[Methods of computerized approach of dysautonomia from a non-invasive pressure signal].

OBJECTIVE

examination of an automated exploration of autonomic neuropathy using the Ewing score and evaluation of sympatho-vagal tone.

MATERIAL

continuous non-invasive collection of blood pressure (BP) data by means of Finapress fingerprobe. The signal was analysed after digitization at 500Hz, sampled and computerised. Values of systolic BP (SBP), diastolic BP (DBP) and heart rate (HR) are analysed by Anapres (Notochord).

PROTOCOL

the pressure monitor is placed on the finger and the reading calibrated to the BP value recorded by auscultatory method on the contralateral arm to give a gap of less than 10 mmHg. BP and HR response to five different manoeuvres are recorded, namely: at rest over 7 minutes, after lying decubitus for 15 minutes; on rising suddenly over 3 seconds, and then over 9 minutes standing still; during 2 respiratory manoeuvres (a) deep breathing over 6 cycles per minute, (b) Valsalva pressure at 40 mmHg sustained over 20 seconds; isometric exercise with sustained handgrip at 30% maximal force sustained over 3 minutes.

ANALYSIS

a dedicated computer programme displays in graphic form BP and HR over each manoeuvre and allows the operator to locate the exact cut-off of normality for each test of the Ewing score and also measure the balance of sympatho-vagal tone by Fourier transformation of the interval data of HR or BP peaks.

APPLICATION

this approach allows evaluation of autonomic function and sympatho-vagal tone by means of 40 minutes of clinical testing and two minutes of automated analysis. This approach seems useful in the assessment of the autonomic nervous system in diabetes.