Presentation: Ambulatory Raynaud’s Monitor: A Novel Measurement Device to Assess Raynaud’s Phenomenon in an Ambulatory Setting (2007)

22 Ambulatory Raynaud’s Monitor: A Novel Measurement Device to Assess Raynaud’s Phenomenon in an Ambulatory Setting

Purpose: Treatment and physiological studies of Raynaud’s phenomenon (RP) are often done in a laboratory setting requiring complex equipment or by eliciting patients’ subjective estimates of the frequency and severity of RP. The Ambulatory Raynaud’s Monitor (ARM) is a novel, miniaturized, band-aid sized device, which is worn on a finger to concurrently measure skin and ambient temperature in an ambulatory setting. This pilot study is designed to test the reliability and feasibility of using this device to characterize RP in scleroderma patients.
Methods: Scleroderma subjects with RP and healthy controls were recruited to wear the ARM for a 3 day study period in February-April 2007. The ARM recorded both ambient (range -30°C to 55°C) and skin temperature (range 0°C to +45°C) every 36 seconds. Data was collected in a battery-powered microprocessor embedded in the ARM and then downloaded to a computer for analysis. Patients pressed an event button on the ARM to record the time of perceived RP events. Outcomes measured included the accumulated time (deg-min) and percent time that the skin temperature remained below 25°C; the Raynaud’s Condition Score (RCS); the Raynaud’s Visual Analog Scale (VAS) component of the Scleroderma Health Assessment Questionnaire; and RP events recorded on a self-reported diary. Subjects also gave an estimate of RP attack frequency prior to study initiation.
Results: Eleven scleroderma subjects with RP and 2 healthy control subjects were analyzed. Subjects’ mean age was 53 years (range 28-66), 77% were female, 77% were Caucasian and 23% were African-American. The mean accumulated time (deg-min) the skin temperature remained below 25°C was 6835 in scleroderma subjects and 528 in controls. The percent time the skin temperature remained below 25°C was 10.5% in scleroderma subjects and 1.3% in controls. The skin temperature was less than 25°C during 50% of all subject device-recorded events. The mean skin and ambient temperatures during 100 subject device-recorded events were 24.95°C (range 10.90-36.39°C) and 21.83°C (range 7.61-32.04°C), respectively. Seven of 11 scleroderma subjects returned completed RCS and self-reported event diaries. The mean RCS score was 2.8 and Raynaud’s VAS was 1.1 among these scleroderma subjects. When comparing the subject self-reported diary to the device-recorded events, we found that 38% of subjects reported fewer than 80% of events recorded by the event button on the ARM. Interestingly, 45% of scleroderma subjects had less than 50% accuracy in predicting their event rates when comparing device-recorded events to the subjects’ estimated expected RP attack frequency.
Conclusions: This pilot study demonstrates the potential of a miniaturized device in measuring skin temperature in an ambulatory setting to determine severity of RP. In future studies, the ARM may be used to characterize patients with RP and provide an outcome measure during therapeutic trials.

 A.A. Shah, None; L.K. Hummers, None; P. Schwartz, Patent holder, 9; B. Le, Patent holder, 9; W. Dellinger, None; D. Stott, None; R.A. Wise, Patent holder, 9; F.M. Wigley, Patent holder, 9.