler method as the reference standard. A total of 110 patients with diabetes mellitus were sequentially examined by two methods. RESULTS: The prevalence of peripheral arterial disease was 32%. The index method obtained valid measurements in 104 (95%) patients. Ankle-brachial index was lower with the index method compared to the reference standard (mean difference: -0.05; 95% confidence interval [CI]: -0.50 to 0.39). This confidence interval was above the boundaries clinically established as equivalence margins in our study. The kappa agreement between two methods was 0.45. The performance of the index method was: sensitivity: 67%; specificity: 87%; positive likelihood ratio: 5.25; negative likelihood ratio: 0.18; positive predictive value: 71%; negative predictive value: 85%; and the area under the receiving operating characteristic curve: 0.87 (95% CI: 0.78-0.93). CONCLUSION: Upper arm automated blood pressure measuring devices cannot replace the handheld Doppler method to estimate the ankle-brachial index in patients with diabetes mellitus.
