Measuring the ankle-brachial index using a stethoscope

Can we measure the ankle-brachial index using only a stethoscope? A pilot study. Fam Pract. 2009 Feb;26(1):22-6. Epub 2008 Nov 20. PMID: 19022870

The ankle-brachial index (ABI) by ausculation is less sensitive than an earlier report of the ABI by palpation. Both methods are less sensitive than the ABI by Doppler ultrasonography.

Patients:

• Cross sectional study of 81 consecutive patients referred for arterograms of any region of the body

Test:

• Ankle-brachial index by auscultation

Reference standard:

• ABI Doppler ultrasonography less than 0.9
  
• Abnormal in 17% of subjects.

Accuracy:

• Sensitivity 71%
• Specificity 91%

• Positive predictive value 62%
• Negative predictive value 94%
• Click here to adjust the pretest probability and recalculate predictive values

Last year, a study reported that the ankle-brachial index by palpation has a sensitivity and specificity of 88% and 82%, respectively as compared to handheld Doppler ultrasonography (PMID 18567610).

This has been added to http://en.citizendium.org/wiki/Ankle_brachial_index

Acute, traumatic knee effusions

Diagnostic value of history taking and physical examination to assess effusion of the knee in traumatic knee patients in general practice. Arch Phys Med Rehabil. 2009 Jan;90(1):82-6. PMID: 19154833

In this study of patients with traumatic knee injuries of less than 5 weeks duration, the prevalence of effusion was 31% by magnetic resonance imaging. Almost three quarters of patients with an effusion had meniscal or ligament tear.

The accuracy of ballottement in detecting effusion was disappointing: sensitivity and specificity 83% and 49%, respectively. The accuracy of self-reported swelling was similar, with sensitivity and specificity 80% and 45%, respectively.

The negative predictive value of ballottement was 86% for patients in this study with a pretest probability of 31% (click here to adjust the pretest probability).

This study has been added to http://en.citizendium.org/wiki/Knee_injury.

Detecting LVEDP elevation

Diagnostic accuracy of Doppler echocardiography for determining left ventricular diastolic pressure elevation: prospective comparison to chest radiography, serum B-type natriuretic peptide, and chest auscultation. Echocardiography. 2008 Oct;25(9):946-54. PMID: 18771556

In a small study of 56 patients, including 19 with a LVEDP > 15 mm Hg (22 ± 4) by left heart catheterization, no patients had rales, 42% had radiographic pulmonary vascular redistribution, and only 11% had BNP > 100 pg/dL.

These results report even less sensitivity for the chest radiograph than we found in our earlier meta-analysis (http://pubmed.gov/894569). These results are also worse than the original large study of the BNP that found a cutoff of > 50 pg/dL gives high sensitivity (http://pubmed.gov/12124404).

It is unclear what led these patients to their catheterization, but the low sensitivities suggest these patients may have had asymptomatic, chronically elevated LVEDP.