Observer variability in recording the peripheral pulses.
T W Meade, M. J. Gardner, P Cannon, PM Richardson · Heart · 1968
Examination of the leg and foot pulses is indi- spensable in the assessment of the patient with sus- pected peripheral arterial disease, so it is important to know how much weight to attach to the findings.The topic of observer variability is of increasing interest in clinical medicine, while population studies can only be of use if methods are repro- ducible, that is provide "the same results on the same subject on two or more occasions, in the hands either of the same or of more than one observer, the subject of the test being in the same state of health or disease" (Fletcher and Oldham, 1964).A previous study of observer variability in recording pulses in the foot gave results from which the authors concluded that there was "very great observer error with respect to the detection of ankle pulses", and that "the inability to detect an ankle pulse by one observer is quite without significance" (Ludbrook, Clarke, and McKenzie, 1962).These are disturbing suggestions for the clinician and the epidemiologist, particularly in view of the consider- able attention currently being paid to the detection of early peripheral arteriosclerosis (Widmer, Green- sher, and Kannel, 1964; Cooper, Hill, and Edwards, 1967; Lancet, 1967).Preparing for population studies of peripheral arterial disease, it was obviously necessary first to carry out a similar study to that of Ludbrook et al. (1962), in order to reassess the value of palpation of the pulses.Apart from an unexplained random element, intra-observer variability may be due to real bio- logical changes of the factor considered, e.g.seasonal changes in blood cholesterol or changes in blood pressure with emotion.In addition, errors generated by the observer and/or his instrument may result in different recordings on separate occasions for a factor that has not altered, e.g. the observer